Abnormally high EEG alpha synchrony during working memory maintenance in twins discordant for schizophrenia.
BACKGROUND
The present analyses aimed to test the prediction that schizophrenia patients and their non-schizophrenic co-twins would display reduced efficiency of the neurocognitive mechanisms subserving active maintenance of spatial information in working memory.


METHODS
Upper alpha frequency band EEG event-related desynchronization and synchronization (ERD/ERS) were calculated as percent changes in power relative to an inter-trial baseline across 4 memory loads in a spatial delayed-response task.


RESULTS
During the delay, the diagnostic groups showed equivalent ERD/ERS activity over posterior scalp regions at the lowest memory load; however, as memory load increased, patients, and to an intermediate degree, their non-schizophrenic co-twins (monozygotic and dizygotic pairs collapsed together), showed significantly greater increases in ERD/ERS amplitude as compared with controls.


CONCLUSIONS
These findings demonstrate abnormally increased ERD/ERS amplitudes with increasing memory load in patients with schizophrenia and their co-twins, consistent with inefficiency of the neurocognitive mechanisms supporting active maintenance of information across a delay.
Department of Psychology, University of California, Los Angeles, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095-1563, United States. bachman@psych.ucla.edu
Peter
P
Bachman
Junghoon
J
Kim
Cindy M
CM
Yee
Sebastian
S
Therman
Marko
M
Manninen
Jouko
J
Lönnqvist
Jaakko
J
Kaprio
Matti O
MO
Huttunen
Risto
R
Näätänen
Tyrone D
TD
Cannon
D000328:Adult; D000513:Alpha Rhythm; D001288:Attention / Q000502:physiology; D002540:Cerebral Cortex / Q000503:physiopathology; D015331:Cohort Studies; D003344:Cortical Synchronization / Q000523:psychology*; D004193:Discrimination Learning / Q000502:physiology*; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009949:Orientation / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000503:physiopathology; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics