Acute Sleep Deprivation Blocks Short- and Long-Term Operant Memory inAplysia

Abstract

Study Objectives: Insufficient sleep in individuals appears increasingly common due to the demands of modern work schedules and technology use. Consequently, there is a growing need to understand the interactions between sleep deprivation and memory. The current study determined the effects of acute sleep deprivation on short and long-term associative memory using the marine mollusk Aplysia californica, a relatively simple model system well known for studies of learning and memory. Methods: Aplysia were sleep deprived for 9 hours using context changes and tactile stimulation either prior to or after training for the operant learning paradigm, learning that food is inedible (LFI). The effects of sleep deprivation on short-term (STM) and long-term memory (LTM) were assessed. Results: Acute sleep deprivation prior to LFI training impaired the induction of STM and LTM with persistent effects lasting at least 24 h. Sleep deprivation immediately after training blocked the consolidation of LTM. However, sleep deprivation following the period of molecular consolidation did not affect memory recall. Memory impairments were independent of handling-induced stress, as daytime handled control animals demonstrated no memory deficits. Additional training immediately after sleep deprivation failed to rescue the induction of memory, but additional training alleviated the persistent impairment in memory induction when training occurred 24 h following sleep deprivation. Conclusions: Acute sleep deprivation inhibited the induction and consolidation, but not the recall of memory. These behavioral studies establish Aplysia as an effective model system for studying the interactions between sleep and memory formation.

Sleep supports inhibitory operant conditioning memory in Aplysia

“…Our experiments add to previous studies in invertebrates indicating that sleep-like states that follow training support consolidation of memory for the respective task (Donlea et al 2009(Donlea et al , 2011Hussaini et al 2009;Zwaka et al 2015;Levy et al 2016), and, of note, they will complement a most recent study in Aplysia showing a similar suppression of memory for the LFI task after a shorter 9-h period of post-training sleep deprivation (Krishnan et al 2016). Consolidating effects, in all these studies emerged in the absence of electrophysiological signs of sleep, as invertebrates have not been shown to display the characteristic electrophysiological signatures, such as slow waves, used to determine sleep in vertebrates.…”

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

“…Thus, when animals are roused and not permitted to rest during the inactive phase, they compensate the following day. In addition, preventing Aplysia from sleeping interferes with memory (Krishnan et al, 2016). …”

Translational changes induced by acute sleep deprivation uncovered by TRAP-Seq

“…Sleep deprivation is a widespread problem affecting more than one-third of U.S. adults and 70% of teenagers (Center for Disease Control and Prevention, 2017) leading to significant impairments in memory and performance. The effects of sleep deprivation on learning and memory are phylogenetically conserved from invertebrates such as Aplysia and Drosophila to humans [1][2][3][4][5]. Sleep disorders have been linked to neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, seemingly increasing disease risk and progression (reviewed in [6]; [7][8][9]).…”