Academic literature on the topic 'Neuronal discrimination'
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Journal articles on the topic "Neuronal discrimination"
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Deng, Yingchun, Peter Williams, Feng Liu, and Jianfeng Feng. "Neuronal discrimination capacity." Journal of Physics A: Mathematical and General 36, no. 50 (December 1, 2003): 12379–98. http://dx.doi.org/10.1088/0305-4470/36/50/003.
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Boynton, Geoffrey M., Jonathan B. Demb, Gary H. Glover, and David J. Heeger. "Neuronal basis of contrast discrimination." Vision Research 39, no. 2 (January 1999): 257–69. http://dx.doi.org/10.1016/s0042-6989(98)00113-8.
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Heeger, D. J. "Neuronal correlates of contrast detection and discrimination." Journal of Vision 2, no. 10 (December 1, 2002): 13. http://dx.doi.org/10.1167/2.10.13.
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Spitzer, H., R. Desimone, and J. Moran. "Increased attention enhances both behavioral and neuronal performance." Science 240, no. 4850 (April 15, 1988): 338–40. http://dx.doi.org/10.1126/science.3353728.
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Single cells were recorded from cortical area V4 of two rhesus monkeys (Macaca mulatta) trained on a visual discrimination task with two levels of difficulty. Behavioral evidence indicated that the monkeys' discriminative abilities improved when the task was made more difficult. Correspondingly, neuronal responses to stimuli became larger and more selective in the difficult task. A control experiment demonstrated that changes in general arousal could not account for the effects of task difficulty on neuronal responses. It is concluded that increasing the amount of attention directed toward a stimulus can enhance the responsiveness and selectivity of the neurons that process it.
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Li, Wu, Peter Thier, and Christian Wehrhahn. "Contextual Influence on Orientation Discrimination of Humans and Responses of Neurons in V1 of Alert Monkeys." Journal of Neurophysiology 83, no. 2 (February 1, 2000): 941–54. http://dx.doi.org/10.1152/jn.2000.83.2.941.
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We studied the effects of various patterns as contextual stimuli on human orientation discrimination, and on responses of neurons in V1 of alert monkeys. When a target line is presented along with various contextual stimuli (masks), human orientation discrimination is impaired. For most V1 neurons, responses elicited by a line in the receptive field (RF) center are suppressed by these contextual patterns. Orientation discrimination thresholds of human observers are elevated slightly when the target line is surrounded by orthogonal lines. For randomly oriented lines, thresholds are elevated further and even more so for lines parallel to the target. Correspondingly, responses of most V1 neurons to a line are suppressed. Although contextual lines inhibit the amplitude of orientation tuning functions of most V1 neurons, they do not systematically alter the tuning width. Elevation of human orientation discrimination thresholds decreases with increasing curvature of masking lines, so does the inhibition of V1 neuronal responses. A mask made of straight lines yields the strongest interference with human orientation discrimination and produces the strongest suppression of neuronal responses. Elevation of human orientation discrimination thresholds is highest when a mask covers only the immediate vicinity of the target line. Increasing the masking area results in less interference. On the contrary, suppression of neuronal responses in V1 increases with increasing mask size. Our data imply that contextual interference observed in human orientation discrimination is in part directly related to contextual inhibition of neuronal activity in V1. However, the finding that interference with orientation discrimination is weaker for larger masks suggests a figure-ground segregation process that is not located in V1.
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Adibi, Mehdi, and Ehsan Arabzadeh. "A Comparison of Neuronal and Behavioral Detection and Discrimination Performances in Rat Whisker System." Journal of Neurophysiology 105, no. 1 (January 2011): 356–65. http://dx.doi.org/10.1152/jn.00794.2010.
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We used the rat whisker touch as a model system to investigate the correlation between the response function of cortical neurons and the behavior of rats in a sensory detection versus discrimination task. The rat whisker–barrel system is structurally well characterized and represents one of the main channels through which rodents collect information about the environment. In experiment 1, we recorded neuronal activity ( n = 235) in the whisker area of the rat somatosensory cortex in anesthetized rats while applying vibrotactile stimuli of varying amplitudes to the whiskers. Neurons showed a characteristic sigmoidal input–output function, with an accelerating nonlinearity at low stimulus amplitudes and a compressive nonlinearity at high stimulus amplitudes. We further quantified the performance of individual neurons for stimulus detection and for discrimination across different stimulus pairs with identical amplitude differences. For near-threshold stimuli, the neuronal discrimination performance surpassed the detection performance despite the fact that detection and discrimination represented identical amplitude differences. This is consistent with the accelerating nonlinearity observed at low stimulus intensities. In the second stage of the experiment, four rats were trained to select the higher-amplitude stimulus between two vibrations applied to their whiskers. Similar to neuronal results, the rats' performance was better for the discrimination task compared with the detection task. The behavioral performance followed the same trend as that of the population of individual neurons. Both behavioral and neuronal data are consistent with the “pedestal effect” previously reported in human psychophysics.
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Matsumora, Takehiro, Kowa Koida, and Hidehiko Komatsu. "Relationship Between Color Discrimination and Neural Responses in the Inferior Temporal Cortex of the Monkey." Journal of Neurophysiology 100, no. 6 (December 2008): 3361–74. http://dx.doi.org/10.1152/jn.90551.2008.
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Earlier studies suggest that the inferior temporal (IT) cortex of the monkey plays a key role in color discrimination. Here, we examined the quantitative relationship between color judgment in monkeys and the responses of color-selective neurons in the anterior part of the IT cortex (area TE) by comparing neuronal activity and behavior recorded simultaneously while the monkeys performed a color-judgment task. We first compared the abilities of single neurons and monkeys to discriminate color. To calculate a neuron's ability to discriminate color, we computed a neurometric function using receiver-operating-characteristics analysis. We then compared the neural and behavioral thresholds for color discrimination and found that, in general, the neural threshold was higher than the behavioral threshold, although occasionally the reverse was true. Variation in the neural threshold across the color space corresponded well with that of the behavioral threshold. We then calculated the choice probability (CP), which is a measure of the correlation between the trial-to-trial fluctuations in neuronal responses and the monkeys' color judgment. On average, CPs were slightly but significantly greater than 0.5, indicating the activities of these TE neurons correlate positively with the monkeys' color judgment. This suggests that individual color-selective TE neurons only weakly contribute to color discrimination and that a large population of color-selective TE neurons contribute to the performance of color discrimination.
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Orban, Guy A., and Rufin Vogels. "The neuronal machinery involved in successive orientation discrimination." Progress in Neurobiology 55, no. 2 (June 1998): 117–47. http://dx.doi.org/10.1016/s0301-0082(98)00010-0.
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Arabzadeh, Ehsan, Colin W. G. Clifford, Justin A. Harris, David A. Mahns, Vaughan G. Macefield, and Ingvars Birznieks. "Single tactile afferents outperform human subjects in a vibrotactile intensity discrimination task." Journal of Neurophysiology 112, no. 10 (November 15, 2014): 2382–87. http://dx.doi.org/10.1152/jn.00482.2014.
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We simultaneously compared the sensitivity of single primary afferent neurons supplying the glabrous skin of the hand and the psychophysical amplitude discrimination thresholds in human subjects for a set of vibrotactile stimuli delivered to the receptive field. All recorded afferents had a dynamic range narrower than the range of amplitudes across which the subjects could discriminate. However, when the vibration amplitude was chosen to be within the steepest part of the afferent's stimulus-response function the response of single afferents, defined as the spike count over the vibration duration (500 ms), was often more sensitive in discriminating vibration amplitude than the perceptual judgment of the participants. We quantified how the neuronal performance depended on the integration window: for short windows the neuronal performance was inferior to the performance of the subject. The neuronal performance progressively improved with increasing spike count duration and reached a level significantly above that of the subjects when the integration window was 250 ms or longer. The superiority in performance of individual neurons over observers could reflect a nonoptimal integration window or be due to the presence of noise between the sensory periphery and the cortical decision stage. Additionally, it could indicate that the range of perceptual sensitivity comes at the cost of discrimination through pooling across neurons with different response functions.
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Smith, Jackson E. T., and Andrew J. Parker. "Correlated structure of neuronal firing in macaque visual cortex limits information for binocular depth discrimination." Journal of Neurophysiology 126, no. 1 (July 1, 2021): 275–303. http://dx.doi.org/10.1152/jn.00667.2020.
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Correlated noise reduces the stimulus information in visual cortical neurons during experimental performance of binocular depth discriminations. The temporal scale of these correlations is important. Rapid (20–30 ms) correlations reduce information within and between areas V1 and V4, whereas slow (>100 ms) correlations between areas do not. Separate cortical areas appear to act together to maintain signal fidelity. Rapid correlations reduce the neuronal signal difference between stimuli and adversely affect perceptual discrimination.
Dissertations / Theses on the topic "Neuronal discrimination"
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Ménardy, Fabien. "Reconnaissance des signaux de communication chez le diamant mandarin : étude des réponses des neurones d’une aire auditive secondaire." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA11T049/document.
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A l’heure actuelle, il reste largement à étudier comment le codage sensoriel des signaux vocaux de communication contribue à leur détection et à leur reconnaissance. Peu d’études se sont, en effet, penchées sur le codage des vocalisations au niveau des régions auditives en fonction de l’individu qui les produit et du degré de familiarité avec cet individu. Dans ce cadre, les oiseaux chanteurs sont un bon modèle parce qu’ils utilisent des vocalisations pour interagir et reconnaître leurs congénères et qu’ils possèdent, de plus, un ensemble de régions auditives. Parmi ces régions, le nidopallium caudomedian (NCM), une aire auditive analogue du cortex auditif secondaire chez les mammifères, est actuellement considérée comme une région spécialisée dans le traitement des vocalisations (chants et cris) de l’espèce : les neurones du NCM répondent plus fortement aux vocalisations de l’espèce qu’à celles d’une autre espèce. À partir de là, parce que chez le diamant mandarin, le cri de distance permet aux individus, mâles ou femelles, de reconnaître leur partenaire sexuel, nous avons cherché à savoir si, chez les femelles comme chez les mâles, les neurones du NCM montraient une discrimination dans leurs réponses auditives entre le cri d’individus connus (parmi lesquels figurait le partenaire sexuel) et ceux d’individus inconnus et si ces réponses reflétaient le degré de familiarité de ces vocalisations. Les enregistrements de l’activité des neurones du NCM, chez des diamants mandarins vigiles (grâce à un système de télémétrie) ou anesthésiés, lors de la présentation de cris de distance, ont révélé, chez les femelles vivant en couple et ayant été familiarisées avec un autre couple de diamants mandarins, une plus forte augmentation de l’activité lors de la diffusion des cris d’individus connus, mâles ou femelles, qu’aux cris d’individus inconnus. Une telle augmentation n’a pas été, en outre, observée chez des femelles contrôles qui n’avaient jamais entendu ces mêmes cris auparavant. De plus, ils ont indiqué que le nombre de neurones montrant un fort degré de sélectivité ainsi que la quantité d’information portée par les trains de potentiels d’action étaient plus importants chez les femelles vivant en couple que chez les femelles contrôles. En revanche, chez les mâles, bien que la plupart des neurones montrait des réponses lors de la diffusion des cris, aucune différence n’a été mise en évidence entre les cris d’individus connus et ceux d’inconnus. Nous avons alors cherché à savoir comment, d’un point de vue acoustique, les cris de distance étaient représentés au sein du NCM. En se basant sur une étude comportementale ayant déterminé quelles étaient les caractéristiques acoustiques qui contribuaient à la reconnaissance de ces cris, nous avons cherché à savoir si les neurones du NCM étaient sensibles à ces mêmes caractéristiques acoustiques. Les résultats ont montré que, chez les femelles, la suppression de la fréquence fondamentale et la modification du timbre du cri du partenaire sexuel ou du propre cri de l’oiseau provoquaient une forte diminution des réponses au sein du NCM alors que, chez les mâles, les réponses variaient selon le paramètre modifié et le type de cri présenté. Nos résultats suggèrent donc que, chez le diamant mandarin, le NCM est impliqué dans le codage du cri de distance. Cependant, ils mettent en évidence des différences dans ce codage entre les mâles et les femelles. Chez les femelles, ce codage permet de discriminer entre les cris d’individus connus et ceux d’individus inconnus alors que chez les mâles, son rôle reste à être déterminé. Chez les femelles, l’expérience sociale au travers de la mémorisation des signaux de communication des individus peut donc façonner les propriétés fonctionnelles des neurones d’une aire auditive secondaire. Ces propriétés pourraient donc continuellement subir des changements pour s'adapter à l’environnement social de l’individuHow sensory signals are encoded in the brain and whether their behavioural relevance affects their encoding are central questions in sensory neuroscience. Studies have consistently shown that behavioural relevance can change the neural representation of sounds in the auditory system, but what occurs in the context of natural acoustic communication where significance could be acquired through social interaction remains to be explored. The zebra finch, a highly social songbird species that forms lifelong pair bonds and uses a vocalization, the distance call, to identify its mate offers an opportunity to address this issue. One auditory area in the songbird telencephalon, the caudo-medial nidopallium (NCM) that is considered as being analogous to the secondary mammalian auditory cortex, has recently emerged as part of the neural substrate for sensory representation of species-specific vocalizations: the activation of NCM neurons is greatest when birds are exposed to conspecific song, as compared to heterospecific song or artificial stimuli. This led us to investigate whether, in the zebra finch, NCM neurons could contribute to the discrimination among vocalizations that differ in their degree of familiarity: calls produced by the mate, by familiar individuals (males or females), or by unfamiliar individuals (males or females). In females, behaviourally relevant calls, i.e. the mate’s call and familiar calls, evoked responses of greater magnitude than unfamiliar calls. This distinction between responses was seen both in multiunit recordings from awake freely moving mated females (using a telemetric system) and in single unit recordings from anesthetized mated females. In contrast, control females that had not heard them previously displayed response of similar magnitude to call stimuli. In addition, more cells showed highly selective responses in mated than in control females suggesting that experience-dependent plasticity in call-evoked responses resulted in enhanced discrimination of auditory stimuli. In males, as in females, call playback evoked robust auditory responses. However, neurons in males did not appear capable of categorizing the calls of individuals (males or females) as ‘‘familiar’’ or ‘‘unfamiliar’’. Then, we investigated how calls are represented in the NCM of zebra finches by assessing whether certain call-specific acoustic cues drove NCM neurons to a greater degree than others. Behavioural studies had previously identified call-specific acoustic cues that are necessary to elicit a vocal response from male and female zebra finches. Single-unit recordings indicated that NCM neurons in females were particularly sensitive to call modifications in the spectral domain: suppressing the fundamental frequency of call stimuli or modifying the relative energy levels of harmonics in call caused a marked decrease in response magnitude of NCM neurons. In males, NCM neurons also appear to be sensitive to call modifications in the spectral domain, however changes in magnitude of responses (increase or decrease) depended on the acoustic cue that had been modified.Our results provide evidence that the NCM is a telencephalic auditory region that contributes to the processing of the distance call, in females as well in males. However, how the distance call is processed and represented in the NCM appears to differ between males and females. In females, the NCM could be involved in dicrimination between call stimuli whereas, in males, its functional role in call-processing remains to be determined. Our results also suggest that, in females, social experience with the call of individuals, by affecting the degree to which neurons discriminated between these calls, may shape the functional properties of neurons in a telencephalic auditory area. The functional properties of auditory neurons may therefore change continuously to adapt to the social environment
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Meisel, Joshua D. (Joshua Daniel). "The genetic, neuronal, and chemical basis for microbial discrimination in Caenorhabditis elegans." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104172.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references.
Discrimination among pathogenic and beneficial microbes is essential for host organism immunity and homeostasis. Increasingly, the nervous system of animals is being recognized as an important site of bacterial recognition, but the molecular mechanisms underlying this process remain unclear. Chapter One discusses how the nematode Caenorhabditis elegans can be used to dissect the genetic and neuronal mechanisms that coordinate behavioral responses to bacteria. In Chapter Two, we show that chemosensory detection of two secondary metabolites produced by Pseudomonas aeruginosa modulates a neuroendocrine signaling pathway that promotes C. elegans avoidance behavior. Specifically, secondary metabolites phenazine- I -carboxamide and pyochelin activate a G protein-signaling pathway in the ASJ chemosensory neuron pair that induces expression of the neuromodulator DAF-7/TGF-[beta]. DAF-7, in turn, activates a canonical TGF-P signaling pathway in adjacent interneurons to modulate aerotaxis behavior and promote avoidance of pathogenic P. aeruginosa. This chapter provides a chemical, genetic, and neuronal basis for how the behavior and physiology of a simple animal host can be modified by the microbial environment, and suggests that secondary metabolites produced by microbes may provide environmental cues that contribute to pathogen recognition and host survival. Genetic dissection of neuronal responses to bacteria in C. elegans can also lend insights into neurobiology more generally. In Chapter Three we show that loss of the lithium-sensitive phosphatase bisphosphate 3'-nucleotidase (BPNT-1) results in the selective dysfunction of the ASJ chemosensory neurons. As a result, BPNT- 1 mutants are defective in behaviors dependent on the ASJ neurons, such as pathogen avoidance and dauer exit. Acute treatment with lithium also causes reversible dysfunction of the ASJ neurons, and we show that this effect is mediated specifically through inhibition of BPNT-1. Finally, we show that lithium's selective effect on the nervous system is due in part to the limited expression of the cytosolic sulfotransferase SSU-1 in the ASJ neuron pair. Our data suggest that lithium, through inhibition of BPNT- 1 in the nervous system, can cause selective toxicity to specific neurons, resulting in corresponding effects on behavior of C. elegans. In Chapter Four I discuss the future directions for the genetic dissection of pathogen recognition in C. elegans.
by Joshua D. Meisel.
Ph. D.
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Ortiz, Cantin. "Neuronal discrimination of visual environments differentially depends on behavioural context in the hippocampus and neocortex." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS311.
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Créer des souvenirs de son environnement est une aptitude fondamentale à la survie, pour trouver de la nourriture, un abri ou échapper à des prédateurs. Pour former des souvenirs spatiaux, il faut générer une carte mentale de l'espace, appelée carte cognitive. On pense que ces cartes apparaissent dans CA1, la couche de sortie de l'hippocampe, une région du cerveau cruciale pour former de nouveaux souvenirs épisodiques. Pour utiliser des souvenirs spatiaux, il faut savoir si un environnement a déjà été visité. Cela nécessite de différencier des environnements qui peuvent paraître similaires mais sont pourtant distincts. Le gyrus denté (DG), la couche d'entrée de l'hippocampe, semble jouer un rôle fondamental pour cela. En effet, il génère des représentations neuronales fortement décorrélées, même lorsque les signaux d'entrée présentent un haut degré de similitude. Avant d'atteindre l'hippocampe, les représentations visuelles se forment dans le cortex visuel primaire (V1). V1 est traditionnellement considéré comme une région qui représente des caractéristiques visuelles de bas niveau, telles que l'orientation et la longueur de barres. Cependant, des recherches récentes ont démontré que, aussi tôt dans le flux sensoriel, les représentations neuronales sont déjà modulées par le comportement et des représentations spatiales émergent.Les distinctions entre ces deux régions étant plus complexes qu'on ne le pensait, nous nous sommes demandé comment elles pouvaient contribuer de manière différenciée au traitement sensoriel. Notre hypothèse est que les cortex sensoriels primaires fournissent une représentation fidèle de l'environnement sensoriel aux autres régions, tandis que l'hippocampe produit une carte cognitive pondérée en fonction de la pertinence comportementale des entrées sensorielles. Pour tester cette hypothèse, nous avons cherché à déterminer comment les stimuli sensoriels complexes dépendent différemment du contexte comportemental dans le V1, le DG et CA1. Nous avons utilisé l'imagerie calcique à deux photons pour enregistrer l'activité neuronale de souris maintenues par la tête et navigant dans un couloir linéaire en réalité virtuelle. Les souris ont été exposées à différents environnements en changeant les textures visuelles le long du couloir virtuel. Pendant la navigation active, les mouvements dans l'environnement virtuel étaient contrôlés par la course de l'animal sur une roue. En revanche, dans la condition, la scène visuelle était complètement découplée des mouvements de l'animal.Nous avons montré que les environnements pouvaient être différenciés à partir de l'activité de neurones uniques dans toutes les régions pendant la navigation active. Dans la condition passive, la discrimination restait élevée dans V1 tandis que dans l'hippocampe elle chutait au niveau de la chance. Un décodeur entraîné à prédire l'environnement visité à partir de l'activité de tous les neurones a révélé que la discrimination au niveau de la population était similairement affectée par le contexte comportemental. En outre, nos résultats indiquent que le degré de discrimination est corrélé avec la vitesse de course dans l'hippocampe, mais pas dans V1. Cela suggère que l'hippocampe dépend davantage du comportement que V1.Nous avons donc conclu que l'engagement dans la tâche est nécessaire pour la discrimination neuronale dans l'hippocampe, alors que cela n'exerce qu'une influence dans V1. Cela suggère que les cortex sensoriels primaires servent de discriminateurs généraux robustes des entrées sensorielles, tandis que l'hippocampe discrimine sélectivement les entrées pertinentes pour le comportement. Dans l'ensemble, ces résultats révèlent comment les informations sur l'environnement sont traitées de manière différenciée lorsqu'elles sont transmises à l'hippocampe avec des implications fondamentales pour notre compréhension de la manière dont le cerveau filtre l'information au fur et à mesure qu'elle est mise à disposition de l'hippocampeForming memories of the environment is essential for survival, whether it is for finding food, escaping predators or seeking shelter. To create spatial memories, one first needs to generate a mental representation of the surroundings, which is referred to as a cognitive map. Such maps are believed to emerge in the hippocampus, a brain region known to play a crucial role in the formation of new episodic memories, and more specifically in its output layer CA1. To efficiently use spatial memories, it is necessary to be able to ascertain whether a location has already been visited. This requires discriminating between potentially similar yet distinct sensory environments. It is thought that the dentate gyrus (DG), the entry layer of the hippocampus, plays a pivotal role in this ability. Indeed, it has been shown to perform neuronal pattern separation by creating decorrelated neuronal representations of its inputs, even when they share a high degree of similarity. Before reaching the hippocampus, sensory signals are initially processed in sensory cortices. Visual representations are formed in the primary visual cortex (V1), which is situated at the earliest stage of the neocortical hierarchy. V1 has traditionally been thought of as a brain region that represents low-level visual features, such as bars of a specific orientation or length. However, recent research has demonstrated that neuronal activity is already behaviourally modulated at this initial level of visual processing, with spatial representations emerging concurrently.Considering the growing evidence that the distinctions between these two regions are more complex than previously thought, we wondered how they may differentially contribute to sensory processing. We hypothesised that primary sensory cortices provide a faithful representation of the sensory environment to distributed brain regions, whereas the hippocampus produces a cognitive map that is weighted according to the behavioural relevance of the sensory inputs. To test this hypothesis, we aimed to determine how complex sensory stimuli differentially depend on the behavioural context in V1, CA1 and DG. We performed two-photon calcium imaging of head fixed mice navigating in a virtual-reality linear track. Mice were exposed to alternating environments by changing visual textures along the virtual corridor. During active navigation, movements in the virtual environment were controlled by the animal motion on a running wheel. By contrast, in a passive open-loop condition, the visual scene was completely uncoupled from animal locomotion.We found that environments could be discriminated based on the activity of single neurons in all regions during active navigation. However, while neurons in V1 maintained a high level of discrimination in the passive exposure condition, those in the hippocampus failed to discriminate between environments. A decoder trained to predict the visited corridor based on the activity of all neurons revealed that the discrimination at the population level was similarly affected by the behavioural context. Moreover, the results indicated that the degree of discrimination correlated with running speed in the hippocampus, but not in V1, which further supports the idea that neuronal activity is more dependent on the current behaviour in the hippocampus than in V1.We concluded that task engagement is therefore necessary for neuronal discrimination in the hippocampus, while it simply modulates it in V1, suggesting that primary sensory cortices serve as robust general-purpose discriminators of sensory inputs, while the hippocampus selectively discriminates behaviourally relevant inputs. Overall, these results reveal how information about the environment is differentially processed as it is transmitted to the hippocampus, with fundamental implications for our understanding of how the brain filters information as it is made available to the memory circuits in the hippocampus
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Ahn, Sungwoo. "Transient and Attractor Dynamics in Models for Odor Discrimination." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1280342970.
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Abolafia, Moya Juan Manuel. "Neuronal basis of auditory adaptation and temporal discrimination in the auditory cortex of the awake freely moving rat." Doctoral thesis, Universitat de Barcelona, 2011. http://hdl.handle.net/10803/31992.
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La adaptación que ocurre en el sistema auditivo es un fenónemo que todos experimentamos cuando dejamos de oir sonidos irrelevantes, constantes o incluso molestos. La adaptación para sonidos conocidos aumenta también la sensibilidad y la percepción para estímulos nuevos o poco conocidos. Por tanto, la similaridad entre la historia previa de estimulación y la subsiguiente también puede influenciar la adaptación. La adaptación a la estimulación repetida es un fenómeno que se ha visto en diferentes modalidades sensoriales o especies de animales. El curso temporal de la adaptación en corteza auditiva primaria (A1) se ha estudiado principalmente en intervalos entre estímulos muy rápidos (<400ms) y diferentes mecanismos han sido sugeridos (inhibición sináptica, disbalance excitación-inhibición, inhibición lateral, disminución de la excitación, o inhibición aumentada), aunque los mecanismos intrínsecos neuronales casi no han sido considerados. Por otro lado, numerosos estudios han mostrado el efecto que tiene la anestesia sobre la excitabilidad cortical, pudiendo, por tanto, afectar al estudio de la adaptación. Por último, la adaptación podría estar influenciada por estructuras subcorticales (como el colículo inferior o el tálamo) aunque la influencia intracortical también se ha demostrado. El primer estudio presentado en este trabajo tiene como objetivo caracterizar, en la rata despierta en movimiento, el curso temporal de la adaptación auditiva en las neuronas únicas de A1 aisladas con tetrodos. Con este propósito, se estudió cómo el intervalo entre estímulos, la duración o la intensidad de la estimulación previa afectaba a la amplitud de respuesta y su latencia de respuesta. También se estudió el curso temporal durante la estimulación sostenida y el fenómeno de la postadaptación.
La comprensión de cómo la actividad neuronal codifica la información sensorial sigue siendo una cuestión fundamental en el campo de la atención auditiva. Así, la codificación de la información temporal es un aspecto clave en A1. El análisis de la “información mutua” de la respuesta neuronal nos permite cuantificar el contenido de la información de la actividad neuronal. Por otro lado, la variabilidad de la respuesta neuronal podría ser un parámetro clave para la codificación de los estímulos relevantes durante una tarea. También, la respuesta neuronal sostenida se ha sugerido que podría aportar información adicional en el animal en comportamiento. Hasta el momento, se desconoce cómo las neuronas únicas de A1 codifican la categoría temporal de los estímulos auditivos. Con este objetivo se registró la actividad de neuronas únicas en A1, por medio de tetrodos, en el animal en comportamiento. Las ratas debían discriminar si dos sonidos idénticos estaban separados por 150 o 300 ms y se ha estudiado el contenido de la información, la variabilidad y las respuestas post-estímulo de la actividad neuronal en el estado atentivo y el pasivo del animal.
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Alzaher, Mariam. "Mismatch negativity, un marqueur neuronal de la plasticité spatiale auditive chez les sujets sourds unilatéraux." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30253.
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Cette thèse évalue les différentes fonctions d'audition spatiale chez 3 types de populations : Normaux entendants (NE), sourds unilatéraux (SU) et sourds bilatéraux (SB). Afin de découvrir les mécanismes qui soulignent les stratégies spatio-auditives adaptative qui sont observés chez les SU avec surdité acquise. Le but principal de la thèse est de vérifier si la MMN pourrait être un marqueur neuronal de la plasticité spatiale auditive observée chez les patients SU, et de vérifier se les corrélats neuronaux sont cohérentes avec les performances spatiales auditives. Deux types d'investigations ont été appliqués sur 20 sujets NE, 21 SU et 14 SB. La première investigation s'agit d'un test d'identification de source sonore mesuré par l'erreur quadratique moyenne (RMS). La deuxième évaluation est une étude électroencéphalographie qui sert à analyser la MMN. La MMN étant défini comme un potentiel évoqué qui reflète la capacité du cerveau à détecter un changement dans les propriétés physiques d'un son. Nous avons utilisé un son standard dans une position de référence (50°) avec 3 déviation par rapport au standard (10°, 20° et 100°) dans des conditions binaurales et monaurales. Les sujets sourds unilatéraux ont été divisé en 3 groupes selon leur performance spatiale. Le groupe des bons performeurs (SU low rms) a montré des meilleurs scores RMS en comparaison avec les NE munie d'un bouchon d'oreille (NE-mon), avec des performances similaires à ceux des sujets NE en binaurale. Une augmentation progressive de la MMN avec l'angle de la déviation par rapport au standard a été noté chez tous les groupes. Avec une réduction importante de la MMN chez les NH en monaurale quand le bouchon a été appliqué du côté du standard. La MMN a montré des résultats cohérents avec nos observations comportementales, ou les sujets SU avec un bon score RMS avait également des amplitudes de la MMN plus importantes que celles des sujets NE en condition monaurale et similaires à celles des NE en condition binaurale. Les sujets SU possèdent des stratégies adaptatives saptio-auditives. Notre étude a pu démontré que la plasticité corticale spatio-auditive qui a lieu suite à la surdité est reflété par la MMN. Les observations neuronales (MMN) sont corrélées avec les observations comportementaux de localisation spatiale. Ce qui signifie que la plasticité corticale qui a lieu chez ces sujets, n'est pas limités aux fonctions d'identification de la source sonores, mais dépasse ces capacités vers des mécanismes plus complexes tel que la détection de déviation et la mémoire à court terme, qui interviennent dans la fonction de discrimination spatiale des sonsThis thesis investigates different spatial hearing functions in 3 types of populations: Normal Hearing Subjects (NHS), Unilateral Hearing Loss patients (UHL) and Bilateral Hearing Loss patients ( BHL). To discover the mechanisms underlying the adaptive strategies that are observed in UHL with acquired deafness. The main aim of the thesis is to verify whether spatial Mismatch Negativity (MMN) could be a neuronal marker of spatial auditory plasticity observed in UHL patients, and to verify whether these neural correlates are consistent with the spatial auditory performance. Two types of investigations were applied to 20 NHS, 21 UHL and 14 BHL. The first investigation is a sound source identification task measured by the root mean square error (RMS). The second assessment is an electroencephalography (EEG) study where we analyzed the amplitude and latency of the MMN. MMN is defined as an auditory evoked potential that reflects the brain's ability to detect a change in one physical property of a sound. We used a standard sound in a reference position (50°) with three deviations from the standard (10° , 20°, and 100°), in binaural and monaural conditions. UHL patients were divided into 3 groups according to their spatial performances. The group of good performers (UHL {low rms}) showed better RMS scores in comparison with NHS with earplugs (NHS-mon), with performances similar to those of NHS subjects in binaural condition. A progressive increase of the MMN with the angle of deviation from the standard was noted in all groups. With a significant reduction of MMN amplitude in monaural NHS when the ear plug was applied on the ipsilateral side of the standard. MMN showed consistent variation with the behavioral observations, where UHL {low rms} patients had larger MMN amplitudes than those of monaural NHS and similar to those of binaural NHS. UHL patients have adaptive spatial auditory strategies. Our study was able to demonstrate that spatial auditory plasticity that occurs after deafness can be reflected by the MMN. Neural observations (i.e. the MMN) are correlated with behavioral observations of spatial source identification. This means that the spatial cortical plasticity, that took place in these subjects, is not limited to the functions of identification of the sound source, but exceeds these capacities towards more complex mechanisms such as deviance detection and short-term memory, that are involved in the spatial discrimination function
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Sun, Weilun [Verfasser], and Alexander [Gutachter] Dityatev. "Role of retrosplenial cortex in context discrimination and the underlying neuronal coding in mouse (mus musculus) / Weilun Sun ; Gutachter: Alexander Dityatev." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2020. http://d-nb.info/1219965065/34.
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Larsson, Johan P. "Modelling neuronal mechanisms of the processing of tones and phonemes in the higher auditory system." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/97293.
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S'ha investigat molt tant els mecanismes neuronals bàsics de l'audició
com l'organització psicològica de la percepció de la parla. Tanmateix,
en ambdós temes n'hi ha una relativa escassetat en quant a modelització.
Aquí describim dos treballs de modelització.
Un d'ells proposa un nou mecanisme de millora de selectivitat de freqüències
que explica resultats de experiments neurofisiològics investigant
manifestacions de forward masking y sobretot auditory streaming en
l'escorça auditiva principal (A1). El mecanisme funciona en una xarxa
feed-forward amb depressió sináptica entre el tàlem y l'escorça, però
mostrem que és robust a l'introducció d'una organització realista
del circuit de A1, que per la seva banda explica cantitat de dades neurofisiològics.
L'altre treball descriu un mecanisme candidat d'explicar la trobada
en estudis psicofísics de diferències en la percepció de paraules entre
bilinguës primerencs y simultànis. Simulant tasques de decisió lèxica
y discriminació de fonemes, fortifiquem l'hipòtesi de que persones
sovint exposades a variacions dialectals de paraules poden guardar
aquestes en el seu lèxic, sense alterar representacions fonemàtiques .Though much experimental research exists on both basic neural mechanisms of hearing and the psychological organization of language perception, there is a relative paucity of modelling work on these subjects. Here we describe two modelling efforts. One proposes a novel mechanism of frequency selectivity improvement that accounts for results of neurophysiological experiments investigating manifestations of forward masking and above all auditory streaming in the primary auditory cortex (A1). The mechanism works in a feed-forward network with depressing thalamocortical synapses, but is further showed to be robust to a realistic organization of the neural circuitry in A1, which accounts for a wealth of neurophysiological data. The other effort describes a candidate mechanism for explaining differences in word/non-word perception between early and simultaneous bilinguals found in psychophysical studies. By simulating lexical decision and phoneme discrimination tasks in an attractor neural network model, we strengthen the hypothesis that people often exposed to dialectal word variations can store these in their lexicons, without altering their phoneme representations.
Se ha investigado mucho tanto los mecanismos neuronales básicos de la audición como la organización psicológica de la percepción del habla. Sin embargo, en ambos temas hay una relativa escasez en cuanto a modelización. Aquí describimos dos trabajos de modelización. Uno propone un nuevo mecanismo de mejora de selectividad de frecuencias que explica resultados de experimentos neurofisiológicos investigando manifestaciones de forward masking y sobre todo auditory streaming en la corteza auditiva principal (A1). El mecanismo funciona en una red feed-forward con depresión sináptica entre el tálamo y la corteza, pero mostramos que es robusto a la introducción de una organización realista del circuito de A1, que a su vez explica cantidad de datos neurofisiológicos. El otro trabajo describe un mecanismo candidato de explicar el hallazgo en estudios psicofísicos de diferencias en la percepción de palabras entre bilinguës tempranos y simultáneos. Simulando tareas de decisión léxica y discriminación de fonemas, fortalecemos la hipótesis de que personas expuestas a menudo a variaciones dialectales de palabras pueden guardar éstas en su léxico, sin alterar representaciones fonémicas.
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Pernot, Etienne. "Choix d'un classifieur en discrimination." Paris 9, 1994. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=1994PA090014.
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Dans cette thèse, nous nous posons le problème de la détermination du classifieur le plus adapté à résoudre un problème donné de discrimination. Le choix du classifieur est déjà guidé par des contraintes opérationnelles, mais au-delà de ces contraintes, et après que le classifieur a été configuré grâce à une base d'apprentissage, c'est le taux de généralisation du classifieur (ou taux de réussite) qui est le critère caractérisant sa performance. Ce taux, généralement inconnu, est estimé à l'aide d'une base de généralisation. Cette estimation dépend donc du problème de discrimination étudié, du classifieur utilisé, de la base d'apprentissage et de la base de généralisation. Ces différentes dépendances sont étudiées soit théoriquement, soit de manière expérimentale, sur une douzaine de classifieurs différents, neuronaux et classiques. Le problème de la validité de la comparaison de deux classifieurs par les estimations de leur taux de généralisation est aussi étudié, et nous obtenons des informations sur les tailles relatives à donner aux bases d'apprentissage et de généralisation. Dans un objectif de comparaison de classifieurs, Neuroclasse, un outil logiciel donnant la possibilité de tester un grand nombre de classifieurs différents, a été développé, et est précisément décrit. Dans Neuroclasse est aussi intégré un système pour la détermination automatique du classifieur fournissant le meilleur taux de généralisation estimé sur une base de généralisation fixée. Ce système est implanté sous forme d'un système expert. Ce système, testé sur différentes bases de données, donne de bons résultats, mais met en évidence un phénomène d'apprentissage de la base de généralisation, dû aux tests successifs de nombreux classifieurs sur une même base de généralisation. Nous étudions ce phénomène expérimentalement, et nous donnons un ordre de grandeur du nombre de classifieurs qu'il est possible de tester en limitant cet effet
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Kang, Jing. "Discrimination and control in stochastic neuron models." Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/3155/.
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Major topics of great interest in neuroscience involve understanding the brain function in stimuli coding, perceptive discrimination, and movement control through neuronal activities. Many researchers are designing biophysical and psychological experiments to study the activities of neurons in the presence of various stimuli. People have also been trying to link the neural responses to human perceptual and behavioral level. In addition, mathematical models and neural networks have been developed to investigate how neurons respond and communicate with each other. In this thesis, my aim is to understand how the central nervous system performs discrimination tasks and achieves precise control of movement, using noisy neural signals. I have studied, both through experimental and modelling approaches, how neurons respond to external stimuli. I worked in three aspects in details. The first is the neuronal coding mechanism of input stimuli with different temporal frequencies. Intracellular recordings of single neurons were performed with patch-clamp techniques to study the neural activities in rats somatosensory cortices in vitro, and the simplest possible neural model—integrate-and-fire model—was used to simulate the observations. The results obtained from the simulation were very consistent with that in the experiments. Another focus of this work is the link between the psychophysical response and its simultaneous neural discharges. I derived that under a widely accepted psychophysical law (Weber’s law), the neural activities were less variable than a Poisson process (which is often used to describe the neuron spiking process). My work shows how psychophysical behaviour reflects intrinsic neural activities quantitatively. Finally, the focus is on the control of movements by neural signals. A generalized approach to solve optimal movement control problems is proposed in my work, where pulses are used as neural signals to achieve a precise control. The simulation results clearly illustrate the advantage of this generalized control. In this thesis, I have raised novel, insightful yet simple approaches to study and explain the underlying mechanism behind the complexity of neural system, from three examples on sensory discrimination and neural movement control.
Books on the topic "Neuronal discrimination"
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Clark, Kelsey L., Behrad Noudoost, Robert J. Schafer, and Tirin Moore. Neuronal Mechanisms of Attentional Control. Edited by Anna C. (Kia) Nobre and Sabine Kastner. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199675111.013.010.
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Covert spatial attention prioritizes the processing of stimuli at a given peripheral location, away from the direction of gaze, and selectively enhances visual discrimination, speed of processing, contrast sensitivity, and spatial resolution at the attended location. While correlates of this type of attention, which are believed to underlie perceptual benefits, have been found in a variety of visual cortical areas, more recent observations suggest that these effects may originate from frontal and parietal areas. Evidence for a causal role in attention is especially robust for the Frontal Eye Field, an oculomotor area within the prefrontal cortex. FEF firing rates have been shown to reflect the location of voluntarily deployed covert attention in a variety of tasks, and these changes in firing rate precede those observed in extrastriate cortex. In addition, manipulation of FEF activity—whether via electrical microstimulation, pharmacologically, or operant conditioning—can produce attention-like effects on behaviour and can modulate neural signals within posterior visual areas. We review this evidence and discuss the role of the FEF in visual spatial attention.
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Chirimuuta, Mazviita, and Ian Gold. The Embedded Neuron, the Enactive Field? Edited by John Bickle. Oxford University Press, 2009. http://dx.doi.org/10.1093/oxfordhb/9780195304787.003.0010.
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This article examines the concept of the receptive field (RF) of visual neurons. It introduces the concept of visual RFs by discussing the classical picture of primary visual cortex (V1) physiology and discusses the psychophysics and computational vision of contrast discrimination to place the visual neurophysiology in context. It evaluates some recent data which questioned the classical conception of the RF and considers some options available for absorbing these data into visual theory.
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Pearce, Tim C. Chemosensation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199674923.003.0017.
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Olfaction in animals still surpasses any technological solution to chemical sensing yet conceived. While certain classes of molecular detection technologies may be capable of high sensitivity to a restricted number of compounds, unique to the biological system is its astonishing dynamic range (over 10 orders of magnitude), combining both extreme levels of sensitivity to certain key compounds of behavioural importance and varying levels of discrimination between an almost infinite variety of ligands, presented both individually and in complex combinations. For over 30 years the olfactory system of insects and mammals has provided biological sensing factors, rich inspiration, and processing principles for use in developing chemical sensing technologies. Here we focus on three such technological translations: recent rapid progress in measuring directly from olfactory binding/receptor proteins and chemosensory neurons as a biohybrid solution to chemical sensing; olfactory system based processing principles and architectures that have been applied to existing chemosensor technologies to achieve real-world sensing performance gains; and full-blown neuromorphic implementations of the olfactory pathways of animals.
Book chapters on the topic "Neuronal discrimination"
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Steinmetz, Michael A., Ranulfo Romo, and Vernon D. Mountcastle. "Cortical Neuronal Mechanisms for Frequency Discrimination in the Somesthetic Sense of Flutter." In Information Processing in the Somatosensory System, 289–303. London: Macmillan Education UK, 1991. http://dx.doi.org/10.1007/978-1-349-11597-6_21.
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Feng, Albert S., and Theodore H. Bullock. "Neuronal Mechanisms for Object Discrimination in the Weakly Electric Fish Eigenmannia Virescens." In How do Brains Work?, 233–50. Boston, MA: Birkhäuser Boston, 1993. http://dx.doi.org/10.1007/978-1-4684-9427-3_25.
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Perez-Uribe, Andres, and Héctor F. Satizábal. "Artificial Neural Networks and Data Compression Statistics for the Discrimination of Cultured Neuronal Activity." In Artificial Neural Networks and Machine Learning – ICANN 2012, 201–8. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-33269-2_26.
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Reichardt, W. "Movement Detection and Figure-Ground Discrimination." In From Neuron to Action, 267–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-662-02601-4_30.
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Linster, C., M. Kerszberg, and C. Masson. "Pheromone detection, ratio discrimination and oscillations: a new approach to olfactory coding." In Computation in Neurons and Neural Systems, 179–84. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2714-5_29.
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Northmore, David P. M., and John G. Elias. "Discrimination of Phase-Coded Spike Trains by Silicon Neurons with Artificial Dendritic Trees." In Computational Neuroscience, 153–57. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4757-9800-5_25.
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Salvadori, G., and G. Biella. "Discriminating Properties of Wide Dynamic Range Neurons by Means of Universal Multifractals." In Fractals in Biology and Medicine, 314–25. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8936-0_24.
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Ohgushi, M., H. Ifuku, and H. Ogawa. "Effects of IV Angiotensin II on Cortical Neurons During a Salt-Water Discrimination GO/NOGO-Task in Monkeys." In Olfaction and Taste XI, 539. Tokyo: Springer Japan, 1994. http://dx.doi.org/10.1007/978-4-431-68355-1_225.
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Tollin, Daniel J. "Interaural Level Difference Discrimination Thresholds and Virtual Acoustic Space Minimum Audible Angles for Single Neurons in the Lateral Superior Olive." In Hearing – From Sensory Processing to Perception, 425–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-73009-5_46.
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THUNBERG, J., F. HELLSTRÖM, M. BERGENHEIM, J. PEDERSEN, and H. JOHANSSON. "NEURONAL CODING AND MOVEMENT DISCRIMINATION IN PROPRIOCEPTION." In Neuronal Coding Of Perceptual Systems, 263–67. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812811899_0021.
Full textConference papers on the topic "Neuronal discrimination"
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Samavat, Mohammad, Dori Luli, and Sharon Crook. "Neuronal network models for sensory discrimination." In 2016 50th Asilomar Conference on Signals, Systems and Computers. IEEE, 2016. http://dx.doi.org/10.1109/acssc.2016.7869533.
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Goh, Aik, Stefan Craciun, Sudhir Rao, David Cheney, Karl Gugel, Justin C. Sanchez, and Jose C. Principe. "Wireless transmission of neuronal recordings using a portable real-time discrimination/compression algorithm." In 2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2008. http://dx.doi.org/10.1109/iembs.2008.4650196.
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Metcalfe, Benjamin, Daniel Chew, Chris Clarke, Nick Donaldson, and John Taylor. "An enhancement to velocity selective discrimination of neural recordings: Extraction of neuronal firing rates." In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6944528.
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Muresan, Denisa Bianca, Raluca-Dana Ciure, Eugen Richard Ardelean, Vasile Vlad Moca, Raul Cristian Muresan, and Mihaela Dins. "Spike sorting using Superlets: Evaluation of a novel feature space for the discrimination of neuronal spikes." In 2022 IEEE 18th International Conference on Intelligent Computer Communication and Processing (ICCP). IEEE, 2022. http://dx.doi.org/10.1109/iccp56966.2022.10053955.
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Castro-Silupu, Wilson, Monica Saavedra-Garcia, Himer Avila-George, Miguel De la Torre-Gomora, and Adriano Bruno-Tech. "Probabilistic or Convolutional-LSTM neuronal networks: a comparative study of discrimination capacity on frozen - thawed fish fillets." In 2022 11th International Conference On Software Process Improvement (CIMPS). IEEE, 2022. http://dx.doi.org/10.1109/cimps57786.2022.10035684.
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Kuebler, Eric S., Elise Bonnema, James McCorriston, and Jean-Philippe Thivierge. "Stimulus discrimination in networks of spiking neurons." In 2013 International Joint Conference on Neural Networks (IJCNN 2013 - Dallas). IEEE, 2013. http://dx.doi.org/10.1109/ijcnn.2013.6706975.
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Price, P., and D. Regan. "Periodicity in orientation discrimination threshold." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.thn4.
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We measured orientation discrimination threshold at 7.5° increments around the clock for an 8-cycle/deg grating subtending 1.0° that was located 1.25° from the foveal center. Threshold was lowest for vertical and horizontal gratings. However, rather than rising monotonically to maxima for oblique orientations, threshold rose sharply to submaxima for gratings inclined at only ~20° to horizontal or vertical before falling to weak subminima at oblique orientations. This finding held for both subjects tested. It is consistent with the idea that orientation discrimination is determined by the reltive activity of two or more orientation-tuned neural elements,1 and that the retinal area tested addressed only 4-8 such elements. This idea can also explain how subjects unconfound orientation change from covarying stimulus parameters even though cortical neurons are generally sensitive to several stimulus parameters.
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Dorogov, Alexander Yu. "Correlation Discriminator of Signals in the Class of Fast Neural Networks." In 2022 III International Conference on Neural Networks and Neurotechnologies (NeuroNT). IEEE, 2022. http://dx.doi.org/10.1109/neuront55429.2022.9805510.
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Chen, Yue, Harold E. Bedell, and Laura J. Frishman. "The Effects of Cross-Spatial-Frequency Adaptation on Speed Discrimination." In Vision Science and its Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/vsia.1996.sad.2.
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The coding of stimulus speed has been accepted to be an important component of motion processing in the visual system. How this coding is implemented, however, is still not entirely clear. In terms of its relationship with spatial and temporal contents of moving targets, speed processing is often modeled as a two-stage process (e.g. Heeger, 1990; Smith & Edgar, 1994). In the first stage, initial speed estimates are generated within individual spatial- and temporal-frequency-tuned mechanism. In the second stage, the outputs of multiple spatio-temporal frequency mechanisms from the first stage are combined to produce the speed codes that are then invariant with respect to spatial frequency. This descriptive model for speed coding makes sense from both functional and experimental perspectives. Functionally, speed coding in the visual system should not vary with respect to spatial frequency; otherwise, non-identical speed coding among spatial frequency mechanisms would perceptually make the different spatial frequency components of a single target appear to move incoherently. Experimentally, it has been demonstrated that whereas the responses of neurons at early stages, such as in VI, are spatial-frequency-tuned, the responses of some neurons at later stages, such as in MT, have broader spatial frequency bandwidths (Newsome, Gizzi & Movshon, 1983), which presumably represent the combination of inputs from several lower-level spatial frequency mechanisms.
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Šuch, Ondrej, Martin Klimo, and Ondrej Škvarek. "Phoneme discrimination using a pair of neurons built from CRS fuzzy logic gates." In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON NUMERICAL ANALYSIS AND APPLIED MATHEMATICS 2014 (ICNAAM-2014). AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4912539.
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