An earlier component of face perception detected by seeing-as-face task.

To investigate the time sequence of the neural processes underlying face perception, magnetoencephalography was performed using a seeing-as-face task, in which visual inputs were identical across two conditions, but subject perceptions differed: one being a non-specific pattern of geographical shapes, the other being a percept of a face. Subtraction between the two conditions revealed a response occurring 120 ms after stimulus onset in right occipital, approximately 50 ms earlier than previously reported response at a latency of 170 ms at the right fusiform gyrus. As our novel task completely excluded differences in low-level properties of visual stimuli between control and face conditions, these two responses were considered specific to face perception. The result supported the two-stage theory of face processing.