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Dopamine neurotransmission has long been known to exert a powerful influence over the vigor, strength, or rate of responding. However, there exists no clear understanding of the computational foundation for this effect; predominant accounts of dopamine’s computational function focus on a role for phasic dopamine in controlling the discrete selection between(More)
The computational framework of reinforcement learning has been used to forward our understanding of the neural mechanisms underlying reward learning and decision-making behavior. It is known that humans vary widely in their performance in decision-making tasks. Here, we used a simple four-armed bandit task in which subjects are almost evenly split into two(More)
A large number of computational models of information processing in the basal ganglia have been developed in recent years. Prominent in these are actor-critic models of basal ganglia functioning, which build on the strong resemblance between dopamine neuron activity and the temporal difference prediction error signal in the critic, and between(More)
This Commentary compares the connections of the dopaminergic system with the striatum in rats and primates with respect to two levels of striatal organization: a tripartite functional (motor, associative and limbic) subdivision and a compartmental (patch/striosome-matrix) subdivision. The topography of other basal ganglia projections to the dopaminergic(More)
Anatomical findings in primates and rodents have led to a description of several parallel segregated basal ganglia-thalamocortical circuits leading from a distinct frontocortical area, via separate regions in the basal ganglia and the thalamus, back to the frontocortical area from which the circuit originates. One of the questions raised by the concept of(More)
The current view of basal ganglia organization holds that functionally corresponding subregions of the frontal cortex, basal ganglia and thalamus form several parallel segregated basal ganglia-thalamocortical circuits. In addition, this view states that striatal output reaches the basal ganglia output nuclei (the substantia nigra pars reticulata (SNR) and(More)
Understanding the effects of motivation on instrumental action selection, and specifically on its two main forms, goal-directed and habitual control, is fundamental to the study of decision making. Motivational states have been shown to 'direct' goal-directed behavior rather straightforwardly towards more valuable outcomes. However, how motivational states(More)
Reinforcement learning (RL) is a process by which organisms learn from their interactions with the environment to achieve a goal (Sutton & Barto, 1998). In RL, learning is contingent upon a scalar reinforcement signal that provides evaluative information about how good an action is in a certain situation, without providing an instructive supervising cue as(More)
The serotonergic system and the orbitofrontal cortex have been consistently implicated in the pathophysiology of obsessive compulsive disorder. Yet, the relations between these two systems and the ways they interact in producing obsessions and compulsions are poorly understood. The present study tested the hypothesis that pathology of the orbitofrontal(More)
This study aimed at developing a rat model of obsessive compulsive disorder based on the hypothesis that a deficient response feedback mechanism underlies obsessions and compulsions. Rats were trained to lever press for food, whose delivery was signaled by the presentation of a compound stimulus (light+tone). Subsequently, the classical contingency between(More)