The neural tides of sleep and consciousness revealed by single-pulse electrical brain stimulation.
Sleep June 11, 2019 Kiyohide Usami, Anna Korzeniewska, Riki Matsumoto et al.
The sleep/wake cycle alters how neural activity spreads across large-scale brain networks. Using single-pulse electrical stimulation in patients with intracranial EEG electrodes, the study found that patterns of neural propagation at high-gamma frequencies (80-150 Hz) differ between wakefulness and sleep stages. During slow-wave sleep, frontal lobe stimulation produced greater propagation toward the parietal lobe than during wakefulness. During REM sleep, propagation decreased within the frontal lobe and increased within the parietal lobe. These directional biases in large-scale cortical network dynamics during REM sleep may help explain some unique experiential aspects of that sleep stage. The findings suggest that conscious awareness and sleep regulation involve changes in the balance of neural propagation across frontal-parietal networks.