Sleep spindles stabilize human thalamocortical networks, inhibiting pathological disruptions

The thalamus plays a crucial role in coordinating sleep-related functions such as memory consolidation, sensory gating, and network stability through spindle oscillations. However, the response of human thalamocortical circuits to pathological disruptions is not well understood. To investigate this, researchers utilized interictal epileptiform discharges (IEDs) as spontaneous disturbances to probe spindle-generating circuits and thalamocortical dynamics in vivo.

Intracranial recordings were conducted over multiple nights in 55 individuals with epilepsy, covering various thalamic nuclei and cortical regions. The study found that sleep spindles were associated with the suppression of IEDs, while IEDs increased the subsequent probability of spindles. This revealed a bidirectional interaction between physiological and pathological activity.

Moreover, nights with lower IEDs were linked to increased spindle occurrence, longer and faster spindle durations, indicating a more stable thalamocortical state. The findings suggest that sleep spindles may serve as regulators of thalamocortical networks, actively responding to and regulating pathological activity.