Retinal axons which form a topographic projection from the eye to the optic tectum can be induced, by a restricted retinal lesion, to shift their termination sites toward the resulting deafferented region in the tectum. The experiments in this proposal will use time lapse imaging to observe the deafferentation-induced morphological changes of individual axons in living Xenopus tadpoles in order to analyze how changes in branch elaboration and elimination contribute to reorganizing the retinotectal projection. The respective contributions to map reorganization of neural electrical activity and of calcium- calmodulin kinase II activity, a potential downstream signal for correlated neuronal activity, will be tested by observing the consequences on axonal reorganization of blocking them. To determine whether axons that come to innervate the previously deafferented tectal region recapitulate the developmental program of initially forming NMDA-only silent synapses , the proportion of silent synapses will be measured in the part of the tectum reinnervated by shifting connections and compared with controls. These experiments will provide new insights about the mechanisms by which tectal innervation is regulated during development.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32EY006963-02
Application #
6164658
Study Section
Special Emphasis Panel (ZRG1-VISA (01))
Program Officer
Oberdorfer, Michael
Project Start
2000-03-01
Project End
Budget Start
2000-03-01
Budget End
2001-02-28
Support Year
2
Fiscal Year
2000
Total Cost
$39,232
Indirect Cost
Name
Cold Spring Harbor Laboratory
Department
Type
DUNS #
065968786
City
Cold Spring Harbor
State
NY
Country
United States
Zip Code
11724
Ruthazer, Edward S; Li, Jianli; Cline, Hollis T (2006) Stabilization of axon branch dynamics by synaptic maturation. J Neurosci 26:3594-603
Ruthazer, Edward S; Akerman, Colin J; Cline, Hollis T (2003) Control of axon branch dynamics by correlated activity in vivo. Science 301:66-70
Sin, Wun Chey; Haas, Kurt; Ruthazer, Edward S et al. (2002) Dendrite growth increased by visual activity requires NMDA receptor and Rho GTPases. Nature 419:475-80