Influence de la dextérité sur la représentation mentale du corps.

Disruption of body representations is central to many neurological and psychiatric disorders such as autotopagnosia and Gerstmann syndrome, yet the characterization and mechanisms by which the brain constructs body representations are not fully understood. Neuropsychological research has shown that mental representations of the body, which specify the spatial relationships between different body parts considering dynamic changes in body posture, differ from physical representations in the somatosensory cortex. Recent experimental studies have shown that structural representations are not as fixed as initially suggested. The purpose of this work was to investigate the mental representation of body extremities and the possible impact of dexterity on the resolution of this representation. To this end, I conducted two tactile recognition experiments in typically developed subjects whose results were compared with a subject who had acquired exceptional toe dexterity. The purpose of the first experiment was to compare the tactile recognition ability of toes, the purpose of our second experiment was to test how finger and toe spacing can influence estimates of the number of fingers or toes located between those stimulated in a gnosis task. The results of Experiment 1 showed that participants were worse at tactile recognition than our aplastic subject and that a lateral bias was present for toes 2 and 3. The results of Experiment 2 showed that our aplastic subject was better at identifying the toes present in the interval involving toes 1, 2 and 3 compared to the control group, the effect of the posture change did not impact our aplastic subject but had an underestimation effect in the counting task for typically developed subjects.