The objectives of this research are to provide a quantitative analysis of the relationships between neuronal structure and function among different types of nerve cells, in isolated, superfused, retina-eyecup preparations of the rabbit and mudpuppy. The methods used in this project combine the recently developed whole cell recording (WCR) technique in the intact retina, with single cell staining by injection of horseradish peroxidase. A major goal of this proposal is to rigorously test the hypothesis that retina ganglion cells are isopotential. Numerous experimental tests of isopotentiality will include charging curve analysis, tests of equipotentiality of EPSPs, reversal potential of spatially separate EPSPs and lock-in amplifier measurements of EPSP conductance changes. WCR will be used to determine the variability of membrane resistance among different neurons by evaluating the physiology and morphology from the same cell; computer based neuronal reconstruction, simulation and analysis will be used to reproduced the biophysical measurements and determine the membrane resistance value required to duplicate the physiologically determined input resistance. In addition, the WCR technique will be used to evaluate ionic conductances of third-order neurons when combined with the application of pharmacological agents which block different types of ionic channels. Of specific interest is the role of Ca++ spikes in ganglion cell information processing. The results of this approach will provide new insights into the role of dendritic form as it relates to function and the cellular mechanisms by which gangloin and amacrine cells integrate synaptic inputs into neuronal activity.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
7R01EY007376-02
Application #
3264330
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1988-09-30
Project End
1992-09-29
Budget Start
1988-09-30
Budget End
1989-09-29
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Type
Schools of Medicine
DUNS #
168559177
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Toris, C B; Eiesland, J L; Miller, R F (1995) Morphology of ganglion cells in the neotenous tiger salamander retina. J Comp Neurol 352:535-59
Carras, P L; Coleman, P A; Miller, R F (1992) Site of action potential initiation in amphibian retinal ganglion cells. J Neurophysiol 67:292-304
Fohlmeister, J F; Coleman, P A; Miller, R F (1990) Modeling the repetitive firing of retinal ganglion cells. Brain Res 510:343-5
Winslow, R L; Miller, R F (1989) A theoretical and experimental study of the effects of non-uniform membrane resistance on the shape of single-cell charging curves. Neuroscience 29:761-71