The role of the parietal cortex in the neural processing of saccadic eye movements

Abstract

The lateral intraparietal area has a signal that describes a saccade target, maintains the memory of a saccade plan during a delay, and describes the saccade itself. It is unlikely, however, that this signal generates a plan for the saccade, because most neurons with this delayed saccade activity also respond, sometimes more strongly, to salient stimuli that are unlikely to be saccade targets. Instead, it is more likely that this saccadic signal performs two functions unrelated to saccade planning itself. The first function is to contribute to a salience map: it is well known that attention is located at the goal of a saccadic eye movement, and recent experiments detailed here show that the attentional advantage of the saccade goal is [figure: see text] maintained throughout the delay period of a memory-guided saccade. The saccade signal, presumably driven by the frontal eye fields or other prefrontal cortical areas, informs the salience map of a saccade plan, and therefore renders the goal of the saccade a salient location for attentional processes and, possibly, to provide targets for future saccades. The second function is to use the saccade signal to provide information by which the parietal cortex can update the visual representation to compensate for an eye movement, thus maintaining a spatially accurate vector map of the visual world despite a moving eye.