Two combinations of numbers (6-2, 6-8) and a single number 6 were given to 6 examinee before sleep, they were asked to react on the ratio of numbers in complex more--less (6-2). During stage 2 sleep unknown numbers and their combinations (5-3, 5-7 and number 5) with the same relationship were presented. The frequency of evoked EEG-responses didn't correspond to the reactions during waking, but reflected the quantitative meanings of the numbers presented. Additional series of experiments with 25 examinee during waking (presented variants of numbers 5-3, 5-7 and 5 with request to react selectively on one of the combinations) showed the primary reaction on the combination "minor number--major number" analogous to the results obtained during sleep. It is suggested that the level of integrative brain activity during sleep promotes the adequate response only in the case when it is the result of more automatized reactions of examinee on usual order of number, i.e. ascending order of numbers.

Human brain reactivity during sleep has been studied. Complex stimuli: auditory stimulus 1 s--interstimulus interval 4 s--verbal instruction to clench one's fist were presented to human subjects at equal 30-second intervals throughout all night's sleep. Conditioned motor and EEG responses were elicited during the second and the third experimental nights by repeating only auditory stimuli at 30- or 15-second intervals respectively. It has been suggested that a short-term memory store functions during sleep for at least 30 s after presenting stimuli.