Recovery of Motor and Cognitive Functions on Forced Waking from Stage 3 Daytime Sleep

The mechanisms of behavioral recovery of various forms on waking from sleep are still not well understood. We report here studies of the recovery of simple motor reactions to a visual stimulus, fine hand–eye coordination, and abstract thinking on waking from the deepest, slow-wave daytime sleep. While awake before sleep and during the first 2 min of waking from sleep, volunteers were offered two types of tasks: visuomotor tasks, in which they had to control a moving object, and arithmetic, in which they had to determine the correctness of putative equalities. The results showed that the speed of simple motor reactions to the appearance of a visual stimulus reached a level characteristic of wakefulness almost immediately after waking (within 4 sec), while much more time was required to restore the ability to determine the correctness or incorrectness of arithmetic equations and carry out precise control of the trajectory of a moving object: about 40 sec (in the arithmetic task) and 60 sec (in the visuomotor task). α-rhythm power on waking was higher than during wakefulness. δ power was increased only at the beginning of waking, when problem-solving was still difficult, while in the second minute of waking, when problem-solving was restored, the δ rhythm decreased. Our data indicate that simple and complex forms of behavior on waking are not restored simultaneously.