summary: Sound stimulation can manipulate brain waves during REM sleep, a stage crucial for memory and cognition. Using advanced technology, researchers may be able to increase the reduced brain oscillation frequency in dementia patients, improving memory function.
This non-invasive technique could pave the way for innovative treatments for dementia by targeting brain activity during sleep, offering hope that memory and cognition could be enhanced with minimal disruption to patients’ lives.
Key Facts:
- Sound stimulation increases brainwave frequencies during REM sleep.
- REM sleep is associated with memory and cognitive function, which declines in dementia.
- This non-invasive technique could lead to new treatments for dementia.
sauce: University of Surrey
A new study from the University of Surrey suggests it is possible to manipulate brain waves during rapid eye movement sleep (REM), a sleep stage associated with memory and cognition. A new technique using sound stimulation allows scientists to speed up brain activity that slows down in dementia patients during this sleep stage.
In this unique study, Surrey scientists, working with the UK Dementia Research Centre for Care Research and Technology at Imperial College London, used closed-loop auditory stimulation, a recently developed technology that precisely targets brain oscillations during sleep.
In this technique, sounds are timed to hit brainwaves at specific parts of their oscillations (for example, the rise and fall phases). The sounds were precisely administered at a rate of six (targeting theta waves) or ten (targeting alpha waves) per second. This was first performed during REM sleep, a period when brain activity is similar to that during wakefulness but movement is inhibited.
Dr Valeria Jaramillo, a Swiss National Science Foundation Postdoctoral Research Fellow at the Surrey Sleep Research Centre and Department of Psychology at the University of Surrey, Emerging Reader at the Dementia UK Institute and first author on the paper, said:
“Brain oscillations help the brain function and aid in how the brain learns and retains information. Brain oscillations during REM sleep are thought to be involved in memory function, but their exact role is still largely unknown.
In dementia, brain activity during REM sleep slows, reducing the ability to remember specific life events and retain information.
“By stimulating brainwaves with sound, we can increase their frequency, which could lead to a better understanding of how brain oscillations during REM sleep promote cognition and how they might improve REM sleep in people with dementia.”
To investigate the effects of stimulation, 18 participants were recruited and monitored overnight at the Surrey Sleep Research Centre. Their sleep was continuously monitored by electrodes attached to their scalp and their brain oscillations were analysed in real time, allowing auditory stimuli to be delivered to precise parts of the oscillations without waking the participants.
Depending on which part of the cycle the auditory stimulation targets, the oscillations can speed up or slow down, demonstrating the ability to manipulate brainwaves.
Professor Dirk Jan Dijk, Director of the Surrey Sleep Research Centre at the University of Surrey, Group Leader at the Dementia UK Institute and lead author of the paper, said:
“Because this technique is non-invasive and takes place while the patient is asleep, it could pave the way for new approaches to treating people with dementia, with less disruption to their lives and allowing a more targeted approach.”
Dr Ines Violante, senior lecturer in psychology and neuroscience at the University of Surrey and lead author of the paper, said:
“Using sound stimulation to alter brain oscillations during sleep could have therapeutic benefits. Currently, there are no medicines that can cure dementia, only slow the progression of the disease or temporarily relieve symptoms. Therefore, it is important to think innovatively to develop new treatment options.”
“Sound stimulation, a non-invasive and inexpensive technology, has the potential to do just that.”
About this Sleep and Neuroscience Research News
author: Natasha Meredith
sauce: University of Surrey
contact: Natasha Meredith – University of Surrey
image: Image courtesy of Neuroscience News
Original Research: Open access.
“Closed-loop auditory stimulation targeting alpha and theta rhythms during REM sleep induces phase-dependent power and frequency changesBy Ines Violante et al. sleep
Abstract
Closed-loop auditory stimulation targeting alpha and theta rhythms during REM sleep induces phase-dependent power and frequency changes
Research Objective
Alpha and theta waves are hallmarks of the human electroencephalogram (EEG) during wakefulness and can be modulated by closed-loop auditory stimulation (CLAS). These waves also occur during rapid eye movement (REM) sleep, but their function here remains unclear. CLAS is a promising tool to pinpoint how these EEG waves contribute to human brain function. Here, we investigate whether CLAS can modulate alpha and theta waves in a phase-dependent manner during REM sleep.
method
High-density EEG was recorded during extended sleep in 18 healthy young adults. Auditory stimuli were presented during phasic and tonic REM sleep, alternating between 6-s on and 6-s off windows. During the on windows, stimuli were phase-locked to four quadrature phases of ongoing alpha or theta waves detected at frontal electrodes.
result
The phase of ongoing alpha and theta oscillations was targeted with high precision during REM sleep. Alpha and theta CLAS evoked phase-dependent changes in power and frequency at the target location. Frequency-specific effects were observed in alpha trough (acceleration) and ascending (deceleration), and theta trough (acceleration) conditions. CLAS-induced phase-dependent changes were observed in both REM sleep substages, whereas auditory evoked potentials were significantly reduced in phasic REM sleep compared to tonic REM sleep.
Conclusion
This study provides evidence that faster REM sleep rhythms can be regulated in a phase-dependent manner by CLAS, providing a new approach to investigate how modulation of REM sleep oscillations influences the contribution of this waking state to brain function.
