Information processing of visually-induced apparent self motion in the cortex of humans: Analysis with magnetoencephalography

The cortical site which processes information on whole-body linear displace ment is unknown. In this study, neuromagnetic responses to a visually-induc ed linear vection were recorded in 5 healthy, right-handed, adult subjects using a 122-channel whole cortex neuromagnetometer. We presented expanding rectangles on the screen which came into view one after another and acceler ated in expanding speed at random cycle, giving the subjects the sensation of linear self motion (linear vection) through an illusory tunnel with occa sional acceleration. Clear responses of magnetic fields related to the acce lerative event were obtained in both hemispheres around the parietal and te mporal regions. The dipole sources of the component were estimated in the c ortex around the superior temporal sulcus, insula and medial superior tempo ral area. Some parts of these regions may have been comprised in the vestib ular cortex, suggesting that it processes the sensation of linear self moti on and plays an important role in space perception.