Cerebral Information Processing during Sleep: Evolutionary and Ecological Approaches

Based on the analysis of extensive clinical, psychophysiologicaland experimental data, the author comes to the conclusion that thewidespread idea of the cerebral information processing during sleeprelated to previous wakefulness and necessary for the formationof long-term memory and other cognitive resources of the brain isinapplicable. This hypothesis is poorly consistent with a rangeof data regarding both slow wave (non-REM) and paradoxical (REM)sleep. The state of the cerebral cortex in non-REM sleep is moreadequately described by the classical term "diffuse cortical inhibition."As for REM sleep, here, too, the very intensive work of the braindoes not play any adaptive role (at least for an adult organism)-informationis processed, figuratively speaking, "idle." All the vast experimentaland clinical material accumulated in recent decades speaks in favorof the "ecological" hypothesis, which considers sleep as periodsof "adaptive inactivity" of the body, increasing its survival ina hostile environment. The function of sleep consists in a radical restructuringof all waking reflexes for the normal course of such periods.