Elsevier

Neuroscience Letters

Volume 240, Issue 3, 16 January 1998, Pages 131-134
Neuroscience Letters

Three hands: fragmentation of human bodily awareness

https://doi.org/10.1016/S0304-3940(97)00945-2Get rights and content

Abstract

We describe patient E.P. who occasionally perceives a `ghost' hand which copies the previous positions of the left hand with a 0.5–1 min time lag, but follows the movement patterns of the right hand. The symptoms started after an operation of a ruptured aneurysm, followed by an infarction of the right frontal lobe; E.P. also has a previously lesioned corpus callosum. Neuromagnetic recordings revealed that activity of the left secondary somatosensory cortex was strongly suppressed during the ghost arm percept, thereby providing an objective correlate for E.P.'s sensations. We conclude that simultaneous mental contents about body scheme may be based on neural information extracted at considerably different times, resulting in fragmentation of bodily awareness.

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Acknowledgements

This study was supported by the Academy of Finland. We thank C. Frith, S. Salenius, G. Curio, O.V. Lounasmaa, R. Paetau, S. Vanni, and V. Virsu for discussions and comments, and M. Illman for help with MEG measurements.

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