Sleep Depth Enhancement Through Ambient Temperature Manipulation in Mice

The restorative properties of deep sleep and its central role in learning and memory are well-recognized but still in the process of being elucidated with the help of animal models. Currently available approaches for deep sleep enhancement are mainly pharmacological and may have undesirable side effects on physiology and behavior. Here, we propose a simple strategy for sleep depth enhancement that involves manipulation of ambient temperature (Ta) using a closed-loop control system. Even mild shifts in Ta are known to evoke thermoregulatory responses that alter sleep-wake dynamics. In our experiments, mice evinced greater proportions of deep NREM sleep as well as REM sleep under the dynamic sleep depth modulation protocol compared to a reference baseline in which Ta was left unchanged. The active manipulation approach taken in this study could be used as a more natural means for enhancing deep sleep in patients with disorders like epilepsy, Alzheimer's disease and Parkinson's, in which poor quality sleep is common and associated with adverse outcomes.