title: Diminished parietal cortex activity associated with poor motion direction discrimination performance in schizophrenia.
abstract: The results of multiple investigations indicate visual motion-processing abnormalities in schizophrenia. There is little information, however, about the time course and neural correlates of motion-processing abnormalities among these subjects. For the present study, 13 schizophrenia and 13 healthy subjects performed a simple motion direction discrimination task with peripherally presented moving grating stimuli (5 or 10 deg/s). Dense-array electroencephalography data were collected simultaneously. The goal was to discern whether neural deviations associated with motion-processing abnormalities among schizophrenia patients occur early or late in the visual-processing stream. Schizophrenia patients were worse at judging the direction of motion gratings, had enhanced early neural activity (about 90 ms after stimulus onset), and deficient target detection-related late neural activity over parietal cortex (about 400 ms after stimulus onset). In addition, there was a strong association (accounting for 36% of performance variance) between poor behavioral performance and lower target detection-related brain activity among schizophrenia patients. These findings suggest that abnormalities in later stages of motion-processing mechanisms, perhaps beyond extrastriate cortex, may account for behavioral deviations among schizophrenia subjects.
authors.affiliation: Smith-Kettlewell Eye Research Institute, San Francisco, CA 94115, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Ryan
authors.initials: R
authors.lastname: Brown
authors.forename: Karen R
authors.initials: KR
authors.lastname: Dobkins
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: McDowell
authors.forename: Brett A
authors.initials: BA
authors.lastname: Clementz
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology; D010296:Parietal Lobe / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000473:pathology* / Q000503:physiopathology; D013223:Statistics as Topic; D013997:Time Factors