Auditory network persistence of stimulus representation in awake and naturally sleeping mice

Persistent neural activity often outlasts sensory stimulation, bridging perception and action. While commonly linked to working memory and decision making, its existence during passive states and sleep remains unclear. Using chronic high-density electrophysiology in freely behaving mice, we show that population spiking activity across the auditory cortical hierarchy enables decoding of past stimuli long after their offset, during both wakefulness and sleep. Time-resolved decoding revealed that in wakefulness, persistent representations decay uniformly across sensory and association cortices, whereas during sleep, persistence is prolonged in association cortex but remains brief in early auditory regions. Recurrent neural network modeling showed that higher internal noise during wakefulness reproduces this pattern, suggesting that reduced interference during sleep stabilizes sensory traces in associative areas. Our results demonstrate that persistent representation is a passive, state-dependent feature of sensory processing, supporting sensory maintenance even in the absence of active engagement.