Mechanisms of face perception in humans: an MEG study]

In this review article, we summarize our results from magnetoencephalography (MEG) and electroencephalography (EEG) studies on face perception. The primary results were as follows: (1) facial (eye and mouth) movements are processed differently from general motion perception, but eye and mouth movements are likely processed in the same manner. (2) In a study investigating the interaction between auditory and visual stimuli relating to vowel sounds in the auditory cortex, vowel sound perception in the auditory cortex, at least in the primary processing stage, was not affected by simultaneously viewing mouth movements. (3) In a study investigating the effects of face contour and features on early occipitotemporal activity when viewing eye movement, there was evidence of specific information processing for eye movements in the occipitotemporal region, and this activity was significantly influenced by whether the movements appeared with the face contour and/or features. (4) In a study investigating the effects of inverting facial contour (hair and chin) and features (eyes, nose and mouth) on the processing of static and dynamic face perception, activity in the right fusiform area was more affected by the inversion of features, whereas activity in the left fusiform area was more affected by disruption of the spatial relationship between the contour and features in static face perception, and activity in the right occipitotemporal area was most affected by inversion of the facial contour in dynamic face perception. (5) In a study investigating the perception of changes in facial emotion, the areas of the brain involved in perceiving changes in facial emotion were found to have not matured by 14 years of age.