Low Frequency Transcranial Alternating Current Stimulation Accelerates Sleep Onset Process.

Jiaxin Xie,Tiejun Liu,Dong Xu,Dezhong Yao,Zhuo Chen,Lin Wang,Shaofei Ying,Chao Xiao,Bin Wu,Junru Ren,Yue Yu

doi:10.1109/tnsre.2021.3131728

Abstract

The aim of this study is to find a kind of low frequency oscillation transcranial alternating current stimulation, which is directly applied to the scalp epidermal, to stimulate the cerebral cortex with a large spatial range of electric field oscillation across the brain hemisphere, and then trigger the start of the Top-Down processing of sleep homeostasis, in the daytime nap. Thirty healthy subjects, to take naps, underwent an intervention of electrical stimulation at 5 Hz, applied to the dorsal lateral prefrontal cortex. The subjects in the experiments were strictly controlled, and opened their eyes when stimulation was transmitted. Subsequently, after 15 min transcranial alternating current stimulation, subjects entered the experimental procedure of sleep. Electroencephalograph was taken at baseline and during sleep. Behavioral indicators were also added to the experiment. We found that the total power of Electroencephalograph activity in the theta band, as well as low-frequency power at 1-7 Hz, was significantly entrained and increased, and that alpha activity was attenuated faster and spindle activity active earlier. Even more, the transition from awake to Non-rapid eye movement stages occurs earlier. Alertness also decreased when the subjects woke up after brief sleep. The intervention of low frequency brain rhythmic transcranial alternating current stimulation may induce accelerated effect on sleep onset process, thereby possibly alleviating the problems related to sleep disorders such as difficulty to reach the real sleep state quickly after lying down.

Highlights

C URTAILING sleep latency is an important desire of many sleep researchers and clinicians [1]
In order to improve the quality of sleep, there are two relatively practical and undoubted approaches to consider: the first is to intervene before sleep, so that the subjects can enter the first cycle of sleep in the shortest time, and achieve sleep homeostasis faster [2]; the second is to enhance the sleep homeostasis, improve the synchronization of brain concussion during sleep, and observe whether the characteristic brain waves, such as slow wave and spindle wave, are significantly improved [3]
According to a recent review [5], the sleep process is accompanied by attenuation of the ascending reticular activating system (ARAS), with the main afferents entering this system coming from hypothalamic lateral orexinergic neurons that promote wakefulness and steady state, and from the ventrolateral preoptic nucleus, which contains sleep promoting aminobutyric acid (GABA) neurons

Summary

Introduction

C URTAILING sleep latency is an important desire of many sleep researchers and clinicians [1]. According to a recent review [5], the sleep process is accompanied by attenuation of the ARAS, with the main afferents entering this system coming from hypothalamic lateral orexinergic neurons that promote wakefulness and steady state, and from the ventrolateral preoptic nucleus, which contains sleep promoting aminobutyric acid (GABA) neurons. These two projections connect to ARAS and maintain circadian rhythms and sleep homeostatic activity. Top-down, cortical activity levels coordinate brain activity and alertness states through a cortico-thalamo-cortical feedback loop, which underscores the crucial role of prefrontal cortical areas [6]

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