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Disrupted cortical conductivity in schizophrenia: TMS-EEG study
Marina Frantseva1, Jie Cui, Faranak Farzan
1Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
Cerebral Cortex (New York, N.Y. : 1991)
|October 9, 2012
Summary
Schizophrenia involves abnormal brain network activity. Transcranial magnetic stimulation (TMS) revealed excessive, widespread cortical activation in schizophrenia patients, linked to symptom severity.
Area of Science:
- Neuroscience
- Psychiatry
- Cognitive Science
Background:
- Schizophrenia is characterized by cognitive integration failures and altered neurocircuit oscillatory properties.
- Abnormal neural network characteristics may disrupt functional connectivity and signal propagation in schizophrenia.
Purpose of the Study:
- To investigate differences in electroencephalography (EEG) responses to transcranial magnetic stimulation (TMS) between schizophrenia patients and healthy controls.
- To explore the relationship between altered cortical activation patterns and schizophrenia symptomology.
Main Methods:
- EEG recordings were used to measure cortical responses to TMS of the motor cortex in individuals with schizophrenia and healthy subjects.
- Analysis focused on the propagation and oscillatory characteristics of TMS-induced neural activation.
Main Results:
- No significant differences were found in the initial TMS response between groups.
- Schizophrenia patients exhibited widespread, recurrent cortical activation post-TMS, unlike healthy controls where activation subsided.
- Increased gamma band activation correlated with positive symptoms, while theta and delta band activation correlated with negative symptoms.
Conclusions:
- Excessive cortical activation in response to stimulation may underlie aberrant signal propagation in schizophrenia.
- This mechanism could contribute to positive symptoms and cognitive deficits by disrupting information processing and exacerbating signal-to-noise ratio issues.
