The parietal reach region codes the next planned movement in a sequential reach task.

Abstract

Distinct subregions of the posterior parietal cortex contribute to planning different movements. The parietal reach region (PRR) is active during the delay period of a memory-guided reach task but generally not active during a memory-guided saccade task. We explored whether the reach planning activity in PRR is related to remembering targets for reaches or if it is related to specifying the reach that the monkey is about to perform. Monkeys were required to remember two target locations and then reach to them in sequence. Before the movements were executed, PRR neurons predominantly represented the reach about to be performed and only rarely represented the remembered target for the second reach. This indicates the area plays a role in specifying the target for the impending reach and may not contribute to storing the memory of subsequent reach targets.