Paradoxical sleep: Prolonged augmentation following learning

The results suggest that PS augmentation may be a neurobiological expression of the long-term process of memory consolidation, and that slow wave sleep (SWS) is augmented in the experimental and yoke control subjects, whereas PS is only augmenting in the experimentals.

Abstract

This experiment provides evidence that learning induces a protracted augmentation of paradoxical sleep (PS) time, lasting for at least 24 h. Albino mice are studied in a counterbalanced crossover design experiment in which each animal is used as its own baseline control and yoke control. The animals are trained for 1 h in an active avoidance task in which the experimental subjects learn to avoid shock as compared to yoke controls receiving an equal number of shocks, but are unable to escape. The statistical analyses reveal that slow wave sleep (SWS) is augmented in the experimental and yoke control subjects, whereas PS isonly augmented in the experimentals. The analyses also reveal that the PS augmentation is primarily a function of a specific increase of the number of PS periods, without any change in the average duration of each PS phase. Further analyses between a slow learning group of animals and fast learners indicate that the PS augmentation is most marked in the slow learners. The results suggest that SWS augmentation is related to the CS-footshock contingency, whereas PS augmentation is a function of something quite unique about a mouse learning to escape or avoid a footshock. This study, taken together with our previous work, suggests that PS augmentation may be a neurobiological expression of the long-term process of memory consolidation.