Cortical layer 6b mediates state-dependent changes in brain activity and effects of orexin on waking and sleep.

Silencing cortical layer 6b in mice reduces EEG power and slows brain oscillations during wake and REM sleep, highlighting its role in brain state regulation.

• Why it matters: Understanding how specific cortical layers influence brain activity is crucial for unraveling mechanisms underlying sleep, wakefulness, and neuropsychiatric disorders, yet L6b remains poorly studied.
• What they did: Researchers used chronic EEG recordings in mice with targeted silencing of L6b neurons, examining effects during normal conditions, sleep deprivation, and orexin administration, focusing on oscillatory activity.
• The result: L6b silencing decreased EEG power and slowed theta frequencies, especially during NREM sleep, and altered responses to orexin, suggesting L6b's importance in modulating brain states and responses to neuropeptides.