Pre-stimulus EEG oscillations correlate with perceptual alternation of speech forms

• Published in: Neuroscience letters Vol. 622; pp. 24 - 29
• Main Authors: Barraza, Paulo, Jaume-Guazzini, Francisco, Rodríguez, Eugenio
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 27-05-2016
• Subjects: Adult; Alpha band; Beta band; Bistable perception; Brain - physiology; Electroencephalography; Evoked Potentials, Auditory; Female; Humans; Linguistics; Male; Middle Aged; Neuronal synchrony; Speech - physiology; Speech perception; Speech Perception - physiology; Verbal transformation effect; Young Adult; Alpha band; Beta band; Bistable perception; Verbal transformation effect; Neuronal synchrony; Speech perception
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2016.04.038

•Pre-stimulus brain dynamics influence the perceptual organization of speech.•Reduced ongoing alpha activity precedes subsequent change of verbal form.•Induced beta oscillations supports fast stabilization of the new verbal form.•Right frontal positivity and posterior negativity evoked by change of verbal form.
Speech perception is often seen as a passive process guided by physical stimulus properties. However, ongoing brain dynamics could influence the subsequent perceptual organization of the speech, to an as yet unknown extent. To elucidate this issue, we analyzed EEG oscillatory activity before and immediately after the repetitive auditory presentation of words inducing the so-called verbal transformation effect (VTE), or spontaneous alternation of meanings due to its rapid repetition. Subjects indicated whether the meaning of the bistable word changed or not. For the Reversal more than for the Stable condition, results show a pre-stimulus local alpha desynchronization (300–50ms), followed by an early post-stimulus increase of local beta synchrony (0–80ms), and then a late increase and decrease of local alpha (200–340ms) and beta (360–440ms) synchrony respectively. Additionally, the ERPs showed that reversal positivity (RP) and reversal negativity components (RN), along with a late positivity complex (LPC) correlate with switching between verbal forms. Our results show how the ongoing dynamics brain is actively involved in the perceptual organization of the speech, destabilizing verbal perceptual states, and facilitating the perceptual regrouping of the elements composing the linguistic auditory stimulus.