title: Transient inability to distinguish between faces: electrophysiologic studies.
abstract: It is not known with certainty at which level of face processing by the cortex the distinction between a familiar and an unfamiliar face is made. Subdural electrodes were implanted under the fusiform gyrus of the right temporal lobe in a patient who developed an unusual inability to distinguish differences between faces as part of the epileptic aura ("all faces looked the same"). A cortical region located posterior to the epileptic focus was identified that exhibited a maximum evoked response to the presentation of facial images (N165), but not to objects, scenes, or character strings. Evoked potentials elicited by a variety of visual images indicated that any perturbation away from novel whole-face stimuli produced submaximal responses from this region of the right temporal lobe. Electrical stimulation of this region resulted in an impairment of face discrimination. It was found that presentation of familiar faces (grandmother, treating physician) produced a different response from that observed for novel faces. These observations demonstrate that within 165 msec of face presentation, and before the conscious precept of face familiarity has formed, this cortical region has already begun to distinguish between a familiar and an unfamiliar face.
authors.affiliation: Pfizer, Inc., Ann Arbor Laboratories, Michigan, USA.
authors.forename: Trevor
authors.initials: T
authors.lastname: Mundel
authors.forename: John G
authors.initials: JG
authors.lastname: Milton
authors.forename: Alexander
authors.initials: A
authors.lastname: Dimitrov
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Wilson
authors.forename: Charles
authors.initials: C
authors.lastname: Pelizzari
authors.forename: Stephen
authors.initials: S
authors.lastname: Uftring
authors.forename: Ivan
authors.initials: I
authors.lastname: Torres
authors.forename: Robert K
authors.initials: RK
authors.lastname: Erickson
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Spire
authors.forename: Vernon L
authors.initials: VL
authors.lastname: Towle
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004594:Electrophysiology / Q000379:methods; D004833:Epilepsy, Temporal Lobe / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D005074:Evoked Potentials, Visual; D005145:Face; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D010364:Pattern Recognition, Visual; D020238:Prosopagnosia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D013702:Temporal Lobe / Q000473:pathology / Q000503:physiopathology; D013997:Time Factors