Selective attention modulates face-specific induced gamma oscillations recorded from ventral occipitotemporal cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Visual Perception

Background:

• Event-related potentials (ERPs) like face-N200 from subdural electrodes suggest an obligatory, attention-insensitive response to faces.
• Neuroimaging studies show task sensitivity in the fusiform hemodynamic response to faces, creating a paradox with ERP findings.

Purpose of the Study:

• To investigate the role of selective attention in face processing by comparing electrophysiological responses to faces and houses.
• To reconcile conflicting findings between electrophysiological and hemodynamic studies of face perception.

Main Methods:

• Recorded cortical surface field potentials from 16 patients using subdural electrodes.
• Patients selectively attended to either faces or houses during the recording.
• Analyzed face-specific gamma activity and the face-N200 component at face-N200 recording sites.

Main Results:

• Face-specific gamma activity at face-N200 sites was significantly modulated by selective attention.
• The face-N200 component itself showed no modulation by selective attention.
• This suggests an initial, attention-insensitive phase followed by an attention-modulated phase in face processing.

Conclusions:

• Attentional modulation of the neural response to faces occurs after an initial, largely attention-insensitive phase.
• The findings reconcile electrophysiological and hemodynamic data, proposing a dual-phase model of face perception.
• This research clarifies the temporal dynamics of attentional effects in visual face processing.