We propose to further determine the functional and connectional organization of the dorsal stream visuomotor pathway from visual areas to motor areas. (1) We will identify functional subregions of posterior parietal cortex using microelectrode stimulation and optical imaging of evoked cortical activity. (2) Tracers will be injected in identified subregions and areas of cortex to reveal the cortical and subcortical connectional network. (3) We will evaluate the functional plasticity of posterior parietal subregions as a result of training on visuomotor tasks. (4) Finally, the functional contributions of subdivisions of the dorsal stream system to the performance of visuomotor tasks and the plasticity of the system will be evaluated after lesions of dorsal stream visual areas and parts of posterior parietal cortex. The results of these experiments will provide a new and extended understanding of the functional organization of the subsystem for visuomotor behavior in primates. In addition, the results will inform clinical interpretations of the consequences of damage to the visuomotor system in humans, and suggest mechanisms of recovery. Favorable therapeutic procedures may be based on the results.

Public Health Relevance

The proposed research will help determine how posterior parietal cortex links vision to action. The studies will define functional subdivisions of posterior parietal cortex, determine how these subdivisions fit into a connectional network, and evaluate the behavioral consequences of the loss of visual inputs to the network.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
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Central Visual Processing Study Section (CVP)
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Steinmetz, Michael A
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Vanderbilt University Medical Center
Schools of Arts and Sciences
United States
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Takahata, Toru; Kaas, Jon H (2017) c-FOS expression in the visual system of tree shrews after monocular inactivation. J Comp Neurol 525:151-165
Stepniewska, Iwona; Cerkevich, Christina M; Kaas, Jon H (2016) Cortical Connections of the Caudal Portion of Posterior Parietal Cortex in Prosimian Galagos. Cereb Cortex 26:2753-77
Kaas, Jon H; Stepniewska, Iwona (2016) Evolution of posterior parietal cortex and parietal-frontal networks for specific actions in primates. J Comp Neurol 524:595-608
Gharbawie, Omar A; Stepniewska, Iwona; Kaas, Jon H (2016) The origins of thalamic inputs to grasp zones in frontal cortex of macaque monkeys. Brain Struct Funct 221:3123-40
Cooke, Dylan F; Stepniewska, Iwona; Miller, Daniel J et al. (2015) Reversible Deactivation of Motor Cortex Reveals Functional Connectivity with Posterior Parietal Cortex in the Prosimian Galago (Otolemur garnettii). J Neurosci 35:14406-22
Balaram, P; Isaamullah, M; Petry, H M et al. (2015) Distributions of vesicular glutamate transporters 1 and 2 in the visual system of tree shrews (Tupaia belangeri). J Comp Neurol 523:1792-808
Balaram, Pooja; Young, Nicole A; Kaas, Jon H (2014) Histological features of layers and sublayers in cortical visual areas V1 and V2 of chimpanzees, macaque monkeys, and humans. Eye Brain 2014:5-18
Cerkevich, Christina M; Lyon, David C; Balaram, Pooja et al. (2014) Distribution of cortical neurons projecting to the superior colliculus in macaque monkeys. Eye Brain 2014:121-137
Cerkevich, Christina M; Collins, Christine E; Kaas, Jon H (2014) Cortical inputs to the middle temporal visual area in New World owl monkeys. Eye Brain 2015:1-15
Kaas, Jon H; Balaram, Pooja (2014) Current research on the organization and function of the visual system in primates. Eye Brain 6:1-4

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