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Mapping the After-effects of Theta Burst Stimulation on the Human Auditory Cortex with Functional Imaging
Published on: September 12, 2012
Noise alters beta-band activity in superior temporal cortex during audiovisual speech processing
Inga M Schepers1, Till R Schneider, Joerg F Hipp
1Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany. Inga.M.Schepers@uth.tmc.edu
Neuroimage
|January 1, 2013
Summary
Visual cues enhance speech recognition, especially in noisy environments. This study shows auditory noise affects brain responses in the superior temporal sulcus (STS), impacting beta-band activity crucial for processing audiovisual speech.
Area of Science:
- Neuroscience
- Auditory Perception
- Speech Processing
Background:
- Speech recognition improves with visual input, particularly in noisy conditions.
- The superior temporal sulcus (STS) is implicated in audiovisual speech processing.
- The precise neural dynamics and noise effects in the STS remain unclear.
Purpose of the Study:
- Investigate how auditory noise impacts audiovisual speech processing using electroencephalography (EEG).
- Examine effects on event-related potentials (ERPs) and oscillatory brain activity.
- Determine the role of the STS in processing speech under varying noise levels.
Main Methods:
- Presented spoken syllables in audiovisual (AV) and auditory-only (A) conditions across three noise levels (none, low, high).
- Analyzed differences between AV and A responses, focusing on ERPs and beta-band oscillations (16-32 Hz).
- Employed source localization techniques (LORETA and linear beamforming) to identify brain regions involved.
Main Results:
- Auditory noise altered central ERPs between 130-150 ms and 170-210 ms, localized to the lateral temporal lobe (superior and middle temporal gyrus).
- Beta-band activity suppression (100-400 ms) was observed in the AV minus A signal.
- This beta-band suppression was reduced under high noise, suggesting altered multisensory processing, and was localized to the STS.
Conclusions:
- Auditory noise modulates audiovisual speech processing, affecting ERPs in the lateral temporal lobe.
- Beta-band activity in the STS is crucial for audiovisual speech processing, even under noisy acoustic conditions.
- Findings highlight the STS's role in integrating auditory and visual speech information robustly.
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