Planning, Coordination, and Communication: The Posterior Parietal Cortex in Eye-Hand Control.

Eye-hand coordination (EHC) is central to everyday behavior. This is often described as a sequential process in which the eyes move first to guide the hand. However, converging behavioral and neurophysiological evidence supports a fundamentally different view: Coordination arises from a distributed network that issues parallel commands and aligns effectors through structured interareal communication. Saccade and reach planning are typically initiated concurrently, with apparent timing differences driven largely by effector dynamics. Experimental dissociations reveal that coupling enhances performance but is not obligatory, particularly in bimanual or naturalistic contexts. Here we emphasize the posterior parietal cortex as a key hub integrating sensory and motor signals for planning and coordination through effector-specific subregions and their interareal interactions. Oscillatory dynamics, notably beta-band coherence, consistently associate with coordination between oculomotor and manual circuits, although whether they causally implement routing or instead index structured interactions remains unresolved. Together, these findings point to a distributed, intercommunicating network that flexibly aligns eye and hand control.