Superadditive responses in superior temporal sulcus predict audiovisual benefits in object categorization

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • Max Planck Institute for Biological Cybernetics

Abstract

Merging information from multiple senses provides a more reliable percept of our environment. Yet, little is known about where and how various sensory features are combined within the cortical hierarchy. Combining functional magnetic resonance imaging and psychophysics, we investigated the neural mechanisms underlying integration of audiovisual object features. Subjects categorized or passively perceived audiovisual object stimuli with the informativeness (i.e., degradation) of the auditory and visual modalities being manipulated factorially. Controlling for low-level integration processes, we show higher level audiovisual integration selectively in the superior temporal sulci (STS) bilaterally. The multisensory interactions were primarily subadditive and even suppressive for intact stimuli but turned into additive effects for degraded stimuli. Consistent with the inverse effectiveness principle, auditory and visual informativeness determine the profile of audiovisual integration in STS similarly to the influence of physical stimulus intensity in the superior colliculus. Importantly, when holding stimulus degradation constant, subjects' audiovisual behavioral benefit predicts their multisensory integration profile in STS: only subjects that benefit from multisensory integration exhibit superadditive interactions, while those that do not benefit show suppressive interactions. In conclusion, superadditive and subadditive integration profiles in STS are functionally relevant and related to behavioral indices of multisensory integration with superadditive interactions mediating successful audiovisual object categorization. The Author

Details

Original languageEnglish
Pages (from-to)1829-1842
Number of pages14
JournalCerebral Cortex
Volume20
Issue number8
Publication statusPublished - Aug 2010

Keywords

  • crossmodal, fMRI, inverse effectiveness, multisensory, object recognition