Computational and causal dissociation in primate striatum during value-guided decision-making

How neural representations carrying similar information across brain regions are translated into behavioral control remains a fundamental question in neuroscience. In the primate striatum, whether subregions make overlapping or dissociable computational and causal contributions to value-guided decisions is unresolved. Here, we show that macaque striatal subregions make dissociable, modality-specific contributions: the putamen is required for tactile-value decisions, the caudate for visual-value decisions, and the ventral striatum for both. Despite broadly shared value encoding, causal necessity is predicted not by the strength of single-neuron value discrimination or population-level decoding, but by neural geometry-behavior coupling. These findings reveal a functional organization of the primate striatum and identify neural geometry-behavior coupling as a key determinant of behavioral control.