Impaired top-down auditory processing despite extensive single-neuron responses during human sleep


Sleep is defined as a reversible, homeostatically-regulated state of a reduced behavioral responsiveness, with a high arousal threshold in response to external sensory stimulation. However, it remains unclear to what extent sleep affects responses along sensory pathways, and whether it modulates specific aspects of the sensory response such as feedforward vs. feedback signaling. We studied this by recording polysomnography, iEEG, microwire LFPs, and neuronal spiking activity during wakefulness and sleep in epilepsy patients. Our results establish the presence of extensive and robust spiking and gamma auditory responses during sleep. By contrast, LFP alpha-beta power decrease, likely reflecting top-down processes, is deficient during sleep suggesting that feedback signaling is key to conscious sensory processing.