Spatial-Temporal Analysis of Face Processing Using an ERP Study of the Thatcher Illusion

A face with the inversion of eyes and mouth relative to the rest parts of the face looks grotesque when viewed upright but not when viewed upside down, which is called "the Thatcher illusion". Brain studies indicate that this is caused by the disruption of facial information processing. However, the neural mechanism of the face processing is still ambiguous. In the current study, we investigated neural correlates of featural and configural processing in faces using a spatial-temporal analysis of event-related potentials (ERP). The results showed that the PI component was affected by face inversion but not by Thatcherization. For the N170 component, the inversion effect was salient while the Thatcherization effect interacted with orientation and hemisphere. A bilaterally distributed effect of Thatcherization was observed in inverted faces and a contrary difference was showed in upright faces. This indicated that the perceptual effect of Thatcher illusion does not parallel N170 component. Combining with the scalp topographies we come to a conclusion that the left occipito-temporal area of the brain is sensitive to featural information of visual face stimuli while the right area is sensitive to configural information.