[Time as a dimension of consciousness. Subjective passage of time during wakefulness, REM, and NREM sleep].

In this paper, the authors review experimental data on the ability to perceive the passage of time during wakefulness and sleep. The evolutionary significance of the sense of time and its role in cognitive functions is discussed. Recent findings on neural mechanisms underlying perception and estimation of time as well as temporal order judgments are described. Similarities and differences of the awareness of time in wakefulness, REM, and NREM sleep are analyzed.