Thalamus mediates neocortical Down state transition via GABAB-receptor-targeting interneurons

•In slow-wave sleep, the Down state transition is an active process •Thalamic burst induces via cortical GABABR activation •Layer 1 NGFC interneurons relay thalamic signal to induce •Midline thalamus synchronizes slow oscillations Slow-wave sleep characterized by near-synchronous alternation of Up states and quiescent in neocortex. Although cortex itself can maintain these oscillations, full expression Up-Down requires intact thalamocortical circuits. Sensory input drive into state. Here we show that midline neurons terminate synchronously across areas. Combining local field potential, single-unit, patch-clamp recordings conjunction with optogenetic stimulation silencing mice vivo, report mediates layer neurogliaform inhibitory acting on GABAB receptors. These results strengthen evidence interactions are essential for mediated receptors, demonstrate transitions areas during natural sleep.