Event-related oscillations in structural and semantic encoding of faces

Abstract

Objective The ability to perceive faces is acquired through an interaction between species-specific biological mechanisms and social experience. To elucidate the mechanisms of the cognitive system underlying face recognition, we investigated cerebral oscillations related to encoding in ‘person identity nodes’. Methods EEG was measured in nine healthy adults during perception of their own face, familiar face and unfamiliar face images. Results Event-related synchronization (ERS) in theta, alpha and beta bands was initially induced in occipito-temporal areas within 0–200 ms of the presentation of facial stimuli. In addition, delta ERS over parietal and left temporal areas was greater in response to familiar faces around 0–800 ms compared with unfamiliar faces. Beta ERS over the right prefrontal area was significantly greater in response to a participant’s own face compared with a familiar face at 400–800 ms post-stimulus. Conclusions ERS within 0–200 ms reflects structural encoding of faces (i.e., N170 of the event related potential). Delta ERS within 0–800 ms suggests an association with memory retrieval. Beta ERS within 400–800 ms is consistent with the cortical areas reported to be strongly related to self-face perception in previous fMRI studies. Significance The delta and beta bands ERS might provide an index of familiarity and self-recognition, respectively.