[State of non-specific activating and inhibitory systems of the brain under hypoxic conditions].

The functional state of the rabbit brain activating system was evaluated by the activation reaction, and the thalamic inhibitory system, by the recruiting response. At the initial phase of hypoxia, excitability of the activating system was enhanced, while at the same time the eugmenting phase of the recruiting response diminished and its inhibitory phase was prolonged. At the "altitude" of about 7000 m, against the background of a gradual weakening of the ascending activating influence of the reticular formation and the hypthalamus, the recruiting response assumed the form of regular; equally negative potentials, which testifies to the activie synchronizing influence of the inhibitory system. At a "rise" to 8500 m, against the background of slow synchronized EEG waves, in most cases there was no activation reaction to the stimulation of the reticular formation and hypothalamus. Neither was there any recruiting response to the stimulation of non-specific thalamic nuclei.