title: Electrical brain responses evoked by human faces in acute psychosis.
abstract: Patients with schizophrenia are known to have behavioral deficits in recognizing faces and facial expressions. However, the ability to process simple visual stimuli appears to be intact in first-episode psychosis. The aim of this study was to examine complex visual processing, especially the event-related potentials (ERPs) elicited by human faces, in early psychosis. Never-medicated patients in acute psychosis (n=18) were compared with healthy controls (n=19). Photographs of human faces were presented in a classic oddball paradigm requiring a motor response to a smiling face. Cerebral sources of ERPs were analyzed of the averaged responses, using minimum norm estimates, and dipole models. Face-sensitive response at 145 ms after the face stimuli was of significantly higher amplitude in our never-medicated patients, and the activity distribution between the groups was clearly different. At the early phase of a psychotic illness, these alterations in face-related neuronal network processes represent perceptual disturbance in psychosis, possibly including state and trait, as well as potential physiological compensatory features.
authors.affiliation: Kuopio University Hospital, Department of Psychiatry, P.O.Box 1777, 70211 Kuopio, Finland. minna.valkonen@kuh.fi
authors.forename: Minna
authors.initials: M
authors.lastname: Valkonen-Korhonen
authors.forename: Ina M
authors.initials: IM
authors.lastname: Tarkka
authors.forename: Ari
authors.initials: A
authors.lastname: Pääkkönen
authors.forename: Jan
authors.initials: J
authors.lastname: Kremlacek
authors.forename: Johannes
authors.initials: J
authors.lastname: Lehtonen
authors.forename: Juhani
authors.initials: J
authors.lastname: Partanen
authors.forename: Jari
authors.initials: J
authors.lastname: Karhu
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005145:Face; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D011618:Psychotic Disorders / Q000503:physiopathology*; D012559:Schizophrenia / Q000503:physiopathology*