Low-frequency EEG oscillations associated with information processing in schizophrenia.
Numerous studies have described attenuated event-related potential (ERP) component amplitudes in schizophrenia (e.g., P300, Mismatch Negativity (MMN), Error Negativity/Error-Related Negativity (Ne/ERN)). Functional magnetic resonance imaging (fMRI) studies have typically shown decreased recruitment of diverse brain areas during performance of tasks that elicit the above ERP components. Recent research suggests that phase-resetting of slow-oscillations (e.g., in the delta and theta bands) underlies the potentials observed in ERP averages. Several studies have reported that slow-oscillations are increased in amplitude in people with schizophrenia at rest. Few studies have examined event-related low-frequency oscillations in schizophrenia. We examined event-related evoked and induced delta and theta activity in 17 people with schizophrenia and 17 healthy controls in two go/no-go task variants. We analyzed stimulus-related and response-related oscillations associated with correct-hits, correct-rejects and false-alarms. Our results reveal a pattern of reduced delta and theta activity for task-relevant events in schizophrenia. The findings indicate that while low-frequency oscillations are increased in amplitude at rest, they are not coordinated effectively in schizophrenia during various information processing tasks including target-detection, response-inhibition and error-detection. This slow-oscillation coordination abnormality may help explain the decreased recruitment of brain areas seen in fMRI studies.
Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada. bates@interchange.ubc.ca
Alan T
AT
Bates
Kent A
KA
Kiehl
Kristin R
KR
Laurens
Peter F
PF
Liddle
D000328:Adult; D000704:Analysis of Variance; D003657:Decision Making / Q000502:physiology; D003700:Delta Rhythm; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008606:Mental Processes / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011336:Probability; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013223:Statistics as Topic; D013826:Theta Rhythm