Dissertations / Theses on the topic 'Orbitofrontal cortex'
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1
Frey, Stephen. "On the orbitofrontal cortex and encoding." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19464.
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Little is known about the human orbitofrontal cortex and its role in encoding information, although studies in the monkey suggest that it plays an important role in memory. This thesis describes a series of functional neuroimaging studies that investigated the contribution of the orbitofrontal cortex when normal human subjects were engaged in encoding information.
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Critchley, H. D. "Sensory processing in the primate orbitofrontal cortex." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308810.
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Chiavaras, Mary M. "The orbitofrontal cortex : sulcal anatomy and cytoarchitectonic correlations." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37646.
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The sulcal patterns of the human orbitofrontal cortex have not been adequately characterized. Classical authors, as well as more recent investigators, have attempted to identify and label the sulci of this part of the brain. Nevertheless, there is considerable confusion regarding the orbital sulcal patterns with inconsistencies in the naming of orbitofrontal sulci in many modern texts. Moreover, a correlation between specific landmarks and architectonic areas has not been demonstrated.A clarification of the patterns of the orbitofrontal sulci and their relationship to architectonic subregions is necessary if the results of functional neuroimaging and other physiological and anatomical findings are to be properly interpreted. Although studies have reported altered activity in the orbitofrontal cortex in relation to various sensory processes and pathological states it has been difficult to relate these changes to specific orbitofrontal regions because of a limited understanding of the anatomical landmarks. The absence of reliable reference markers forces the use of vague terminology (e.g., "orbital frontal activation") in describing the location of functional changes in the orbital frontal cortex.
The aim of this doctoral thesis was to gain a better understanding of the sulcal pattern of the human orbitofrontal cortex and its relation to the underlying cytoarchitecture. The first study resolved the confusion associated with the orbitofrontal sulci by identifying, quantifying, and precisely localizing the various orbital sulci from fifty human magnetic resonance scans that were transformed into the standardized stereotaxic space of Talairach and Tournoux (1988). The second study compared the individual sulci and sulcal patterns of these fifty human brains with the brains of fifty adult rhesus monkeys. Having examined the orbitofrontal sulci in these two species, a nomenclature for the human orbitofrontal sulci was established which was based on comparable sulci in the less convoluted macaque monkey brain while trying to preserve many of the familiar labels associated with this region in the human brain. The final part of this thesis examined the orbitofrontal cytoarchitecture of 10 human adult cerebral hemispheres to determine if a correlation exists between the different orbital sulci and the borders of the architectonic subregions.
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Berlin, Heather. "Impulsivity, the orbitofrontal cortex and borderline personality disorder." Thesis, University of Oxford, 2003. http://ora.ox.ac.uk/objects/uuid:df454308-aea1-448a-9237-83735452947f.
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Damage to the orbitofrontal cortex (OFC) has been associated with disinhibited or socially inappropriate behaviour and emotional irregularities in both humans and monkeys. Prominent characteristics of several personality disorder syndromes, in particular Borderline Personality Disorder (BPD), are impulsivity and affective instability. This investigation aimed to determine if certain aspects of the Borderline Personality syndrome, in particular impulsivity, are associated with OFC dysfunction. Basic questionnaires of personality, emotion, and impulsivity together with tasks sensitive to frontal lobe dysfunction that assess possible factors related to impulsivity, including time perception, sensitivity to reinforcers, and spatial working memory (SWM), were administered to OFC lesion, BPD, non-OFC prefrontal cortex lesion control, and normal control participants. OFC and BPD patients performed similarly, in that they were more impulsive, reported more inappropriate behaviours, BPD traits, anger, and less happiness than both control groups. They were also less open to experience and had a faster perception of time (in terms of time production) than normal controls. They performed differently on other tasks: BPD patients were less extraverted and conscientious and more neurotic and emotional than all other groups. OFC patients had more severe deficits in reversing stimulus-reinforcer associations compared to all other groups and had a faster perception of time (in terms of time estimation) than normal controls. Both OFC and non-OFC lesion patients had mixed lesions that included dorsolateral prefrontal cortex (DLFC) damage. Accordingly, they both had SWM deficits, a task used to control for DLFC damage, compared to normal and BPD participants. Since BPD participants were not impaired on this task and non-OFC patients did not perform poorly on the same tests that OFC patients did, the neuropsychological deficits of BPD and OFC patients could not be attributed to SWM deficits or DLFC dysfunction. The findings suggest that some of the cognitive/behavioural deficits commonly found in BPD patients are related to OFC dysfunction while others are unrelated and are perhaps related to other brain systems. The possibility of amygdala dysfunction is discussed. The similarities and dissociations found between BPD and OFC patients on certain tasks may lead to a better understanding of the aetiology of BPD and the functions of the OFC. Theoretical and therapeutic implications of the findings are discussed.
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Gregory, Amanda Louise. "Orbitofrontal cortex dysfunction in adolescent psychopathy neuropsychological function, violent behavior, and MRI volumetrics /." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3032405.
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Bennett, Sophie Heloise. "Investigating the role of excitatory circuitry in the orbitofrontal cortex in social cognition." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/investigating-the-role-of-excitatory-circuitry-in-the-orbitofrontal-cortex-in-social-cognition(26bc1cc8-1acd-4b53-b018-21aed5984d8b).html.
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Impaired social cognition is a common component of many neurodevelopmental conditions. These impairments impair quality of life. However, the factors shaping social development and accompanying neural circuitry are not well understood. The brain regions that contribute to social cognition are called the “social brain”. The orbitofrontal cortex is one of the brain regions that constitute the “social brain”. Damage to the orbitofrontal cortex causes profound deficits in social cognition, including disinhibition and aggression. Dysfunctional circuitry in the orbitofrontal cortex may contribute to impaired social cognition in neurodevelopmental disorders. However, the role played by neuronal circuitry in the orbitofrontal cortex to social cognition is unclear. I sought to examine the role of excitatory circuitry within the orbitofrontal cortex in social cognition. I first explored the contribution of excitatory circuitry in the orbitofrontal cortex to impaired social behaviour in Nrxn1α KO mice. These mice carry a genetic microdeletion that is a risk factor for multiple neurodevelopmental disorders, including autism and schizophrenia. Previous experiments have demonstrated that these mice display impaired social behaviour. I found that impaired social behaviour in Nrxn1α KO mice was accompanied by a reduction in short-term facilitation of pyramidal synapses. The second aim of my thesis was to investigate the role of sensory experience in shaping the development of social cognition and accompanying “social brain” circuitry. This was achieved by depriving rodents of whisker input during a sensitive period of social development. I found that a short period of whisker deprivation led to long-lasting changes in rodent play behaviour. However, this was not accompanied by changes in excitatory circuitry in the orbitofrontal cortex.
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Chakirova, Goultchira. "Orbitofrontal sulcogyral morphology : its distribution, structural and functional associations, and predictive value in different diagnostic groups." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8098.
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Bipolar affective disorder and schizophrenia are highly heritable psychiatric illnesses and the leading causes of worldwide disability. The orbitofrontal cortex (OFC) is a region of the frontal lobe with wide spread connectivity with other brain areas involved in reward, motivation and emotion. Evidence from various neuroimaging, genetic, post-mortem and brain lesion studies suggest that orbitofrontal cortex may play a role in pathophysiology of mental illnesses. This thesis sought to investigate the pathogenesis of major psychiatric illnesses through the investigation of orbitofrontal morphology in schizophrenia and bipolar disorder and through its associations with brain structure and function. Orbitofrontal morphology and its structural and functional associations were examined in healthy controls, patients with schizophrenia or bipolar affective disorder, and those at high genetic risk using functional and structural MRI. In the first study we found that the orbitofrontal type III is more frequent and the orbitofrontal type I is less common in the right hemisphere in patients with schizophrenia while in patients with bipolar disorder type III appears more often in both left and right hemispheres. We then sought to examine the relationship of orbitofrontal morphology to disease risk in a study of 146 people at high risk of developing schizophrenia and 110 people at high risk of developing bipolar disorder. We discovered that in the unaffected high risk groups the orbitofrontal type III predicted the development of later psychiatric illnesses, when combined with anterior cingulate morphology. Finally we showed, in a further study, that OFC morphology was associated with measures of schizotypy, brain structure, brain function and cognition. In conclusion, orbitofrontal morphology is linked to major psychiatric disorder and has significant structural and functional associations. As orbitofrontal sulcogyral patterns are formed in early life a fuller awareness of their relevance to brain function holds out the prospect that we could use such measures as an indicator of vulnerability to the development of illness later in life. This work points to the potential for the foundation of a theory of predictive associations between morphological patterns and the development of psychosis.
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Jenni, Nicole Lynn. "Modulation of probabilistic discounting and probabilistic reversal learning by dopamine within the medial orbitofrontal cortex." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62568.
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Weighing the value of a reward against its likelihood of delivery is a necessary component of adaptive decision-making. The medial subregion of the orbitofrontal cortex (OFC) plays a key role in this form of cognition, as inactivation of this subregion in rats alters behaviour during risk/reward decision-making and a probabilistic assay of cognitive flexibility. The medial OFC receives dopaminergic input from midbrain neurons, yet whether dopamine (DA) modulates medial OFC function has been virtually unexplored. Here, we assessed how D₁ and D₂ receptors in the medial OFC may modulate adaptive decision-making in the face of probabilistic outcomes. One series of experiments assessed probabilistic reversal learning, while another set of studies assessed risk/reward decision-making using a probabilistic discounting task. Separate groups of well-trained rats, received intra-medial OFC microinfusions of selective D₁ or D₂ antagonists prior to task performance. Our results indicate that blocking D₁ receptors in the medial OFC impaired while blockade of D₂ receptors facilitated the number of reversals completed. This may be due to an impairment in probabilistic reinforcement learning, as effects were mediated by changes in errors during the initial discrimination of the task. One function for DA within the medial OFC might therefore be to inform about responses that yield a higher probability of reward over less profitable options to maintain adaptive choice. During risk/reward decision-making, blocking D₁ receptors reduced risky choice driven by an increase in negative feedback sensitivity. Blockade of D₂ receptors increased risky choice, mediated instead by an increase in reward sensitivity. This implicates medial OFC DA in dampening the win-stay/lose-shift strategy to limit the use of immediate reward feedback in situations where rats have prior knowledge about reward profitability. These findings highlight a novel role for medial OFC DA in guiding behavior in situations of reward uncertainty. Medial OFC D₁ and D₂ receptors play dissociable and opposing roles in different forms of reward-related action selection. Elucidating how DA within different nodes of mesocorticolimbic circuitry biases behavior in these situations will expand our understanding of the mechanisms regulating optimal and aberrant decision-making.Arts, Faculty of
Psychology, Department of
Graduate
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Hosokawa, Takayuki. "Neuronal responses of the macaque orbitofrontal cortex related to the prediction of rewarding and aversive outcomes." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/145143.
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Cerpa, Gilvonio Juan Carlos. "Cortex préfrontal et flexibilité comportementale : implication de la noradrénaline." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0367.
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La survie d’un organisme nécessite qu’il soit capable de prendre des décisions adaptées dans un environnement changeant. Ces décisions dépendent de multiples processus cognitifs qui ont pu être étudiés par l’intermédiaire des apprentissages associatifs. Ainsi, le contrôle de l’action repose sur des processus distribués au sein de larges circuits cérébraux impliquant notamment les régions préfrontales. Ces fonctions du cortex préfrontal sont largement influencées par l’action de neuromodulateurs, parmi lesquels la noradrénaline, qui pourrait jouer un rôle essentiel dans la flexibilité comportementale. Mon travail de thèse a donc cherché à déterminer l’implication de l’innervation noradrénergique du cortex préfrontal dans l’adaptation à des changements des conséquences de l’action. Une première partie a consisté à étudier l’organisation de l’innervation noradrénergique au sein de différentes aires préfrontales par des méthodes de quantification automatisée. Dans une deuxième partie, nous avons utilisé un protocole instrumental nécessitant un apprentissage flexible des relations causales entre actions et conséquences. A l’aide de ce protocole et de toxines induisant une déplétion noradrénergique, nous avons démontré l’implication de la noradrénaline au sein d’une région du cortex préfrontal, le cortex orbitofrontal, pour la flexibilité comportementale nécessaire au contrôle de l’action, en particulier pour prendre en compte des changements dans l’identité et la valeur des récompenses associées à cette action. Une comparaison avec le cortex préfrontal médian d’une part, et avec le rôle de l’innervation dopaminergique d’autre part, suggère que le rôle de la noradrénaline est spécifique de la région et de l’espèce neurochimique. Dans une troisième partie, nous avons développé plusieurs approches pharmacogénétiques visant à préciser les phases de l’apprentissage impliquant la modulation noradrénergique, et observé certaines limites de ces approches. Ces travaux confirment l’importance de l’action neuromodulatrice sur les fonctions préfrontales et surtout étendent nos connaissances des circuits cérébraux impliqués dans le contrôle de l’action permettant l’adaptation à un environnement changeantAn organism depends for its survival on the ability to take adaptive decisions in an ever-changing environment. These decisions involve several cognitive processes that can be revealed by the study of associative learning processes. Thus, action control has been found to rely on processes that distribute across a network of cerebral structures including prefrontal regions. Prefrontal functions are largely influenced by neuromodulators such as noradrenaline, which is thought to be involved in behavioural flexibility. My Ph.D. project therefore aimed at clarifying the role of noradrenergic modulation of prefrontal cortex regions in adapting a subject’s behaviour to changes in action consequences. In the first chapter, we studied the organization of noradrenergic innervation in the various prefrontal areas, by means of an automated quantification method. In the second chapter, we applied a behavioural protocol requiring flexible learning of the causal relationships between actions and their outcomes. Using this protocol and neurotoxins to deplete prefrontal regions from noradrenergic innervation, we showed that noradrenaline in a specific area, the orbitofrontal cortex, was necessary to action control, in particular to mediate changes in the identity and value of expected outcomes. Comparing this contribution to the role of medial prefrontal cortex on one hand, and of dopaminergic modulation on the other hand, suggests that the role of noradrenergic neuromodulation is both region- and mediator-specific. In the third chapter, we developed a series of chemogenetic approaches to identify the temporal involvement of noradrenaline in the various phases of the task, and we identified some of the limits of these approaches. This work confirms the importance of neuromodulation in prefrontal cortical function and furthers our understanding of cerebral circuits involved in action control and adaptation to a changing environment
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Macaulay, Katherine. "The influence of self-reported ethnic origin and mood on elicited emotion and brain reactivity to happy and sad social films." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6563.
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In recent years Social Neuroscience has started to investigate how mood and culture influence social and emotional situations. In the present study differences in elicited emotion and neural activation were investigated when participants viewed films depicting social interactions. Film clips are preferred stimuli for elicitation of emotion in laboratory studies, but given the lack of standardised film sets in the literature, two behavioural studies were conducted prior to imaging. The first study (147 females, 30 males; 98.8% 18 to 24 years) identified a set of clips that elicited emotion profiles in which the target emotion (happy, sad) was strongest, as well as neutral clips, and demonstrated an effect of participants’ stable mood. The second study (143 females, 19 males; mean age 19.2 years) optimised the stimulus set and demonstrated effects of self-reported ethnic origin, mood and interest on profiles of elicited emotion. In the fMRI investigation 33 female and 8 male participants (mean age 19.2 years) viewed film clips in a block design experiment with loose and tight t-contrasts and retrospective ratings of elicited emotion. Across all-participants, social interaction depicting sadness activated key emotion-related structures such as left amygdala and insula, and medial frontal cortex that were not significantly activated with social interaction depicting happiness. However, greater activation was observed for Europeans than for non-Europeans in orbitofrontal cortex, anterior and posterior cingulate for happy social interaction and in hippocampus, precuneus and retrosplenial cortex for sad social interaction. Individual differences in trait emotions and stable mood were measured with PANAS-X. For high fatigue participants greater activation was observed in the left amgydala for happy social interaction. For participants with high positive stable mood greater activation was observed in the insula for happy and sad social interaction. The research described here indicates that self-reported ethnic origin and mood are potentially significant influences on elicited emotion and brain reactivity to positive and negative social and emotional situations.
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Mowrer, Samantha M. "Regulatory Focus Modulates Reward-Related Neural Activity." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243952078.
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Liu, Lulu. "Temporal cognition: subjective time and its connection with memory in frontotemporal dementia." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/27780.
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Although ubiquitous and central to everyday life, how humans apprehend, experience, and mentally navigate time remains poorly understood. This thesis aimed to explore subjective time in healthy ageing, as well as pathological ageing, frontotemporal dementia (FTD), namely, behavioural-variant frontotemporal dementia (bvFTD), semantic dementia (SD) and progressive nonfluent aphasia (PNFA), to determine profiles and neural correlates of subjective time in older adults and dementia syndromes, and to reveal how subjective time alterations potentially relate to everyday memory impairments across syndromes.
Employing multiple time perception tasks, Chapters 3 and 4 reveal compromised subjective time in healthy ageing and bvFTD but intact performance in language variants of FTD (a combination of SD and PNFA). Time perception in FTD relates to grey matter density decrease in predominantly frontoinsular brain regions and the basal ganglia (i.e., putamen and caudate), as well as decreased functional connectivity of the frontoparietal network and salience network. Furthermore, Chapter 5 demonstrates past- and future-oriented memory disturbances in both Alzheimer’s disease (AD) and bvFTD, rather than SD and PNFA, with neuroimaging analyses suggesting the role of the orbitofrontal cortex in everyday memory across past and future contexts in dementia. Taken together, these findings provide novel insights on the complex nature of time perception across healthy ageing and pathological ageing, with the potential to inform the characterisation and management of FTD.
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Yamada, Makiko. "The role of the amygdala and the orbitofrontal cortex in social cognition : implications for social dysfunction in schizophrenia." Kyoto University, 2006. http://hdl.handle.net/2433/144067.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第12411号
人博第329号
新制||人||81(附属図書館)
17||D||188(吉田南総合図書館)
24247
UT51-2006-J403
京都大学大学院人間・環境学研究科人間・環境学専攻
(主査)教授 大東 祥孝, 教授 船橋 新太郎, 助教授 齋木 潤, 助教授 村井 俊哉
学位規則第4条第1項該当
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Bunch, Katie, and n/a. "A Relational Complexity Approach to the Development of Hot/Cool Executive Functions." Griffith University. School of Psychology, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070713.121052.
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Previous research indicates that many important changes in executive functions, or higher cognitive capacities, occur between the ages of three and five years. Additionally, a distinction can be made between the cognitive functions associated with two different cortical regions. The functions of the dorsolateral prefrontal cortex (DL-PFC) are assessed using 'cool' tasks that are abstract and decontextualised. In contrast, the functions of the orbitofrontal cortex (OFC) are assessed using 'hot' tasks that require flexible appraisal of the affective significance of stimuli (Zelazo & Müller, 2002). Different clinical populations have been hypothesized to differ in terms of their impairment on tasks associated with each area of functioning. Current research conclusions regarding the primacy of hot versus cool executive function impairments are limited, however, as they have not taken complexity into account. That is, tasks currently used in investigations of hot and cool executive functions might differ in terms of the complexity of the cognitive processes that the tasks require. Therefore, comparisons across tasks may be misleading because these tasks vary in terms of the demands they place on participants as well as their hot versus cool status. While complexity theories have been applied to a number of cool tasks, only one hot task, those measuring theory-of-mind abilities, have been analysed in terms of complexity. One aim of the current research was to modify several tasks presumed to measure OFC performance to include a complexity manipulation. Tasks from three hot domains (conditional discrimination, the Children's Gambling Task, and future-oriented decision-making) were analysed in terms of their relational complexity, that is, the number of related entities or arguments inherent in a task or concept (Halford, 1993). Based on these complexity analyses, binary-relational and ternary-relational items of each of these tasks were developed or existing tasks were selected and/or modified. The binary-relational items were closely matched to the ternary-relational items in terms of stimuli and procedure, however, they were lower in complexity. After pilot testing, the three new measures of hot executive functioning were included in a larger test battery that was administered to a sample of 120 normally developing 3-, 4-, 5- and 6-year-old children. Existing binary- and ternary-relational items assessing theory-of-mind (a hot task) and three cool measures (transitivity, class inclusion and the Dimensional Change Card Sort test) were also included. The inclusion of measures of both hot and cool executive functions, each with complexity manipulated, allowed for the examination of a possible differential age of emergence of executive abilities associated with the DL-PFC versus the OFC. In support of the relational complexity approach, significant complexity effects were found across all seven tasks. Items at a higher level of complexity were experienced as relatively more difficult by children of all ages. Significant effects of age were also observed, with performance across all tasks increasing with age. The age effects were strongest on the ternary-relational items. The pass-fail data indicated that the majority of children in all age groups succeeded on the binary-relational items. However, it was not until a median of five years of age that children were able to process ternary relations. Consequently, the ternary-relational items produce the greatest differences in performance between the four age groups. The overall pattern of the results also suggested that a distinction can be made between the ages of emergence of abilities associated with the OFC versus the DL-PFC. The results of the pass-fail percentages, patterns of age-related change and age effects on domain factor scores all suggested that while hot executive functions may begin to develop around four years of age, similar levels of improvement are not seen in cool executive functions until five years of age. Thus, the ability to succeed on ternary-relational items of hot executive function tasks appeared to emerge slightly earlier than the cool executive function tasks. Complexity appears to be a critical factor underlying children's performance on executive function tasks, and future assessment regarding the development of executive abilities will benefit from keeping this in mind. While some refinement of new task items may be beneficial, the current test battery may have utility in further examinations of the executive profiles underlying clinical groups, such as children with autism and ADHD.
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Bunch, Katie. "A Relational Complexity Approach to the Development of Hot/Cool Executive Functions." Thesis, Griffith University, 2006. http://hdl.handle.net/10072/367631.
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Previous research indicates that many important changes in executive functions, or higher cognitive capacities, occur between the ages of three and five years. Additionally, a distinction can be made between the cognitive functions associated with two different cortical regions. The functions of the dorsolateral prefrontal cortex (DL-PFC) are assessed using 'cool' tasks that are abstract and decontextualised. In contrast, the functions of the orbitofrontal cortex (OFC) are assessed using 'hot' tasks that require flexible appraisal of the affective significance of stimuli (Zelazo & Müller, 2002). Different clinical populations have been hypothesized to differ in terms of their impairment on tasks associated with each area of functioning. Current research conclusions regarding the primacy of hot versus cool executive function impairments are limited, however, as they have not taken complexity into account. That is, tasks currently used in investigations of hot and cool executive functions might differ in terms of the complexity of the cognitive processes that the tasks require. Therefore, comparisons across tasks may be misleading because these tasks vary in terms of the demands they place on participants as well as their hot versus cool status. While complexity theories have been applied to a number of cool tasks, only one hot task, those measuring theory-of-mind abilities, have been analysed in terms of complexity. One aim of the current research was to modify several tasks presumed to measure OFC performance to include a complexity manipulation. Tasks from three hot domains (conditional discrimination, the Children's Gambling Task, and future-oriented decision-making) were analysed in terms of their relational complexity, that is, the number of related entities or arguments inherent in a task or concept (Halford, 1993). Based on these complexity analyses, binary-relational and ternary-relational items of each of these tasks were developed or existing tasks were selected and/or modified. The binary-relational items were closely matched to the ternary-relational items in terms of stimuli and procedure, however, they were lower in complexity. After pilot testing, the three new measures of hot executive functioning were included in a larger test battery that was administered to a sample of 120 normally developing 3-, 4-, 5- and 6-year-old children. Existing binary- and ternary-relational items assessing theory-of-mind (a hot task) and three cool measures (transitivity, class inclusion and the Dimensional Change Card Sort test) were also included. The inclusion of measures of both hot and cool executive functions, each with complexity manipulated, allowed for the examination of a possible differential age of emergence of executive abilities associated with the DL-PFC versus the OFC. In support of the relational complexity approach, significant complexity effects were found across all seven tasks. Items at a higher level of complexity were experienced as relatively more difficult by children of all ages. Significant effects of age were also observed, with performance across all tasks increasing with age. The age effects were strongest on the ternary-relational items. The pass-fail data indicated that the majority of children in all age groups succeeded on the binary-relational items. However, it was not until a median of five years of age that children were able to process ternary relations. Consequently, the ternary-relational items produce the greatest differences in performance between the four age groups. The overall pattern of the results also suggested that a distinction can be made between the ages of emergence of abilities associated with the OFC versus the DL-PFC. The results of the pass-fail percentages, patterns of age-related change and age effects on domain factor scores all suggested that while hot executive functions may begin to develop around four years of age, similar levels of improvement are not seen in cool executive functions until five years of age. Thus, the ability to succeed on ternary-relational items of hot executive function tasks appeared to emerge slightly earlier than the cool executive function tasks. Complexity appears to be a critical factor underlying children's performance on executive function tasks, and future assessment regarding the development of executive abilities will benefit from keeping this in mind. While some refinement of new task items may be beneficial, the current test battery may have utility in further examinations of the executive profiles underlying clinical groups, such as children with autism and ADHD.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Psychology
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Mobini, Sirous. "Behavioural analysis of the roles of the ascending monoaminergic pathways and the orbitofrontal cortex in impulse control and motivation." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368261.
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Lasseter, Heather C. Fuchs Rita. "Involvement of the lateral orbitofrontal cortex in context-induced and cocaine-primed reinstatement of cocaine seeking behavior in rats." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2338.
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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2009.Title from electronic title page (viewed Jun. 26, 2009). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Psychology Behavioral Neuroscience." Discipline: Psychology; Department/School: Psychology.
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Mikheenko, Yevheniia. "The neural and neurochemical basis of emotion regulation : contribution of amygdala and orbitofrontal serotonin in the common marmoset (Callithrix jacchus)." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607922.
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Boas, Cyrus Antônio Villas. "Avaliação comportamental e eletrofisiológica da atividade do córtex pré-frontal em processos de tomada de decisões em ratos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-20052015-095851/.
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As teorias mais influentes acerca do funcionamento do córtex pré-frontal (PFC) tomam essa estrutura como um córtex de associação e de integração de informações oriundas de outras estruturas nervosas. Isso implicaria na participação direta do PFC nos processos de memória operacional e em processo atencionais. Estudos hodológicos e neurofisiológicos sugerem, que o córtex orbitofrontal (OFC) seria responsável pela integração de informações de caráter sensorial, motivacional e afetivo, enquanto o córtex pré-frontal ventromedial (vmPFC) seria diretamente ligado ao OFC, tendo um papel crucial na codificação de estímulos emocionais oriundos da amígdala. Nesse contexto, é aceito que a integração das informações feita por essas estruturas seja essencial para o processo de tomada de decisões, uma vez que esse comportamento necessita de uma avaliação do ambiente em termos de comparações de situações novas a experiências prévias armazenadas na memória, assim como um balanço entre custos, benefícios e cálculo de possíveis valores da recompensa. Para testar essas hipóteses, ratos com danos seletivos no vmPFC foram submetidos testes de avaliação de ansiedade e medo condicionado no paradigma de teste e reteste no labirinto em cruz elevado (LCE), assim como a testes de memória de referência espacial e memória operacional no labirinto aquático de Morris. Outro grupo de animais teve matrizes de multi-eletrodos implantadas no OFC para a avaliação da atividade neuronal dessa estrutura em um teste envolvendo tomada de decisões, no qual devem escolher entre ganhar 1 pellet de chocolate imediatamente ou 4 pellets envolvendo atrasos variados. No teste no LCE, animais com lesão no vmPFC diferem dos animais controle por apresentarem uma diminuição do tempo de avaliação de risco sem apresentar alterações nos parâmetros que aferem memória, atividade locomotora e ansiedade. No teste de memória de referência espacial após treinamento extensivo de busca pela plataforma em um mesmo local no labirinto aquático, animais com lesão persistem no local quando se retira a plataforma (probe test). Já no teste de memória operacional, no qual a localização da plataforma é alterada diariamente, esses animais não diferem do grupo controle. Na tarefa envolvendo tomada de decisões, observou-se uma atividade eletrofisiológica de neurônios do OFC relacionada ao momento crítico no qual o animal deve realizar uma escolha. Em conjunto, esses resultados mostram que o vmPFC está relacionado à flexibilidade comportamental e tomada de decisões, possivelmente em conjunto com o OFC, cuja atividade neuronal sugere uma participação nos processos de tomada de decisões e de elaboração de estratégiasThe most influential theories on the function of the prefrontal cortex (PFC) suggest that this structure is an association cortex, responsible for integration of information received from other parts of the brain. This would implicate in direct participation of the PFC in working memory and attentional processes. Given this context, hodological and neurophysiological studies suggest that the orbitofrontal cortex (OFC) would be responsible for the integration of sensory, motivational and affective aspects, while the ventromedial prefrontal cortex (vmPFC), which is directly connected to the OFC, would have a key role in encoding emotional stimuli from the amygdala. It is well accepted that the processing of these aspects of information is crucial for decision-making processes, given the fact that this expression of behavior requires an evaluation of the environment in terms of comparing novel situation to previous experiences, as well as processing the balance between costs, outcomes and reward values. In order to test these hypotheses, rats with selective lesions to the vmPFC were subjected to the elevated plus maze (EPM) to evaluate anxiety and conditioned fear in the test retest paradigm. Animal were also tested in a spatial reference memory and a working memory tasks in the Morris water maze. Another group of rats had multi-electrode arrays chronically implanted in the OFC for the evaluation of the neuronal activity during a decision-making task, in which the animals had to choose between a small reward of one chocolate pellet immediately and a large reward of four chocolate pellets after varying delays. The results of the EPM show that animals with lesion to the vmPFC differ from control animals by showing diminished time evaluating risk in the second exposure to the EPM, without damage to locomotor activity, memory and anxiety levels. In the reference spatial memory task in the water maze, after extensive training searching for the hidden platform in the same location, lesioned animals persisted searching for the platform in that particular location after it was removed (probe test). However, in the working memory task, in which the platform is presented in a different location each day, lesioned animals did not differ from control animals. In the decision-making task, differential electrophysiological activity in OFC neurons was observed, particularly in the moment of the task in which the animal was required to perform the choice between rewards. Together, these results suggest that the vmPFC is related to behavioral flexibility and decision-making, possibly acting together with the OFC, which neuronal activity suggests participation in decision-making processes
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Rudrauf, David. "Aspects of the dynamics of the human cerebral cortex during induction of emotion." Paris 6, 2005. http://www.theses.fr/2005PA066353.
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Rotgé, Jean-Yves. "Rôle des voies thalamo-corticales dans le trouble obsessionnel-compulsif : approches méta-analytique et physiopathologique chez l'homme et l'animal." Thesis, Bordeaux 2, 2010. http://www.theses.fr/2010BOR21783/document.
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Le trouble obsessionnel-compulsif (TOC) est un trouble anxieux fréquent et invalidant. Pour un grand nombre de patients, il existe une résistance aux thérapeutiques actuellement disponibles, soulignant toute l'importance de mieux préciser la physiopathologie du TOC. Le principal objectif de cette thèse est d’étudier les altérations anatomiques et fonctionnelles des voies thalamo-corticales intéressant le cortex orbitofrontal (COF) et le cortex cingulaire antérieur (CCA) dans le TOC. Pour cela, nous avons utilisé plusieurs outils complémentaires permettant d’appréhender cette problématique sous différents angles méthodologiques.Concernant les altérations anatomiques associées au TOC, nous avons rapporté les données de méta-analyses des études de neuro-imagerie volumétrique et morphométrique ainsi que les résultats d'une étude originale d'imagerie volumétrique. Une diminution du volume orbitofrontal, une augmentation du volume thalamique et une relation entre ces modifications de volumes ont été observées chez les patients avec TOC comparativement aux témoins. Les modifications de densité de matière grise concernaient le COF et le putamen dans le sens d'une augmentation et les cortex pariétal et préfrontal dorsolatéral dans le sens d'une diminution dans le TOC.Concernant les altérations fonctionnelles associées au TOC, nous avons détaillé un travail de méta-analyse des études d'imagerie fonctionnelle, un travail expérimental chez le primate basé sur des manipulations pharmacologiques intra-cérébrales, puis un travail expérimental chez l'homme reposant sur le développement d'une tâche comportementale originale couplée à l'imagerie fonctionnelle. Dans notre méta-analyse, nous avons décrit la participation fonctionnelle de régions comme le COF, le thalamus et le striatum lorsque des symptômes obsessionnels et compulsifs étaient provoqués chez des patients. Chez le primate subhumain, nous avons montré qu'une hyperactivation du noyau ventral-antérieur, par levée de l'inhibition GABAergique, entraînait l'apparition de comportements pseudo-compulsifs. Ensuite, à l'aide d'une tâche originale qui mettait les sujets en situation de vérifier, nous avons mis en évidence que les dysfonctions orbitofrontales associées au doute lors de la prise de décision n'étaient pas modulées ni par les informations contextuelles (signaux d'erreur), ni par la réponse comportementale chez les patients avec TOC comparativement à des sujets témoins.Enfin, la superposition des cartes morphométriques et fonctionnelles a trouvé une relation entre les altérations anatomiques et fonctionnelles au sein du COF. Nos résultats soulignent toute l'importance des voies thalamo-orbitofrontales dans la physiopathologie du TOCObsessive-compulsive disorder (OCD) is a frequent and disabling anxiety disorder. Available treatments are effective for most patients but impairing residual symptoms and treatment resistance are common in OCD patients. Therefore, a better understanding of OCD pathophysiology is essential for further improvement of therapeutic strategies. The main goal of my thesis was to assess the anatomical and funtional thalamocortical alterations associated with OCD. Concerning the anatomical thalamocortical alterations associated with OCD, we conducted two meta-analyses of anatomical neuroimaging studies and an original volumetric neuroimaging study. We reported a smaller thalamic volume and a greater orbitofrontal volume, but also an inverse relationship between the volume changes in OCD patients compared with healthy subjects. Furthermore, we showed that gray matter density within the orbitofrontal cortex and the putamen were enhanced in OCD. Concerning the functional thalamocortical alterations associated with OCD, we reported data coming from a meta-analysis of functional neuroimaging studies, an experimental study in subhuman primates using local brain pharmacological manipulations and an event-related neuroimaging study in OCD patients. In our meta-analysis, we showed that the orbitofrontal cortex, the thalamus and the striatum were involved in the mediation of OCD symptoms. In subhuman primates, the pharmacologically induced overactivity within the ventralanterior thalamic nucleus leaded to the emergence of compulsive-like behaviors. Then, in our neuroimaging study, we found that doubt-related orbitofrontal dysfunctions were not modulated by neither error signals nor compulsive-like behaviors in OCD patients, compared with healthy subjects. Finally, we described by using meta-analytic data that anatomical and functional brain alterations overlap with the lateral orbitofrontal cortex in OCD. In conclusion, our results suggest that the thalamo-orbitofrontal network may play a primary role in the genesis and mediation of OCD symptoms
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Svensson, Johan. "Neural Correlates of Pleasure : A Review of the Neuroscientific Literature of Pleasure." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-9890.
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Pleasure is part of hedonic well-being, with roots back to Epicurus 2000 years ago. With the new evolving neuroscientific methods of the late 20th and beginning of the 21st century, we are now able to study the biological components of pleasure. This thesis aims to review empirical studies on the neural correlates of pleasure, which can have important implications for well-being, and treatment of addiction and affective disorders. Recent studies have suggested that pleasure can be separated into coding and causing. Discoveries show that causing of pleasure is created in so called hedonic hot spots, areas of the brain that intensely creates pleasure in the shell of nucleus accumbens and in the ventral pallidum. Areas that codes pleasure on the other hand is represented into more cortical areas of the brain, including orbitofrontal cortex, anterior cingulate cortex and anterior insular cortex. There has been a growing understanding about how pleasure is represented in the brain, and a discussion on interpretations and limitations are provided followed by future research suggestions in the final section.
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Shaw, Lynda Joan. "Emotional processing of natural visual images in brief exposures and compound stimuli : fMRI and behavioural studies." Thesis, Brunel University, 2009. http://bura.brunel.ac.uk/handle/2438/3203.
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Can the brain register the emotional valence of brief exposures of complex natural stimuli under conditions of forward and backward masking, and under conditions of attentional competition between foveal and peripheral stimuli? To address this question, three experiments were conducted. The first, a behavioural experiment, measured subjective valence of response (pleasant vs unpleasant) to test the perception of the valence of natural images in brief, masked exposures in a forward and backward masking paradigm. Images were chosen from the International Affective Picture System (IAPS) series. After correction for response bias, responses to the majority of target stimuli were concordant with the IAPS ratings at better than chance, even when the presence of the target was undetected. Using functional magnetic resonance imaging (fMRI), the effects of IAPS valence and stimulus category were objectively measured on nine regions of interest (ROIs) using the same strict temporal restrictions in a similar masking design. Evidence of affective processing close to or below conscious threshold was apparent in some of the ROIs. To further this line of enquiry, a second fMRI experiment mapping the same ROIs and using the same stimuli were presented in a foveal (‘attended’) peripheral (‘to-be-ignored’) paradigm (small image superimposed in the centre of a large image of the same category, but opposite valence) to investigate spatial parameters and limitations of attention. Results are interpreted as showing both valence and category specific effects of ‘to-be-ignored’ images in the periphery. These results are discussed in light of theories of the limitations of attentional capacity and the speed in which we process natural images, providing new evidence of the breadth of variety in the types of affective visual stimuli we are able to process close to the threshold of conscious perception.
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Papageorgiou, Georgios. "Neural mechanisms of reward-guided learning and irrational decision-making." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:fe0d3aa4-5bc4-4469-8098-3895f7cc48d2.
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The ability to take effective decisions is fundamental for successful environmental adaptation and survival. In this thesis, I investigated situations in which decisions appear irrational, at least from certain standpoints. I conducted a behavioural decision-making experiment in two groups of macaques: controls and a group with ventromedial prefrontal cortex/medial orbitofrontal cortex (vmPFC/ mOFC) lesions. Some choices lead to compound outcomes composed of different constituent parts. Control macaques' decisions suggested their estimates of the value of the compound were biased away from the sum of the values of the constituents and towards their mean. Lesions of vmPFC/mOFC diminished the size of the effect so that macaques in some ways appeared to make more rational decisions. Based on the results of this experiment I devised a similar Functional Magnetic Resonance Imaging (fMRI) paradigm with the control animals. This demonstrated strong vmPFC/mOFC activity when similar decisions were made and suggested a value comparison process. In addition, I investigated the role of dopamine in learning using Fast-Scan Cyclic Voltammetry (FSCV), while rats performed a simple decision-making task. Theories about the role of dopamine in learning have focused on the possibility that it codes scalar reward value prediction errors. Less consideration has been given to the possibility that dopamine might reflect prediction errors about reward identities regardless of value. I measured dopamine in the nucleus accumbens when unexpected changes in reward value or identity occurred while rats executed a two-choice two-reward instrumental task. Dopamine levels in the nucleus accumbens reflected reward value prediction errors. In addition, however, they also reflected some information about reward identity under some circumstances. Further investigation suggested that this might be due to differences in the nutritional value of different reward types that did not have clear measurable impacts of behaviour in the tasks that I used.
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Johnson, Alex R. "The Relationship between Decision Making Deficits and Drug Addiction: A Neurobiological Approach." Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/cmc_theses/615.
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Drug addiction is a complex behavioral disorder that has been extensively studied in an attempt to uncover its underlying biological mechanisms. This paper contributes to the literature on addiction by demonstrating that addiction is a result of an improperly functioning decision making process. The areas of the brain that are most implicated in decision making demonstrate significant overlap with those areas most affected by addiction. Specifically, the limbic structures of the brain (amygdala, basal ganglia, and mesolimbic reward pathway) and the prefrontal cortices (orbitofrontal cortex, dorsolateral prefrontal cortex, and ventromedial prefrontal cortex) are discussed in relation to their involvement in prominent theories of decision making such as Prospect Theory and the Somatic Marker Hypothesis. This paper will then use the above knowledge regarding the specific brain mechanisms that control decision making and apply it to neurobiological theories of addiction. The view that addiction is a behavioral disorder that results primarily from a degradation of the brain mechanisms involved in decision making processes is important to consider because it can help provide a concrete approach to developing more individualized and effective treatment programs in the future.
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Dahlquist, Clara. "Somatosensory system; touch : Physiology and Neuronal Correlates of Discriminative and Affective Touch." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-9718.
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This essay is about the somatosensory system, which is divided into different kinds of touch. Described briefly are the proprioceptive touch, which is transported to the brain via A-alfa fibers and transmits information about e. g. limb position and movement. The cutaneous touch is the main focus and it is divided into discriminative touch and affective touch. The first corresponds to stimuli such as vibration and pressure and is transported via A-beta axons. The second, affective touch, corresponds to e.g. painful and pleasant stimuli which are transported to the brain via A-delta and C-fibers. The aim of the essay is to give an overview of the sense of touch, by doing a literature search, including a discussion of relevant neuronal correlates focusing particularly on affective touch. Moreover, the physiological aspects of touch will be presented. The sources that are used are review and original articles taken from databases such as ScienceDirect, and some articles send by the author. Some books have also been used to find more general knowledge. The conclusion for the essay is that touch is important for humans to function in everyday life. Additional, a specific receptor called C- tactile (CT) is identified to correspond to gentle touch and is suggested to have a vital role for humans in maintaining and forming social bounds. Moreover, discriminative touch is associated with activation in the primary and secondary somatosensory cortex, whereas affective touch seems to be associated with activity in the orbitofrontal cortex, cingulate cortex and the insula cortex, as well as the prefrontal cortex, which is suggested to be activated during interpersonal touch. Further, the sense touch needs to be more researched in order to understand its functions and benefits deeper.
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Ribeiro, Amyres Carvalho. "Dano seletivo no córtex orbitofrontal em ratos não interfere na aquisição de uma tarefa de escolha intertemporal nem no seu desempenho quando adquirida previamente a lesão." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-20092018-105312/.
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O córtex orbitofrontal é apontado como uma estrutura fundamental para a tomada de decisão baseada em valor. Acredita-se que sua função envolva a valoração de recompensas a partir da integração de informações sensoriais e memória, a fim de comparar custos e benefícios. Resultados conflitantes sobre os efeitos da lesão do córtex orbitofrontal em tarefas de escolha intertemporal geram questionamentos sobre o nível de especialização de sua função. O presente estudo almeja testar a hipótese de que a participação do córtex orbitofrontal no desempenho de tarefa de escolha intertemporal depende da experiência dos animais com a tarefa em relação ao momento da lesão. Para isto foi utilizada uma tarefa de escolha intertemporal em que os animais deveriam escolher entre dois reforços distintos, um deles menor e entregue imediatamente após a resposta, e o outro maior porém entregue após um determinado tempo de espera após a resposta. Foram incluídos quatro grupos, dois experimentais envolvendo lesão neurotóxica do córtex orbitofrontal e dois controle-operados submetidos a procedimentos idênticos, exceto pela indução de lesão (os grupos controle foram, posteriormente a análises dos resultados comportamentais e constatada ausência de diferença, fundidos num único grupo controle). Um grupo experimental e um correspondente grupo controle foram submetidos a neurocirurgia antes da exposição a 15 sessões de treino na tarefa. Um outro grupo experimental e seu correspondente controle foram submetidos a treinamento similar, porém, depois da neurocirurgia. Posteriormente, todos os animais foram submetidos a 10 sessões adicionais de treino na mesma tarefa e, a seguir, a outras 10 sessões de treino de reversão, em que os locais previamente associados aos esquemas de reforço foram invertidos. Os resultados revelaram que todos os grupos se comportaram de maneira semelhante nas diferentes fases experimentais, independente do momento de realização da lesão ou mesmo da própria lesão, indicando que o córtex orbitofrontal intacto não é necessário para a aquisição e o desempenho da tarefa de escolha intertemporal. Esses resultados levam a conclusão de que danos seletivos do córtex orbitofrontal não geram prejuízos no desempenho de escolhas intertemporaisThe orbifrontal cortex is pointed out as a fundamental structure for value-based decision making. It is believed that its function involves the valuation of rewards from the integration of sensory information and memory in order to compare costs and benefits. Conflicting results on the effects of the orbifrontal cortex lesion on tasks of intertemporal choice bring about questions on the level of specialization of its function. The purpose of the present study is to test the hypothesis that the participation of the orbifrontal cortex in the task performance of intertemporal choice depends on the experience of the animal with the task in relation to the moment of injury. For this, an intertemporal choice task was used in which the animals had to choose between two distinct reinforcements, one smaller and delivered immediately after the response and the other larger but delivered after a certain waiting time after the response. Four groups were included, two experimental groups involving neurotoxic injury and two control groups, submitted to identical procedures, except for the induction of lesion (the control groups were, after an analysis of behavioral results and found no difference, merged into a single group control) an experimental group and a corresponding control group underwent neurosurgery before being exposed to 15 training tasks sessions. Another experimental group and its corresponding control underwent similar training, yet, after neurosurgery. Afterward, all the animals were submitted to 10 additional training sessions on the same task and later to another 10 reversal sessions, in which the sites previously associated to the reinforcement schemes were inverted. The results revelead that all groups behaved similarly in the different experimental phases regardless the time of injury or even the lesion itself, showing that the intact orbifrontal cortex is not necessary for the acquisition and performance of the task of intertemporal choice. These results lead to the conclusion that selective orbifrontal cortex damages do not generate losses in the performance of intertemporal choices
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Oliveira, Katia Cristina de. "Análise estereológica postmortem do córtex orbitofrontal de indivíduos acomeditos por transtorno obsessivo-compulsivo ou por transtorno afetivo bipolar." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5144/tde-25022014-114411/.
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INTRODUÇÃO: O transtorno afetivo bipolar (TAB) e o transtorno obsessivocompulsivo (TOC) estão entre as dez condições médicas mais incapacitantes. No entanto, suas bases neurobiológicas são ainda desconhecidas. Os estudos postmortem podem dar uma boa contribuição para o entendimento da fisiopatologia desses transtornos, pois permitem a comparação das alterações celulares, citoarquitetônicas e moleculares com as manifestações clínicas, além de auxiliarem numa melhor compreensão dos achados dos estudos de neuroimagem. OBJETIVOS: Comparar a densidade neuronal, volume e número total de neurônios do córtex orbitofrontal (COF) e suas sub-regiões: antero-medial (AM), médio-orbitofrontal (MO) e antero-lateral (AL) entre casos psiquiátricos e controles; Verificar se há diferenças de densidade neuronal, volume e número total de neurônios do COF entre os casos de TAB e casos de TOC e controles. MÉTODOS E CASUÍSTICA: 17 encéfalos de indivíduos acima de 50 anos foram coletados, diagnosticados e submetidos a análises estereológicas, sendo três indivíduos acometidos por TAB, sete indivíduos acometidos por TOC e sete controles saudáveis pareados por idade, gênero e hemisfério cerebral analisado. Um hemisfério foi fixado por perfusão com formalina 20% e processado para estudos neuroestereológicos, enquanto o outro teve as 45 regiões de interesse dissecadas e congeladas a -80ºC para futuros estudos moleculares. RESULTADOS: O COF e suas sub-regiões apresentaram menor densidade neuronal no grupo total de casos vs. controles (p < 0,05). No entanto, não houve diferença em relação ao volume. A subregião MO apresentou um número menor de neurônios nos casos que em controles (p < 0,05). Curiosamente, na análise de densidade neuronal das camadas corticais, apenas a camada IV não apresentou diferença estatisticamente significante entre casos e controles. CONCLUSÕES: Nossos achados mostram que alterações no COF podem estar envolvidas com a fisiopatologia do TOC ou TAB, e indicam que podem haver interações entre elas e, além disso, concordam com estudos de imagem funcional e de atividades cerebrais na região MO que nos faz refletir que além de uma perda neuronal, há também uma hipoativação e uma redução funcional. Estudos com um número maior de amostras e com diferenciação celular poderão trazer novas contribuições para o entendimento da fisiopatologia desses transtornos neuropsiquiátricosINTRODUCTION: Bipolar disorder (BD) and obsessive compulsive disorder (OCD) are within the ten medical condition promoving incapacity worldwide. To date, their neuropathological substrates are yet to be disclosed. Postmortem studies designed to estimate cytoarchitectonic and molecular changes for clinical and imaging correlation, have the potencial to undercover pathophysiological aspects of these conditions. OBJECTIVE: Objective: To compare neuronal density, volume and total neuron number of orbitofrontal cortex (OFC) as a whole and divided by sub-regions: anteromedial (AM), medio-orbitofrontal (MO) and antero-lateral (AL) among BD, OCD and matched controls. METHODS: We used 17 postmortem brains sourced from the Psy- BBBABSG. All the subject were older than 50 years and were classified based on clinical evaluation in BD, OCD and healthy control. Subjects were matched by age, gender and brain hemisphere. One hemisphere were perfusion fixed with 20% formalin and used for neuroestereological studies. The second hemisphere had ROIs dissected and snap frozen for future molecular studies. OUTCOMES: Neuron density in OFC and the sub-regions were decreased in cases vs. controls (p < 0,05). This result was observed in cortical layers analyses with exception of layer IV. We did not observed significant changes in volume. The MO sub-region had reduced total neuron number in cases than in controls (p < 0,05). CONCLUSION: Ours results suggest that OFC changes may be part of BD and OCD pathogenesis. These results go in line with functional imaging findings. Further studies with a higher number of cases and adressing specific neuron types are needed
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Moulier, Buchbinder Virginie. "Etude en imagerie par résonance magnétique fonctionnelle des corrélats cérébraux de l’excitation sexuelle chez des patients pédophiles." Paris 6, 2009. http://www.theses.fr/2009PA066747.
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Les abus sexuels commis sur les enfants constituent un problème de santé publique grave et fréquent. La pédophilie est une paraphilie, dont les bases cérébrales sont encore peu connues et dont la prise en charge thérapeutique peut s’avérer délicate. Depuis plus d’une dizaine d’années, le développement des techniques d’imagerie cérébrale a permis l’exploration anatomique et fonctionnelle du cerveau humain et a renouvelé les perspectives en matière de connaissances des bases neurales de la sexualité. Dans la première partie de cette thèse, nous avons cherché à approfondir nos connaissances sur les régions cérébrales impliquées dans l’excitation sexuelle chez les volontaires sains hétérosexuels à l’aide d’un paradigme expérimental impliquant la présentation de stimuli photographiques et de stimuli vidéos. Un système de pléthysmographie pénienne volumétrique adapté à l’environnement IRM a été développé. Chez les volontaires sains, nous avons mis en évidence que la phase initiale de la tumescence pénienne en réponse à des stimuli sexuels visuels de type photographique était contrôlée par un ensemble de régions du cortex frontal, pariétal, du gyrus cingulaire antérieur et de l’insula. En outre, le système des neurones miroirs pourrait participer à la médiation de l’excitation sexuelle, induite par l’observation d’activités sexuelles présentées dans des extraits vidéo. En effet, le niveau d’activation des régions appartenant au système des neurones miroirs était corrélé avec l’amplitude de l’érection pénienne. Dans la seconde partie de cette thèse, nous avons cherché à explorer les corrélats cérébraux de l’excitation sexuelle chez les personnes souffrant de pédophilie. Dans une étude de groupe, nous avons mis en évidence que les patients pédophiles présentaient un pattern d’activation différent de celui des volontaires sains. Conformément à notre hypothèse principale, lors de la présentation de photographies d’enfants ordinaires sans caractère pornographique, le gyrus orbitaire antérieur droit s’activait plus chez les patients pédophiles que chez les témoins, ce qui pourrait représenter le corrélat neural de l’évaluation par ces patients de ces photographies d’enfants comme stimuli ayant une signification sexuelle. De plus, plusieurs régions considérées dans notre modèle comme jouant un rôle inhibiteur, telles que le gyrus temporal moyen droit et le noyau caudé gauche, présentaient un défaut d’activation chez les patients pédophiles étudiés comparés aux témoins. Enfin, nous avons mené une étude longitudinale en IRM fonctionnelle d’un patient pédophile avant puis sous traitement par agoniste de la GnRH (leuproréline). En réponse à la présentation de photographies ordinaires d’enfants, le patient présentait une réduction de l’activation dans le cortex orbitofrontal droit lors de la séance sous traitement par rapport à la séance avant traitement. Une telle réduction ne s’observait pas chez le sujet témoin. En conclusion, ces résultats, qui demandent à être confirmés par une étude portant sur des échantillons plus larges, indiquent que le cortex orbitofrontal droit pourrait être impliqué dans l’attribution par ces patients d’un caractère sexuellement motivant à des stimuli représentant des enfants. De plus, ces résultats suggèrent que cette activité du cortex orbitofrontal droit est réduite sous l’effet de la diminution de la testostérone plasmatique induite pharmacologiquement.
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Gregory, Nicola Jean. "The influence of socio-biological cues on saccadic orienting." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3231.
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Previous research has suggested that viewing of another’s averted eye gaze causes automatic orienting of attention and eye movements in observers due to the importance of eye gaze for effective social interaction. Other types of visual cues with no social or biological relevance, such as arrows, are claimed not to produce such a direct effect on orienting behaviour. The finding that processing of eye gaze is reduced in individuals with Autistic Spectrum Disorders as well as following damage to the orbitofrontal cortex of the brain, suggests that gaze processing is indeed critical for effective social behaviour and therefore eye gaze may constitute a “special” directional cue. This thesis tested these ideas by examining the influence of socio-biological (eye gaze and finger pointing) and non-social cues (arrows and words) on eye movement responses in both healthy control participants and those with damage to the frontal lobes of the brain. It further investigated the relationship between orienting to gaze and arrow cues and autistic traits in a healthy population. Important differences between the effects of socio-biological and non-social cues were found on saccadic eye movements. Although in the pro-saccade tasks, arrow cues caused a similar facilitation of responses in the cued direction as eye gaze and pointing cues, in the anti-saccade tasks (in which participants have to respond away from the location of a peripheral onset), arrows had a greatly reduced effect on oculomotor programming relative to the biologically relevant cues. Importantly, although the socio-biological cues continued to influence saccadic responses, the facilitation was in the opposite direction to the cues. This finding suggests that the cues were being processed within the same "anti-response" task set (i.e. "go opposite") as the target stimulus. Word cues had almost no effects on saccadic orienting in either pro- or anti-saccade tasks. Schematicised eye gaze cues had a smaller magnitude effect than photographic gaze cues suggesting that ecological validity ("biological-ness") is an important factor in influencing oculomotor responses to social cues. No relationship was found between autistic traits and orienting to gaze or arrow cues in a large sample of males. However, findings from the neurological patients point to a possible double-dissociation between the neural mechanisms subserving processing of socio-biological and non-social cues, with the former reliant on the orbitofrontal cortex, and the latter on lateral frontal cortex. Taken together, these results suggest that biologically relevant cues have privileged access to the oculomotor system. The findings are interpreted in terms of a neurocognitive model of saccadic orienting to socio-biological and non-social cues, and an extension to an existing model of saccade generation is proposed. Finally, limitations of the research, its wider impact and directions for future work are discussed.
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Bation, Rémy. "Stimulation électrique par courant continu (tDCS) dans les Troubles Obsessionnels et Compulsifs résistants : effets cliniques et électrophysiologiques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1344/document.
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Les Troubles Obsessionnels et Compulsifs (TOC) sont un trouble mental sévère et fréquemment résistant. La physiopathologie du trouble se caractérise par des anomalies au sein des boucle cortico-striato-thalamo-cortical entrainant une hyper-activité du cortex orbito-frontal, du cortex cingulaire antérieur, du putamen. Au cours des dernières années, des anomalies structurales et fonctionnelles du cervelet ont de plus été mise en évidence dans les TOC venant compléter le modèle existant.Nous avons mise au point un protocole de traitement par tDCS ciblant le cortex orbito-frontal gauche et le cervelet droit pour les TOC résistants. Dans une première étude, nous avons étudié la faisabilité de ce protocole de traitement dans une étude ouverte. Cette étude a mis en évidence une réduction significative des symptômes dans une population de patient à haut niveau de résistance. Dans une deuxième étude, nous avons évaluer l’effet de ce traitement dans un protocole randomisé, contrôlé et parallèle contre placebo. Cette étude n’a pas confirmé l’efficacité de ce protocole de traitement. Dans cette même population, nous avons au cours du protocole mesuré les paramètres d’excitabilité corticale au niveau du cortex moteur par stimulation magnétique transrânienne. Nous avons ainsi mis en évidence que la tDCS provoquait une augmentation significative des processus d’inhibition (Short Interval Cortical Inhibition : SICI ) et une diminution non significative des processus de facilitation (Intra Cortical Facilitation : ICF). L’étude des effets cliniques et électro-physiologiques de cette approche thérapeutique novatrice dans les TOC résistants n’a pas permis de confirmer son intérêt clinique malgré un impact de ce protocole sur les modifications de l’excitabilité corticale inhérentes aux troubles. Ces données ont été mise en relation avec la littérature afin de proposer des perspectives d’évolution dans l’utilisation de la tDCS dans les TOC résistantsObsessive-compulsive disorder (OCD) is a severe mental illness. OCD symptoms are often resistant to available treatments. Neurobiological models of OCD are based on an imbalance between the direct (excitatory) and indirect (inhibitory) pathway within this cortico-striato-thalamo-cortical loops, which causes hyperactivation in the orbito-frontal cortex, the cingular anterior cortex, the putamen. More recently, the role of cerebellum in the OCD physiopathology has been brought to light by studies showing structural and functional abnormalities. We proposed to use tDCS as a therapeutic tool for resistant OCD by targeting the hyperactive left orbito-frontal cortex with cathodal tDCS (assumed to decrease cortical excitability) coupled with anodal cerebellar tDCS. In a first study, we studied the feasibility of this treatment protocol in an open-trial. This study found a significant reduction in symptoms in a population with a high level of resistance. In a second study, we evaluated the effect of this treatment in a randomized-controlled trial. This study did not confirm the effectiveness of this intervention. We have assessed motor cortex cortical excitability parameters by transcranial magnetic stimulation. We thus demonstrated that the tDCS caused a significant increase of inhibition processes (Short Interval Cortical Inhibition: SICI) and a nonsignificant decrease in the facilitation processes (Intra Cortical Facilitation (ICF)). In addition, clinical improvement assessed by Clinical Global Impression at the end of the follow-up period (3 months) was positively correlated with SICI at baseline.tDCS with the cathode placed over the left OFC combined with the anode placed over the right cerebellum decreased hyper-excitability in the motor cortex but was not significantly effective in SSRI- resistant OCD patients. These works were discussed in light of the available literature to create future prospect in the field of tDCS treatment for OCD resistant patients
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Batten, Seth Richard. "MEASURING GLUTAMATE AND OXYGEN IN BRAIN REWARD CIRCUITS IN ANIMAL MODELS OF COCAINE ABUSE AND DECISION-MAKING." UKnowledge, 2019. https://uknowledge.uky.edu/psychology_etds/165.
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Drug-specific reward and associated effects on neural signaling are often studied between subjects, where one group self-administers drug and a separate group self-administers a natural reinforcer. However, exposure to drugs of abuse can cause long-term neural adaptations that can affect how an organism responds to drug reward, natural reward, and their reward-associated stimuli. Thus, to isolate drug-specific effects it is important to use models that expose the same organism to all of the aforementioned. Multiple schedules provide a means of dissociating the rewarding effects of a drug from the rewarding effects of food within a single animal. Further, drug users do not take drugs in isolation; rather, they are often faced with several concurrently available commodities (e.g. monetary goods, social relationships). Thus, using choice measures to assess the relative subjective value of drug reinforcers in both humans and animals promotes a translational understanding of mechanisms that govern drug-associated decision-making. Thus, in order to gain a more translational view of the neurobehavioral mechanisms that underlie drug-associated behavior, in the first study, glutamate was measured in the nucleus accumbens core (NAcC) and prefrontal cortex (PrL) in freely-moving rats as they behaved in a cocaine-food multiple schedule procedure. In the second study, oxygen dynamics were measured in the orbitofrontal cortex (OFC) of freely-moving rats as they behaved in a cocaine/food choice procedure. The results from the first study showed that, in the NAc and PrL, there was an increase in glutamate release when animals earned cocaine. Further, the number of glutamate peaks that occurred per cocaine lever press and per cocaine reinforcer was increased compared to food. In the second study, OFC oxygen dynamics were positively correlated with cocaine/food choice and generally tracked preference. Further, OFC oxygen dynamics were greater to cocaine related events. Taken together, these results showed the feasibility of combining electrochemical measurements with complex drug-related behavioral procedures. These results also highlight the importance of the PrL, NAcC, and OFC in the valuation of drug and non-drug commodities. Overall, these results add to our understanding of the neurobehavioral mechanisms that guide drug-associated behavior and create more precise experimental avenues to research potential treatments.
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van, der Plas Ellen Aaltje Adriana. "Social functioning and brain structure in adolescents and young adults with isolated cleft lip and palate." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1273.
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Social isolation is commonly reported in individuals with isolated cleft lip and palate (ICLP), and is often cited as due to secondary factors of living with a facial malformation. However, the data are mixed, and the literature is biased to self-report studies. This study aimed to go beyond self-report data, and various components of social functioning were examined in a group of males with and without ICLP. The main aim of the study was to assess and compare social motivation in ICLP, and to relate social adjustment to brain structure. It was predicted that males with ICLP would be more likely to be socially isolated; however, self-concept was predicted to be similar to the comparison group (NC). Additionally, males with ICLP were predicted to have reduced social motivation (i.e., social abulia). Finally, volumes of the medial orbitofrontal cortex (mOFC) and the cerebellum were predicted to be related to social outcomes. The sample's age range was 13 - 25 years old, and 20 males with ICLP were compared to a group of 20 NC males. MRI scans were obtained from all the participants. As expected, males with ICLP were more likely to be socially isolated. Against predictions, they also had lower self-concept relative to the NC group. However, self-concept was not related to the extent of facial abnormality in the ICLP group. In line with predictions, the study did provide evidence for social abulia as a mechanism for social isolation, as males with ICLP had a more positive attitude after being socially excluded relative to excluded NC males. Unexpectedly however, the groups responded the same to social pressure, as all participants were more likely to take riskier turns in a driving simulator experiment when someone behind them was honking. Finally, social adjustment was significantly correlated with the volume of the mOFC, and posterior cerebellum white matter. Both correlations suggested that individuals with larger volumes were more likely to be better socially adjusted. In conclusion, the study provided evidence for a potentially different mechanism of social isolation in ICLP, and showed that brain morphology may at least partly underlie social dysfunction as well.
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Gueguen, Maëlle. "Dynamique intracérébrale de l'apprentissage par renforcement chez l'humain." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAS042/document.
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Chaque jour, nous prenons des décisions impliquant de choisir les options qui nous semblent les plus avantageuses, en nous basant sur nos expériences passées. Toutefois, les mécanismes et les bases neurales de l’apprentissage par renforcement restent débattus. D’une part, certains travaux suggèrent l’existence de deux systèmes opposés impliquant des aires cérébrales corticales et sous-corticales distinctes lorsque l’on apprend par la carotte ou par le bâton. D’autres part, des études ont montré une ségrégation au sein même de ces régions cérébrales ou entre des neurones traitant l’apprentissage par récompenses et celui par évitement des punitions. Le but de cette thèse était d’étudier la dynamique cérébrale de l’apprentissage par renforcement chez l’homme. Pour ce faire, nous avons utilisé des enregistrements intracérébraux réalisés chez des patients épileptiques pharmaco-résistants pendant qu’ils réalisaient une tâche d’apprentissage probabiliste. Dans les deux premières études, nous avons d’investigué la dynamique de l’encodage des signaux de renforcement, et en particulier à celui des erreurs de prédiction des récompenses et des punitions. L’enregistrement de potentiels de champs locaux dans le cortex a mis en évidence le rôle central de l’activité à haute-fréquence gamma (50-150Hz). Les résultats suggèrent que le cortex préfrontal ventro-médian est impliqué dans l’encodage des erreurs de prédiction des récompenses alors que pour l’insula antérieure, le cortex préfrontal dorsolatéral sont impliqués dans l’encodage des erreurs de prédiction des punitions. De plus, l’activité neurale de l’insula antérieure permet de prédire la performance des patients lors de l’apprentissage. Ces résultats sont cohérents avec l’existence d’une dissociation au niveau cortical pour le traitement des renforcements appétitifs et aversifs lors de la prise de décision. La seconde étude a permis d’étudier l’implication de deux noyaux limbiques du thalamus au cours du même protocole cognitif. L’enregistrement de potentiels de champs locaux a mis en évidence le rôle des activités basse fréquence thêta dans la détection des renforcements, en particulier dans leur dimension aversive. Dans une troisième étude, nous avons testé l’influence du risque sur l’apprentissage par renforcement. Nous rapportons une aversion spécifique au risque lors de l’apprentissage par évitement des punitions ainsi qu’une diminution du temps de réaction lors de choix risqués permettant l’obtention de récompenses. Cela laisse supposer un comportement global tendant vers une aversion au risque lors de l’apprentissage par évitement des punitions et au contraire une attirance pour le risque lors de l’apprentissage par récompenses, suggérant que les mécanismes d’encodage du risque et de la valence pourraient être indépendants. L’amélioration de la compréhension des mécanismes cérébraux sous-tendant la prise de décision est importante, à la fois pour mieux comprendre les déficits motivationnels caractérisant plusieurs pathologies neuropsychiatriques, mais aussi pour mieux comprendre les biais décisionnels que nous pouvons exhiberWe make decisions every waking day of our life. Facing our options, we tend to pick the most likely to get our expected outcome. Taking into account our past experiences and their outcome is mandatory to identify the best option. This cognitive process is called reinforcement learning. To date, the underlying neural mechanisms are debated. Despite a consensus on the role of dopaminergic neurons in reward processing, several hypotheses on the neural bases of reinforcement learning coexist: either two distinct opposite systems covering cortical and subcortical areas, or a segregation of neurons within brain regions to process reward-based and punishment-avoidance learning.This PhD work aimed to identify the brain dynamics of human reinforcement learning. To unravel the neural mechanisms involved, we used intracerebral recordings in refractory epileptic patients during a probabilistic learning task. In the first study, we used a computational model to tackle the brain dynamics of reinforcement signal encoding, especially the encoding of reward and punishment prediction errors. Local field potentials exhibited the central role of high frequency gamma activity (50-150Hz) in these encodings. We report a role of the ventromedial prefrontal cortex in reward prediction error encoding while the anterior insula and the dorsolateral prefrontal cortex encoded punishment prediction errors. In addition, the magnitude of the neural response in the insula predicted behavioral learning and trial-to-trial behavioral adaptations. These results are consistent with the existence of two distinct opposite cortical systems processing reward and punishments during reinforcement learning. In a second study, we recorded the neural activity of the anterior and dorsomedial nuclei of the thalamus during the same cognitive task. Local field potentials recordings highlighted the role of low frequency theta activity in punishment processing, supporting an implication of these nuclei during punishment-avoidance learning. In a third behavioral study, we investigated the influence of risk on reinforcement learning. We observed a risk-aversion during punishment-avoidance, affecting the performance, as well as a risk-seeking behavior during reward-seeking, revealed by an increased reaction time towards appetitive risky choices. Taken together, these results suggest we are risk-seeking when we have something to gain and risk-averse when we have something to lose, in contrast to the prediction of the prospect theory.Improving our common knowledge of the brain dynamics of human reinforcement learning could improve the understanding of cognitive deficits of neurological patients, but also the decision bias all human beings can exhibit
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Chow, Jonathan Jenn-Sheng. "COCAINE CHOICE: A NOVEL PROCEDURE FOR INVESTIGATING NEURONAL ACTIVATION MEDIATING COCAINE PREFERENCE." UKnowledge, 2018. https://uknowledge.uky.edu/psychology_etds/151.
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Cocaine use disorder is a significant health problem, negatively impacting individuals afflicted. While preclinical self-administration research has provided invaluable insight into the neurobehavioral mechanisms that underlie cocaine abuse, cocaine use outside of the laboratory occurs within an environment where other goods are also available ubiquitously. Although there is an ever-increasing literature investigating drug vs. non-drug choice in rodent models and how alternative goods can compete with the subjective value of cocaine, the neurobiological mechanisms that are associated with cocaine preference remains largely unknown. Additionally, current drug vs. non-drug choice studies use procedures that confound preference with intake, such that preference measures are directly reflective of individual experience with drug and non-drug reinforcers earned through the choices that are made; simply, preference and intake are the same. Moreover, differences in cocaine experience can result in differential neural adaptations, thus making it difficult to determine if the neurobiological mechanisms underlying choice are related to preference or drug intake. Herein a novel choice procedure, which controls for reinforcer intake (controlled reinforcer ratio; CRR), was used to explore how certain reinforcer dimensions (i.e., magnitude and frequency) influence cocaine preference. In addition, neuronal activity, measured via c-fos expression, in the orbitofrontal cortex and nucleus accumbens, areas associated with decision-making and valuation, for cocaine and food were independently targeted and labeled using fluorescent in situ hybridization and fluorescent immunohistochemistry. First, unlike prototypical choice procedures where preference and intake are confounded, the CRR choice procedure was able to dissociate the two. Under the CRR choice procedure, it was revealed that both magnitude and frequency, independent dimensions of reinforcement, greatly influence preference for cocaine. Furthermore, the CRR choice procedure was sensitive to manipulations known to influence cocaine preference while keeping reinforcer intake constant. When neuronal activity was examined after CRR training, the number of cocaine activated cells, relative to food activated cells, did not correlate with individual preferences for cocaine despite overall reinforcer intake being held constant. Instead, results suggest neuronal activity for cocaine was related to overall cocaine intake. Overall, these results give impetus for utilizing the CRR choice procedure to better investigate how drug and non-drug reinforcers are afforded differential subjective value and compete for preference. Moreover, use of a CRR choice procedure may lead to identification of specific neurobehavioral mechanisms and lead toward future development of more effective pharmacological and behavioral treatments to ameliorate substance use disorders.
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Noonan, MaryAnn Philomena. "Linking actions to outcomes in the frontal lobe." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:e1bcccd1-2182-4f1d-94bd-b80ce67efb0e.
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Behaviour is guided by accumulated experience, valuation and comparison. While many aspects associated with these functions are mediated by the frontal lobes, the precise contribution from particular regions remains debated. This thesis will deal with how an organism comes to select an option and will specifically focus on the role of the orbitofrontal cortex (OFC) in two mechanisms in this process: learning of outcome specificities and selecting between multiple options based on their expected values. Despite evidence emphasizing anatomical and connective heterogeneity within this structure, the OFC is often regarded as a uniform region. This thesis aims to resolve some of this uncertainty by assuming that the medial and lateral regions of the OFC contribute differentially to learning and decision-making. Two distinct methodologies were used in these investigations. First, the contribution of the medial OFC to social and emotional processing was examined. The findings from this study disprove previously held beliefs that the medial regions of the OFC guide social and emotional behaviours, but indicted a role for this region in value-guided decision-making. The second study examined functional differences between the lateral and medial OFC by making circumscribed lesions to either region in macaque monkeys. The animals performed a number of 3-armed bandit tasks which were designed to investigate different aspects of value assignment and comparison. The results show that while lateral OFC was required for "credit assignment" – the correct assignment of values to visual cues – medial OFC was critical for comparison of the cues' values during decision-making. In unchanging probabilistic environments, mOFC lesions induced decision-making impairments when value comparison was difficult without affecting credit assignment and associative learning. By contrast, lateral OFC lesions caused the opposite pattern of impairment. The final study used human-neuroimaging techniques to investigate the differential representation of outcome-specific contingency learning and found not only that the expectation of a unique outcome facilitated learning and memory recall but that this was supported by a neural network which included the lateral regions of the OFC and the anterior cingulate cortex. Activity in the mOFC did not correlate with outcome-specific contingency learning but instead reflected both the value associated with the receipt and expectation of a reward. Taken together, the results from this thesis suggest that specific parts of the OFC make markedly different contributions to these very different cognitive functions.
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Mackert-Wilts, Ivonne [Verfasser]. "Elektrophysiologische Aktivität des orbitofrontalen Cortex auf Belohnungsreize in Depression / Ivonne Mackert-Wilts." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2010. http://d-nb.info/1024054454/34.
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Pierson, Jamie L. "The Role of Prediction Error in the Reconsolidation of Contextual Fear Memory." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1564058234405263.
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Tayó, Juli Mª del Carmen. "Funciones orbitofrontales en la enfermedad de Alzheimer." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/145865.
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INTRODUCCIÓN: Estudios realizados con roedores y primates demuestran la implicación del córtex orbitofrontal en el aprendizaje de estímulos, en tareas de aprendizaje social y en la toma de decisiones en el ámbito social. También numerosos estudios con humanos ponen de manifiesto la relación del córtex orbitofrontal con la falta de empatía, la conducta social inapropiada, la incapacidad para reconocer el componente social de las expresiones faciales y el déficit en la integración y en la comunicación social. En efecto, el córtex orbitofrontal es importante para la conducta emocional y social y en definitiva para interaccionar de una forma adecuada. El deterioro cognitivo en la enfermedad de Alzheimer es progresivo y tiende a un síndrome afaso-apracto-agnósico debido a una atrofia en los lóbulos temporales, frontales, parietales y occipitales. Sin embargo, hay estudios que ponen de relieve que el córtex orbitofrontal es la corteza con menos placas neuríticas. Hay resultados diversos y contradictorios respecto a la capacidad para reconocer emociones de las expresiones faciales y la capacidad para las habilidades sociales en los enfermos de Alzheimer.
OBJETIVOS: El primero consiste en mostrar la preservación de las funciones asociadas al córtex orbitofrontal en la enfermedad de Alzheimer. El segundo es estudiar si en todos los grados de deterioro de la enfermedad de Alzheimer se preserva la capacidad de percibir situaciones sociales.
MÉTODO: Mediante muestreo prospectivo se seleccionaron para el estudio 45 pacientes con enfermedad de Alzheimer que acudían a la consulta externa ambulatoria entre 67 y 89 años y 15 sujetos control entre 66 y 89 años. Se les administró una batería neuropsicológica general, pruebas orbitofrontales específicas, una escala de conducta frontal, un rol playing de interacción social y un visionado de conductas sociales.
RESULTADOS: Los resultados de las pruebas neuropsicológicas de la batería general muestran que los pacientes con enfermedad de Alzheimer respecto al grupo control presentan un declive cognitivo desde las fases incipientes de la enfermedad en las áreas de memoria, lenguaje, atención, praxias y gnosias observándose diferencias significativas entre los grupos con una magnitud grande del efecto (r>0,5). En relación a las pruebas orbitofrontales específicas en la prueba de objetos alternados no aparecen diferencias significativas entre los grupos; tampoco hay diferencias significativas en interacción social y en el visionado de situaciones positivas comparadas con las negativas. No hay diferencias significativas en el visionado de situaciones sociales entre los grupos control, incipiente y leve. En el Iowa Gambling Test no aparecen diferencias significativas entre el grupo control y los 3 grupos de pacientes, tampoco hay diferencias entre los grupos en apatía, en disfunción ejecutiva y en desinhibición. En otro grupo de pruebas como el test de la mirada hay diferencias entre el grupo control y los grupos de pacientes (p<0,05). También hay diferencias significativas entre los grupos en el test de meteduras de pata con una magnitud grande del efecto (r>0,5). En el visionado de situaciones sociales las diferencias eran significativas entre el grupo moderado y el resto de grupos con una magnitud grande del efecto (r>0,5).
CONCLUSIONES: Los pacientes con enfermedad de Alzheimer presentan alteraciones en los resultados de las pruebas orbitales en las fases incipientes de la enfermedad sin embargo se mantienen estables a pesar de la progresión de la demencia. Únicamente los grupos de pacientes incipiente y leve mantienen la capacidad para captar situaciones sociales tanto positivas como negativas, comprenderlas y tener empatía con ellas. También preservan las interacciones sociales básicas.INTRODUCTION: Studies in rodents and primates demonstrate the involvement of the orbitofrontal cortex in learning stimuli, social learning tasks and decision-making in the social field. Numerous studies on human beings also highlight the relation between the orbitofrontal cortex and lack of empathy, inappropriate social behaviour, inability to recognize the social component of facial expressions and integration and social communication deficits. Indeed, the orbitofrontal cortex is important for emotional and social behaviour and ultimately to interact in a suitable manner. Cognitive decline in Alzheimer 's disease is progressive and tends to an aphasic-apractic-agnosic syndrome due to atrophy in the temporal, frontal, parietal and occipital lobes. However, there are studies that show that the orbitofrontal cortex is the cortex with fewer neuritic plaques. There are various and conflicting results regarding the ability to recognize emotions from facial expressions and the ability for social skills in people with Alzheimer's. OBJECTIVES: The first objective is to show the preservation of the functions associated with orbitofrontal cortex in Alzheimer 's disease. The second objective is to study if the ability to perceive social situations is preserved in all degrees of impairment of Alzheimer 's disease. METHOD: Using prospective sampling 45 patients with Alzheimer 's disease attending outpatient consultation 67 to 89 years-old and 15 control subjects 66 to 89 years-old were selected for the study. They were administered a general neuropsychological battery, specific orbitofrontal tests, a behaviour scale frontal, a social interaction role-playing and social behaviours display viewing. RESULTS: The results of the general neuropsychological battery tests show that Alzheimer's disease patients, vs. the control group, presented cognitive decline from the early phases of the disease in the areas of memory, language, attention, praxia and gnosia, with significative differences between groups with a large magnitude of effect (r>0,5). Regarding specific orbitofrontal tests on Alternate Object Test no significant differences between groups were found; nor significant differences in social interaction or viewing situations (positive compared to negative). There are no significant differences in the viewing of social situations between control, incipient and mild groups. In the Iowa Gambling Test no significant differences between the control group and the 3 groups of patients; there is no difference between the groups in apathy, executive dysfunction and disinhibition. In another set of tests such as the Eyes Task there are differences between the control and patient groups (p<0,05). There are also significant differences between groups in the Faux Pas Task with a large magnitude of effect (r>0,5). On social situation viewing there were significant differences between the moderate group and the other groups with a large magnitude of the effect (r> 0,5). CONCLUSIONS: Patients with Alzheimer's disease show alteration on orbital tests result in incipient stages of the disease but remain stable despite the progression of dementia. Only incipient and mild patient groups retain the ability to capture social situations both positive and negative, understand them and empathize with them. They also preserve basic social interactions.
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Jackson, Stacey Anne Winifred. "Modelling the neuropsychopharmacology of obsessive-compulsive disorder in the common marmoset (Callithrix jacchus)." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288835.
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This thesis extends the understanding of the neural and neurochemical contributions to two forms of behavioural adaptation, reversal learning and contingency degradation, in which stimulus/action-reward contingencies are altered. The results are interpreted within the psychological framework of the compulsivity construct, and their implications for the pathological behaviour of obsessive-compulsive-disorder (OCD) are considered. The orbitofrontal cortex (OFC) and striatum are key brain structures involved in reversal learning, as are the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT) and dopamine (DA) within those respective regions. However, there has been little empirical evidence of how these two structures and neurochemical systems interact, especially in the functional context of reversal learning. In Chapter Three, the impact of experimentally-induced reductions of 5-HT in the anterior OFC on monoamine levels in subcortical structures such as the striatum and amygdala was determined, DA being found to be significantly up-regulated in the amygdala. Functionally, 5-HT depletion of the OFC has previously been shown to induce deficits in reversal learning. To determine the possible causal significance of amygdala dopamine up-regulation for said reversal learning deficit, the effects of blocking the upregulation with the infusion of intra amygdala DA receptor antagonists following bilateral OFC 5-HT depletion were investigated in a reversal learning paradigm. In Chapter Four, the differential roles of regions of striatum were examined in visual reversal learning. Two recent investigations in non-human primates highlighted the role of the striatum in reversal learning,but pinpointed the critical region to be either the ventromedial caudate or the putamen. Marmosets were trained on a serial reversal task that allowed multiple acute neural manipulations, and the ventromedial caudate and putamen were then reversibly inactivated using the GABAA agonist muscimol. Results indicated dose-related impairments specifically in reversal learning within the putamen, with sparing of discrimination retention. By contrast, similar reversible inactivation of the caudate nucleus produced marked deficits in visual discrimination performance (retention). In Chapter Five, the neural basis of action-outcome contingency knowledge was investigated by inactivating distinct regions of the PFC, the perigenual ACC (pgACC; area 32) and the anterior OFC, and determining response sensitivity to the degradation of action-outcome contingencies. In previous work, excitotoxic lesions of either the pgACC or the OFC had been found to induce insensitivity to contingency degradation in marmosets. However, the design of that experiment did not allow specification of whether stimulus- or action-outcome associations were disrupted, and a precise neural locus could not be determined for the behavioural effects as the OFC lesions included parts of the lateral and medial OFC. I therefore developed a novel contingency degradation paradigm that distinguished between stimulus- and action-outcome associations to enable the study of acute pharmacological manipulations in both brain regions. The pgACC and OFC were reversibly inactivated using GABAA-GABAB agonists (muscimol-baclofen). Whereas the pgACC inactivation produced selective deficits in sensitivity to action-outcome contingency degradation, OFC inactivation reduced the suppressive effect of noncontingent reward on responding more generally but left intact sensitivity to degradation of the contingencies. These results are discussed in terms of different theories of the functions of the pgACC and OFC. In the final discussion the findings on the neural substrates of reversal learning and contingency degradation are drawn together in terms of their significance for theories of PFC involvement in cognitive control, and for the understanding of OCD and other neuropsychiatric disorders.
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Gerboga, Fatma [Verfasser], Katrin [Akademischer Betreuer] Amunts, and Jörg [Gutachter] Felsberg. "Identifizierung eines neuen zytoarchitektonischen Areals im lateralen orbitofrontalen Cortex beim Menschen / Fatma Gerboga ; Gutachter: Jörg Felsberg ; Betreuer: Katrin Amunts." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2019. http://d-nb.info/1192974433/34.
Full text
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Nogueira, Mañas Ramon. "Decision-making as an encoding-decoding process and its correlation with neuronal activity and behaviour." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/456320.
Full textAbstract:
Un dels objectius més importants de la neurociència teòrica és determinar
quins són els principis fonamentals subjacents en el processament de
la informació al cervell i en última instància caracteritzar el nexe entre
l’activitat neuronal i el comportament. Tot i que s’han produït avenços
importants en aquesta direcció, encara estem lluny de poder proporcionar
respostes clares i robustes a aquesta pregunta. En aquesta tesi presentaré un conjunt de resultats que han estat analitzats des del paradigma de
codificació-decodificació en la presa de decisions, una part fonamental
de la cognició. En particular, presentaré un conjunt de resultats electrofisiològics, comportamentals i matemàtics que han estat utilitzats per a
estudiar la codificació d’informació a l’escorça de micos conductuals i en
la integració de l’evidència prèvia amb la sensorial en rates realitzant una
tasca perceptual de presa de decisions acoblada a la seva resposta.Uno de los objetivos más importantes de la neurociencia teórica es determinar cuáles son los principios fundamentales subyacentes en el procesamiento de la información en el cerebro y en última instancia caracterizar el nexo entre la actividad neuronal y el comportamiento. Aunque se han producido importantes avances en esta dirección, aún estamos lejos de poder proporcionar respuestas claras y robustas para esta pregunta. En esta tesis voy a presentar un conjunto de resultados que han sido analizados desde el paradigma de codificación-decodificación en la toma de decisiones, una parte fundamental de la cognición. En particular, voy a presentar un conjunto de resultados electrofisiológicos, comportamentales y matemáticos que han sido usados para estudiar la codificación de información en la corteza de monos conductuales y en la integración de la evidencia previa con la sensorial en ratas realizando una tarea perceptual de toma de decisiones acoplada a su respuesta.
One of the most important goals in theoretical neuroscience is to determine what are the fundamental principles underlying the processing of information in the brain and ultimately characterize the link between neuronal activity and behavior. Even though many important steps have been done in this direction, we are still far from providing a clear and robust answer to this question. In this thesis I will present a set of results that will be analyzed under the encoding-decoding framework in decision-making, a fundamental part of cognition. In particular, I will present a set of electrophysiological, behavioral and mathematical results that have been used to study the encoding of information on the cortex of behaving monkeys and the integration of sensory with prior evidence on rats performing an outcome-coupled perceptual decision-making task.
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Timbie, Clare. "Circuitry of emotion: integration in orbitofrontal cortex." Thesis, 2016. https://hdl.handle.net/2144/15267.
Full textAbstract:
The amygdala and orbitofrontal cortex are critical sites for processing emotional content. The amygdala sends dense pathways preferentially to the posterior orbitofrontal cortex (pOFC) and to the magnocellular part of the mediodorsal thalamic nucleus (MDmc), which is itself robustly connected with pOFC. This tri-partite circuit is thought to be activated when associating stimuli with emotional value, and is necessary to flexibly adapt behavior to changing circumstances, but its features and synaptic interactions are unknown. Labeling of pathways with distinct neural tracers in rhesus monkeys revealed that amygdalar terminals in pOFC were denser and larger compared to those in other prefrontal cortices. Further, amygdalar terminals in pOFC were even larger than thalamocortical terminals, which are considered highly efficient drivers of cortical neurons. In comparison with thalamocortical pathways, amygdalar terminals innervated more excitatory neurons and were more frequently multisynaptic. These features suggest that the amygdala sends a highly efficient excitatory pathway to pOFC. Among a small proportion of innervated inhibitory neurons, the pathway from the amygdala to pOFC preferentially targeted the neurochemical classes of calbindin and calretinin inhibitory neurons in the upper layers, which are functionally suited to suppress distracting stimuli and enhance relevant signals. Further, the amygdalar pathway to MDmc targeted thalamocortical relay neurons, including those that project to pOFC, providing a second route for amygdalar signals to reach cortex. Neurochemical and morphological differences among terminals suggest that the direct pathway from the amygdala to pOFC and the indirect route through MDmc arise from separate neuronal populations in the amygdala. In MDmc, axon terminals from the amygdala formed synaptic triads, a thalamic specialization connecting excitatory projection neurons and local inhibitory neurons. This synaptic specialization is akin to what is found in sensory thalamic nuclei connecting peripheral sensory afferents with cortex. By analogy, the amygdala may act as a sensor of affective value, relaying signals about internal states to cortex through MDmc. The synaptic specializations shown here in the circuit that tightly interlinks the amygdala, MDmc, and pOFC shed light on the functional circuitry for emotional behavior and its disruption in psychiatric disorders such as phobias and obsessive compulsive disorder.
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Bonacchi, N. "Spatial goals and actions in the orbitofrontal cortex." Doctoral thesis, 2017. http://hdl.handle.net/10362/76957.
Full textAbstract:
"The orbitofrontal cortex (OFC) is thought to be involved in the
representation of anticipated behavioral outcomes that drive goaldirected
behavior. Among the properties of goals or outcomes that may
be represented in the OFC is their spatial location, a fundamental feature
of goals for animals that rely heavily on locomotion for foraging. Previous
studies have described neural correlates of choice and goal location in
rats performing spatial two-alternative choice tasks. However, relatively
little is known about the spatial properties of these OFC neural
representations.(...)"
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Andrews, Katharine DiAnn. "Orbitofrontal Cortex and Social Processing in Rodent Models." Diss., 2019. http://hdl.handle.net/1805/19636.
Full textAbstract:
Indiana University-Purdue University Indianapolis (IUPUI)Social processing is the reception, interpretation, and reciprocation of social information and is critical for mental health. The neural structures, circuits, and substrates regulating these complex mechanisms are not well understood. Social processing in the form of social safety learning, as measured by a rat model of social familiarity-induced anxiolysis (SoFiA), was impaired following mild blast traumatic brain injury (mbTBI). Initial findings indicated that mbTBI altered resting state network activity in the orbitofrontal cortex (OFC) and was associated with accumulation of neurotoxin marker, acrolein, in lateral prefrontal cortex (PFC) (including OFC), indicating OFC as a brain region of interest that may contribute to social processing. Measuring GABA and Glutamate-related gene expression in OFC of mbTBI or sham-exposed rat brain revealed specific elevations of metabotropic glutamate receptor type 1 and 5 (mGluR1/5) expression in mbTBI but not sham OFC. Exposure-naïve rats intracranially injected with mGluR1/5 agonist demonstrated attenuated SoFiA, and this coincided with an impairment of social recognition (SR) behavior. Additionally, inactivation of OFC by local intracranial injection of GABAA agonist, muscimol, impaired two different measures of SR in which two conspecifics, or members of the same species, one novel and one familiar, were presented and required discrimination. Novelty seeking, decision-making, memory, and gregariousness were tested in isolation to determine OFC contributions to these specific behavioral contributions to SR test performance. OFC inactivation did not impair novelty seeking, non-social decision-making, or non-social memory as measured by novel object recognition (NOR) test, or gregariousness or social decision-making as measure by social preference (SP) test. When measuring SR behavior via consecutive presentation of two different conspecifics, OFC inactivation did not impact SR. Therefore, OFC is not directly responsible for social recognition, but rather the discrimination or ability to act upon discrimination of two simultaneously present conspecifics. These data suggest a novel role for OFC in high order processing or execution of action based on social information.
2 years (2021-05-24)
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CERRUTI, Stefania. "A structural magnetic resonance imaging studyof Orbitofrontal Cortex in Psychosis." Doctoral thesis, 2012. http://hdl.handle.net/11562/400336.
Full textAbstract:
ABSTRACT
BACKGROUND: La corteccia Orbitofrontale (OFC) è la parte più inferiore e ventrale della corteccia prefrontale ed è situata tra le orbite degli occhi. Grazie alle sue connessioni con l’amigdala, l’ippocampo, il talamo, la corteccia prefrontale dorso laterale e il lobo temporale superiore, è coinvolta in numerosi processi cognitivi come l’integrazione sensoriale, meccanismi di ricompensa e punizione, decision-making, regolazione delle emozioni e controllo degli impulsi. Lesioni alla OFC producono deficit cognitivi, affettivi e sociali simili a quelli presenti nella schizofrenia. Anche se con qualche inconsistenza, esistono evidenze di una riduzione di volume della OFC nella schizofrenia, e questa riduzione sembra associata con la psicopatologia e con alterazioni della cognizione. Tuttavia, non è ancora chiaro se queste riduzioni di volume sono presenti prima dell’insorgere della malattia o se insorgono con il progredire della stessa.
OBIETTIVI: Gli obiettivi dello studio erano misurare i volumi della OFC e delle sue sottoaree, tracciati sulle immagini di risonanza magnetica, in un gruppo di pazienti affetti da schizofrenia (SCZ), in un gruppo di pazienti all’esordio psicotico (FEP), reclutati all’interno del progetto “Psychosis Incident Cohort Outcome Study” (PICOS), e in un gruppo di controlli sani (HC) e di studiare i cambiamenti nel tempo dei volumi della OFC in questo campione.
METODI: Sono state raccolte le variabili sociodemografiche e cliniche di 26 pazienti con schizophrenia, 16 pazienti all’esordio e 21 controlli sani. Le sessioni di risonanza magnetica sono state condotte tramite uno scanner 1,5 T e le immagini sono state analizzate mediante il software BRAINS2. I soggetti hanno effettuato una seconda risonanza dopo un periodo medio di 3 anni. La OFC e le sue sottoaree sono state tracciate e segmentate in sostanza grigia e bianca.
RISULTATI: Nel confronto trasversale, il volume della sostanza bianca e di quella grigia della parte laterale sinistra della OFC erano maggiori negli SCZ, rispetto ai FEP e ai HC. Nel confronto longitudinale, il volume della sostanza grigia della OFC dei FEP ha avuto un maggior decremento nel tempo rispetto a quello degli SCZ e dei HC.
DISCUSSIONE: La parte laterale sinistra della OFC sembra una regione particolarmente interessata da alterazioni volumetriche nella schizofrenia. La riduzione nel tempo di sostanza grigia della OFC nei FEP sembra confermare l’ipotesi che il volume cerebrale è maggiormente affetto da riduzione nella prima fase della malattia.ABSTRACT BACKGROUND: The orbitofrontal cortex (OFC) is the most inferior and ventral region of the prefrontal cortex that lies above the orbits. Through its connections with the amygdala, hyppocampus, thalamus, dorsolateral prefrontal cortex and superior temporal lobe, it is involved in several cognitive processes, such as sensory integration, reward mechanism, decision-making, mood regulation and impulse control. OFC dysfunction is implicated in cognitive, affective and social impairments similar to those present in schizophrenia. Although with some inconsistencies, there is evidence that OFC volumes are reduced in schizophrenia, and that they may be associated with psychopathology and altered cognition. However, it is still not clear whether OFC deficits are present before the onset of the disease or whether they occur with the progression of the illness. OBJECTIVES: The aims of the study were to measure the volumes of the OFC and its subregions, as traced on MRI scans, in a group of schizophrenia patients (SCZ), in a group of First Episode Psychosis patients (FEP), recruited in the context of the Psychosis Incident Cohort Outcome Study (PICOS), and a in group of healthy controls (HC) and to investigate the changes in OFC volumes over time in this cohort. METHODS: socio-demographical and clinical data were initially acquired from 26 SCZ patients, 16 FE patients and 21 HC subjects. The MRI sessions were conducted using a 1.5 T scanner and the images were analyzed using the BRAINS2 software. Subjects were scanned the second time after a mean follow up period of 3 years. The OFC and its medial and lateral subregions were traced and they were segmented for grey and white matter. RESULTS: In the cross sectional comparison, both the white and grey matter of the left lateral OFC was found to be increased in SCZ patients in respect to FEP patients and HC. In the longitudinal comparison the OFC grey matter volume of FEP patients had a greater decrease across time than those of chronic SCZ patients and HC. DISCUSSION: The left lateral OFC seems to be a brain region particularly affected by volume alteration in schizophrenia. The OFC grey matter reduction in FEP patients across time might confirm the assumption that brain volume is more affected by loss in the very first time of the illness.
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Saez, Rebecca. "Representations of Relative Value Coding in the Orbitofrontal Cortex and Amygdala." Thesis, 2013. https://doi.org/10.7916/D81C23ZP.
Full textAbstract:
In order to guide behavior, humans and animals must flexibly evaluate the motivational significance of stimuli in the environment. We sought to determine if, in different contexts, neurons in the amygdala and orbitofrontal cortex (OFC) indeed rescale their calculation of the motivational significance of stimuli that predict rewards. We used a "contrast revaluation" task in which the reward associated with one stimulus is held constant while other rewards within a particular context (or block of trials) change. This manipulation modulates the relative significance of the reward associated with one stimulus without changing its absolute amount. We recorded the activity of individual neurons in the amygdala and OFC of two monkeys while they performed the contrast revaluation task. On every trial, a monkey viewed one of two conditioned stimuli (CSs; distinct fractal patterns), each predictive of a different reward amount. CSs were novel for every experiment. Unconditioned stimulus (US, liquid reward) delivery followed CS presentation and a brief temporal gap (trace interval). The task consisted of three trial blocks, with switches between blocks occurring without warning. The presentation of CS2 predicted either a small (first and third blocks) or large US (second block). The presentation of CS1 predicted delivery of a medium US in all blocks. Thus CS1 corresponded to the "better" trial type in blocks 1 and 3, but not 2. Anticipatory licking behavior indicated that the monkey adapted its behavior depending upon the relative amount of expected reward. Although the reward amount associated with CS1 remained constant throughout the experiment, anticipatory licking decreased in block 2 and increased in block 3 - the blocks in which CS1 trials had become relatively less (block 2) and more (block 3) valuable. Strikingly, many individual amygdala and OFC neurons also modulated their responses to CS1 depending upon the block. Because this CS predicts the exact same reward in each block, these neurons cannot simply represent the sensory properties of a US associated with a CS. This finding demonstrates that amygdala and OFC neurons are often sensitive to the relative motivational significance of a CS, and not just to the sensory properties of its associated US or to the absolute value of the specific reward. Neurons in both the OFC and amygdala encode the relative value of CS1 but OFC neurons significantly encode relative value earlier than amygdala neurons. Cells in the amygdala and OFC code different properties during different time intervals during the trial and are consistent in valence when they code multiple properties. This implies that neurons are tracking state value: the overall motivational value of an organism's internal and external environment across time and sensory stimuli. Neurons that code relative value during the CS-trace interval and during reinforcement are also consistent in the valence that they code further supporting that these cells track state value. The neurons code with the same sign and strength whether the neuron is representing the relative value of the reward with no sensory input of the reward during CS or trace interval, or actually experiencing the reward during the US interval. Further, amygdala and OFC neural activity was correlated with the animal's behavioral performance, suggesting that these neurons could form the basis for animal's behavioral adaptation during contrast revaluation. These neural representations could also support behavior in other situations requiring flexible and adaptive evaluation of the motivational significance of stimuli.
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Jiang-Xie, Li-Feng, and 江謝立峰. "Dlgap2 Mutant Mice Demonstrate Exacerbated Aggressive Behaviors and Orbitofrontal Cortex Deficits." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/66401755523294167857.
Full textAbstract:
碩士國立臺灣大學
腦與心智科學研究所
101
As the elegant structures designed for neural communication, synapses are the building bricks of our mental functions. Recently, many human clinical studies point out genetic mutations in synaptic proteins may lead to dysfunctions of social cognition. Dlgap2/Sapap2, as one of the main components of scaffold proteins in postsynaptic density (PSD), has been shown to play a critical role in autism spectrum disorders (ASD). We generated Dlgap2-/- mice and discovered that they displayed exacerbated aggression in the resident-intruder paradigm and elevated social dominance in the tube test. With biochemical, ultra-structural, and electrophysiological analyses, Dlgap2-/- mice exhibited synaptic deficits in orbitofrontal cortex (OFC), a brain region recognized as a negative regulator of aggressive behaviors. Our findings clearly demonstrate that Dlgap2 plays vital roles in social behaviors of murine and proper synaptic functions of OFC.
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"Contributions of rat hippocampus and orbitofrontal cortex to recent and remote memory consolidation." Tulane University, 2010.
Find full textAbstract:
Systems level consolidation is the process by which memories that are initially dependent on one memory system for recall become independent of that system over time. Current theories of consolidation propose that some, but not all, forms of memory initially dependent on the hippocampus may be consolidated in the neocortex. One rodent memory model that undergoes consolidation outside of the hippocampus is social transmission of food preferences (STFP). Of interest, there has been some evidence to indicate that the orbitofrontal cortex (OFC) may be involved in the remote recall of socially transmitted food preferences. The experiments conducted within this dissertation test specific hypotheses about the contributions of the hippocampus and OFC to learning and memory for STFP. Levels of transcription factors involved in consolidation were measured following acquisition, recent recall, and remote recall across several brain regions implicated in STFP memory. These findings indicate a time-limited role for the hippocampus and an increasing contribution of the OFC. In addition, excitotoxic lesions of the hippocampus and orbitofrontal cortex were made to test the necessity of these regions in STFP acquisition, consolidation, and recall. Consistent with previous reports, damage to the hippocampus impaired recent recall but spared remote recall and acquisition. Damage to the OFC had no effect on acquisition or recall. The main conclusion from this work is that the OFC is not necessary for STFP acquisition or systems consolidation, but it may serve a non-mnemonic function as the memory degrades over timeacase@tulane.edu