Organização da prática e o impacto da privação de sono na recuperação de memórias motoras consolidadas

Abstract

The benefits of less repetitive practice in motor learning compared to more repetitive practice support the idea of greater memory strengthening. Studies in the literature explain these benefits, primarily identified in transfer tests. Additionally, the importance of sleep in the process of memory consolidation and strengthening is well-established in literature. However, there are no studies investigating the impacts of sleep deprivation on the recovery of these strengthened memories when comparing less repetitive practice to more repetitive practice. Thus, the primary objective of the present study was to investigate different practice organization models and the impact of sleep deprivation on the recovery of consolidated motor memories. The specific objectives were to examine the effects of practice organization during the acquisition phase, on learning tests, and the effects of practice organization and sleep deprivation on the recovery of long-term motor memory. For this purpose, the hypotheses proposed were: (1) constant practice will result in better performance during the acquisition phase, (2) random practice will lead to better performance on learning tests, and (3) the deleterious effects of sleep deprivation will be identical across groups after the memories have been consolidated. Wistar rats (n=32) were used, divided into two groups, which performed the motor task on the rotarod for two consecutive days (acquisition phases 1 and 2). Group division was determined after conducting a pilot study (Appendix 1). The constant practice group (same rotation frequency) and the random practice group (rotation frequency randomized among three distinct frequencies) underwent retention tests 24 hours, 10 days, and 16 days after the acquisition phase. These tests demonstrated how much learning from the acquisition phase was retained, while transfer tests showed how well that learning adapted to different parameters. After the 16th-day test, sleep deprivation was induced for four hours over three consecutive days. Following one day of rest, the animals were retested at the same rotation frequency as the 16th-day test. Descriptive data analyses suggested better performance of constant practice compared to random practice during the acquisition phase, and the change in the learning curve observed in the learning test could also be seen in rats. In inferential analysis, constant practice did not show the expected performance in the acquisition phase, and random practice did not exhibit the anticipated performance on the learning tests. However, as expected, sleep deprivation conducted 17 days after the acquisition phase had the same effect on both groups post-sleep deprivation. The findings of this study pave the way for future research on the relationship between sleep deprivation and practice organization.