Single and Sequential REM sleep episodes in humans: a phylogenetic left-over?

The occurrence of REM sleep in the rat appears to be under the control of either sleep related processes and homeostatic regulation of physiological variables. With respect to this, it has been observed that in this species REM sleep may occur in the form of two types of episodes, Single and Sequential episodes, which are supposed to play a different functional role. Since it is possible to distinguish Single and Sequential REM sleep episodes also in human beings, the aim of this pilot study was to asses whether a sleep deprivation may differently affect these two types of REM episodes. The sleep deprivation was induced in young human subjects by a progressive restriction of sleep within the same night period. Seventy-two PSG tracing belonging to six subjects have been analyzed. The results show that sleep deprivation does not significantly affect the relative occurrence of Single and Sequential REM sleep episodes, suggesting that in human beings these two types of REM episodes might not have a different functional role.