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Neural correlates of auditory-visual stimulus onset asynchrony detection
K O Bushara1, J Grafman, M Hallett
1National Institute of Neurological Disorders and Stroke, Human Motor Control Section, and Cognitive Neuroscience Section, National Institutes of Health, Bethesda, Maryland 20892-1428, USA.
Summary
The brain detects auditory-visual synchrony using a network including the right insula. This network, particularly the insula, is key for multisensory integration and perceptual illusions.
Area of Science:
- Neuroscience
- Cognitive Science
- Sensory Processing
Background:
- Intersensory temporal synchrony is crucial for multisensory integration.
- Perceptual illusions can arise from erroneous temporal binding of sensory inputs.
- The neural mechanisms for detecting temporal synchrony between senses are not well understood.
Purpose of the Study:
- To investigate the neural basis of detecting auditory-visual stimulus onset asynchrony.
- To identify brain regions and networks involved in processing temporal synchrony between auditory and visual stimuli.
Main Methods:
- Positron emission tomography (PET) was used to measure brain activity.
- Interregional covariance analysis was employed to examine functional interactions between brain areas.
Main Results:
- Detecting auditory-visual asynchrony activated a widespread neural network, including insular, parietal, prefrontal, and cerebellar regions.
- The right insula showed the highest task-specific activity.
- Functional interactions were observed between the insula, posterior thalamus, and superior colliculus.
Conclusions:
- The insula plays a significant role in detecting temporal synchrony between auditory and visual stimuli.
- The insula, through connections with the tectal system, may mediate early auditory-visual interactions.
- These mechanisms likely underlie phenomena like the ventriloquist and McGurk illusions.