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B. E. Stein, T. J. Perrault, Jr., J. W. Vaughan, B. A. Rowland; Visual-Auditory (Multisensory) Plasticity in Adult Superior Colliculus Neurons. Invest. Ophthalmol. Vis. Sci. 2009;50(13):1432.
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© ARVO (1962-2015); The Authors (2016-present)
Superior colliculus (SC) neurons have the remarkable capability to integrate information from different senses. However, as shown in the cat, this capacity depends on influences from cortex, and it fails to develop if cortex (i.e., the anterior ectosylvian and rostral lateral suprasylvian cortices) is rendered inactive for several weeks during early life. Thus, when tested as adults (6mos-1.5 yrs), SC neurons of such animals failed to exhibit multisensory integration, and the animals failed to exhibit the behavioral benefits of multisensory integration in orientation and localization tasks. Surprisingly, however, after behavioral retesting at 5 years of age, they were now capable of using visual-auditory cues synergistically: their behavioral performance was markedly enhanced above that in response to either cue alone. SC neurons were now examined to test the possibility that they had acquired their multisensory integration capabilities late in life to support these behaviors.
Single visual-auditory neurons were recorded in the SC in semichronic anesthetized cats. Neurons were presented with repeated modality-specific (visual, auditory) and cross-modal (visual-auditory) stimuli in interleaved fashion.
The properties of many of these SC neurons now proved to be indistinguishable from those in normal animals. They responded to stimuli from different modalities individually, and their responses to cross-modal stimuli were comprised of more impulses, contained more information, and had shorter latencies and/or greater speed of information transmission than to the most effective of the component stimuli.
The data suggest two possibilities that must be examined in the future: 1) the brain is capable using experience later in life to establishing the essential cortico-SC circuits that normally develop early in life, or 2) the brain is able to develop a novel circuit later in life that can accomplish the same aim.Supported by NIH grants EY016716 and NS36916
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