A model of working memory: bridging the gap between electrophysiology and human brain imaging
Neural Networks - Special issue on the global brain: imaging and modelling
The computational role of dopamine D1 receptors in working memory
Neural Networks - Computational models of neuromodulation
An integrative theory of the phasic and tonic modes of dopamine modulation in the prefrontal cortex
Neural Networks - Computational models of neuromodulation
Neuromodulation and Plasticity in an autonomous robot
Neural Networks - Computational models of neuromodulation
Assessing Machine Volition: An Ordinal Scale for Rating Artificial and Natural Systems
Adaptive Behavior - Animals, Animats, Software Agents, Robots, Adaptive Systems
Sustained activities and retrieval in a computational model of the perirhinal cortex
Journal of Cognitive Neuroscience
A model of computation and representation in the brain
Information Sciences: an International Journal
Memory-based cognitive framework: a low-level association approach to cognitive architectures
ECAL'09 Proceedings of the 10th European conference on Advances in artificial life: Darwin meets von Neumann - Volume Part I
Information Sciences: an International Journal
From an executive network to executive control: A computational model of the n-back task
Journal of Cognitive Neuroscience
Modelling working memory through attentional mechanisms
ICANN'06 Proceedings of the 16th international conference on Artificial Neural Networks - Volume Part I
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The prefrontal cortex (PFC) is crucially involved in the executive component of working memory, representation of task state, and behavior selection. This article presents a large-scale computational model of the PFC and associated brain regions designed to investigate the mechanisms by which working memory and task state interact to select adaptive behaviors from a behavioral repertoire. The model consists of multiple brain regions containing neuronal populations with realistic physiological and anatomical properties, including extrastriate visual cortical regions, the inferotemporal cortex, the PFC, the striatum, and midbrain dopamine (DA) neurons. The onset of a delayed match-to-sample or delayed nonmatch-to-sample task triggers tonic DA release in the PFC causing a switch into a persistent, stimulus-insensitive dynamic state that promotes the maintenance of stimulus representations within prefrontal networks. Other modeled prefrontal and striatal units select cognitive acceptance or rejection behaviors according to which task is active and whether prefrontal working memory representations match the current stimulus. Working memory task performance and memory fields of prefrontal delay units are degraded by extreme elevation or depletion of tonic DA levels. Analyses of cellular and synaptic activity suggest that hyponormal DA levels result in increased prefrontal activation, whereas hypernormal DA levels lead to decreased activation. Our simulation results suggest a range of predictions for behavioral, single-cell, and neuroimaging response data under the proposed task set and under manipulations of DA concentration.