Auditory processing up to cortex is maintained during sleep spindles.

Sleep spindles are transient 11-16 Hz brain oscillations generated by thalamocortical circuits. Their role in memory consolidation is well established, but how they play a role in sleep continuity and protection of memory consolidation against interference is unclear. One theory posits that spindles or a neural refractory period following their offset act as a gating mechanism, blocking sensory information en route to the cortex at the level of the thalamus. An alternative model posits that spindles do not participate in the suppression of neural responses to sound, although they can be produced in response to sound. We present evidence from three experiments using electroencephalography and magnetoencephalography in humans that examine different evoked responses in the presence of and following sleep spindles. The results provide convergent empirical evidence suggesting that auditory processing up to cortex is maintained during sleep spindles, and their refractory periods.