Parieto-frontal networks for eye-hand coordination and movements.

Eye-hand coordination lies at the core of our daily actions and interactions with objects and people around us, and is central to understanding how the brain creates internal models of the action space and generates movement within it. Eye-hand coordination remains a very complex and elusive problem, which is further complicated by its distributed representation in the brain. In fact, evolution did not confine such a crucial function to a single area, but rather assigned it to several distributed cortical and subcortical systems, where encoding mechanisms can satisfy multiple demands and the consequences of lesions are less disruptive. We will discuss evidence suggesting that eye-hand coordination is, indeed, an emerging function of internal parietal operations and of their interplay with frontal cortex, where the cortical eye and hand motor output domains reside. Therefore, coordination of eye and hand movements requires an appropriate spatiotemporal activation of the subcortical structures which control the eyes and hand. In this distributed network, information transfer between different cortical areas and with subcortical structures is based on temporally dispersed communication patterns.