Modality-specific tracking of attention and sensory statistics in the human electrophysiological spectral exponent

• Published in: eLife Vol. 10
• Main Authors: Waschke, Leonhard, Donoghue, Thomas, Fiedler, Lorenz, Smith, Sydney, Garrett, Douglas D, Voytek, Bradley, Obleser, Jonas
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 21-10-2021; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Acoustic Stimulation; Anesthesia; Anesthetics, Intravenous - pharmacology; Approximation; Attention; Attention - physiology; Brain - physiology; EEG; Electrodes; Electroencephalography; Electrophysiological Phenomena - physiology; electrophysiology; Female; human; Humans; Investigations; Ketamine - pharmacology; Male; Neuroscience; Photic Stimulation; Propofol - pharmacology; Sensory integration; Statistics; Visual stimuli; Young Adult; electrophysiology; human; EEG; neuroscience
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.70068

A hallmark of electrophysiological brain activity is its 1/f-like spectrum - power decreases with increasing frequency. The steepness of this 'roll-off' is approximated by the spectral exponent, which in invasively recorded neural populations reflects the balance of excitatory to inhibitory neural activity (E:I balance). Here, we first establish that the spectral exponent of non-invasive electroencephalography (EEG) recordings is highly sensitive to general (i.e., anaesthesia-driven) changes in E:I balance. Building on the EEG spectral exponent as a viable marker of E:I, we then demonstrate its sensitivity to the focus of selective attention in an EEG experiment during which participants detected targets in simultaneous audio-visual noise. In addition to these endogenous changes in E:I balance, EEG spectral exponents over auditory and visual sensory cortices also tracked auditory and visual stimulus spectral exponents, respectively. Individuals' degree of this selective stimulus-brain coupling in spectral exponents predicted behavioural performance. Our results highlight the rich information contained in 1/f-like neural activity, providing a window into diverse neural processes previously thought to be inaccessible in non-invasive human recordings.