Ganglion cells in the retina may project to either the ipsilateral or contralateral side of the brain, depending upon their class and on their retinal position. The long-long-term objective is to understand the determinants of the """"""""decussation pattern"""""""" of the distinct retinal ganglion cell classes in mammals.
The specific aim of this proposal is to define the relative roles of two hypothesized mechanisms: 1) decussation patterns are produced as a consequence of regressive events that selectively eliminate cells projecting to the inappropriate side of the brain; or 2) decussation patterns are produced as a consequence of selective axonal navigation at the chiasmatic region, where some timeand/or position-dependent event determines the side of choice. Studies will use the visual systems of adult and developing cats and ferrets, in which there are well-characterized differences in decussation patterns between the retinal ganglion cell classes and between the species. These species and cell class differences are the basis for the proposed experiments. The experimental approach employed is to assess either the nature of the crossed and uncrossed ganglion cell distributions on the retina (the """"""""decussation pattern""""""""), or to determine the organization of optic fibers in the chiasmatic region, either a) during development, b) in the normal adult, or c) as a consequence of some early manipulation to the visual pathway. The experiments will make use of the techniques of Horseradish peroxidase histochemistry or carbocyanine dye diffusion, with which cells in the temporal retina can be identified according to their side of projection; tritiated thymidine autoradiography, with which the order of genesis of the retinal cells projecting to the different hemispheres can be determined; myelin staining of axonal classes, with which the fiber organization of the adult chiasm can be determined; and electron microscopy, with which the position of growth cones at different regions in the developing chiasmatic region can be defined. Finally, a novel tissue culture technique is described for studying chiasmatic pathway decisions during development.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY008415-02
Application #
3265760
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1991-01-01
Project End
1994-12-31
Budget Start
1992-01-03
Budget End
1992-12-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of California Santa Barbara
Department
Type
Schools of Arts and Sciences
DUNS #
City
Santa Barbara
State
CA
Country
United States
Zip Code
93106
Johnson, P T; Geller, S F; Reese, B E (1998) Distribution, size and number of axons in the optic pathway of ground squirrels. Exp Brain Res 118:93-104
Reese, B E; Urich, J L (1994) Does early enucleation affect the decussation pattern of alpha cells in the ferret? Vis Neurosci 11:447-54
Reese, B E; Thompson, W F; Peduzzi, J D (1994) Birthdates of neurons in the retinal ganglion cell layer of the ferret. J Comp Neurol 341:464-75
Reese, B E; Maynard, T M; Hocking, D R (1994) Glial domains and axonal reordering in the chiasmatic region of the developing ferret. J Comp Neurol 349:303-24
Reese, B E (1993) Clinical implications of the fibre order in the optic pathway of primates. Neurol Res 15:83-6
Reese, B E; Baker, G E (1993) The re-establishment of the representation of the dorso-ventral retinal axis in the chiasmatic region of the ferret. Vis Neurosci 10:957-68
Baker, G E; Reese, B E (1993) Chiasmatic course of temporal retinal axons in the developing ferret. J Comp Neurol 330:95-104
Reese, B E; Guillery, R W; Mallarino, C (1992) Time of ganglion cell genesis in relation to the chiasmatic pathway choice of retinofugal axons. J Comp Neurol 324:336-42
Cavalcante, L A; Allodi, S; Reese, B E (1992) Fiber order in the opossum's optic tract. Anat Embryol (Berl) 186:589-600
Reese, B E; Baker, G E (1992) Changes in fiber organization within the chiasmatic region of mammals. Vis Neurosci 9:527-33