Schedule of Events | Symposia

Attentional inhibition by alpha power is modulated by faster theta rhythm and audio-visual congruency during natural speech perception

Poster Session A - Saturday, March 29, 2025, 3:00 – 5:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Hyojin Park¹ (h.park@bham.ac.uk), Gabriel Byczynski²; ¹University of Birmingham, ²Trinity College Dublin

Audio-visual speech processing is a fundamental aspect of human communication; however, the neural oscillatory mechanisms, particularly those involving alpha rhythms, that underlie attention in tasks requiring attention and suppression remain unclear. To investigate this, we employed a complex audio-visual paradigm designed to explore how alpha rhythms, along with slower frequencies, monitor and integrate audio-visual information under congruent and incongruent conditions. Participants were presented with a TED Talk video while listening to auditory stimuli under three conditions: (1) congruent audio delivered to both ears, (2) congruent audio in one ear and incongruent audio in the other, with attention directed toward the congruent audio, and (3) congruent audio in one ear and incongruent audio in the other, with attention directed toward the incongruent audio. To examine lateralized attention effects, participants were divided into left-attending and right-attending groups across individuals. By analyzing fluctuations in alpha power with regards to audio-visual congruency and the side of attention, we observed a notable finding: First, alpha power fluctuations, falling within the faster theta range. Second, this emerged exclusively in the left-attending group. This result indicates a lateralized relationship between low-frequency rhythms and alpha-band activity, highlighting the role of alpha rhythms as a mediator of attention in audio-visual speech processing. Also, these findings underscore the importance of lateralized neural dynamics in tasks involving selective attention and suppression, providing new insights into the oscillatory mechanisms underlying audio-visual integration in human communication.

Topic Area: ATTENTION: Multisensory