title: Emotional expressions modulate low α and β oscillations in a cortically blind patient.
abstract: Studies of cortical blindness have suggested that some residual visual function may persist without perceptual awareness, a condition known as blindsight. To investigate electrophysiological evidence of unconscious processing of emotional stimuli, we examined the event-related oscillations (EROs) in a 62year-old male patient (TN) with affective blindsight during random stimulation of three facial expressions (fearful, happy and neutral). Spectral power analysis in response to the different emotions revealed significant differences between fearful and happy faces over the right frontal regions at 7-8Hz (low α), and between emotional and neutral faces over the left frontal sites at 12-13Hz (low β) in a time period between 100-400ms after visual stimulus onset. These results demonstrate that emotional face processing occurs very early in time in the absence of any functional striate cortex, and further reveals the existence of specific oscillatory frequencies that reflect unconscious processing of facial expressions in affective blindsight.
authors.affiliation: Laboratory of Experimental Neuropsychology, Faculty of Psychology, University of Geneva, 1205 Geneva, Switzerland; Neuropsychology Unit/Neurology Clinic, Geneva University Hospital, 1211 Geneva 4, Switzerland. Electronic address: Marzia.delzotto@hcuge.ch.
authors.forename: Marzia
authors.initials: M
authors.lastname: Del Zotto
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Deiber
authors.forename: Lore Billie
authors.initials: LB
authors.lastname: Legrand
authors.forename: Beatrice
authors.initials: B
authors.lastname: De Gelder
authors.forename: Alan John
authors.initials: AJ
authors.lastname: Pegna
mesh_terms: D000513:Alpha Rhythm / Q000502:physiology*; D000704:Analysis of Variance; D001611:Beta Rhythm / Q000502:physiology*; D001766:Blindness / Q000473:pathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D003463:Cues; D004569:Electroencephalography; D004644:Emotions / Q000502:physiology*; D005149:Facial Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology
keywords: Affective blindsight; Brain oscillations; Emotion; Hemispheric asymmetry; Time frequency analysis