YVES ROSSETTI
Institut National de la Santé et de la Recherche Médicale, INSERM, Bron and University Claude Bernard Lyon I, France

Origins of the self and the body: how do they communicate after brain lesion?

Brain lesions do affect sensory and motor capacities of the body and/or cognitive functions which include self awareness and recognition. Neglect patients often cumulate the two categories of handicap. As a top-down effect of their neurological condition, neglect patients often present with anosognosia of their sensori-motor deficits or hemiasomatognosia. This classical clinical observation suggests that the higher level cognitive function can be dissociated from the lower level or more peripheral ones. Interestingly recent results suggest that similar effects can be observed in healthy subjects when signal processing is challenged, which point to an inherent bias to reject ownership of body parts. This may explain why patients often show rejection of body parts but do not show self attribution of other's body parts. Conversely, the most effective interventions on the neglect syndrome are achieved through bottom-up interventions: vestibular stimulation and prism adaptation are two main striking examples of sensory or sensori-motor interventions that produce unexpected therapeutic benefits on the patient's higher level functions. These interventions suggest in turn that sensori-motor functions can powerfully affect cognition. Examples for this paradoxical specific communication between 'the self' and 'the body' will be described in neglect and other patients. It will be argued that explicit communication between the body and the self can be strongly disrupted when simultaneously the higher cognitive levels can be implicitly fed with powerful information which may reorganise their function.

References:
Pisella L., Rode G., Farnè A., Tilikete C., Rossetti Y. (2006) Prism Adaptation in the Rehabilitation of Patients with Visuo-spatial Cognitive Disorders. Current Opinion in Neurology, 19(6):534-542.

Rode G., Pisella L., Rossetti Y., Farnè A., Boisson D. (2003) Bottom-up transfer of visuo-motor plasticity. Prism adaptation. Progress in Brain Research. 273-287.

Rode G., Jacquin-Courtois S., Revol P., Pisella L., Sacri A.S., Boisson, Rossetti Y. (2007) Bottom-up effects of sensory conflict and adaptation on mental imagery: sensorimotor grounds for high level cognition? In:
Mast F.W. L. Jäncke, Spatial Processing in Navigation, Imagery, and Perception. Springer Science.

Rode G., Luauté J., Klos T., Courtois-Jacquin J., Revol P., Pisella P., Holmes N.P., Boisson D., Rossetti Y. Bottom-up visuo-manual adaptation: consequences for spatial cognition
In: Sensorimotor Foundations of Higher Cognition, Attention and Performance XXII, P. Haggard, Y. Rossetti and M. Kawato (Eds), Oxford University Press, 2007.

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