Electrophysiological correlates of presaccadic remapping in humans

Abstract

Saccadic eye movements cause rapid displacements of space, yet the visual field is perceived as stable. A mechanism that may contribute to maintaining visual stability is the process of predictive remapping, in which receptive fields shift to their future locations prior to the onset of a saccade. We investigated electrophysiological correlates of remapping in humans using event-related potentials. Subjects made horizontal saccades that caused a visual stimulus to remain within a single visual field or to cross the vertical meridian, shifting between visual hemifields. When an impending saccade would shift the stimulus between visual fields (requiring remapping between cerebral hemispheres), presaccadic potentials showed increased bilaterality, having greater amplitudes over the hemisphere ipsilateral to the grating stimulus. Results are consistent with interhemispheric remapping of visual space in anticipation of an upcoming saccade.