The preferential processing of relevant sounds continues during NREM sleep

Description

Objectives / Introduction: The sleeping brain continues to process sensory infomration from the environment and elicits different responses to auditory stimuli of varying saliency levels, i.e. different names and/or voices. However, whether these responses serve sensory processsing or sleep protection remians an open question. In this study, we investigated sleep-specific brain responses to auditory stimuli of different characteristics and measured the auditory-induced sleep-specific responses such as; K-complexes, sleep spindles and micro-arousals, during non-rapid eye movement (NREM) sleep.
Methods: We recorded polysomnography data from 17 healthy subjects in a full night of sleep with auditory stimulation. Stimuli were the subject's own name and two unfamiliar names, spoken by either a familiar voice (FV) or an unfamiliar voice (UFV). We compared the amounts of triggered K-complexes, spindles and micro-arousals between different names and voices.
Results: During NREM sleep, the brain responded preferentially to UFV stimuli by eliciting more K-complexes (F(1,16) = 15, p = 0.001, ⴄp2 = 0.48) followed by more micro-arousals (F(1,16) = 10.56, p = 0.005, ⴄp2 = 0.40). When K-complexes were triggered, UFV stimuli evoked larger event-related potential response (∑t(16) = -409.46, p = 0.005), that started with a deeper inhibition that was followed by a stronger excitation. Moreover, spectral analysis revelaed that UFV stimuli triggered higher activity in a broadband frequency range (from 0.5 to 12 Hz: ∑t(16) = 8325, p = 0.002, from 15-23 Hz: ∑t(16) = 4778, p = 0.01) . Interestingly, these differences in brain responses between UFV and FV disappeared when no K-complexes were triggered.
Conclusions: Our findings suggest that the sleeping brain continues to preferentially process auditory information during NREM sleep with a central role for K-complexes. Moreover, our results point towards a dual function for K-complexes in maintaining a trade-off between sleep protection and sensory processing to enable the brain to benefit as much as possible from sleep.
Disclosure: Nothing to disclose

Period	24 Sep 2020
Event title	25th Congress of the European Sleep Research Society 2020: ESRS Virtual Congress 2020
Event type	Online-Conference
Location	Virtual Congress
Degree of Recognition	International