Forward Models and State Estimation in Posterior Parietal Cortex

Abstract

During on-line control of movement, the posterior parietal cortex (PPC) serves as a functional bridge between sensory and motor areas in the brain. One of the sensorimotor functions of this area appears to be prediction of the state of the arm during movement. Because sensory information is substantially delayed, it has been proposed that the brain makes use of an internal forward model that integrates both sensory and motor feedback signals to estimate current and upcoming positions and motions of the limb during reaching. These predicted states are more useful for rapid on-line control than are delayed sensory signals. The first part of this chapter focuses on investigations of on-line control mechanisms in PPC. The results of these studies indicate that one of the functions of PPC is to serve as a forward model. The second section highlights research that aims to read-out forward state estimates from PPC neurons and harness them for direct control of neural prostheses.