EEG coherence during hemispheric activation in schizophrenics

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Electroencephalogram (EEG) alpha-band coherence reflects functional connectivity between brain regions.
• Altered brain connectivity is implicated in the pathophysiology of schizophrenia.
• Understanding hemispheric differences in connectivity is crucial for schizophrenia research.

Purpose of the Study:

• To investigate the reactivity of EEG alpha-band coherence during motor tasks in individuals with chronic schizophrenia compared to healthy controls.
• To examine hemispheric differences in EEG coherence changes between resting and motor performance states.
• To explore potential neurophysiological markers of disrupted brain coordination in schizophrenia.

Main Methods:

• EEG recordings were obtained from 18 chronic schizophrenic patients and 30 healthy controls.
• Alpha-band coherence was measured between central and parietal regions for left and right hemisphere tasks.
• Coherence changes from rest to motor task performance (reactivity) were analyzed, comparing left and right hemispheric functions.

Main Results:

• Normal controls showed increased left central-parietal coherence for left tasks and decreased right coherence for right tasks.
• Schizophrenia patients exhibited decreased central-parietal coherence for both left and right tasks, with a more pronounced effect on the left.
• This resulted in a reversed interhemispheric difference in coherence reactivity in patients, suggesting a left-sided deviation.
• Other examined coherences (lateral-precentral, precentral-central) did not show significant left-right deviations in patients.

Conclusions:

• Findings suggest defective coordination of left central-parietal brain regions during motor tasks in individuals with chronic schizophrenia.
• The reversed interhemispheric difference in EEG coherence reactivity may indicate a specific neurophysiological abnormality in schizophrenia.
• EEG coherence analysis offers insights into the functional connectivity deficits underlying motor control impairments in schizophrenia.