Stage-specific contributions of dorsal and ventral premotor cortices to the acquisition of arbitrary visuomotor associations.

The acquisition and consolidation of arbitrary visuomotor mappings (AVMMs) engage premotor regions, yet the distinct contributions of the dorsal (PMd) and ventral (PMv) premotor cortices remain unclear. Here, we applied continuous theta-burst stimulation (cTBS) immediately before AVMM learning to transiently disrupt PMd, PMv, or an occipital control site (V1) in 19 healthy young adults, using a within-subjects design. Participants learned arbitrary stimulus-response associations through trial-and-error feedback and completed a 24-h delayed recall test. Trial-by-trial accuracy and response times were modeled using state-space and Rescorla-Wagner frameworks to quantify learning dynamics, prediction errors, and stabilization across days. Disruption of both PMd and PMv slowed early acquisition of AVMMs to a comparable extent relative to V1. However, only PMd disruption additionally impaired next-day recall, rendering recall performance dependent on sleep quality and decoupled from learning-day performance, whereas recall following PMv disruption remained comparable to the control condition. These findings indicate that PMd, but not PMv, contributes to the stabilization of newly learned visuomotor associations, providing causal, stage-specific evidence for a functional dissociation within the human premotor cortex: PMd and PMv support early rule formation and exploratory learning, whereas only PMd contributes to subsequent stabilization of newly learned visuomotor associations. Furthermore, they emphasize the modulatory influence of sleep on memory retention when consolidation processes are compromised, advancing mechanistic models of premotor contributions to associative sensorimotor learning.