Sleep deprivation and memory consolidation in rats: A meta-analysis of experimental studies

Sleep deprivation (SD) continues to be used today to examine the role of sleep across diverse cognitive domains. Extensive research has been conducted to investigate the impact of SD on memory, though findings across studies have been inconsistent. This meta-analysis systematically assessed the effects of SD on memory performance in rats and identified the factors that may moderate these effects. PubMed, PsychInfo, Google scholar, and Scopus databases were used to search for studies. Out of 128 identified studies, 25 studies with 78 reports were included in the final analysis. A random effects meta-analysis was performed, along with subgroup analysis and meta-regression. The results showed that overall, SD has a negative impact on memory in rats. Additionally, sex, memory response type, and number of learning trials for spatial tasks can act as moderators of the relationship between SD and memory. The type of memory task and assessment method used contributed to variability in observed outcomes, with hippocampus-dependent tasks showing the most pronounced memory impairments. The number of learning trials for spatial tasks also moderated the effects, with more trials mitigating the impact of SD. These findings reinforce the role of sleep in memory, particularly for hippocampus-dependent tasks.