Bodily ownership modulation in defensive responses: physiological evidence in brain-damaged patients with pathological embodiment of other's body parts.
Do conscious beliefs about the body affect defensive mechanisms within the body? To answer this question we took advantage from a monothematic delusion of bodily ownership, in which brain-damaged patients misidentify alien limbs as their own. We investigated whether the delusional belief that an alien hand is their own hand modulates a subcortical defensive response, such as the hand-blink reflex. The blink, dramatically increases when the threated hand is inside the defensive peripersonal-space of the face. In our between-subjects design, including patients and controls, the threat was brought near the face either by the own hand or by another person's hand. Our results show an ownership-dependent modulation of the defensive response. In controls, as well as in the patients' intact-side, the response enhancement is significantly greater when the threat was brought near the face by the own than by the alien hand. Crucially, in the patients' affected-side (where the pathological embodiment occurs), the alien (embodied) hand elicited a response enhancement comparable to that found when the threat is brought near the face by the real hand. These findings suggest the existence of a mutual interaction between our conscious beliefs about the body and the physiological mechanisms within the body.
SAMBA - SpAtial, Motor &Bodily Awareness - Research Group, Psychology Department, University of Turin, Turin, Italy.
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Fossataro
SAMBA - SpAtial, Motor &Bodily Awareness - Research Group, Psychology Department, University of Turin, Turin, Italy.|San Camillo Hospital of Turin, Turin, Italy.
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Gindri
Ausiliatrice - Don Gnocchi Hospital of Turin, Turin, Italy.
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Mezzanato
SAMBA - SpAtial, Motor &Bodily Awareness - Research Group, Psychology Department, University of Turin, Turin, Italy.|Neuroscience Institute of Turin (NIT), University of Turin, Italy.
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Pia
SAMBA - SpAtial, Motor &Bodily Awareness - Research Group, Psychology Department, University of Turin, Turin, Italy.|San Camillo Hospital of Turin, Turin, Italy.
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Garbarini
D000328:Adult; D001767:Blinking; D001930:Brain Injuries / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006225:Hand / Q000502:physiology*; D018594:Human Body; D006801:Humans; D008297:Male; D010550:Personal Space; D055815:Young Adult