Thomas P White1, Verghese Joseph1, Eileen O'Regan1, Kay E Head2, Susan T Francis2, Peter F Liddle3. 1. Division of Psychiatry, University of Nottingham, A Floor, South Block, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom. 2. Sir Peter Mansfield Magnetic Resonance Centre, University Park, University of Nottingham, Nottingham NG7 2RD, United Kingdom. 3. Division of Psychiatry, University of Nottingham, A Floor, South Block, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom. Electronic address: peter.liddle@nottingham.ac.uk.
Abstract
OBJECTIVE: To delineate regional brain activity associated with the alpha oscillations related to perception of sensory stimuli, and test the hypothesis that the synchronisation of alpha oscillations with stimulus onset is impaired in schizophrenia. METHODS: Joint independent component analysis was applied to electroencephalographic and functional magnetic resonance imaging data recorded in 19 individuals with schizophrenia and 19 healthy individuals during a vibrotactile somatosensory task. RESULTS: In healthy individuals the strongest component was dominated by alpha oscillations, and was associated not only with activity in somatosensory regions but also in the insula and anterior cingulate cortex (the salience network). In schizophrenia, the strongest component had low alpha power and activity was limited mainly to somatosensory regions. Furthermore, in the healthy group, but not the patients, significant correlation was observed between the strongest component and evoked gamma power. CONCLUSION: The correlation between the alpha-dominated component and evoked gamma power is consistent with the hypothesis that gamma localised to sensory cortex elicits stimulus-locking of spatially distinct, large-scale ongoing alpha oscillations. Furthermore, this hypothesised mechanism appears to be disrupted in schizophrenia. SIGNIFICANCE: These findings suggest that a weakened alpha-gamma interaction underlies impaired recruitment of the brain during sensory information processing in schizophrenia. 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
OBJECTIVE: To delineate regional brain activity associated with the alpha oscillations related to perception of sensory stimuli, and test the hypothesis that the synchronisation of alpha oscillations with stimulus onset is impaired in schizophrenia. METHODS: Joint independent component analysis was applied to electroencephalographic and functional magnetic resonance imaging data recorded in 19 individuals with schizophrenia and 19 healthy individuals during a vibrotactile somatosensory task. RESULTS: In healthy individuals the strongest component was dominated by alpha oscillations, and was associated not only with activity in somatosensory regions but also in the insula and anterior cingulate cortex (the salience network). In schizophrenia, the strongest component had low alpha power and activity was limited mainly to somatosensory regions. Furthermore, in the healthy group, but not the patients, significant correlation was observed between the strongest component and evoked gamma power. CONCLUSION: The correlation between the alpha-dominated component and evoked gamma power is consistent with the hypothesis that gamma localised to sensory cortex elicits stimulus-locking of spatially distinct, large-scale ongoing alpha oscillations. Furthermore, this hypothesised mechanism appears to be disrupted in schizophrenia. SIGNIFICANCE: These findings suggest that a weakened alpha-gamma interaction underlies impaired recruitment of the brain during sensory information processing in schizophrenia. 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.