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Contribution Details

Type Journal Article
Scope Discipline-based scholarship
Title Temporal characteristics of audiovisual information processing
Organization Unit
Authors
  • G Fuhrmann Alpert
  • G Hein
  • N Tsai
  • M J Naumer
  • R T Knight
Item Subtype Original Work
Refereed Yes
Status Published in final form
Language
  • English
Journal Title Journal of Neuroscience
Publisher Society for Neuroscience
Geographical Reach international
ISSN 0270-6474
Volume 28
Number 20
Page Range 5344 - 5349
Date 2008
Abstract Text In complex natural environments, auditory and visual information often have to be processed simultaneously. Previous functional magnetic resonance imaging (fMRI) studies focused on the spatial localization of brain areas involved in audiovisual (AV) information processing, but the temporal characteristics of AV information flow in these regions remained unclear. In this study, we used fMRI and a novel information-theoretic approach to study the flow of AV sensory information. Subjects passively perceived sounds and images of objects presented either alone or simultaneously. Applying the measure of mutual information, we computed for each voxel the latency in which the blood oxygenation level-dependent signal had the highest information content about the preceding stimulus. The results indicate that, after AV stimulation, the earliest informative activity occurs in right Heschl's gyrus, left primary visual cortex, and the posterior portion of the superior temporal gyrus, which is known as a region involved in object-related AV integration. Informative activity in the anterior portion of superior temporal gyrus, middle temporal gyrus, right occipital cortex, and inferior frontal cortex was found at a later latency. Moreover, AV presentation resulted in shorter latencies in multiple cortical areas compared with isolated auditory or visual presentation. The results provide evidence for bottom-up processing from primary sensory areas into higher association areas during AV integration in humans and suggest that AV presentation shortens processing time in early sensory cortices.
Free access at PubMed ID
Digital Object Identifier 10.1523/JNEUROSCI.5039-07.2008
PubMed ID 18480290
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Additional Information Holder of copyright: The Society for Neuroscience