BMI Seminar // Sleep spindles - where they come from, what they do

Sleep spindles belong to the best known oscillatory patterns in the EEG that appear during periods of drowsiness and non-REM sleep. Spindles are found in all mammals and have been linked to sleep architecture, but also to some of the most pertinent sleep functions, such as memory consolidation and protection from environmental stimuli.
Although the sleep spindle is a thalamically generated network event relayed to cortex, still little is known about its impact on cortical state and the circuit bases of its multiple functions. We recently found that in both mouse and human, cortical spindle-related power during non-REM sleep is organized on an infra-slow time scale (45-50 s) during which sleep’s fragility to sensory stimuli, sleep-related signatures of memory consolidation and variations in cardiac activity are coordinated. Over this time scale, the elementary needs of sleep to be both, continous and fragile, are reconciled. This qualifies sleep spindle dynamics as a hallmark for the sequence of autonomic and central nervous system states that make up non-REM sleep.