Understanding the detection of salient auditory stimuli by the deep layer of the superior colliculus (dSC) during REM and NREM sleep offers valuable insights into the neurophysiological mechanisms of state-dependent auditory information processing. We recorded local field potentials (LFP) from dSC, electrocorticogram (ECoG) from frontal/parietal cortical regions, and neck electromyogram (EMG) in freely moving rats during sleep and awake states under oddball paradigm auditory stimulations. Our analysis focused on mismatch negativity (MMN) responses and event-related spectral perturbation (ERSP) in slow gamma (30-60 Hz) activity (SGA) and medium gamma (60-95 Hz) activity (MGA) frequency bands in wakefulness, REM and NREM sleep using three different intensities (35-, 55-, 80-dB) of stimulation. Data were analyzed using repeated-measure two-way ANOVA and Linear Mixed Model. We found that salient auditory stimuli significantly increased MMN responses in the dSC across nearly all conditions, specifically in REM, compared to other vigilance states. However, we observed a substantial increase of ERSP in SGA (P < 0.0001) during NREM sleep, while a significant increase of ERSP in MGA (p < 0.001) was observed during both REM and NREM sleep. These findings add further insights into the role of the dSC in the state-dependent processing of auditory information.

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