Distinct representation of cognitive flexibility and habitual stability in the primate putamen, caudate, and ventral striatum

The putamen is believed to receive value information from the ventral striatum to the caudate and then to the putamen for the generation of habitual actions. However, it is a question what value the putamen neurons process and whether the putamen receives serially processed value through the striatal structures. We found that neurons in the primate putamen, caudate, and ventral striatum selectively encoded flexibly updated values for adaptive choices with similar learning speeds, rather than stably sustained values for habit. In reversal value learning, rostral striatum neurons dynamically adjusted their value discrimination responses for adaptive saccades following reversals. Notably, the value acquisition speeds within trials were similar, proposing a parallel value update in each striatal region. However, in stable value retrieval, most did not encode the values for habitual saccades. Our findings suggest that the rostral striatum including the putamen is selectively involved in the parallel processing of cognitive flexibility. ### Competing Interest Statement The authors have declared no competing interest.