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Mise en évidence d'électrogenèses spécifiques de l'hémisphère droit non-dominant chez l'Homme intact

par Desmedt, Jean Edouard
Référence Bulletin de l'Académie nationale de médecine, 161, 9, page (623-626)
Publication Publié, 1977

Article révisé par les pairs

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Résumé :

After numerous attempts, the author has perfected a task that is well defined in time (to assure the coherence of the average cycles of the ordinator) and which would nevertheless be capable of mobilising the subject's attention during a series of successive trials, and more particularly to bring into play the cerebral capacities generally considered as associated with the right hemisphere. The task consists in the active tactile exploration with the aid of the index finger of a circular spindle (10 mm. in diameter) with a 1.5 mm hiatus in it; the electronic program governing the subject's movements step-by-step allows the hiatus to be pointed in different directions from one trial to another, according to a random sequence. The subject must then, at times determined by the program, identify by palpation the position of the gap in relation to his own body. As is shown in Fig. 1, which is typical of this series of experiments on right-handed subjects, active palpation determines the appearance of an important and prolonged positive electrogenesis in the right parietal zone of the brain. Comparison of trials with palpation of the gap (thick line) with control trials of palpation of a spindle with no gap (thus giving no spatial information to the subject) shows that this positive electrogenesis is lateralised to the right and that it lasts from 0.5 to 1.0 second after his early components. The simultaneous recording of the electro-oculogram allows all the oculomotor artefact to be excluded. Moreover, the right parietal electrogenesis has been found, whether the active palpation is done with the right or the left index finger, to follow a random sequence. The results supply arguments in favor of the view that there is no unilateral dominance of the left hemisphere and that each of the two hemispheres possesses different capacities, the capacities of the right hemisphere being able to show themselves even while the commissural interactions through the corpus callosum are intact.