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1
Greenberg, Paul Arthur. "Functional Stability and Learning in the Dorsolateral Prefrontal Cortex". Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1030%5F1%5Fm.pdf&type=application/pdf.
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Lanoue, Amelie Cecile. "Neuropathology in the dorsolateral prefrontal cortex in Parkinson's disease". Thesis, Boston University, 2013. https://hdl.handle.net/2144/11112.
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Thesis (Ph.D.)--Boston UniversityDegeneration of dopaminergic neurons in the substantia nigra pars compacta is the hallmark neuropathological feature of Parkinson's disease (PD). Multiple lines of evidence from anatomical and imaging studies indicate that cell loss or cell dysfunction also occur in other brain regions. The dorsolateral prefrontal cortex (DLPFC) is a region of interest because it could be implicated in both cognitive and motor symptoms of PD. However, studies in this brain region are limited and the extent of pathology is unclear. Work in this thesis was aimed at identifying possible neuropathology in post-mortem PD tissue from Brodmann area 9 (BA9), a region of the DLPFC. In the first study, using design-based stereology and radioisotopic in situ hybridization histochemistry (ISHH), we found that expression of two mitochondrial genes, NDUFS1 and COX1, was not altered and that no global loss of neurons occurs in BA9 in PD. In a second study, using ISHH and gene expression microarray analysis (One-Color Agilent 60-mer Whole Human Genome Microarray), we found decreased gene expression of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD67) in BA9 in PD, an effect that was not paralleled by a decrease in the numbers of GAD67 mRNA-expressing neurons. In a third study, using ISHH, we found that gene expression of the calcium-binding protein parvalbumin, which is selectively expressed in a subset of cortical GABAergic interneurons, is decreased in BA9 in PD. However, we found no loss of immunolabeled parvalbumin-positive neurons in BA9 in PD. In summary, the results indicate that expression of two key markers of GABAergic activity, GAD67 and parvalbumin, is depressed in BA9 in PD and that these effects are not due to a loss of neurons. This suggests that GABAergic neurotransmission is deficient in the DLPFC in PD and we propose that treatments aimed at restoring GABAergic inhibition in BA9 would have therapeutic efficacy in the symptomatic treatment of PD.
3
Fernandes, Ninette M. "The Detection of Prefrontal Cortex Development into Early Adulthood". Marietta College / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=marietta1164924291.
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Keifer, Ekaterina. "Performance of patients with ventromedial prefrontal, dorsolateral prefrontal, and non-frontal lesions on the Delis-Kaplan Executive Function System". Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/830.
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Executive functioning is a multidimensional concept encompassing higher-order adaptive abilities, such as judgment, decision-making, self-monitoring, planning, and emotional regulation. Disruption in executive functioning often results in devastating impairments in vitally-important areas of life, such as one's ability to hold employment and maintain social relationships.
Executive functions have been associated primarily with the prefrontal cortex. However, the nature and degree of the association between frontal lobe damage and performance on executive functioning tests remains controversial. Research suggests that the association may vary based on the specific location of damage within the prefrontal cortex, as well as the used measure of executive functioning. Few investigations have systematically addressed these variables. The current study employed the lesion method to investigate the relationship between performance on a battery of executive functioning tests and damage to specific regions of the prefrontal cortex. Three groups of participants with lesions in one of the locations of interest [ventromedial prefrontal (VMPC, n = 14), dorsolateral prefrontal (DLPC, n = 14), and non-frontal (n = 18)] were administered the Delis-Kaplan Executive Function System (D-KEFS, 2001), a comprehensive battery of executive functioning tests. Results revealed no statistically-significant differences between group performances on the D-KEFS primary measures. However, a qualitative analysis of the results revealed several meaningful group differences. It appears that some relationship exists between frontal lobe damage, particularly in the DLPC, and decreased performance on several executive functioning tests but further research overcoming the methodological limitations of most existing literature on this topic is needed to clearly resolve this issue.
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Nord, Camilla Laxmi. "The role of dorsolateral prefrontal cortex dysfunction in depression and its treatment with non-invasive brain stimulation". Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/10038161/.
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Major depression is a common and debilitating condition. However, initial treatment is ineffective for almost half of all patients. This thesis aims to clarify the mechanisms of a novel putative treatment for depression, transcranial direct current stimulation (tDCS), which targets the dorsolateral prefrontal cortex (DLPFC). The first experimental chapter tests whether DLPFC tDCS alters emotional face perception, akin to the acute effects of antidepressant drugs. Our analyses revealed that tDCS does not exert an antidepressant-like effect on emotion perception, but may affect non-emotional cognition. The second experimental chapter examines neural activation in depressed patients, unaffected first-degree relatives of depressed patients, and healthy controls during the n-back working memory task and a facial emotion processing task. During the n-back, depressed patients showed pronounced DLPFC hypoactivation, while at-risk participants were indistinguishable from healthy controls, consistent with the hypothesis that DLPFC dysfunction might be a useful target for depression treatment. In the final two chapters, I report results from a double-blind randomized controlled trial that for the first time tested DLPFC tDCS as an augmentation strategy to psychotherapy in depression, measuring its neural, cognitive, and clinical effects. On the primary outcome measure (observer-rated depressive symptoms) active tDCS did not show a significant improvement over sham stimulation, although the difference was in the hypothesised direction. However, baseline DLPFC activation during the n-back strongly predicted clinical outcome, with this association specific to the active tDCS condition. Thus, baseline DLPFC activation might serve as a putative ‘biomarker’ for clinical response to tDCS. In the general discussion, these experimental findings are discussed in the context of contemporary theories of depression. This thesis adds new insights into the possible mechanisms of tDCS as a treatment for depression. It also demonstrates the added value of neuroimaging to psychiatry clinical trials, highlighting a potential role for predicting treatment outcome.
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Plakke, Anderson Bethany Joy. "Auditory working memory: contributions of lateral prefrontal cortex and acetylcholine in non-human primates". Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/1060.
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Traditionally, working memory and its neural underpinnings have been studied in the visual domain. A rich and diverse amount of research has investigated the lateral prefrontal cortex (lPFC) as a primary area for visual working memory, while another line of research has found the neurotransmitter acetylcholine (ACh) to be involved. This dissertation used auditory cues and found similar patterns of activity for processing auditory working memory information within a task compared to visual working memory processes. The first two experimental chapters demonstrated that the cholinergic system is involved in auditory working memory in a comparable fashion to its role in visual working memory. In chapter 2, blocking ACh impaired performance on an auditory working memory task in a dose dependent manner. Chapter 3 investigated the specificity of the effect of blocking ACh by administering an ACh agonist (physostigmine) at the same time as an ACh antagonist (scopolamine). When both drugs were administered together performance on the delayed matching-to-sample task (DMTS) task improved compared to performance on scopolamine alone. These results support the hypothesis that ACh is involved in auditory working memory.
Chapter 4 investigated the neural correlates of auditory working memory in area 46 and found that this region of the lPFC contains neurons that are responsive to auditory working memory components in a very similar way to how it this region encodes information during visual working memory tasks. Neurons in the lPFC are responsive to visual or auditory cues, the delay portion of tasks, the wait time (i.e. decision making period), response, and reward times. This type of coding provides support for the theories that position the lPFC as a key player in recognition and working memory regardless of modality.
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Miléa, Dan. "Le lobe frontal dans le contrôle de la motricité oculaire". Paris 6, 2003. http://www.theses.fr/2003PA066225.
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Brooks, Samantha J., Jonathan Cedernaes i Helgi B. Schiöth. "Increased prefrontal and parahippocampal activation with reduced dorsolateral prefrontal and insular cortex activation to food images in obesity : a meta-analysis of fMRI studies". Uppsala universitet, Funktionell farmakologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-199757.
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BACKGROUND AND OBJECTIVES: Obesity is emerging as the most significant health concern of the twenty-first century. A wealth of neuroimaging data suggest that weight gain might be related to aberrant brain function, particularly in prefrontal cortical regions modulating mesolimbic addictive responses to food. Nevertheless, food addiction is currently a model hotly debated. Here, we conduct a meta-analysis of neuroimaging data, examining the most common functional differences between normal-weight and obese participants in response to food stimuli. DATA SOURCE: We conducted a search using several journal databases and adhered to the 'Preferred Reporting Items for Systematic Reviews and Meta-analyses' (PRISMA) method. To this aim, 10 studies were found with a total of 126 obese participants, 129 healthy controls, equaling 184 foci (146 increased, 38 decreased activation) using the Activation Likelihood Estimation (ALE) technique. Out of the 10 studies, 7 investigated neural responses to food versus non-food images. RESULTS: In response to food images, obese in comparison to healthy weight subjects had increased activation in the left dorsomedial prefrontal cortex, right parahippocampal gyrus, right precentral gyrus and right anterior cingulate cortex, and reduced activation in the left dorsolateral prefrontal cortex and left insular cortex. CONCLUSIONS: Prefrontal cortex areas linked to cognitive evaluation processes, such as evaluation of rewarding stimuli, as well as explicit memory regions, appear most consistently activated in response to images of food in those who are obese. Conversely, a reduced activation in brain regions associated with cognitive control and interoceptive awareness of sensations in the body might indicate a weakened control system, combined with hypo-sensitivity to satiety and discomfort signals after eating in those who are prone to overeat.
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Hawco, Colin Shaun. "The role of the dorsolateral prefrontal cortex in self-initiating elaborative episodic encoding: evidence from fMRI and TMS". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114200.
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Several clinical populations (e.g. Schizophrenia, Alzheimer's disease, frontal lobe damage, and healthy aging with memory decline) display memory deficits which may be related to a failure to engage efficient memory encoding strategies. However, these groups often show improved memory performance when cued towards the use of efficient encoding strategies, suggesting the deficits are related to self-initiating elaborative encoding processes. At present, little is know about the neural correlates of self-initiating elaborative encoding strategies in episodic memory. The purpose of this thesis was to better understand the process of initiating elaborative encoding strategies. We hypothesized that the left dorsolateral prefrontal cortex (DLPFC) was involved in self-initiating elaborative encoding strategies. Experiment 1 was an fMRI study in which we presented conditions in which participants were either cued to use an efficient encoding strategy (semantic analysis) or were not cued to do so (a self-initiated condition), while presenting stimuli with variable semantic relatedness. We observed activity in the left DLPFC and bilateral supramarginal gyrus in response to semantic relatedness in the non-semantic (self-initiated) encoding condition. In experiment 2, we attempted to confirm the role of the left DLPFC in self-initiating elaborative encoding using transcranial magnetic stimulation (TMS), a method in which we can transiently disrupt neural activity in a limited cortical area. We performed stimulation of the left DLPFC and a control site (the vertex) during a memory encoding task. We observed a significant correlation in a subsequent cued recall task (a measure of encoding success) between the effects of TMS during encoding and participant's use of memory strategies during encoding only in the condition in which self-initiated elaborative encoding was beneficial to memory performance. This suggests a causative role for the DLPFC in self-initiating elaborative encoding. Experiment 3 was a concurrent TMS-fMRI study. Participants performed an encoding task (similar to the self-initiated condition in experiment 1) while we measured brain activity using fMRI. TMS stimulation was presented for 300ms on ¾ of trials. The onset of stimulation was varied, starting at 200ms, 600ms, or 1000ms after stimulus onset. We observed time-specific changes in neural activity in response to TMS stimulation, suggesting that concurrent TMS-fMRI can be used to measure time-varying interactions between the DLPFC and distal brain regions These three experiment provide evidence o f the role of the left DLPFC in self-initiating elaborative encoding strategies, and the utility of TMS and fMRI (separately or combined) as research techniques to address these techniques. These studies also demonstrate the utility of our selected paradigms to directly address the issue of self-initiating elaborative encoding (rather than correlating activity to specific encoding strategies).Plusieurs populations cliniques (ex. schizophrénie, maladie d'Alzheimer, lésions du lobe frontal, vieillissement normal avec déclin de mémoire) démontrent des déficits de mémoire qui peuvent être reliés à une incapacité d'initier des stratégies efficaces d'encodage de mémoire. Cependant, ces groupes démontrent souvent une amélioration de leur performance lorsqu'on les aide à choisir une stratégie d'encodage efficace, suggérant que les déficits seraient reliés à l'utilisation spontanée de stratégies d'encodage élaborées. A ce jour, nous savons très peu de choses à propos des corrélats neuronaux de l'utilisation spontanée de stratégies d'encodage élaborées. Le but de cette thèse est de mieux comprendre les processus de l'initiation de stratégies d'encodage élaborées. Nous émettons l'hypothèse que le cortex préfrontal dorsolatéral (DLPFC) est impliqué dans l'utilisation spontanée de stratégies d'encodage élaborées. L'expérience 1 consiste en une étude d'IRMf dans laquelle nous avons présenté des conditions dans lesquelles les participants étaient guidés à utiliser une stratégie d'encodage efficace (analyse sémantique) ou non guidés d'utiliser cette stratégie (condition auto-initiée), en présentant des stimuli de relations sémantiques variées. Nous avons observé une activité dans le DLPFC gauche et le gyrus supramarginal bilatéral en réponse à la relation sémantique dans la condition d'encodage non-sémantique (auto-initiée). Dans l'expérience 2, nous avons tenté de confirmer le rôle du DLPFC gauche dans l'utilisation spontanée de stratégies d'encodage élaborées en utilisant la stimulation magnétique transcrânienne (SMT), une méthode avec laquelle nous pouvons perturber l'activité neuronale de façon transitoire dans une aire corticale limitée. Nous avons performé une stimulation du DLPFC gauche et d'un site contrôle (le vertex) durant une tâche d'encodage de mémoire. Nous avons observé une corrélation significative dans la tâche de reconnaissance subséquente (une mesure de la réussite de l'encodage) entre les effets de la SMT durant l'encodage et l'utilisation de stratégies de mémoire du participant pendant l'encodage seulement dans la condition où l'utilisation spontanée de stratégies d'encodage élaborées était bénéfique pour la performance de mémoire. Ceci suggère un rôle causal du DLPFC dans l'utilisation spontanée de stratégies d'encodage élaborées. L'expérience 3 était une étude simultanée de SMT-IRMf. Les participants devaient faire une tâche d'encodage (similaire à la condition auto-initiée de l'expérience 1) pendant que l'on mesurait l'activité du cerveau avec l'IRMf. Une SMT était faite pendant 300ms sur les trois-quarts des essais. Le début de la stimulation était varié, commençant à 200ms, 600ms ou 1000ms après le début du stimulus. Nous avons observé des changements spécifiques au temps dans l'activité neuronale en réponse à la stimulation SMT, indiquant que l'utilisation simultanée de SMT-IRMf peut être utilisée pour mesurer l'interaction en fonction du temps entre le DLPFC et les régions distales du cerveau. Ces trois expériences apportent des évidences du rôle du DLPFC gauche dans l'utilisation spontanée de stratégies d'encodage élaborées et l'utilité de la SMT et de l'IRMf (séparément ou combinées) comme techniques de recherche pour étudier ces processus. Ces études démontrent aussi l'utilité de nos paradigmes pour étudier directement l'utilisation spontanée de stratégies d'encodage élaborées (au lieu de corréler l'activité à des stratégies d'encodage spécifique).
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Bunch, Katie, i 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
Full Text
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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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Rosero, Pahi Mario Alberto [Verfasser], i Herta [Akademischer Betreuer] Flor. "The role of the hippocampus and dorsolateral prefrontal cortex in implicit learning of contextual information / Mario Alberto Rosero Pahi ; Betreuer: Herta Flor". Heidelberg : Universitätsbibliothek Heidelberg, 2019. http://d-nb.info/1187342149/34.
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Heinze-Köhler, Katharina [Verfasser], i Markus [Akademischer Betreuer] Heinrichs. "The role of left and right mid-dorsolateral prefrontal cortexin planning: a brain stimulation approach = Die Bedeutung des linken und rechten mittleren dorsolateralen präfrontalen Cortex für Planungsprozesse: Untersuchungen mit Gehirnstimulationsverfahren". Freiburg : Universität, 2014. http://d-nb.info/1123481679/34.
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Araujo, Ricardo Rafael de. "Modulação da orientação temporal e espacial da atenção por meio de estimulação transcraniana por corrente contínua". Universidade Presbiteriana Mackenzie, 2011. http://tede.mackenzie.br/jspui/handle/tede/1548.
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Previous issue date: 2011-02-25Fundo Mackenzie de Pesquisa
Attention can be understood as a set of neural mechanisms that enhance the processing of relevant information, thoughts or actions while ignoring irrelevant or scattered stimuli. Thus, attention allows the organism to interact in a proper way with the environment. Among the brain structures associated with the control of attention, the Dorsolateral Prefrontal Cortex (DLPFC) has a remarkable role in current literature as a region associated with behavioral control. Transcranial Direct Current Stimulation (TDCS) is based on the application of a low intensity electric current through electrodes placed in the scalp, aimed at modulating the activity of different brain areas. This technique has been used to study brain functions. This study has the objective of verifying how attention can be modulated through the application of bilateral tDCS on DLPFC using measures of reaction time (RT) in tasks of temporal and spatial orientation. To accomplish that, two experiments were planned and executed. In the first one, which focused on the voluntary orienting of spatial attention, each participant had to orient attention to the position indicated by an arrow; in the second, on voluntary orienting of temporal attention, each participant had to orient attention to the most frequent time interval of visual targets. In both cases, participants had to respond as fast as possible when the target was displayed by pressing a joystick key. RTs were registered. The sample was composed of 18 undergraduate students, age range 19-25 years old (12 for the first experiment and 6 more for the second). In each experiment, subjects were submitted to three tDCS conditions (anodal, cathodal and sham) on the DLPFC during the undertaking of tests. Analyses of variance were made, in order to compare the involved factors. For the experiment of spatial orientation, the anodal condition produced lower RTs, when compared to sham. For the temporal orienting experiment it was observed that, in the anodal modulation, RTs were increased for the less frequent interval (500 ms), indicating that the anodal tDCS can have influenced in a more effective way attentional orienting to the most frequent intervals. Therefore it is possible to postulate the existence of a facilitating effect of anodal tDCS in the modulation of DLPFC, which generated an impact in attentional orienting, lowering RTs to the valid condition (spatial) when compared to sham tDCS.
A atenção pode ser compreendida como um conjunto de mecanismos neurais que facilitam o processamento de informações, pensamentos ou ações relevantes enquanto ignoram outros irrelevantes ou dispersos. Deste modo a atenção permite que o organismo interaja de maneira adequada com o ambiente. Dentre as estruturas cerebrais associados ao controle da atenção, o Córtex Prefrontal Dorsolateral (CPFDL) tem tomado papel de destaque na literatura atual como uma região associada ao controle comportamental. A Estimulação Transcraniana por Corrente Contínua (ETCC) se baseia na aplicação de corrente elétrica de baixa intensidade por meio de eletrodos posicionados no escalpe com o objetivo de modular a atividade de diferentes regiões cerebrais e tem sido utilizada como modo de estudo da função cerebral. Esse trabalho tem como objetivo verificar como a atenção pode ser modulada a partir da aplicação ETCC bilateral sobre o CPFDL, utilizando medidas de tempo de reação (TR) em tarefas de orientação temporal e espacial. Para Tanto foram planejados e executados dois experimentos. No primeiro experimento, relativo à orientação voluntária da atenção espacial, cada participante deveria orientar a atenção para a posição do espaço indicada por uma seta. O segundo experimento, relativo à orientação voluntária da atenção temporal, cada participante deveria orientar a atenção para o intervalo temporal de maior recorrência. Em ambos os casos os participantes deveriam responder o mais rapidamente possível ao aparecimento do alvo pressionado uma tecla de joystick registrando-se assim o seu TR. Participaram desse estudo 18 alunos de graduação (12 no primeiro desenho experimental, e para o segundo desenho experimental foram adicionados mais 6 colaboradores) na faixa etária de 19 à 25 anos. A cada sessão os colaboradores deveriam responder a ambos os experimento enquanto eram submetidos a diferentes polaridades de ETCC (anódica, catódica e placebo) sobre o CPFDL. Foram feitas análises de variância para comparar os fatores estudados. No experimento de orientação espacial a condição anódica produziu TR menores em comparação à condição placebo. No caso do experimento de orientação temporal foi observado que na modulação anódica houve um aumento nos TR no intervalo menos recorrente de 500 ms, indicando que a ETCC anódica pode ter influenciado de modo mais efetivo o direcionamento atencional aos intervalos mais freqüentes. Neste sentido é possível sugerir a existência de um efeito facilitatório da ETCC anódica na moducalçao do CPFDL, o que gerou um impacto no direcionamento atencional, diminuindo os TR para a condição valida (orientação espacial) quando comparados a ETCC placebo.
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Mell, Thomas, Isabell Wartenburger, Alexander Marschner, Arno Villringer, Friedel M. Reischies i Hauke R. Heekeren. "Altered function of ventral striatum during reward-based decision making in old age". Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4523/.
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Normal aging is associated with a decline in different cognitive domains and local structural atrophy as well as decreases in dopamine concentration and receptor density. To date, it is largely unknown how these reductions in dopaminergic neurotransmission affect human brain regions responsible for reward-based decision making in older adults. Using a learning criterion in a probabilistic object reversal task, we found a learning stage by age interaction in the dorsolateral prefrontal cortex (dIPFC) during decision making. While young adults recruited the dlPFC in an early stage of learning reward associations, older adults recruited the dlPFC when reward associations had already been learned. Furthermore, we found a reduced change in ventral striatal BOLD signal in older as compared to younger adults in response to high probability rewards. Our data are in line with behavioral evidence that older adults show altered stimulus-reward learning and support the view of an altered fronto-striatal interaction during reward-based decision making in old age, which contributes to prolonged learning of reward associations.
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Lindberg, Markus. "Neural correlates of lucid dreaming and comparisons with phenomenological aspects". Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-10236.
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Research on the neural correlates of lucid dreaming has recently gained more underlying data. By exploring seven studies that investigated the neural basis of lucid dreaming, this essay sought to examine which neural correlates are associated with lucid dreaming and how proposed neural correlates relate to phenomenological aspects. Dorsolateral prefrontal cortex (DLPFC) was judged as the region most associated with lucid dreaming, in support of a DLPFC hypothesis. Support for reactivation of DLPFC in lucid dreaming consisted of data from electroencephalography, functional magnetic resonance imaging, and transcranial direct current stimulation. Phenomenological aspects associated with this region involved meta-awareness, working-memory, decision-making, and conscious perception. Other regions of interest were parietal areas, frontal areas, and precuneus. Data was not always compatible, implying need for further research. The possibility of further research was judged as promising, based on a recent study inducing lucid dreaming in a significant percent of its test subjects.
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Gold, Brian T. "The human dorsolateral prefrontal cortex a critical neural module in the transformation of information within working memory : evidence from fMRI of deductive reasoning at 4 T /". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0027/NQ39266.pdf.
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Braasch, Marie Y. "The Effects of Age and Working Memory Ability on Frontal Lobe Oxygenation During Working Memory Tasks". Ohio University Honors Tutorial College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1275937579.
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Wohlwend, Martin. "Investigation of an Exercise-Induced State of Hypofrontality : And its Potential Association with Central Fatigue". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for nevromedisin, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16840.
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The reticular-activating hypofrontality model of acute exercise (RAH) predicts exercise-induced hypoactivity in frontal cortex which mediates executive function. Connors Continuous Performance Test (CCPT) was used to investigate changes in executive function during- and post treadmill running in healthy volunteers (n=30, 15 male). In a randomized order, subjects performed the CCPT at rest, during low- (LI; 63% maximal heart rate; MHR) and moderate intensity (MI; 75% MHR). Separately, subjects then performed isocalorifically matched exercise bouts of LI, MI and high intensity interval training (HIT) consisting of 4x4 min with 90% MHR and 3 min recovery at 60-70% MHR. Repeated measures ANOVAs revealed main effects of exercise intensity for reaction time RT during- (p≤0.001) and post exercise (p≤0.0001). Subsequent analyses showed an overall increase of RT during exercise compared to rest (p≤0.005). RT decreased significantly from rest to post exercise levels in an exercise intensity dependent, linear fashion (p≤0.0001). Commission errors showed a non significant linear trend to increase both during (p=0.057), and post exercise (p=0.052) as a function of intensity. In a follow up study, we sought to relate observed exercise effects to frontal cortex activity through the use of transcranial direct current stimulation (tDCS) (n=4) and transcranial magnetic stimulation (TMS) over the dorsolateral prefrontal cortex (DLPFC). Prior to TMS stimulation cortical excitability was estimated post running through motor-evoked potentials (MEP) elicited from the primary motor cortex (M1) induced by single burst TMS and measured in the first dorsal interosseous (FDI) muscle using electromyography. At rest, inhibitory cathodal tDCS with left DLPFC cathode and right supraorbital anode led to improved reaction time and increased amount of commission errors, whereas anodal stimulatory tDCS in the immediate post exercise period was unable to recover the post exercise effect. Continuous theta burst stimulation over the left DLPFC post running further impaired inhibitory control and facilitated reaction time. Different findings during- and after- exercise suggests that potential contributing mechanisms such as computational and metabolic factors may be differentially active during these respective conditions. Furthermore, the fact that an inhibitory TMS protocol pronounced the post running effects even more and that we were able to mimic the reported RAH effects at rest with inhibitory frontal tDCS, but observed different patterns during exercise, suggests that the latter state cannot be fully explained by reducing activity in the left frontal cortex alone. Failure to modify the after exercise effect with stimulatory tDCS also supports an interplay of different factors and might emphasize the strong, robust effects of exercise that cannot simply be attenuated by current application. Increases in MEP post running for 35min paired with the observed performance decrements imply an excited state of M1 and might serve as an explanatory cross-link to central fatigue suggesting that a hypofrontal state might enhance the motor cortical drive to activate muscles.
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Psomiades, Marion. "Altérations cérébrales structurales et fonctionnelles spécifiques des hallucinations auditives résistantes chez les patients atteints de schizophrénie". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1218.
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Les hallucinations auditives (HA) sont présentes chez 70% à 80% des patients atteints de schizophrénie et sont résistantes aux traitements pharmacologiques dans environs 25% cas. Ces symptômes induisent une détresse importante chez les sujets et grèvent le pronostic. Dans ce travail, nous avons mis en avant des altérations cérébrales spécifiques aux HA chez des patients atteints de schizophrénie. Dans une première étude, en utilisant la méthode de DTI, nous avons montré que les patients atteints de schizophrénie avec HA ont une intégrité du faisceau arqué, supérieure à celle mesurée chez des patients atteints de schizophrénie sans HA. Dans une seconde étude, en utilisant la méthode de SRM, nous avons montré une augmentation de NAA, reflet du métabolisme neuronal, dans le cortex préfrontal dorsolatéral de l'hémisphère droit chez les patients atteints de schizophrénie avec HA comparé au CPFDL gauche et à des patients atteints de schizophrénie sans HA. Dans ces deux études, le taux de NAA du CPFDL droit et l'intégrité du faisceau arqué ont été associés à la sévérité des HA présentes chez les patients. Dans notre dernière étude, nous avons montré une association entre le taux de BDNF périphérique, marqueur de la plasticité neuronale, et le taux de NAA mesuré dans le CPFDL droit, chez les patients atteints de schizophrénie résistante. Ces résultats montrent qu'il existe une pathophysiologie spécifique des HA chez les patients atteints de schizophrénie et mettent en avant l'importance de stratifier les patients sur la base de leurs symptômes prédominants dans les futures études pathophysiologiques de la schizophrénieAuditory hallucinations (AH) are present in 70% to 80% of patients with schizophrenia and are resistant to pharmacological treatments in 25% of cases. These symptoms induce significant distress in patients and predict a bad prognosis. In this work we have highlighted cerebral alterations specific to AH in patients suffer from schizophrenia. In a first study, using DTI method, we showed that patients with schizophrenia and AH have an arcuate fasciculus integrity, reflected by the measurement of fractional anisotropy (FA) greater than the one measured in patients with schizophrenia without AH. In a second study, using MRS method, we showed an increase of NAA level measured in the dorsolateral prefrontal cortex (DLPFC) in the right hemisphere in patients with schizophrenia and AH compared to the DLPFC in the left hemisphere and compared to patients with schizophrenia and without AH. Moreover, in these two studies we showed an association between AH severity and the arcuate fasciculus integrity in the left hemisphere and an association between AH severity and NAA levels in the right DLPFC. Finally, in our last study, we quantified BDNF levels using ELISA method and showed an association between peripheral BDNF level, a marker of neuronal plasticity, and NAA levels in the right DLPFC, marker of neuronal metabolism, in patients with treatment-resistant schizophrenia. These results show that there is a specific pathophysiology of AH in patients with schizophrenia and highlight the importance of stratifying patients on the basis of their predominant symptoms in future pathophysiological studies of schizophrenia
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Caetano, Sheila Cavalcante. ""Avaliação volumétrica e neuroquímica do córtex pré-frontal dorsolateral esquerdo de pacientes pediátricos com transtorno depressivo maior: um estudo utilizando espectroscopia por ressonância magnética de próton"". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/5/5142/tde-18042006-144855/.
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A Ressonância Magnética e a Espectroscopia por Ressonância Magnética de Hidrogênio têm sido empregadas em estudos anatômicos e neuroquímicos do Transtorno Depressivo Maior (TDM). Dezenove crianças com TDM e 24 controles saudáveis foram avaliados em um magneto de 1,5 Tesla (Philips Intera 8.1.1.). Em comparação aos controles saudáveis, crianças com TDM apresentaram: menores volumes de hipocampo esquerdo; e no voxel único em CPFDL esquerdo: menores níveis dos compostos de colina, e maiores níveis de mio-inositol em CPFDL esquerdo. Menores níveis dos compostos de colina podem refletir uma diminuição da renovação de membranas. Maiores níveis de mio-inositol podem representar uma alteração no sistema de segundos mensageiros intracelularesMagnetic resonance imaging and proton magnetic resonance spectroscopy have been applied to anatomical and neurochemical studies of Major Depressive Disorder (MDD). Nineteen children with MDD and 24 healthy controls were evaluated on a 1.5 Tesla (Philips Intera 8.1.1.) MRI. Compared to healthy controls, children with MDD presented: smaller left hippocampal volumes; and lower levels of choline-containing-compounds and higher myo-inositol levels in the left DLPFC. Lower levels of choline-containing-compounds in pediatric patients with MDD may reflect lower cell membrane turn-over. Higher myo-inositol levels in MDD may represent a disturbed secondary messengers system
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Oliveira, Rogério Adas Ayres de. "O efeito da estimulação magnética transcraniana repetitiva do córtex pré-frontal dorsolateral esquerdo na dor central decorrente de acidente vascular cerebral". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5138/tde-10032017-085905/.
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Introdução e objetivos: A dor central pós-acidente vascular cerebral (DCAVC) é causada pela lesão vascular de estruturas somatossensitivas encefálicas e comumente refratária aos tratamentos farmacológicos disponíveis atualmente. A estimulação magnética transcraniana repetitiva (EMTr) do córtex pré-frontal dorsolateral (CPFDL) pode alterar o limiar da dor térmica de indivíduos saudáveis e exercer efeito analgésico na dor aguda pós-operatória e em doentes com síndrome fibromiálgica. No entanto, seu efeito na dor neuropática e na DCAVC, em particular, ainda não foi avaliado. O objetivo do presente estudo, delineado de modo prospectivo, duplamente encoberto e controlado com placebo foi o de se avaliar o efeito analgésico da EMTr do CPFDL em doentes com DCAVC. Casuística e métodos: 21 doentes foram incluídos aleatoriamente em dois grupos, os do grupo ativo (EMTr-A) e os do grupo placebo (EMTr-S) e tratados, respectivamente, com dez sessões diárias de EMTr verdadeira (EMTr-A) ou sham (EMTr-S) do CFPDL esquerdo (10 Hz, 1250 pulsos/dia). A Escala Visual Analógica (EVA), o Questionário de Dor Neuropática e o Questionário de Dor McGill foram utilizados para avaliar-se a DCAVC. A depressão, a ansiedade e a qualidade de vida foram avaliadas, respectivamente, com a Escala de Hamilton para Depressão, Escala de Hamilton para Ansiedade e o Short Form Health Survey com 36 itens. As avaliações foram realizadas antes do início do estudo, durante a fase de estimulação e uma, duas e quatro semanas após a aplicação da última sessão de EMTr-A ou EMTr-S. O desfecho principal foi a alteração da intensidade da dor medida no último dia de estimulação em relação à intensidade do seu valor basal de acordo com a EVA. Foi programada uma análise interina dos resultados ao término da avaliação da metade dos doentes programados de acordo com o protocolo de tratamento. Resultados: Os escores médios basais da EVA foram 6,86 (+/- 1,79) e 6,8 (+/- 2,20) para os doentes dos grupos EMTr-A e EMTr-S, respectivamente; a variação média da EVA após o décimo dia de estimulação foi de - 0,07 (+/- 0,24) para os doentes do grupo EMTr-A e 0,1 (+/- 0,7) para o os do grupo EMTr-S. O tamanho do efeito do tratamento foi 0,02 (d de Cohen= 0,04). O estudo foi encerrado devido à significativa falta de eficácia da EMTr-A. Conclusão: A EMTr do CPFDL esquerdo não proporcionou efeito analgésico em doentes com DCAVCIntroduction and objectives: Central post-stroke pain (CPSP) is caused by an encephalic vascular lesion of the somatosensory pathways and is refractory to current pharmacological treatments. Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) can change thermal pain threshold and cause analgesia in healthy subjects and also in acute post operatory pain as well as in fibromyalgia patients. However, its effect on neuropathic pain and particularly in CPSP patients has not been assessed yet. The aim of this prospective, double blind, shamcontrolled study was to evaluate the analgesic effect of left DLPFC rTMS in CPSP patients. Patients and methods: 21 patients were randomly included in two groups: the active (A-rTMS) group and the placebo (S-rTMS) group and were treated, respectively, with 10 daily sessions of real rTMS (A-rTMS) or sham (S-rTMS) of the left DLPFC (10 Hz, 1250 pulses/day). Visual Analogue Scale (VAS), Neuropathic Pain Questionnaire and McGill Pain Questionnaire were used to evaluate the CPSP. The depression, the anxiety and the quality of life were evaluated, respectively, with the Hamilton Scale for Depression, Hamilton Scale for anxiety and the Short Form Health Survey with 36 items. Outcomes were assessed at the baseline, during the stimulation phase and at one, two and four weeks after the last session of ArTMS or S-rTMS. The main outcome was pain intensity change measured with the VAS at the last session of A-rTMS or S-rTMS, compared to the baseline. Interim analysis was scheduled when the first half of the patients have completed the study. Results: The average baseline scores of VAS were 6.86 (+/- 1.79) and 6.8 (+/- 2.20), respectively, for the groups A-rTMS and S-rTMS. The average variation of VAS after the 10th stimulation session was - 0.07 (+/- 0.24) for A-rTMS and 0.1 (+/- 0.7) to the S-rTMS group and the effect size of A-EMTr was 0.02 (Cohen\'s d= 0.04). The study was discontinued due to the significant lack of efficacy of the A-rTMS. Conclusion: Repetitive transcranial magnetic stimulation of the left DLPFC did not provide an analgesic effect in CPSP patients
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Nery, Fabiano Gonçalves. "Estudo do córtex pré-frontal dorsolateral esquerdo de pacientes portadores de transtorno afetivo bipolar em comorbidade com alcoolismo através do uso de espectroscopia por ressonância magnética de hidrogênio". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/5/5142/tde-31082009-153516/.
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Cerca de 50% dos pacientes portadores de transtorno afetivo bipolar (TAB) apresentam comorbidade com abuso ou dependência de álcool. A presença de alcoolismo nos pacientes com TAB está associada a manifestações clínicas mais graves e a uma pior resposta ao tratamento do transtorno de humor. Entretanto, as anormalidades neurobiológicas subjacentes à co-ocorrência de TAB e alcoolismo são desconhecidas. Neste estudo, nosso objetivo foi o de comparar o perfil neuroquímico do córtex pré-frontal dorsolateral esquerdo de pacientes portadores de TAB e diagnóstico prévio de alcoolismo ao de pacientes portadores de TAB não-alcoolistas e ao de indivíduos saudáveis, usando espectroscopia por ressonância magnética de hidrogênio. Para isso, obtivemos uma aquisição de espectroscopia de hidrogênio de voxel único e tempo de eco curto em campo magnético de 1,5 Tesla do córtex préfrontal dorsolateral esquerdo em 23 pacientes bipolares alcoolistas, 27 pacientes bipolares não-alcoolistas e 57 indivíduos saudáveis. Níveis absolutos de N-acetilaspartato (NAA), compostos de colina, creatina mais fosfocreatina, mio-inositol, glutamato mais glutamina (Glu+Gln), e glutamato foram determinados e comparados entre os três grupos. Pacientes bipolares alcoolistas apresentaram níveis menores de Glu+Gln (p = 0,06) e de glutamato (p = 0,03) do que pacientes bipolares nãoalcoolistas. Pacientes bipolares alcoolistas apresentaram níveis menores de NAA do que controles saudáveis (p = 0,06). Esses achados sugerem que anormalidades do sistema glutamatérgico, e, possivelmente, da integridade neuronal, estão presentes no córtex pré-frontal dorsolateral esquerdo de pacientes portadores de TAB em comorbidade com alcoolismo. Tais anormalidades podem caracterizar processos fisiopatológicos que seriam específicos da comorbidade entre TAB e alcoolismo.About 50% of bipolar disorder (BD) patients present comorbidity with alcohol abuse or dependence. The presence of alcoholism in BD is associated with worse clínical manifestations and refractoriness to treatment of the mood disorder. Nevertheless, the neurochemical underpinnings that underlie the co-occurrence of bipolar disorder and alcoholism are unknown. In this study, we sought to compare the neurochemical profile of the left dorsolateral pre-frontal cortex of BD patients with a prior diagnosis of alcoholism to non-alcoholic BD patients and healthy controls (HC), using proton (1H) magnetic resonance spectroscopy. We obtained a short-TE, single-voxel 1H spectroscopy acquisition at 1.5 Tesla from the left dorsolateral pré-frontal córtex (DLFPC) of 23 alcoholic BD patients, 27 non-alcoholic BD patients and 57 HC. Absolute levels of N-acetyl-aspartate (NAA), choline-containing compounds, phosphocreatine plus creatine, myo-inositol, glutamato plus glutamina (Glu+Gln) and glutamato were determined and compared among the three groups. Alcoholic BD patients showed lower Glu+Gln (p = 0.06) and glutamate levels (p = 0.03) than non-alcoholic BD patients. Alcoholic BD patients tended to have lower NAA levels than HC (p = 0.06). These findings suggest that glutamatergic abnormalities, and possibly, neuronal integrity abnormalities, are present in the left DLPFC of BD patients with comorbid alcoholism. Such abnormalities may characterize pathophysiological processes that are specific for the comorbidity between BD and alcoholism.
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Rosa, Carlos Eduardo. "Disfunção neuroquímica na depressão periparto". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/17/17138/tde-27072016-151947/.
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A depressão periparto (PPD) é subtipo altamente prevalente e subdiagnosticado do transtorno depressivo maior (MDD), e causa um importante sofrimento para a mulher, sua família e seu filho. Uma interação complexa entre hormônios, neurotransmissores e fatores genéticos e ambientais pode estar envolvida na etiologia da PPD. Contudo, estudos de neuroimagem na PPD ainda são escassos, particularmente os que identificam alterações neuroquímicas. Sabe-se que a região do córtex pré frontal dorsolateral (dlPFC) está relacionada à funções executivas no circuito pré frontal, e juntamente com o giro do cíngulo anterior (ACG) faz parte das vias neuronais envolvidas no processamento emocional, desde a geração, regulação e reavaliação do estado afetivo. Existem evidências de que ambas as áreas estejam disfuncionais na MDD. A avaliação neuroquímica obtida pela espectroscopia de próton por ressonância magnética (MRS) permite inferir o metabolismo, a neurotransmissão e a viabilidade do tecido neuronal de interesse destas áreas fronto-límbicas. Objetivo: comparar puérperas com depressão periparto (grupo PPD) com puérperas saudáveis (grupo HP) quanto à avaliação neuroquímica no dlPFC esquerdo e no ACG bilateral. Métodos: 36 puérperas do grupo PPD e 25 puérperas do grupo HP foram submetidas à duas entrevistas psiquiátricas estruturadas e à aplicação de questionários e escalas psicométricas, sendo a segunda avaliação realizada seccionalmente à MRS. A MRS foi adquirida pro MRI com campo de 3 Tesla, estando o volume de interesse (VOI) posicionado no dlPFC esquerdo e no ACG bilateral e processada pelo software LCModel. Os resultados neuroquímicos expressos em valores absolutos e normalizados pela creatina (razão metabólito/creatina) foram analisados por ANCOVA, incluindo a idade, o tempo de puerpério e o tipo de contraceptivo, enquanto covariáveis. Resultados: No dlPFC, o grupo PPD apresentou menores valores de Glu/Cr (-0,17; p=0,05), Glx (-0,95 mM; p=0,04), Glx/Cr (-0,22; p=0,03), NAA (-0,60 mM; p<0,01), e NAA/Cr (-0,13; p=0,02) em relação ao grupo HP. No ACG, o uso de hormônios contraceptivos somente com progestágenos resultou em um aumento dos valores de Glu (2,18 mM; p=0,03), Glx (1,84 mM; p=0,03), e redução de Cho/Cr (-0,08; p=0,03) quando comparados ao grupo que não utilizou somente progestágenos, independentemente dos grupos HP e PPD. Conclusão: Os níveis reduzidos de Glu e NAA no grupo PPD estão relacionados, respectivamente, à disfunção metabólica glutamatérgica e neuroglial no dlPFC, o que pode explicar sintomas cognitivos também relacionados à PPD, tal como já verificado no MDD. O uso de hormônios contraceptivos com progestágenos isoladamente interferiu com a neuroquímica do ACG, mas não se relacionou com a PPD. Embora o aumento do glutamato possa sugerir uma hiperfuncionalidade do ACG, e a redução da Cho/Cr representar diminuição de \"turnover\" da membrana lipídica ou da transdução sináptica, seu significado clínico e fisiopatológico ainda é incerto. Estes resultados contribuem com a compreensão dos substratos neuroquímicos de PPDPeripartum depression (PPD) is a highly prevalent subtype of major depressive disorder (MDD) related to a significant loss for mother, family and baby. An Interaction between hormones, genetic, and environmental factors must be involved in its etiology. However, neuroimaging studies on PPD are still rare, particularly those that identify neurochemical changes. However, neuroimaging studies in PPD are still rare, particularly those that identify neurochemical changes. It is known that the region of the dorsolateral prefrontal cortex (dlPFC) is related to executive functions in the prefrontal circuit, and together with the anterior cingulate gyrus (ACG) is part of the neural pathways involved in emotional processing, including the generation, regulation, and reappraisal of affective state. And, there is evidence that both areas are dysfunctional in MDD. The neurochemical evaluation obtained by spectroscopy of proton magnetic resonance (MRS) allows to infer metabolism, neurotransmission and the viability of the neuronal tissue of interest these frontal-limbic areas. Objective: Compare postpartum women with peripartum depression (PPD group) with healthy postpartum women (HP group) regarding the neurochemical evaluation in the left dlPFC and bilateral ACG. Methods: 36 postpartum women of PPD group and 25 postpartum women of the HP group were subjected to two structured psychiatric interviews and questionnaires and psychometric scales, with the second evaluation performed sectionally at MRS. The MRS was obtained by 3-T MRI system with the volume of interest (VOI) positioned on the left dlPFC and bilateral ACG and processed by LC Model software. The neurochemical results expressed in absolute values and normalized by creatine (reason metabolite/creatine) were analyzed using ANCOVA, including age, postpartum time, the type of contraceptive as covariates. Results: In the dlPFC, PPD group presented significantly lower values of Glu/Cr (-0.17; p=0.05), Glx (-0.95mM; p=0.04), Glx/Cr (-0.22; p=0.03), NAA (-0.60mM; p<0.01), and NAA/Cr (-0.13; p=0.02) than HP. In ACG, progestogens isolated contraceptive hormones use resulted in significantly increased Glu (2.18mM; p=0.03), Glx (1.84mM; p=0.03), and reduced Cho/Cr (-0.08; p=0.03), compared to women without use them, regardless of diagnostic groups. Conclusions: The reduced levels of Glu and NAA in the PPD group are related respectively to the glutamatergic and neuroglial metabolic dysfunction in the dlPFC, which may explain cognitive symptoms also related to PPD as already verified in MDD. Progestogens isolated contraceptive hormones use interfered with neurochemistry of ACG, but not associated with PPD. Although the increase of glutamate may suggest an overactive ACG, and lower Cho/Cr represent decrease of the lipid membrane turnover or synaptic transduction its clinical and pathophysiological significance remains uncertain. These results contribute to the understanding of the neurochemical substrates of PPD
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Junior, Claudinei Eduardo Biazoli. "Inferência do tempo de atividade neural a partir do efeito BOLD em ressonância magnética funcional". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5151/tde-20072011-170109/.
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A inferência do curso temporal da atividade neural a partir do efeito BOLD é um importante problema, ainda em aberto. A forma da curva BOLD não reflete diretamente as características temporais da atividade eletrofisiológica dos neurônios. Nessa tese, é introduzido o conceito de tempo de processamento neural (TPN) como um dos parâmetros do modelo biofísico da função de resposta hemodinâmica (HRF). O objetivo da introdução desse conceito é obter estimativas mais acuradas da duração da atividade neural a partir do efeito BOLD, que possui auto grau de nãolinearidade. Duas formas de estimar os parâmetros do modelo do efeito BOLD foram desenvolvidas. A validade e aplicabilidade do conceito de TPN e das rotinas de estimação foram avaliadas por simulações computacionais e análise de séries temporais experimentais. Os resultados das simulações e da aplicação foram comparados com medidas da forma da HRF. O experimento analisado consistiu em um paradigma de tomada de decisão na presença de distratores emocionais. Esperase que o TPN em áreas sensoriais primárias seja equivalente ao tempo de apresentação de estímulos. Por outro lado, o TPN em áreas relacionadas com a tomada de decisão deve ser menor que a duração dos estímulos. Além disso, o TPN deve depender da condição experimental em áreas relacionadas ao controle de distratores emocionais. Como predito, o valores estimados do TPN no giro fusiforme foram equivalentes à duração dos estímulos e o TPN no giro do cíngulo dorsal variou com a presença de distrator emocional. Observou-se ainda lateralidade do TPN no córtex pré-frontal dorsolateral. As medidas da forma da HRF obtidas por um método convencional não dectectaram as variações observadas no TPNThe extraction of information about neural activity dynamics related to the BOLD signal is a challenging task. The temporal evolution of the BOLD signal does not directly reflect the temporal characteristics of electrical activity of neurons. In this work, we introduce the concept of neural processing time (NPT) as a parameter of the biophysical model of the hemodynamic response function (HRF). Through this new concept we aim to infer more accurately the duration of neuronal response from the highly nonlinear BOLD effect. We describe two routines to estimate the parameters of the HRF model. The face validity and applicability of the concept of NPT and the estimation procedures are evaluated through simulations and analysis of experimental time series. The results of both simulation and application were compared with summary measures of HRF shape. We analysed an experiment based on a decision-making paradigm with simultaneous emotional distracters. We hypothesize that the NPT in primary sensory areas is approximately the stimulus presentation duration. On the other hand, the NPT in brain areas related to decisionmaking processes should be less than the stimulus duration. Moreover, in areas related to processing of an emotional distracter, the NPT should depend on the experimental condition. As predicted, the NPT in fusiform gyrus is close to the stimulus duration and the NPT in dorsal anterior cingulate gyrus depends on the presence of an emotional distracter. Interestingly, the estimated NPTs in the dorsolateral prefrontal cortex indicate functional laterality of this region. The analysis using standard measures of HRF did not detect the variations observed in our method (NPT)
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Kaufman-Simpkins, Liam. "Antisaccades: A Probe into the Dorsolateral Prefrontal Cortex in Alzheimer's Disease". Thesis, 2008. http://hdl.handle.net/1807/17185.
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The number of people living with Alzheimer’s Disease (AD) is projected to
increase dramatically over the next few decades, making the search for treatments and
tools to measure the progression of AD increasingly urgent. The antisaccade task, a
hands- and language-free metric, may provide a functional index of the Dorsolateral
Prefrontal Cortex (DLPFC), which is damaged in the later stages of AD. Patients with
AD make significantly more antisaccade errors than controls, however, performance in
mild AD has remained unexplored. We hypothesized that mild patients will make more
errors than controls. Thirty AD patients and 31 age-match controls completed both
laptop-based and clinical versions of the antisaccade task. Two thirds of patients with AD
made significantly more errors and corrected less of their errors than age-matched
controls. Our findings indicate that antisaccade impairments exist in mild AD, suggesting
DLPFC pathology may be present earlier than suggested by previous studies.
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Chiang, Yung-Tai, i 江詠泰. "Using Repetitive Transcranial Magnetic Stiulation at Dorsolateral Prefrontal Cortex to Explore the effect of Pain Threshold". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/3665hq.
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碩士國立陽明大學
醫學工程研究所
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In this thesis work, we compared the analgesic effects of high-frequency (10 Hz) repetitive Transcranial Magnetic Stimulation (rTMS) applied to the primary motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC) respectively. Pain sensation was elicited by direct-current (DC) electrical stimulation applied at the contralateral wrist. rTMS applied to M1 and DLPFC both significantly elevated the pain threshold at 15 minutes, 30 minutes, and 1 hour after rTMS. However, the analgesic effect of rTMS was stronger when applied to M1. We further compared the rTMS effects with respect to M1 and DLPFC, where electrical stimulation was given through a small concentric electrode that had been shown to stimulate specifically the small A-delta nerve fibers. The analgesic effect of rTMS was measured using a participant-assessed visual analog scale (VAS) ranging from 0 to 10 for no to the most intolerable pain respectively. rTMS at both stimulation sites (M1 and DLPFC) reduced VAS by 20-30% at 15-30 minutes after rTMS, but the effect was not significant compared to sham TMS. Our findings show that high-frequency rTMS is effective to reduce pain sensation when applied to M1 or DLPFC. From the preliminary experiment using small concentric electrodes, we found that rTMS might be also effective to relieve pain mediated by small nerve fibers. Future studies combining rTMS and functional imaging are warranted to identify regions underlying the analgesic effect of rTMS.
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Alsamkari, Afraa Awad. "Gene expression in neurological disease: autism and Parkinson's disease". Thesis, 2016. https://hdl.handle.net/2144/19182.
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Parkinson’s disease (PD) and autism are prevalent diseases in two disparate age groups. The neuropathology underlying these diseases involves the major neurotransmitters, dopamine and GABA, and/ or their receptors. The current study investigated mRNA gene expressions of the GAD67 in autistic striatum and the DRD1 in the Parkinsonian dorsolateral prefrontal cortex. In situ hybridization histochemistry for GAD67 mRNA levels in postmortem striatal specimens from autistic individuals was compared to those of normal controls. Similarly, a nonradioactive in situ hybridization newly emerging method, RNAscope, was used to assess the D1 receptor mRNA gene expression in postmortem specimens of the dorsolateral prefrontal cortex of PD and control brains. The GAD67 mRNA labeling intensity that was measured on X-ray films and on emulsion radioautograph sections did not vary significantly between the autistic samples and the normal control samples. On the other hand, DRD1 mRNA levels showed a significant increase in the Parkinsonian dorsolateral prefrontal cortex specimens as compared to their normal counterparts. The GAD65 mRNA labeling results corresponded with the GAD67 mRNA levels. The similar GAD67 and GAD65 mRNA patterns in the autism group and the control group may suggest that the hyper-excitability hypothesis can be accounted for by an increase in the glutamatergic activity rather than a decrease in the GABAergic system. The increase in the DRD1 mRNA in the Parkinson’s disease dorsolateral prefrontal cortex may be interpreted in light of the expected upregulation of the D1 receptor in cases of dopamine depletion as the treatment-status was unknown. In conclusion, research investigating the neurotransmitters’ gene expression in Parkinson’s disease and in autism spectrum disorder needs more neurobiological studies in order to establish some knowledge regarding the temporality, and the genetic profile mapping of the diseases. Likewise, more research is encouraged to relate the symptoms and behaviors associated with disease to their anatomical origins.
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Städtgen, Mario [Verfasser]. "Effects of transcranial magnetic stimulation over the dorsolateral prefrontal cortex on cognitive control and on the autonomic nervous system / vorgelegt von Mario Städtgen". 2008. http://d-nb.info/98983249X/34.
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Na, Sabrina. "Practice Effects on a Working Memory Task in Adult Survivors of Pediatric Brain Tumors: An fMRI Investigation". 2015. http://scholarworks.gsu.edu/psych_theses/130.
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Behavioral studies have documented impaired working memory in childhood brain tumor survivors; however, neural mechanisms have yet to be identified using fMRI. The current study investigated BOLD response differences between twenty survivors (Mean age=23.1(4.14), 55% female) and twenty age- and gender-matched controls from the start to the end of a twenty minute 3-back task. There were no differences in task performance between groups or over time. Effects of practice were present in left prefrontal regions, with both groups showing decreases in activation as the task progressed. There were qualitative and quantitative differences in the brain regions that survivors recruited relative to controls in bilateral prefrontal (including the dorsolateral prefrontal cortex) and parietal cortices. Findings suggest that areas under top-down control of the dorsolateral prefrontal cortex become less activated with practice, and that survivors may require more top-down processing and attentional control to perform at similar levels to healthy controls.
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Grundeis, Felicitas. "The Influence of non-invasive Prefrontal/Frontal Brain Stimulation on Food Reappraisal Abilities and Calorie Consumption in Obese Females". 2019. https://ul.qucosa.de/id/qucosa%3A36271.
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Previous studies suggest that non-invasive transcranial direct current stimulation (tDCS) applied to the prefrontal cortex modulates food choices and calorie intake in obese humans. In a fully randomized, placebo-controlled,
within-subject and double-blinded study, we applied single sessions of anodal,
cathodal, and sham tDCS to the left dorsolateral prefrontal cortex (DLPFC) and
contralateral frontal operculum in 25 hungry obese women and investigated possible influences on food reappraisal abilities as well as calorie intake. We hypothesized that tDCS, (i) improves the ability to regulate the desire for visually presented foods and, (ii) reduces their consumption. We could not confirm an effect of anodal or cathodal tDCS, neither on the ability to modulate the desire for visually presented foods, nor on calorie consumption. The present findings do not support the notion of prefrontal/frontal tDCS as a promising treatment option for obesity.:1. Introduction
1.1 Obejective of investigation
1.1.1 Obesity
1.1.2 Homeostasis versus hedonism?
1.1.3 Regulating the desire to eat
1.1.4 Obesity and the brain
1.2 Previous studies
1.2.1 EEG study
1.2.2 Buffet study
1.3 Transcranial direct current stimulation (TDCS)
1.4 TDCS study
2 Publication
3 Summary of work
3.1 Data Acquisition ans analysis
3.2 Results and discussion
3.2.1 Absence of evidence is not evidence of absence
3.2.2 Multifactorial influence on behavior
3.2.3 Limitations of study design
3.2.4 Limitations of method
3.3 Outlook
4 References
5 Attachments
5.1 Academic contribution
5.2 Erklärung über die eigenständige Abfassung der Arbeit
5.3 Einreichungserklärung
5.4 Curriculum vitae
5.5 Publications
5.6 Acknowledgements
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Lehr, Albert. "Modulation of neuronal excitability in the cognitive control network by electrical stimulation". Thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-139F-3.
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Kumar, Saurabh. "EEG study on the differences between lean and obese individuals during regulation of food desire". Doctoral thesis, 2017. https://ul.qucosa.de/id/qucosa%3A16798.
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Lowe, Cassandra. "The effects of continuous theta burst stimulation (cTBS) to the left dorsolateral prefrontal cortex on executive control resources, subjective food cravings, and the consumption of appetitive snack foods". Thesis, 2014. http://hdl.handle.net/10012/8202.
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Prior research has demonstrated that stronger executive control resources (ECR) are positively associated with healthy dietary habits. Given that ECRs are understood to involve the operation of the prefrontal cortex, specifically the dorsolateral prefrontal cortex (DLPFC), the differential operation of the DLPFC may explain individual differences in dietary self-control. The present study was designed to examine the causal status of the relationship between DLPFC function and two parameters of dietary self-control: subjective food cravings and the consumption of appetitive snack foods. Using a within subjects design, 21 female participants received both active and sham continuous theta burst stimulation (cTBS) to the left dorsolateral prefrontal cortex. Subjective food cravings were assessed before and after each stimulation session, and the amount of food consumed during a bogus taste test was objectively measured following each stimulation session. In addition, following each stimulation session participants completed three standardized ECR measures. Results indicated that participants consumed significantly more snack foods following active as compared to sham stimulation, but this finding was specific to the consumption of appetitive foods (i.e., milk chocolate and potato chips). In addition, as compared with sham stimulation, performance on the Stroop task was significantly impaired following active stimulation. Finally, stronger food cravings were reported following active relative to sham stimulation, but these were highly selective the reinforcement-anticipation aspect of cravings. Together, these results support the contention that the ECRs, as modulated through DLPFC activity, regulates food cravings and the consumption of palatable energy dense foods.
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Pinho, Ana Luísa Grilo. "Inside of the Creative Mind: Unravelling the Neurocognitive Mechanisms of Musical Creativity". Doctoral thesis, 2015. http://hdl.handle.net/10316/27005.
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Tese de doutoramento em Ciências da Saúde, no ramo de Ciências Biomédicas, apresentada à Faculdade de Medicina da Universidade de CoimbraCreativity emerges from the individual or collective intellect in order to unfold the conundrum of life and give rise to meaningful deliberations for the attainment of a flourishing life. More specifically, creativity is commonly defined, within the framework of psychology, as a creative act or product that shall fulfill two main criteria: (i) it shall be novel (i.e. original and unexpected) and (ii) qualified judges shall agree upon its valuable contribution to the field. The cognitive science approach to creativity investigates the intellectual processes and representations concerned with the creative thinking. The methodologies of cognitive science, derived from the technological advancements of the past sixty years, have begun to adopt a more definitive and systemic perspective. Neuroscience has emerged, under this context, as the scientific study dedicated to explore the biological substrates of the nervous system, by utilizing a multitude of techniques such as neuroimaging. Cognitive neuroscience, in particular, studies the neural correlates of mental processes and it constitutes the central approach here adopted to study musical creativity. The primary goal of this thesis was thus to investigate the neurocognitive mechanisms underlying musical creativity. Functional magnetic resonance imaging was used to measure brain activity in thirty nine professional pianists and musical improvisation was employed as the ecologically valid behavioral model that could most accurately represent creative musical performance. Study I sought to investigate the specific neurocognitive effects derived from expertise in musical improvisation. A natural question that arises is whether extensive improvisational musical training may induce neuroplasticity in the brain. Many of the observed correlates of general musical training reflect not only acquisition of highly specific sensorimotor skills but also cognitive abilities required for various aspects of musical expertise. However, no study has previously focused on the effects of training musical improvisation. The results revealed a significant negative association between improvisational training and activity in a number of cortical regions in the right hemisphere. Also, improvisational training was specifically associated with functional connectivity during musical improvisation, using the premotor and prefrontal regions (previously reported to be involved during extemporization) as seed regions and controlling for age and conventional piano practice. More experienced improvisers showed higher functional connectivity during improvisation between prefrontal, premotor, and motor regions of the frontal lobe. Furthermore, the results were shown not be confounded by more experienced improvisers producing more complex improvisations. Study II explored the contribution of the dorsolateral prefrontal cortex (DLPFC) in creative cognition. Different neuroimaging studies have shown so far seemingly paradoxical results regarding the implications of the DLPFC in creative functioning. On one hand, DLPFC has been argued to exert active control over free generative tasks by inhibiting habitual responses, thus enabling more original output; on the other hand, a deactivation and concomitant decrease in monitoring and focused attention has been suggested to facilitate more spontaneous associations and novel insights. Here, the study highlights that creative cognition can be implemented in different ways given different circumstances. Two categories of behavioral conditions were specified in the experimental design to convey constraints either on the musical structure (set of pitches) or on the emotional expression (happiness or fear) of the improvisations. The results confirmed higher activity in the right DLPFC, as well as in the parietal lobe and right dorsal premotor cortex, when contrasting structural conditions with emotional conditions. These results suggest higher attentional effort and cognitive control when the participants had to conform to the structural constraints. Conversely, deactivations were identified for the emotional constraints in the same regions, plus other regions explicitly contributing to emotion processing. In addition, DLPFC was found functionally connected with the frontoparietal network as well as the cerebellum during structural conditions and to various regions comprising the default network during emotional conditions.
A criatividade emerge do universo intelectual, tanto individual como colectivo, com o objectivo de superar as limitações da existência e de promover decisões que conduzam a uma vida mais plena. No âmbito da psicologia, a criatividade é por norma definida como um acto ou produto criativo que deve cumprir com dois requisitos principais: (i) constituir algo novo (ou seja, ser original e inesperado) e (ii) reunir o consenso dos especialistas acerca da sua contribuição única na área. De acordo com a abordagem seguida em ciências da cognição, a criatividade é estudada a partir dos processos e representações intelectuais envolvidos no pensamento criativo. As respectivas metodologias, decorrentes dos avanços tecnológicos nos últimos sessenta anos, adoptaram uma perspectiva mais definitiva e sistémica. A neurociência surgiu, dentro deste contexto, como o estudo científico que se dedica a investigar os substratos neuronais, recorrendo para isso a uma diversidade de técnicas, entre as quais a neuro-imagem. Em particular, a neurociência da cognição estuda os substratos neuronais associados aos processos mentais, sendo esta a abordagem central adoptada no presente trabalho com vista ao estudo da criatividade musical. O principal objectivo desta tese foi, portanto, investigar os mecanismos neuro-cognitivos subjacentes à criatividade musical. A actividade cerebral de trinta e nove pianistas profissionais foi registada com recurso à ressonância magnética funcional, enquanto estes improvisavam pequenas peças musicais. O estudo I teve o objectivo de investigar os efeitos neuro-cognitivos especificamente decorrentes da experiência em improvisação musical. A questão, aqui colocada, remete-se à identificação dos processos de neuroplasticidade que derivam da prática extensiva em improvisação musical. Muitos dos mecanismos observados e associados ao treino musical reflectem não só a aquisição de habilidades motoras e sensoriais de elevada especificidade, mas também o desenvolvimento de capacidades cognitivas essenciais em diversos aspectos relativos à experiência musical. No entanto, nenhum estudo, até ao momento, se focou nos efeitos relativos à prática improvisacional em música. Os resultados revelaram uma correlação negativa e significativa entre a prática improvisacional e a actividade cerebral, num conjunto de regiões corticais do hemisfério direito. Os resultados evidenciaram, também, que a prática improvisacional está associada a uma maior conectividade funcional entre diversas áreas do córtex pré-frontal, prémotor e motor do lobo frontal, durante a improvisação musical. A idade dos participantes e a prática musical convencional foram introduzidas no modelo de regressão linear como variáveis de controlo. Além disso, os resultados não apresentaram qualquer relação com a complexidade das peças produzidas por pianistas com maior experiência musical. O estudo II examinou a contribuição do córtex pré-frontal dorsolateral (CPFDL) no processo cognitivo criativo. Até agora, diversos estudos em neuro-imagem têm revelado resultados aparentemente paradoxais no que respeita às implicações do CPFDL na actividade funcional responsável pelo pensamento criativo. Por um lado, foi comprovado que o CPFDL exerce um controlo activo sobre tarefas de produção livre, inibindo respostas habituais e promovendo consequentemente resoluções mais originais; por outro lado, a desactivação e concomitante diminuição do CPFDL, durante actividades cognitivas relacionadas com monitorização e concentração, sugere que esta região agiliza processos mentais de associação espontânea e de concretização de novas ideias. O presente estudo destaca que o mecanismo cognitivo associado à criatividade pode ser implementado de diversas formas, dependendo das circunstâncias externas. Duas categorias de restrições foram especificadas no paradigma experimental, de modo a condicionar o comportamento dos participantes. Essas restrições referiam-se à estrutura musical (conjunto de notas) ou à expressão emocional (alegria ou medo) das respectivas improvisações. Os resultados confirmaram uma maior actividade do CPFDL direito, do lobo parietal e do córtex pré-motor dorsal direito, durante a improvisação condicionada pela estrutura da música, quando comparada com a improvisação dependente da expressão emocional transmitida pela música. Os resultados sugeriram, portanto, um esforço maior na atenção prestada e um elevado controlo cognitivo, durante as improvisações condicionadas pela estrutura musical imposta. Em oposição, foram identificadas desactivações nas mesmas regiões, assim como em regiões tipicamente associadas ao processamento de emoções, durante as improvisações cujo desempenho remete para a expressão emocional da música. Além disso, os resultados comprovam que o CPFDL está funcionalmente conectado à rede de comunicação fronto-parietal e ao cerebelo, durante as improvisações condicionadas pela estrutura musical. Por sua vez, os resultados demonstram que o CPFDL está conectado a regiões associadas à rede neuronal em modo padrão, durante as improvisações musicais condicionadas pela expressão emocional.
FCT - SFRH/BD/33895/2009
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Costa, Dalila Matos. "Efeitos a curto prazo da combinação da terapia cognitivo comportamental com estimulação transcraniana por corrente contínua na depressão major: um estudo piloto". Master's thesis, 2021. http://hdl.handle.net/1822/75408.
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Dissertação de mestrado integrado em Psicologia AplicadaA Perturbação Depressiva Maior (PDM) é das doenças mentais com maior prevalência a nível mundial. A Terapia Cognitivo Comportamental (TCC) é uma abordagem muito utilizada no tratamento da Depressão, tendo um ótimo suporte empírico sobre a sua eficácia. A Estimulação Transcraniana por Corrente Contínua (ETCC) é uma técnica neuromodulatória não invasiva, segura e fácil de usar. Neste estudo clínico piloto, controlado e duplo cego, dez indivíduos com PDM foram randomizados para receber uma de duas condições (TCC combinada com ETCC ativa, n=6; TCC combinada com ETCC sham, n=4) ao longo de 6 semanas de intervenção, havendo monitorização de sintomas num período de 3 meses. Ambos os grupos diminuem a sintomatologia depressiva após o término da intervenção. Contudo é no grupo ativo que se observam melhorias e diferenças estatisticamente significativas no humor e em outras medidas clínicas sintomatológicas nos vários momentos de seguimento. Não obstante aos resultados promissores, é necessário o aumento da amostra.
Major Depressive Disorder (MDD) is one of the most prevalent mental illness worldwide. Cognitive Behavioral Therapy (CBT) is one of the most widely used approaches in the treatment of depression, with excellent empirical support for its effectiveness. Transcranial Direct Current Stimulation (TDC’s) it’s a technique neuromodulatory and non-invasive, safe and easy to use. In this pilot, controlled, double-blind clinical study, ten subjects with MDD were randomized to receive one of two conditions (CBT combined with active TDC’s, n=6; CBT combined with TDC’s sham, n=4) over 6 weeks of intervention, with symptom monitoring over a period of 3 months. Both groups decrease the depressive symptoms after the end of the intervention. However, it is in the active group that there are statistically significant improvements and differences in mood and in other symptomatic clinical measures at different times of follow-up. Despite the promising results, it is necessary to increase the sample.
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VILLA, SANCHEZ BERNARDO. "The placebo effect in the motor domain: a neural and behavioral approach". Doctoral thesis, 2019. http://hdl.handle.net/11562/995396.
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The placebo effect is a fascinating psychobiological phenomenon that allows to investigate the mind-body interaction. It is typically induced by the application of an inert treatment along with verbal suggestion of beneficial outcomes. The placebo effect has been deeply investigated in the field of pain, although different lines of evidence suggest that it is also present in other domains, like the motor domain. Extending our knowledge of the placebo effect in the motor domain can have important future translational impacts in sports and pathology. The aim of my PhD project was to study the placebo effect in the motor domain at two different levels: the neural and the behavioral level. Regarding the neural level, knowledge on the brain regions related to placebo effect in the motor domain is limited. We aimed at filling in this knowledge gap by investigating the role of the dlPFC, a brain region also involved in placebo analgesia. The dlPFC elaborates expectation, a cognitive function at the basis of the placebo effect and shares some connections with other brain regions involved in motor control. Hence, there are many clues to hypothesize a role of the dlPFC in the motor placebo effect. To tackle this issue, three different experiments were conducted in which the dlPFC was stimulated by means of transcranial direct current stimulation (tDCS) together with a placebo procedure on force production. We found that the left dlPFC is involved in the expectation-induced enhancement of force, specifically in those subjects who respond to the placebo effect (placebo-responders). Regarding the behavioral level, it should be noticed that many behavioral studies have shown that the placebo effect can enhance different aspects of motor performance associated to sports, such as force, speed or endurance. It is still unknown, however, whether the placebo effect can also improve other motor functions, important for many daily life activities, like balance or motor sequence learning. Thus, another objective of my PhD was to investigate the potential influence of the placebo effect on two motor functions that are closer to daily life activities. To this aim, a first study was conducted to understand whether balance control, a motor function needed for many daily life activities and for preventing falls, could be enhanced in healthy participants by a placebo procedure consisting 9 of verbal suggestion. We found that different parameters of balance (in the three-dimensional space and in the medial-lateral direction) and the subjective perception of stability were improved by the placebo procedure. A second behavioural study was run to investigate whether the application of a placebo treatment consisting of verbal suggestion could help in improving motor sequence learning. In this case, we also aimed to tackle a differential role of two types of placebo treatments: one motor and one cognitive. The motor placebo procedure consisted of transcutaneous electrical nerve stimulation (TENS) applied the hand muscles involved in the task together with verbal information on the beneficial effects on muscle activity. The cognitive placebo procedure consisted of sham transcranial direct current stimulation (tDCS) applied over the frontal region together with verbal information on the beneficial effects on attention. Our findings did not show a clear improvement of performance following the placebo procedures, but a significant effect on the subjective perception of fatigue. More precisely, while the placebo procedure directed to the motor function (TENS) could reduce the perception of physical fatigue, the placebo procedure focused on cognitive functions (sham tDCS) could decrease the perception of both mental and physical fatigue. Altogether these investigations represent an attempt to deepen our understanding of the neural correlates of the motor placebo effect and to enlarge the potential behavioural influence of placebos on different motor functions.
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Deldar, Zoha. "Rehaussement de la mémoire de travail et de l'inhibition de la douleur par la neuromodulation du cortex préfrontal dorsolatéral gauche chez des personnes jeunes et âgées = Improving working memory and pain inhibition using neuromodulation of left dorsolateral prefrontal cortex in young and older persons". Thèse, 2019. http://depot-e.uqtr.ca/id/eprint/9220/1/032342541.pdf.
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Chand, Ganesh. "Oscillatory Network Dynamics in Perceptual Decision-Making". 2015. http://scholarworks.gsu.edu/phy_astr_diss/79.
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Synchronized oscillations of ensembles of neurons in the brain underlie human cognition and behaviors. Neuronal network oscillations can be described by the physics of coupled dynamical systems. This dissertation examines the dynamic network activities in two distinct neurocognitive networks, the salience network (SN) and the ventral temporal cortex-dorsolateral prefrontal cortex (VTC-DLPFC) network, during perceptual decision-making (PDM).
The key nodes of the SN include the right anterior insula (rAI), left anterior insula (lAI), and dorsal anterior cingulate cortex (dACC) in the brain. When and how a sensory signal enters and organizes within the SN before reaching the central executive network including the prefrontal cortex has been a mystery. Second, prior studies also report that perception of visual objects (face and house) involves a network of the VTC—the fusiform face area (FFA) and para-hippocampal place area (PPA)—and the DLPFC. How sensory information enters and organizes within the VTC-DLPFC network is not well understood, in milliseconds time-scale of human’s perception and decision-making. We used clear and noisy face/house image categorization tasks and scalp electroencephalography (EEG) recordings to study the dynamics of these networks. We demonstrated that beta (13–30 Hz) oscillation bound the SN, became most active around 100 ms after the stimulus onset, the rAI acted as a main outflow hub within the SN, and the SN activities were negatively correlated with the difficult tasks. We also uncovered that the VTC-DLPFC network activities were mediated by beta (13-30 Hz) and gamma (30-100 Hz) oscillations. Beta activities were enhanced in the time frame 125-250 ms after stimulus onset, the VTC acted as main outflow hub, and network activities were negatively correlated with the difficult tasks. In contrast, gamma activities were elevated in the time frame 0-125 ms, the DLPFC acted as a main outflow hub, and network activities—specifically the FFA-PPA pair—were positively correlated with the difficult tasks. These findings significantly enhance our understanding of how sensory information enters and organizes within the SN and the VTC-DLPFC network, respectively in PDM.
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Lafontaine, Marc Philippe. "Modulation de l'apprentissage visuel par stimulation électrique transcrânienne à courant direct du cortex préfrontal". Thèse, 2012. http://hdl.handle.net/1866/8997.
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Le traitement visuel répété d’un visage inconnu entraîne une suppression de l’activité neuronale dans les régions préférentielles aux visages du cortex occipito-temporal. Cette «suppression neuronale» (SN) est un mécanisme primitif hautement impliqué dans l’apprentissage de visages, pouvant être détecté par une réduction de l’amplitude de la composante N170, un potentiel relié à l’événement (PRE), au-dessus du cortex occipito-temporal. Le cortex préfrontal dorsolatéral (CPDL) influence le traitement et l’encodage visuel, mais sa contribution à la SN de la N170 demeure inconnue. Nous avons utilisé la stimulation électrique transcrânienne à courant direct (SETCD) pour moduler l’excitabilité corticale du CPDL de 14 adultes sains lors de l’apprentissage de visages inconnus. Trois conditions de stimulation étaient utilisées: inhibition à droite, excitation à droite et placebo. Pendant l’apprentissage, l’EEG était enregistré afin d’évaluer la SN de la P100, la N170 et la P300. Trois jours suivant l’apprentissage, une tâche de reconnaissance était administrée où les performances en pourcentage de bonnes réponses et temps de réaction (TR) étaient enregistrées. Les résultats indiquent que la condition d’excitation à droite a facilité la SN de la N170 et a augmentée l’amplitude de la P300, entraînant une reconnaissance des visages plus rapide à long-terme. À l’inverse, la condition d’inhibition à droite a causé une augmentation de l’amplitude de la N170 et des TR plus lents, sans affecter la P300. Ces résultats sont les premiers à démontrer que la modulation d’excitabilité du CPDL puisse influencer l’encodage visuel de visages inconnus, soulignant l’importance du CPDL dans les mécanismes d’apprentissage de base.Repeated visual processing of an unfamiliar face suppresses neural activity in face-specific areas of the occipito-temporal cortex. This "repetition suppression" (RS) is a primitive mechanism involved in learning of unfamiliar faces, which can be detected through amplitude reduction of the N170 event-related potential (ERP). The dorsolateral prefrontal cortex (DLPFC) exerts top-down influence on early visual processing. However, its contribution to N170 RS and learning of unfamiliar faces remains unclear. Transcranial direct current stimulation (tDCS) transiently increases or decreases cortical excitability, as a function of polarity. We hypothesized that DLPFC excitability modulation by tDCS would cause polarity-dependent modulations of N170 RS during encoding of unfamiliar faces. tDCS-induced N170 RS enhancement would improve long-term recognition reaction time (RT) and/or accuracy rates, whereas N170 RS impairment would compromise recognition ability. Participants underwent three tDCS conditions in random order at ~72 hour intervals: right anodal/left cathodal, right cathodal/left anodal and sham. Immediately following tDCS conditions, an EEG was recorded during encoding of unfamiliar faces for assessment of P100 and N170 visual ERPs. P300 was analyzed to detect prefrontal function modulation. Recognition tasks were administered ~72 hours following encoding. Results indicate the right anodal/left cathodal condition facilitated N170 RS and induced larger P300 amplitudes, leading to faster recognition RT. Conversely, the right cathodal/left anodal condition caused increases in N170 amplitudes and RT, but did not affect P300. These data are the first to demonstrate that DLPFC excitability modulation can influence early visual encoding of unfamiliar faces, highlighting the importance of DLPFC in basic learning mechanisms.
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Calvo, Alberto Lema. "Transcranial Random Noise Stimulation (tRNS) on Attention Network Test (ANT): an exploratory study". Master's thesis, 2017. http://hdl.handle.net/1822/48135.
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Dissertação de mestrado integrado em PsicologiaSpeed-accuracy tradeoff (SAT) refers to the adjustment between response speed and its accuracy, a process mediated through cortical and subcortical circuits. However, it remains unclear whether SAT can be modulated by the effects of tRNS and/or tDCS. In order to explore this effect, we used the attention network test (ANT). This tasks allowed us to test three independent networks related to both subcortical activity (alerting and orienting) and cortical level (executive). We hypothesized that performance would increase for alerting and orienting networks with tRNS whereas tDCS would increase performance in executive network. Moreover, to make the SAT effect more prominent, instructions that emphasized speed and accuracy were also introduced. Eighteen healthy students undertook three experimental sessions of tRNS, anodal tDCS and sham over the left dlPFC while performing the ANT. Results showed that no significant effect was found for stimulation. Instructions, however, showed a significant difference between speed condition and standard condition. Thus, SAT was successfully manipulated by instruction condition but not by stimulation.
O Speed-accuracy tradeoff (SAT) é definido como o ajustamento entre a velocidade e a exatidão de uma determinada resposta. Este processo é mediado por vias corticais e subcorticais suceptíveis de serem alteradas através de métodos de estimulação elétrica transcraniana. No presente estudo, dois tipos de estimulação, ETRN e ETCC, foram combinados com uma tarefa atencional (ANT) com o intuito de avaliar os seus efeitos nas vias corticais e subcorticais associadas ao SAT. Era esperado que a ETRN aumentasse o desempenho em vias atencionais subcorticais (de alerta e de orientação) enquanto que a ETCC melhorasse o desempenho na via atencional cortical (executiva). De igual modo, as instruções da tarefa também foram alteradas para manipular o SAT, favorecendo assim a velocidade ou a exatidão da resposta. Dezoito participantes saudáveis receberam de forma aleatorizada três sessões de estimulação (ETRN, ETCC, sham) unilateral sobre o CPFDL esquerdo. Os resultados mostram que a estimulação ETRN e ETCC não obteveram efeitos nas vias atentionais. As instruções, no entanto, revelam que quando o ênfase é colocado na velocidade da resposta, a via atencional executiva apresenta menor eficiência. Desta forma, O SAT apenas foi manipulado com sucesso através das intruções e não da estimulação.
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Silva, Afonso Jorge Vaz da. "Estimulação transcraniana por corrente contínua combinada com terapia cognitivo comportamental no tratamento da depressão major". Master's thesis, 2020. http://hdl.handle.net/1822/69723.
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Dissertação de mestrado integrado em PsicologiaA Perturbação Depressiva Major (PDM) é uma doença mental com grande prevalência a nível mundial. Como tratamento padronizado não-farmacológico, a Terapia Cognitivo Comportamental (TCC) é uma técnica terapêutica com um bom suporte-empírico estabelecido para a depressão. Por sua vez, a Estimulação Transcraniana por Corrente Contínua (ETCC) é uma técnica neuromodulatória segura, não-invasiva, económica, fácil de administrar e indolor. Apesar da já evidenciada eficácia, não são claros os efeitos da combinação das duas técnicas na redução dos sintomas da PDM. Neste estudo clínico piloto, controlado e duplo cego, seis sujeitos diagnosticados com PDM foram randomizados para receberem uma de duas condições possíveis. A primeira, TCC combinada com ETCC ativa bilateral sobre o córtex pré-frontal dorsolateral ou a segunda, TCC combinada com ETCC sham, ao longo das seis semanas de intervenção. Os indivíduos foram posteriormente seguidos durante um período de três meses. Ambos os grupos melhoraram significativamente na sintomatologia depressiva após término da intervenção, contudo não se encontraram diferenças estatisticamente significativas entre os grupos. Estes efeitos mantiveram-se ao longo do seguimento. Apesar dos resultados promissores, é fundamental o aumento do tamanho da amostra.
Major Depressive Disorder (MDD) is a mental illness with a high worldwide prevalence. As a standardized non-pharmacological treatment, the Cognitive Behavioral Therapy (CBT) is a therapeutic technique well-established, and empirically supported for depression, including for those that have not responded to antidepressants. Transcranial Direct Current Stimulation (tDCS) is a safe, non-invasive, not expensive, easy to administrate, and well tolerated neuromodulatory technique. Despite the already proven effectiveness, it is not yet clear what are the effects of using the combination of these two interventions on MDD symptoms. In this pilot clinical trial, double-blind study, a total of six subjects with MDD were randomized to receive CBT combined with bilateral active tDCS over the DLPFC or CBT combined with sham tDCS, during six weeks of intervention. Subsequently, the participants were followed by three months. The participant’s humor significantly ameliorated in both groups after the treatment, however there was no statistically significant differences between groups. These effects remained during follow up assessments. Future studies should increase the sample size.
Este projeto está financiado pela Fundação para a Ciência e a Tecnologia (FCT) - PTDC/PSI-ESP/29701/2017
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Kremer, Kristina. "Vergleichende MR-volumetrische Untersuchung des dorsolateralen präfrontalen Kortex bei Schizophrenie, Bipolarer Störung, Zwangserkrankung und gesunden Kontrollpersonen". Doctoral thesis, 2011. http://hdl.handle.net/11858/00-1735-0000-0006-B1BF-3.
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Pohlers, Henriette. "Einfluss der transkraniellen Gleichstromstimulation auf die stimmungsabhängige Informationsverarbeitung bei gesunden Probanden". Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-0006-B2B3-4.
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Dumont, Laurence. "Évaluation systématique des effets de la tDCS sur le DLPFC et applications en technologies de l'information". Thèse, 2017. http://hdl.handle.net/1866/20616.
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Ambrus, Géza Gergely. "Low Intensity Transcranial Electrical Stimulation: Effects on Categorization and Methodological Aspects". Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-EF6F-7.
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Siegle, Micha Benjamin. "Einfluss von transkraniellen Wechselstromstimulationen im Thetabereich auf die Bearbeitung der Stroop-Aufgabe". Doctoral thesis, 2021. http://hdl.handle.net/21.11130/00-1735-0000-0005-15A1-D.
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