Abstract
Study ObjectivesClosed-loop auditory stimulation (CLAS) is a method for enhancing slow oscillations (SOs) through the presentation of auditory clicks during sleep. CLAS boosts SOs amplitude and sleep spindle power, but the optimal timing for click delivery remains unclear. Here, we determine the optimal time to present auditory clicks to maximize the enhancement of SO amplitude and spindle likelihood.MethodsWe examined the main factors predicting SO amplitude and sleep spindles in a dataset of 21 young and 17 older subjects. The participants received CLAS during slow-wave-sleep in two experimental conditions: sham and auditory stimulation. Post-stimulus SOs and spindles were evaluated according to the click phase on the SOs and compared between and within conditions.ResultsWe revealed that auditory clicks applied anywhere on the positive portion of the SO increased SO amplitudes and spindle likelihood, although the interval of opportunity was shorter in the older group. For both groups, analyses showed that the optimal timing for click delivery is close to the SO peak phase. Click phase on the SO wave was the main factor determining the impact of auditory stimulation on spindle likelihood for young subjects, whereas for older participants, the temporal lag since the last spindle was a better predictor of spindle likelihood.ConclusionsOur data suggest that CLAS can more effectively boost SOs during specific phase windows, and these differ between young and older participants. It is possible that this is due to the fluctuation of sensory inputs modulated by the thalamocortical networks during the SO.
Highlights
The use of non-pharmacological and non-invasive techniques to enhance slow-wave sleep (SWS) is a rapidly growing research area
Sleep slow oscillations (SOs) and spindles are critical for memory and restorative functions
Concurrent indings have demonstrated that phase-locked auditory stimulation boosts SO waves and spindles while enhancing associated cognitive and physiological processes
Summary
The use of non-pharmacological and non-invasive techniques to enhance slow-wave sleep (SWS) is a rapidly growing research area. In CLAS, an acoustic click is applied during the peaks of SOs, producing an increase in the amplitude of the ongoing wave and in fast spindle activity during the period of stimulation [14] This technique can increase overnight memory retention for a word-pair matching task in young and older adults [14, 15], it has demonstrated to boost hippocampal activity [16], impact on immune processing [3] and have a positive effect on the autonomic function in sleep [17]. CLAS appears not to affect the consolidation of other memory tests such as inger tapping, picture memory or memory of names and faces [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
