Effects of acute hypoxia on the EEG and impulse activity of the neurons of various brain structures in rats.

The EEG and impulse activity of the neurons of the cerebral cortex and other structures of the brain were studied in the dynamics of hypoxic influence. In the initial phase of hypoxia (2000-6000 m), activation of the EEG and impulse discharge of neurons set in; in this case EEG activation arose earlier and was more pronounced. In the second phase of hypoxia (7500-10,000 m), the EEG changed in the direction of a reorganization of the frequency spectrum from one rhythm to another - from fast to slow activity of the type of delta waves. At this time the impulse activity was gradually suppressed, and the cortical neurons exhibited higher sensitivity to hypoxia and were inhibited earlier than the cells of the hypothalamus and medulla oblongata.