Changes in cross-frequency coupling following closed-loop auditory stimulation in non-rapid eye movement sleep

Area of Science:

• Neuroscience
• Sleep Science
• Cognitive Neuroscience

Background:

• Non-rapid eye movement (NREM) sleep rhythms, including delta and sigma activity, are crucial for brain recovery and memory consolidation.
• Experience-dependent plasticity during wakefulness influences these sleep rhythms.
• Closed-loop auditory stimulation can selectively target slow waves, influencing local brain activity and neuroplasticity.

Purpose of the Study:

• To investigate if closed-loop auditory stimulation targeting slow waves affects not only main sleep rhythms but also their cross-frequency coupling.
• To determine the spatial extent of these modulations within the brain.

Main Methods:

• Utilized closed-loop auditory stimulation targeting the up-phase of slow waves during NREM sleep.
• Recorded electroencephalogram (EEG) data to analyze changes in delta, theta, and sigma power.
• Assessed cross-frequency coupling between different sleep oscillations.
• Examined the spatial distribution of these changes.

Main Results:

• Closed-loop auditory stimulation globally increased delta, theta, and sigma power.
• Changes in cross-frequency coupling were spatially restricted.
• A significant increase in delta-sigma coupling was observed over the right parietal area, posterior to the stimulation target.

Conclusions:

• Closed-loop auditory stimulation can locally modulate the coupling between delta phase and sigma power.
• This modulation occurs in a targeted region, suggesting a potential mechanism for manipulating sleep-dependent neuroplasticity.
• Findings support the use of targeted stimulation to influence specific brain network functions during sleep.