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The Beauchamp Lab studies the neural mechanisms for multisensory integration and visual perception in human subjects. Many
The Beauchamp Lab studies the neural mechanisms for multisensory integration and visual perception in human subjects. Many tasks require us to integrate information from multiple modalities. For instance, when trying to understanding spoken language, we make use of both the auditory information we hear from the spoken speech and the visual information from the facial movements of the talker. Multisensory integration is especially important under conditions in which one modality is degraded, such as when conversing in a noisy room. Even in healthy young adults, there is considerable variability in people's ability to integrate auditory and visual speech, but this difference in even more pronounced when other populations are examined. Very young children rely exclusively on auditory information to understand language, but in normal lifespan development visual speech plays an increasing role, sometimes becoming dominant as hearing declines with age. Other populations also show interesting differences: deaf children are commonly implanted with a cochlear implant to allow them to hear, but the lack of auditory input to multisensory areas at a young age sometimes prevents them from from properly integrating auditory and visual speech. To understand the neural basis of multisensory integration, the primary method used is blood-oxygen level dependent functional magnetic resonance imaging (BOLD fMRI). fMRI experiments are conducted using the research-dedicated 3 tesla scanner in the UT MRI Center adjacent to the lab. Because of the limited temporal and spatial resolution of fMRI, we often combine it with other methods. Our main supplemental technique is transcranial magnetic stimulation, which temporarily inactivates a region of the brain. By combining fMRI and TMS in the same subject, we can determine if a region of activity observed in fMRI is truly important for the cognitive operation of interest. Other useful technique is electrical recording from patients implanted with electrodes for the treatment of medically intractable epilepsy, because it allows direct recording of the activity of small populations of neurons. Anatomically, the primary focus of the lab is on the superior temporal sulcus, a brain area critical for both the integration of auditory, visual, and somatosensory information and for the perception of complex visual motion, such as mouth movements.
Revision as of 21:49, 21 February 2011