Efficient value encoding through convergence of tactile and visual value information in the primate putamen

Abstract

The processing of diverse sensory values by a limited number of basal ganglia neurons raises the question of whether each value is processed independently or combined as the number of neurons decreases from the cortex to downstream structures. Here, we discovered that tactile and visual values were partially converged in the primate putamen, enhancing its efficiency in encoding values while preserving modality information. Humans and monkeys performed tactile and visual value discrimination tasks. Notably, the human putamen selectively represented both tactile and visual values in fMRI scans. Single-unit electrophysiology further revealed that half of the individual neurons in the macaque putamen encoded both tactile and visual values, and the other half encoded each value separately. The bimodal value neurons enable more efficient value encoding using fewer neurons than the modality-selective value neurons. Our data suggest that the basal ganglia system uses modality convergence to efficiently encode values with limited resources.