Neural alpha oscillations index context-driven perception of ambiguous vowel sequences

Claude Alain; Katharina Göke; Dawei Shen; Gavin M Bidelman; Lori J Bernstein; Joel S Snyder

doi:10.1016/j.isci.2023.108457

Neural alpha oscillations index context-driven perception of ambiguous vowel sequences

iScience. 2023 Nov 14;26(12):108457. doi: 10.1016/j.isci.2023.108457. eCollection 2023 Dec 15.

Authors

Claude Alain^{1

2}, Katharina Göke¹, Dawei Shen¹, Gavin M Bidelman³, Lori J Bernstein⁴, Joel S Snyder⁵

Affiliations

¹ Rotman Research Institute, Toronto, ON M6A 2E1, Canada.
² Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada.
³ Department of Speech, Language and Hearing Sciences and Program in Neuroscience, Indiana University, Bloomington, IN 47408, USA.
⁴ Department of Psychiatry, University of Toronto and University Health Network, Toronto, ON M5G 2C4, Canada.
⁵ Department of Psychology, University of Nevada, Las Vegas, NV 89154, USA.

Abstract

Perception of bistable stimuli is influenced by prior context. In some cases, the interpretation matches with how the preceding stimulus was perceived; in others, it tends to be the opposite of the previous stimulus percept. We measured high-density electroencephalography (EEG) while participants were presented with a sequence of vowels that varied in formant transition, promoting the perception of one or two auditory streams followed by an ambiguous bistable sequence. For the bistable sequence, participants were more likely to report hearing the opposite percept of the one heard immediately before. This auditory contrast effect coincided with changes in alpha power localized in the left angular gyrus and left sensorimotor and right sensorimotor/supramarginal areas. The latter correlated with participants' perception. These results suggest that the contrast effect for a bistable sequence of vowels may be related to neural adaptation in posterior auditory areas, which influences participants' perceptual construal level of ambiguous stimuli.

Keywords: Audiology; Behavioral neuroscience; Linguistics; Sensory neuroscience.