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Conscious perception is greatly diminished during sleep, but the underlying circuit mechanism is poorly understood. We show that cortical ignition—a brain process shown to be associated with conscious awareness in humans and non-human primates—is strongly suppressed during non-rapid-eye-movement (NREM) sleep in mice due to reduced cholinergic modulation and rapid inhibition of cortical responses. Brain-wide functional ultrasound imaging and cell-type-specific calcium imaging combined with optogenetics showed that activity propagation from visual to frontal cortex is markedly reduced during NREM sleep due to strong inhibition of frontal pyramidal neurons. Chemogenetic activation and inactivation of basal forebrain cholinergic neurons powerfully increased and decreased visual-to-frontal activity propagation, respectively. Furthermore, although multiple subtypes of dendrite-targeting GABAergic interneurons in the frontal cortex are more active during wakefulness, soma-targeting parvalbumin-expressing interneurons are more active during sleep. Chemogenetic manipulation of parvalbumin interneurons showed that sleep/wake-dependent cortical ignition is strongly modulated by perisomatic inhibition of pyramidal neurons. [Display omitted] • Visual-to-frontal cortex activity propagation is strongly reduced during NREM sleep • Responses of frontal pyramidal neurons are strongly inhibited during NREM sleep • Basal forebrain cholinergic neurons powerfully modulate frontal cortical ignition • Increased perisomatic inhibition during NREM sleep suppresses cortical ignition Investigation into the circuit mechanisms that diminish awareness during sleep shows that frontal cortical ignition is suppressed during NREM sleep due to reduced cholinergic modulation and a shift from dendritic to perisomatic inhibition of frontal cortical pyramidal neurons. [ABSTRACT FROM AUTHOR]