β- And γ-band EEG power predicts illusory auditory continuity perception

Area of Science:

• Auditory Neuroscience
• Cognitive Neuroscience
• Neuroscience

Background:

• Auditory systems possess mechanisms for detecting novel sounds, segregating sound sources, and restoring masked sounds.
• Perceptual restoration, crucial in noisy environments, allows tracking sounds despite masking.
• The continuity illusion demonstrates perceptual restoration, where sounds with gaps are perceived as intact.

Purpose of the Study:

• To investigate brain activity associated with the auditory continuity illusion using electroencephalography (EEG).
• To explore the role of pre-stimulus brain states in influencing the perception of auditory continuity.

Main Methods:

• Utilized high-temporal-resolution EEG to record brain activity.
• Employed a within-subject design where masking noise levels were individually adjusted.
• Stimuli were presented to elicit either the continuity illusion or correct gap detection, ensuring perceptual differences drove brain activity variations.

Main Results:

• Pre-stimulus gamma-band (34-80 Hz) EEG power predicted continuity illusion perception in 10 out of 14 participants.
• Beta and gamma-band (12-80 Hz) power before stimulus onset was informative for subsequent perceptual decisions.
• Baseline brain activity significantly influenced the strength of the continuity illusion.

Conclusions:

• Baseline brain states, particularly in the beta and gamma frequency bands, play a crucial role in auditory continuity illusion perception.
• These findings suggest that the brain's readiness before auditory stimulus presentation impacts how masked sounds are perceived.