Abstract

The overall goal of the proposed research is to determine the pathway(s) by which visual information is transmitted to the superior colliculus (SC) neurons that innervate nuclei which, in turn, control head and eye movements. The sensory information that deep layer, SC cells send to medullary and spinal structures is thought to be critically involved in orienting and attentional behavior. However, the visual input pathways for these SC neurons have not been defined. Previous physiological and light microscopic experiments have suggested several potential sources of critical visual input to deep layer output cells in the rodent SC. Superficially directed dendrites of deep layer neurons may receive retinal input and/or synapses from the axon collaterals of visually responsive superficial layer cells. Alternatively, direct retinal projections to the deep laminae and/or axonal projections from the superficial to the deep layers might provide the necessary visual input for these cells. We will combine anterograde transport, intracellular horseradish peroxidase injection, and electron microscopic techniques to determine which of these potential pathways actually exist in the hamster's SC. We will then combine electrophysiological recording with reversible inactivation techniques to determine which of the pathways defined in the electron microscope provide(s) the necessary visual input to deep layer output cells.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
9R01NS032540-06
Application #
2270810
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1988-12-03
Project End
1997-11-30
Budget Start
1993-12-03
Budget End
1994-11-30
Support Year
6
Fiscal Year
1994
Total Cost
Indirect Cost

  Institution

Name
University of Toledo
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
807418939
City
Toledo
State
OH
Country
United States
Zip Code
43614