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Delusions of alien control in the normal brain
S-J Blakemore1, D A Oakley, C D Frith
1Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK. s.blakemore@ucl.ac.uk
Neuropsychologia
|April 2, 2003
Summary
Hypnosis induced a sense of alien control in healthy individuals by altering brain activity. This suggests that overactivation in the cerebellar-parietal network may underlie delusions of control in schizophrenia.
Area of Science:
- Neuroscience
- Psychiatry
- Cognitive Psychology
Background:
- Delusions of alien control, or passivity experiences, are key symptoms in schizophrenia.
- These symptoms involve misattributing self-generated actions to external sources.
Purpose of the Study:
- To investigate the neural correlates of misattributing self-generated movements to an external source using hypnosis in healthy individuals.
- To compare brain activity during self-attributed versus externally attributed movements.
Main Methods:
- Hypnosis was used to induce a misattribution of self-generated movement in healthy participants.
- Positron Emission Tomography (PET) was used to measure brain activity during active movements.
- Brain activity was compared between movements correctly attributed to the self and those misattributed to an external source.
Main Results:
- Active movements misattributed to an external source showed significantly higher activations in the parietal cortex and cerebellum compared to self-attributed movements.
- Hypnotic suggestion altered the functioning of the cerebellar-parietal network.
Conclusions:
- The findings suggest that altered functioning of the cerebellar-parietal network may lead to the experience of self-produced actions as external.
- Overactivation of this network could be implicated in the brain mechanisms underlying delusions of control in schizophrenia.