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Minoru Kimura"Neuronal basis of reward-based action selection in the basal ganglia"

Abstract :


Estimation of the reward an action will yield is critical in decision-making.
To elucidate the role of the basal ganglia in this process, we recorded striatal neurons of monkeys who chose between left- and right-handle-turns based on the estimated reward probabilities of the actions. During a delay period before the choices, activity of more than one-third of striatal projection neurons was selective to the values of one of the two actions. Fewer neurons were tuned to relative values or action choice. These results suggest representation of action values in the striatum, which can guide action selection in the basal ganglia circuit.
Action value coding in the striatum may be a core feature of information processing in the basal ganglia. The striatum is the primary target of dopaminergic signals which regulate plasticity of cortico-striatal synaptic transmission conveying signals of actions and cognition. Thus, the striatum may be the locus where reward value is first encoded in the brain. I will discuss about the possible involvement of the basal ganglia and dopamine system in action selection.      

Selected publications

Samejima K, Ueda Y, Doya K, Kimura M (2005) Representation of action-specific reward values in the striatum. Science.Nov 25;310(5752):1337-40.
Takafumi Minamimoto, Yukiko Hori, and Minoru Kimura (2005) Complementary Process to Response Bias in the Centromedian Nucleus of the Thalamus.Science. 17 1798-1801.
Yamada H., Matsumoto N., and Kimura M (2004) Tonically Active Neurons in the Primate Caudate Nucleus and Putamen Differentially Encode
Instructed Motivational Outcomes of Action.
J. Neurosci.,24: 3500 - 3510.

Thomas Boraud