The role of the eyes in processing an intact face and its scrambled image: A dense array ERP and low-resolution electromagnetic tomography (sLORETA) study

Abstract

The aim of the present study was to test whether the eyes of an intact face produced a specific brain response compared to the mouth, nose, or hair and whether their specificity was also maintained in a scrambled face. Fifteen subjects were asked to focus visual attention on global and single elements in intact faces and in their scrambled image. EEG data were recorded from 256-Hydrocel Geodesic Sensor-Net200. Event-related potentials (ERPs) analyses showed a difference between the intact face and the scrambled face from N170 component until 600 ms on the occipito-temporal montage and at 400–600 ms on the frontal montage. Only the eyes showed a difference between conditions (intact/scrambled face) at 500 ms. The most activated source detected by sLORETA was the right middle temporal gyrus (BA21) for both conditions and for all elements. Left BA21 resulted in significantly more activation in response to eyes in the intact face compared to the eyes in the scrambled face at 500 ms. The left BA21 has a central role in high-level visual processing and in understanding others' intentions. These findings suggest a specificity of the eyes and indicate that the eyes play the social and communicative role of comprehending the nonverbal intentions of others only when inserted in an intact face.

Keywords:

• Visual ERP
• Face processing
• Middle temporal gyrus
• sLORETA
• Eyes processing

Acknowledgments

The authors thank the Proof-Reading-Service for their English language editing.