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.