par Bremer, Frédéric 
;Bonnet, Valérie
Référence Electroencephalography and clinical neurophysiology, 2, 1-4, page (389-400)
Publication Publié, 1950
;Bonnet, ValérieRéférence Electroencephalography and clinical neurophysiology, 2, 1-4, page (389-400)
Publication Publié, 1950
Article révisé par les pairs
| Résumé : | 1. 1. The repetitive reaction of the primary acoustic area of the cortex (cat) which follows its reponse to a brief sound stimulus are to be classified in quick and slow after-discharges. The quick after-discharge characterizes the waking state of the non-narcotized ("encéphale isolé" preparation) or of the lightly etherized brain. The slow after-discharge appears when the brain is in a state of functionnal depression uncomplicated by an excitatory component: barbiturate narcosis of middle depth, initial stage of anoxia, natural sleep. 2. 2. The quick after-discharge represents the transitory intensification of the spontaneous cortical activity. It partakes its complex, neuro-humoral determinism, notably its reinforcement by thalamo-cortical impulses. 3. 3. The slow after-discharge is formed by the responses of the cortical interneurones to the volleys of impulses discharged repetively by the thalamic and mesencephalic relay-nuclei, whose fundamental tendency to autorythmicity is more resistant to depressive conditions than the cortical neurones one. The known properties of neuronic autorythmicity account for the phenomenon and its characteristics. Its explanation by a cortico-thalamic reverberation is directly contradicted by the fact that a slow after-discharge having the same characteristics than the cortical one recorded at the same time on the opposite hemisphere, is observed in the sensory response of the medial geniculate body previously "decerebrated" by the excision of the homolateral hemisphere (experiments on the non narcotized brain). © 1950. |
