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Neural complexity and the spectral slope characterize auditory processing in wakefulness and sleep
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  • Sigurd Alnes,
  • Lea Bächlin,
  • Kaspar Schindler,
  • Athina Tzovara
Sigurd Alnes
University of Bern

Corresponding Author:[email protected]

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Lea Bächlin
University of Bern
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Kaspar Schindler
Inselspital University Hospital Bern
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Athina Tzovara
University of Bern
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Auditory processing and the complexity of neural activity can both indicate residual conscious-ness levels and differentiate between states of arousal. However, how measures of neural signal diversity, or complexity, manifest in evoked activity, and, more generally, how the electrophys-iological characteristics of auditory responses change in states of reduced consciousness, re-main under-explored. Here, we tested the hypothesis that measures of neural complexity and the spectral slope would discriminate stages of sleep not only in spontaneous EEG, but also in auditory-evoked responses. High-density EEG was recorded in 21 participants to determine the spatial relationship between these measures, and between spontaneous and auditory-evoked signals. Results showed that the complexity and the spectral slope in the 2-20 Hz range dis-criminated between sleep stages and had a high correlation in sleep. In wakefulness, complexity was strongly correlated to the 20-40 Hz spectral slope. Auditory stimulation resulted in reduced complexity in sleep compared to spontaneous activity and modulated the spectral slope in wake-fulness. These findings demonstrate the persistence of electrophysiological markers of arousal during both spontaneous and evoked EEG activity and have direct applications to studies using auditory stimulation to probe neural functions in states of reduced consciousness.
10 Mar 2023Submitted to European Journal of Neuroscience
11 Mar 2023Submission Checks Completed
11 Mar 2023Assigned to Editor
11 Mar 2023Review(s) Completed, Editorial Evaluation Pending
21 Mar 2023Reviewer(s) Assigned
08 May 2023Editorial Decision: Revise Major
08 Aug 20231st Revision Received
08 Aug 2023Review(s) Completed, Editorial Evaluation Pending
08 Aug 2023Submission Checks Completed
08 Aug 2023Assigned to Editor
08 Aug 2023Reviewer(s) Assigned
11 Sep 2023Editorial Decision: Revise Major
24 Oct 2023Review(s) Completed, Editorial Evaluation Pending
11 Nov 2023Editorial Decision: Accept