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Updated: Jul 7, 2025
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Functional Imaging of Auditory Cortex in Adult Cats using High-field fMRI
Published on: February 19, 2014
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Visual Stimuli Modulate Local Field Potentials But Drive No High-Frequency Activity in Human Auditory Cortex.
Jyrki Ahveninen1,2, Hsin-Ju Lee3,4, Hsiang-Yu Yu5,6
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts 02129 jahveninen@mgh.harvard.edu.
Summary
Visual stimuli can influence auditory cortices (ACs), but intracranial recordings show this is modulation, not active visual processing. Broadband high-frequency activity, a marker of neuronal firing, was not increased by visual input in the ACs.
Area of Science:
- Neuroscience
- Auditory perception
- Sensory integration
Background:
- Neuroimaging suggests visual input influences human auditory cortices (ACs).
- It remains debated whether this reflects active visual processing or mere modulation of auditory processing.
- Broadband high-frequency activity (BHFA) is a potential marker for neuronal firing.
Purpose of the Study:
- To investigate whether visual stimuli elicit active visual processing in human ACs.
- To differentiate between active processing and modulation of auditory function by visual stimuli.
- To examine the role of BHFA in cross-sensory influences within ACs.
Main Methods:
- Used stereo-EEG depth electrodes in 16 participants near ACs.
- Presented auditory, visual, and audiovisual stimuli.
- Analyzed intracranial event-related potentials (iERPs) and broadband high-frequency activity (BHFA) using inverse modeling.
Main Results:
- Cross-sensory responses to visual stimuli were observed in ACs, lagging auditory responses.
- Visual stimuli modulated low-frequency oscillations and triggered event-related desynchronization.
- Crucially, BHFA in ACs did not significantly increase following visual stimuli, even in audiovisual conditions.
Conclusions:
- Intracranial recordings confirm cross-sensory modulations of auditory processing by visual stimuli in human ACs.
- Evidence does not support active visual processing within the ACs.
- Visual influences on ACs appear to be modulatory rather than driven by visual neuronal firing.
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