The nature of the intrinsic organization of the neocortex is a central question in developmental neurobiology. The mature neocortex is a mosaic of functionally and anatomically specialized areas that share a fundamental laminar and columnar structure. The central question is whether the neocortex is an unspecified, unified structure on which local identity is imposed by an external agency like the thalamus or whether it contains intrinsic local identity that attracts and organizes particular input structure and specifies certain output. The development of the tangential and laminar specificity of thalamic projections to the cortex will be investigated in two experimental conditions. In the first experiment, a region of dorsal neocortex, principally visual cortex, will be removed in utero prior to the arrival of the first thalamic axons in the cortex, and the development, survival, mature projection pattern and volume of arbor of thalamic axons will be investigated. In the second manipulation, a developmental deletion of the layer IV and varying amounts of the supragranular layers will be made using a mitotic inhibitor, MAM (methylazoxymethanol acetate), with a parallel analysis. The intent of both of these manipulations is to delete the target population prior to any interaction of axon and target populations, and thus reveal any intrinsic specificity in the choice of cortical and laminar terminal area by incoming thalamocortical axons, and the mechanisms of population matching between the thalamus and cortex. The clinical significance of this work is direct: in addition to supplying basic information about the nature of cortical reorganization after brain damage, we will be directly describing what happens to the cortex after early local deletions, such as might happen with a vascular accident, or after a cytotoxic insult.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
3R01NS019245-16S1
Application #
6358270
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Spinella, Giovanna M
Project Start
1983-08-01
Project End
2002-06-30
Budget Start
2000-07-01
Budget End
2002-06-30
Support Year
16
Fiscal Year
2000
Total Cost
$76,930
Indirect Cost
Name
Cornell University
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Kingsbury, Marcy A; Lettman, Nadine A; Finlay, Barbara L (2002) Reduction of early thalamic input alters adult corticocortical connectivity. Brain Res Dev Brain Res 138:35-43
Kingsbury, M A; Graf, E R; Finlay, B L (2000) Altered development of visual subcortical projections following neonatal thalamic ablation in the hamster. J Comp Neurol 424:165-78
Darlington, R B; Dunlop, S A; Finlay, B L (1999) Neural development in metatherian and eutherian mammals: variation and constraint. J Comp Neurol 411:359-68
Finlay, B L; Hersman, M N; Darlington, R B (1998) Patterns of vertebrate neurogenesis and the paths of vertebrate evolution. Brain Behav Evol 52:232-42
Woo, T U; Finlay, B L (1996) Cortical target depletion and ingrowth of geniculocortical axons: implications for cortical specification. Cereb Cortex 6:457-69
Woo, T U; Niederer, J K; Finlay, B L (1996) Cortical target depletion and the developing lateral geniculate nucleus: implications for trophic dependence. Cereb Cortex 6:446-56
Troilo, D; Xiong, M; Crowley, J C et al. (1996) Factors controlling the dendritic arborization of retinal ganglion cells. Vis Neurosci 13:721-33
Xiong, M; Finlay, B L (1996) What do developmental mapping rules optimize? Prog Brain Res 112:351-61
Finlay, B L; Darlington, R B (1995) Linked regularities in the development and evolution of mammalian brains. Science 268:1578-84
Xiong, M; Pallas, S L; Lim, S et al. (1994) Regulation of retinal ganglion cell axon arbor size by target availability: mechanisms of compression and expansion of the retinotectal projection. J Comp Neurol 344:581-97

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