Daily rhythm of locomotor activity is abolished during rapid eye movement sleep deprivation in the rat

Abstract

Applying a modified flowerpot technique, which made it possible to use a test animal as its own control, twenty-four hour cycles of locomotor activity were recorded in eight juvenile male rats on 12/12 hr light/dark (LD) schedule during six days of rapid eye movement (REM) sleep deprivation. It was found that the LD difference in locomotor activity unrelated to feeding was instantaneously abolished during REM sleep deprivation. The daily rhythm of food-directed activity, however, was only gradually attenuated. Due to this equalisation in the light and dark activity the rats gave an impression of hyperactivity during the light hours although the total daily motor output after an initial increase returned close to the baseline value.