Evoked magnetic field elicited by motion aftereffect(Mind viewed through cognitive neuroscience: Neuroimaging, a window on the brain)

Abstract

Neural correlates of motion aftereffect (MAE) was investigated using magnetoencephalogram (MEG). MAE is an after effect caused by prolonged viewing of visual motion. After gazing at a moving pattern for a while, a stationary image will appear to move in the opposite direction. Evoked magnetic field was measured when a subject observing MAE in which concentric circles appear to continuously contracting after viewing expanding real motion. Visual evoked magnetic fields (VEFs) were averaged from 37 cortical points over occipital, temporal and parietal areas of the human brain during observing MAE. MRI (magnetic resonance imaging) brain images and estimated equal current dipole locus was fitted for each subject. The results clearly indicated the main brain location activated by MAE appears to be conjunction region (meeting area of lateral occipitotemporal sulcus and inferior temporal sulcus) over the parieto-occipitotemporal cortex, corresponding to the human homologue of area MT.