Distinct neural dynamics in prefrontal and premotor cortex during flexibleperceptual decisions

Abstract

The neural mechanisms underlying flexible perceptual decisions, where the mapping between sensory input and motor action changes depending on context, remain unclear. Here we show that prefrontal and premotor cortex use distinct neural dynamics to implement different computations during flexible decisions. We trained monkeys to discriminate the dominant color of a red-green checkerboard and report their decision by choosing one of two targets1;2. By randomizing the target configuration on a trial-by-trial basis, we ensured a flexible mapping between color (red vs. green) and action choice (left vs. right), necessitating a nonlinear exclusive- or (XOR) computation3-5. We found that neural dynamics in dorsolateral prefrontal cortex (DLPFC) led to higher-dimensional population representations than those in dorsal premotor cortex (PMd). Neural activity in DLPFC first separated by target configuration, then by color choice and action choice after stimulus onset, reflecting the XOR computation. In contrast, neural dynamics in PMd led to lower-dimensional representations that only reflected action choice, the output of the XOR computation. These higher-dimensional representations in DLPFC enabled earlier decoding of both color choice and action choice compared to PMd, and were strongest in anterior and ventral DLPFC6. These findings reveal distinct computations by neural dynamics: prefrontal cortex implements flexible sensorimotor mappings through high-dimensional representations while dorsal premotor cortex reflects only the selected action.