Role joue par les voies et aires de projection lemniscales dans le controle des afferences extralemniscales au cours du sommeil naturel chez le chat

Abstract

1. 1. The evolution during sleep of somatic responses recorded in the centrum medianum (CM) of twenty cats with implanted electrodes was studied, following section of the lemniscal paths or uni- or bilateral ablation of the primary somatomotor cortex. 2. 2. After such lesions the changes in amplitude of the CM responses during the various stages of sleep are almost completely abolished and the responses during wakefulness and fast sleep remain similar to those normally encountered during slow wave sleep. 3. 3. The usual alterations, that is, a reduction in the amplitude of the responses during fast sleep and wakefulness, are again found 4 weeks after uni- or bilateral lemniscal section or unilateral cortical ablation. This recovery does not occur after bilateral ablation of the somatomotor cortex. 4. 4. Thus, during slow wave sleep, there appears to be a reduction of the inhibitory influence which the somatomotor cortex exercises on extralemniscal afferents while, in contrast, this influence is increased during fast sleep and wakefulness. The site of action of this inhibitory influence, the mechanisms of its action, of its suppression after lesions and of its reappearance after 4 weeks are discussed.