Abstract:
Movement-related cortical potentials (MRPs) were recorded in an auditory dichotic selective attention experiment in patients with focal lesions centered in either posterior superior temporal gyrus (temporal) or in lateral parietal cortex (parietal). Controls and temporal patients generated comparable pre-movement negative shifts (NSs) and motor potentials (MPs), onsetting about 400 ms prior to movement and maximal in amplitude over scalp sites contralateral to button press. Unilateral parietal cortex lesions markedly reduced the NSs but preserved the MP component of the MRP. The results indicate that human parietal association cortex exerts modulatory input to sensorimotor cortex, beginning at least 400 ms prior to movement. The differential effect on the NSs and MPs by parietal lesions suggests that these MRP components may have independent intracranial generators.