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Neuropsychologia
Volume 41, Issue 8 , 2003, Pages 1058-1067

Delusions of alien control in the normal brain

S. -J. Blakemore, , a, D. A. Oakleyb and C. D. Fritha

a Wellcome Department of Imaging Neuroscience, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK

b Hypnosis Unit, Department of Psychology, University College London, Gower Street, London WC1E 6BT, UK

Received 28 May 2002; accepted 8 November 2002. ; Available online 18 February 2003.

Abstract

Delusions of alien control, or passivity experiences, are symptoms associated with schizophrenia in which patients misattribute self-generated actions to an external source. In this study hypnosis was used to induce a similar misattribution of self-generated movement in normal, healthy individuals.

Positron Emission Tomography (PET) was employed to investigate the neural correlates of active movements correctly attributed to the self, compared with identical active movements misattributed to an external source. Active movements attributed to an external source resulted in significantly higher activations in the parietal cortex and cerebellum than identical active movements correctly attributed to the self. We suggest that, as a result of hypnotic suggestion, the functioning of this cerebellar-parietal network is altered so that self-produced actions are experienced as being external. These results have implications for the brain mechanisms underlying delusions of control, which may be associated with overactivation of the cerebellar-parietal network.

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"Understanding delusions of alien control"

Johannes Roessler

The common theme of delusions of alien control is the idea that one's psychological states or one's bodily movements are being controlled by others, in a way that involves none of the mechanisms we ordinarily use to influence others' attitudes and behaviour. For example, one schizophrenic patient described her situation as follows: 'when I reach my hand for the comb it is my hand and arm which move, and my fingers pick up the pen, but I don't control them (..) I am just a puppet who is manipulated by cosmic strings. When the strings are pulled my body moves and I can't prevent it.' Common psychiatric classifications distinguish passivity of volition, as in this example, from passivity of emotion (patients report that their expressive behaviour manifests someone else's emotions) and passivity of impulse (patients report that they experience externally generated impulses). A similar condition is the phenomenon of thought insertion, where patients claim that someone else's thoughts have been put in their mind.

I want to discuss three questions raised by delusions of alien control. (1) What makes it so hard to understand the delusions? (2) Is it nevertheless possible to understand them? (3) What, if anything, can reflection on the first two questions teach us about what it is to be aware of a mental state, or action, as one's own?

http://www.unifr.ch/philo/espp/abstracts/05.htm

== Disorders of self-monitoring I

Delusions of alien control Auditory hallucinations Thought insertion

Disorders of self-monitoring II

Symptoms proposed to arise from a deficit in self monitoring where actions are appraised on the basis of peripheral feedback.

There has been a loss of awareness of one's own intentions.

Disorders of monitoring the intentions of others I

Delusions of reference Paranoid delusions Third person auditory hallucinations

Disorders of monitoring the intentions of others II

Resulting from a failure to infer knowledge or intentions of others

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