8 research outputs found

    Brain-Inspired Computing

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    This open access book constitutes revised selected papers from the 4th International Workshop on Brain-Inspired Computing, BrainComp 2019, held in Cetraro, Italy, in July 2019. The 11 papers presented in this volume were carefully reviewed and selected for inclusion in this book. They deal with research on brain atlasing, multi-scale models and simulation, HPC and data infra-structures for neuroscience as well as artificial and natural neural architectures

    Brain Computations and Connectivity [2nd edition]

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    This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations. Brain Computations and Connectivity is about how the brain works. In order to understand this, it is essential to know what is computed by different brain systems; and how the computations are performed. The aim of this book is to elucidate what is computed in different brain systems; and to describe current biologically plausible computational approaches and models of how each of these brain systems computes. Understanding the brain in this way has enormous potential for understanding ourselves better in health and in disease. Potential applications of this understanding are to the treatment of the brain in disease; and to artificial intelligence which will benefit from knowledge of how the brain performs many of its extraordinarily impressive functions. This book is pioneering in taking this approach to brain function: to consider what is computed by many of our brain systems; and how it is computed, and updates by much new evidence including the connectivity of the human brain the earlier book: Rolls (2021) Brain Computations: What and How, Oxford University Press. Brain Computations and Connectivity will be of interest to all scientists interested in brain function and how the brain works, whether they are from neuroscience, or from medical sciences including neurology and psychiatry, or from the area of computational science including machine learning and artificial intelligence, or from areas such as theoretical physics

    Neurocomputational models of corticostriatal interactions in action selection

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    Schema theory is a framework based on the idea that behaviour in many areas depends on abstractions over instances called schemas, which work in a cooperative or sequential fashion, but also compete with each other for activation. Cooper & Shallice (2000) provide an implementation of schema-theory with their model that simulates how routine actions works in healthy and neurologically-impaired populations. While schema theory is helpful in representing functional interactions in the action-perception cycle, it has no commitment to a specific neural implementation. Redgrave et al.’s (2001) model of the basal ganglia is, in principle, compatible with a device that regulates the competition among schemas, carrying out action selection. This thesis is mainly concerned with improving the neurobiological plausibility of the schema theoretic account of action selection without sacrificing its theoretical underpinning. We therefore start by combining an implementation of schema-theory with a reparametrised version of the original basal ganglia model, building the model from the ground up. The model simulates two widely used neuropsychological tasks, the Wisconsin Card Sorting Test (WCST), and the Brixton Task (BRX). In order to validate the model, we then present a study with 25 younger and 25 over-60 individuals performing the WCST and BRX, and we simulate their performance using the schema-theoretic basal ganglia model. Experimental results indicate a dissociation between loss of representation (present in older adults) and perseveration of response (absent in older adults) in the WCST, and the model fits adequately simulate these findings while grounding the interpretation of parameters to the neurobiology of aging. We subsequently present a further study with 50 participants, 14 of whom have an ADHD diagnosis, performing the WCST under an untimed and a timed condition, and we then use our model to fit response time. Results indicate that impulsivity traits, but not inattention ones, predict a slower tail of responses in the untimed task and an increased number of missed responses and variability across subtasks. Using the model, we show that these results can be produced by variation of a combination of two parameters representing basal ganglia activity and top-down excitation. We conclude with recommendations on how to improve and extend the model

    Neurocomputational models of corticostriatal interactions in action selection

    Get PDF
    Schema theory is a framework based on the idea that behaviour in many areas depends on abstractions over instances called schemas, which work in a cooperative or sequential fashion, but also compete with each other for activation. Cooper & Shallice (2000) provide an implementation of schema-theory with their model that simulates how routine actions works in healthy and neurologically-impaired populations. While schema theory is helpful in representing functional interactions in the action-perception cycle, it has no commitment to a specific neural implementation. Redgrave et al.’s (2001) model of the basal ganglia is, in principle, compatible with a device that regulates the competition among schemas, carrying out action selection. This thesis is mainly concerned with improving the neurobiological plausibility of the schema theoretic account of action selection without sacrificing its theoretical underpinning. We therefore start by combining an implementation of schema-theory with a reparametrised version of the original basal ganglia model, building the model from the ground up. The model simulates two widely used neuropsychological tasks, the Wisconsin Card Sorting Test (WCST), and the Brixton Task (BRX). In order to validate the model, we then present a study with 25 younger and 25 over-60 individuals performing the WCST and BRX, and we simulate their performance using the schema-theoretic basal ganglia model. Experimental results indicate a dissociation between loss of representation (present in older adults) and perseveration of response (absent in older adults) in the WCST, and the model fits adequately simulate these findings while grounding the interpretation of parameters to the neurobiology of aging. We subsequently present a further study with 50 participants, 14 of whom have an ADHD diagnosis, performing the WCST under an untimed and a timed condition, and we then use our model to fit response time. Results indicate that impulsivity traits, but not inattention ones, predict a slower tail of responses in the untimed task and an increased number of missed responses and variability across subtasks. Using the model, we show that these results can be produced by variation of a combination of two parameters representing basal ganglia activity and top-down excitation. We conclude with recommendations on how to improve and extend the model
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