Modulation of Total Sleep Time by Transcranial Direct Current Stimulation (tDCS)

Abstract

Arousal and sleep are fundamental physiological processes, and their modulation is of high clinical significance. This study tested the hypothesis that total sleep time (TST) in humans can be modulated by the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS) targeting a 'top-down' cortico-thalamic pathway of sleep-wake regulation. Nineteen healthy participants underwent a within-subject, repeated-measures protocol across five nights in the sleep laboratory with polysomnographic monitoring (adaptation, baseline, three experimental nights). tDCS was delivered via bi-frontal target electrodes and bi-parietal return electrodes before sleep (anodal 'activation', cathodal 'deactivation', and sham stimulation). Bi-frontal anodal stimulation significantly decreased TST, compared with cathodal and sham stimulation. This effect was location specific. Bi-frontal cathodal stimulation did not significantly increase TST, potentially due to ceiling effects in good sleepers. Exploratory resting-state EEG analyses before and after the tDCS protocols were consistent with the notion of increased cortical arousal after anodal stimulation and decreased cortical arousal after cathodal stimulation. The study provides proof-of-concept that TST can be decreased by non-invasive bi-frontal anodal tDCS in healthy humans. Further elucidating the 'top-down' pathway of sleep-wake regulation is expected to increase knowledge on the fundamentals of sleep-wake regulation and to contribute to the development of novel treatments for clinical conditions of disturbed arousal and sleep.

Neural signature of tDCS, tPCS and their combination: Comparing the effects on neural plasticity

“…Based on the previous tPCS results (see previous paragraph) it seems feasible that the thalamus, due to its role as electrographical generator through the thalamo-cortical circuits, could stimulate the bottom-up connectivity. On the contrary, tDCS seems to target a top-down cortico-thalamic pathway [28]. Thus, it may be possible that the sum of effects, as distinct as the ones induced by tDCS and tPCS, can result in an the cancellation of the individual signatures of these techniques in brain activity.…”

Targeting Arousal and Sleep through Noninvasive Brain Stimulation to Improve Mental Health

“…For instance, tODCS in the EEG δ frequency range during slow-wave sleep increased δ activity and improved sleep-related declarative memory consolidation [21]. Moreover, a repetitive anodal tDCS protocol applied bilaterally to the frontal cortex prior to sleep increased indices of arousal during wakefulness (high-frequency resting-state EEG power) and reduced the total sleep time in healthy humans [22] as well as in a patient with hypersomnia [23], but not in patients with insomnia [24], which is indicative for brain state-dependent effects of the protocol. In contrast to TMS, transcranial current stimulation is easy to apply, even in a home setting, with only minor side effects when using protocols within standard safety limits [6].…”

“…Recently, a repetitive stimulation protocol of bifrontal anodal tDCS prior to sleep has been shown to decrease total sleep time in healthy humans [22] and in a patient with organic hypersomnia after reanimation [23]. Future studies are needed to test whether this protocol or further refined protocols can be used to improve hypersomnia.…”

Brain rhythm attractor breakdown in Alzheimer's disease: Functional and pathologic implications

“…Attractor separation by consolidating wakefulness is more likely to be achieved, instead, through well-established interventions that target circadian (e.g., light therapy and melatonin) or homeostatic processes (e.g., coffee and transcranial current stimulation possibly involving adenosine pathways) [116–119]. In the case of transcranial current stimulation, attractor separation could be also pursued through SWS consolidation using different stimulation parameters [118,120–122]. As for light therapy and melatonin use in AD, research has shown conflicting results on their separate use, but results are more promising from combined use [119,123,124].…”