Multiscale intracranial EEG dynamics across sleep-wake states: toward memory-related processing

Area of Science:

• Neuroscience
• Sleep Science
• Cognitive Neuroscience

Background:

• Sleep is crucial for memory consolidation.
• Neural dynamics across multiple timescales are involved.
• Understanding these dynamics is key to memory processing.

Purpose of the Study:

• To characterize spectral activity, neuronal avalanche dynamics, and temporal correlations during different sleep-wake states.
• To investigate the spatial distribution and functional relevance of these dynamics.
• To explore how these neural signatures relate to memory processing.

Main Methods:

• Utilized intracranial EEG (iEEG) recordings from patients.
• Analyzed spectral power, neuronal avalanche size, and temporal correlations (Detrended Fluctuation Analysis).
• Compared these measures across N2, N3, REM sleep, and wakefulness, examining regional variations.

Main Results:

• N2 and N3 sleep showed increased low-frequency power, larger neuronal avalanches, and enhanced long-range temporal correlations.
• REM sleep and wakefulness exhibited reduced temporal persistence and fewer large-scale cascades.
• Distinct regional patterns were observed, particularly in medial temporal and frontal areas.

Conclusions:

• Sleep-wake states exhibit unique spatio-temporal neural dynamics.
• These dynamics, especially during N2/N3 sleep, may create a neural landscape favoring memory stabilization and reconfiguration.
• iEEG is valuable for understanding the multiscale structure of sleep-related brain dynamics and their link to memory.