Thalamic oscillations distinguish natural states of consciousness in humans.

A brain oscillation between 19 and 45 Hz, never before reported, occurs in the human central thalamus only during REM sleep and wakefulness, disappearing during non-REM sleep. This oscillation also distinguishes REM sleep microstates, coinciding with bursts of eye movements. The finding suggests a distinct electrophysiological signature in the central thalamus that differentiates conscious states, offering a new target for studying thalamic roles in consciousness and for refining treatments for disorders of consciousness.

Study at a glance

Abstract

Natural states of consciousness are thought to be regulated by deep brain structures such as the thalamus. However, very little is known about the underlying electrophysiology in humans. Here, using a rare opportunity to directly record from the human thalamus, we identify a hitherto-unreported brain-state-specific oscillation of approximately 19-45 Hz. This oscillation is present only during rapid eye movement (REM) sleep and wakefulness, while being absent during non-REM sleep. The 19-45 Hz oscillation further distinguishes REM sleep microstates, co-occurring with bursts of eye movements, and is specific to the central thalamus, a structure implicated in causing global brain state transitions. The discovery of a distinct oscillatory signature in the central thalamus that distinguishes conscious states opens up avenues to further investigate thalamic contributions to states of consciousness in humans and potentially to refine interventions to treat disorders of consciousness.