Abstract
Recent studies have provided evidence that information processing occurs during sleep as well as in the daytime. This paper reviews the literature on information processing during sleep from the viewpoints of 1) input : response to external stimuli during sleep, 2) processing : consolidation and improvement of learned memory during sleep, and 3) output : temporal features of dream occurrence and characteristics of dream content. Although during sleep the ability to respond to external stimuli decreases, psychological functions, such as attention and motivation, are maintained. Sleep is required after training in order to improve certain types of procedural and declarative memory. Dreaming occurs frequently in the morning, and altered association of semantic memories is related to the unique quality of dream contents. Progress in the study of information processing during sleep will provide further understandings of human cognitive function and mental activity. (Japanese Journal of Physiological Psychology and Psychophysiology, 25 (1) : 17-34, 2007.)
