Pre-stimulus EEG oscillations correlate with perceptual alternation of speech forms.
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.
CIAE, Centro de Investigación Avanzada en Educación, Universidad de Chile, 8330014 Santiago, Chile. Electronic address: paulo.barraza@ciae.uchile.cl.
Paulo
P
Barraza
School of Psychology, Pontificia Universidad Católica de Chile, 8940000 Santiago, Chile; School of Education, Universidad Mayor, 7500994 Santiago, Chile. Electronic address: ftjaume@uc.cl.
Francisco
F
Jaume-Guazzini
School of Psychology, Pontificia Universidad Católica de Chile, 8940000 Santiago, Chile. Electronic address: erodrigb@uc.cl.
Eugenio
E
Rodríguez
D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008037:Linguistics; D008297:Male; D008875:Middle Aged; D013060:Speech / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
Alpha band; Beta band; Bistable perception; Neuronal synchrony; Speech perception; Verbal transformation effect