Concurrent saliency and intentional maps in posterior parietal cortex

The goal for motor action represents the desired state of the individual when interacting with the world. Investigating how the goal is generated requires clarifying spatial extrapolation that involves perceptual and action processes. Here, we recorded neural activity from monkeys manually intercepting a circularly moving target being occluded. The saliency and intentional maps, which developed to locate the target of interest and the intended action goal, were thus distinguished in neural activity recorded from the lateral intraparietal cortex (LIP) and parietal reach region (PRR). Dynamic internal representations spanning from visual registration to state estimation were unveiled in both areas, with the goal for the interception being inferred as the visual consequence of the movement. The motion extrapolation was found to be an intrinsic part of movement planning, so that the continuous and stable spatial extrapolation from motion to action was prevalent in both areas. The goal estimation based on the sensory extrapolation rationalized the concurrency and correlation of saliency and intentional maps, which were found to switch their dominance by reorganizing the read-out dimensions of the spatial manifold. The extrapolation achieved at both the perceptual and motor stages not only bridged the saliency and intentional maps, but also revealed the form of the state estimation in guiding predictive sensorimotor control.