Spatio-temporal Analysis of Brain Activities on Aperture Problem

Abstract

The aperture problem is a motion perception through a small window involved ambiguity both in a speed and a direction of the motion. It has been analyzed in various experimental approaches with knowledge about the early motion process in visual pathways of the human brain. Some of the present authors had investigated correct answer rate of the moving orientation and analyzed brain activities with different experimental parameters, such as line speed, radius of the apertures, and length of a line. The present authors recorded electroencephalograms (EEGs) from a subject and estimated their sources and latencies in the brain using the equivalent current dipole source localization (ECDL) method. We compared localized ECDs for two different line speeds (Type 1: 10msec/pixel and Type 2: 20msec/pixel). At the latency of the appearance of aperture, ECDs were localized along the ventral pathway concern with the recognition of form. After appearance of the line, ECDs were localized along the dorsal pathway concern with the recognition of movement. In addition, after appearance of another aperture, ECDs were localized to the middle frontal gyrus and the inferior frontal gyrus.