Psychostimulants and sleep-dependent memory consolidation_WhitehurstLN

This is a within-subject, double-blind, placebo-controlled design, where we investigated the impact of morning administration (9AM) of dextroamphetamine on recognition memory for negative and neutral pictures after 12 hours of wake and 24 hours with sleep. Stimulants provided a 6% memory enhancement for neutral pictures after 12-hrs of wake. However, stimulants impaired sleep (decreased total sleep time and minutes in slow wave sleep (SWS) and increased sleep latencies). In addition, recognition for neutral pictures showed significant reductions at 24 hours in the stimulant compared to the placebo condition, and this memory impairment was statistically mediated by SWS latency. No performance differences between drug conditions were found for negative pictures at any time point. We tested the hypothesis that stimulant-driven performance impairment was related to poor sleep by introducing a hypnotic drug (i.e. zolpidem) at night which, when paired with the stimulant during the day, restored both the sleep and, critically, the memory performance deficit, compared with the stimulant alone.

本研究采用被试内、双盲、安慰剂对照实验设计，探究了上午9点晨起服用右苯丙胺（dextroamphetamine）对个体在12小时清醒状态与24小时睡眠后，负性与中性图片再认记忆的影响。实验结果显示，在12小时清醒状态后，中枢兴奋剂可使中性图片的记忆表现提升6%。但与此同时，该类兴奋剂会对睡眠产生损害：总睡眠时间、慢波睡眠（slow wave sleep, SWS）时长均缩短，睡眠潜伏期延长。此外，相较于安慰剂组，兴奋剂组在24小时时间点的中性图片再认成绩出现显著下降，且该记忆损害可通过慢波睡眠潜伏期实现统计学中介效应。而在任意时间点，两组药物干预下的负性图片再认表现均无显著差异。本研究验证了如下假说：日间服用兴奋剂导致的记忆表现损害与睡眠质量不佳相关。具体而言，夜间辅以催眠药物唑吡坦（zolpidem）时，相较于单独使用兴奋剂的组别，联合给药方案可同时恢复受损的睡眠状态与记忆表现缺陷，其中记忆表现的恢复为核心观测结果。