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Heywood M., Petry,, Martha E. Bickford, PhD; What is the role of the pulvinar nucleus in visual motion processing?. Journal of Vision 2012;12(9):1372. doi: 10.1167/12.9.1372.
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To effectively interact with our environment, body movements must be coordinated with the perception of visual movement. We will present evidence that regions of the pulvinar nucleus that receive input from the superior colliculus (tectum) may be involved in this process. We have chosen the tree shrew (Tupaia belangeri, a prototype of early primates), as our animal model because tectopulvinar pathways are particularly enhanced in this species, and our psychophysical experiments have revealed that tree shrews are capable of accurately discriminating small differences in the speed and direction of moving visual displays. Using in vivo electrophysiological recording techniques to test receptive field properties, we found that pulvinar neurons are responsive to moving visual stimuli, and most are direction selective. Using anatomical techniques, we found that tectorecipient pulvinar neurons project to the striatum, amygdala, and temporal cortical areas homologous to the primate middle temporal area, MT/V5. Using in vitro recording techniques, immunohistochemistry and stereology, we found that tectorecipient pulvinar neurons express more calcium channels than other thalamic nuclei and thus display a higher propensity to fire with bursts of action potentials, potentially providing a mechanism to effectively coordinate the activity of cortical and subcortical pulvinar targets. Collectively, these results suggest that the pulvinar nucleus may relay visual movement signals from the superior colliculus to subcortical brain regions to guide body movements, and simultaneously to the temporal cortex to modify visual perception as we move though our environment.
Meeting abstract presented at VSS 2012
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