The mammalian neocortex is the product of a complex evolutionary history. Research on the organization of sensory projections to the telencephalon of nonmammalian vertebrates has demonstrated the presence of cortical equivalent """"""""cluster"""""""" of neurons within the Dorsal Ventricular Ridge (DVR) of the telencephalon. These """"""""clonal clusters"""""""" may correspond to individual laminae of the mammalian neocortex. The microcircuitry of connections between """"""""clusters"""""""" within the tectofugal pathways appears to correspond to the interlaminar organization of extrastriate visual pathways of the neocortex. Further analysis of this pathway will help clarify the role of the extrastriate system in visual performance. Studies will concentrate on the organization of visual pathways within the DVR, the relationship of the DVR to the neocortex, and possible role of the subventricular zone of Stensaas in the ontogeny of neocortex in mammals. The DVR may correspond to the Subventricular Zone (SVZ) of Stensaas in the developing neocortex of mammals. Specific studies will include: A. Analysis of the organization, histochemistry and morphology of the neurons of the tectofugal pathway in the DVR of birds. B. Interrelationship of the thalamofugal and tectofugal pathways. C. Production of monoclonal antibodies to identify """"""""clonal clusters"""""""" and their possible cross reactivity with single laminae of the neocortex of mammals. E. Investigate the role of the SVZ of mammals as a possible representative of the Dorsal Ventricular Ridge, and its participation in the development of neocortex. These studies will clarify our understanding of the role of tectofugal pathways in vision, the evolutionary origins of the mammalian neocortex, and both normal and abnormal developmental events in the ontogeny of the mammalian neocortex. Methods to be employed include pathway tracing methods, single cell filling, immunohistochemistry, monoclonal antibodies and in situ hybridization to identify the transmitters/peptides, receptors and related proteins mediating organization and communication in these two pathways.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024560-06
Application #
3409287
Study Section
Neurology A Study Section (NEUA)
Project Start
1986-07-01
Project End
1995-11-30
Budget Start
1991-12-01
Budget End
1992-11-30
Support Year
6
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Type
Schools of Medicine
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
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Fredes, Felipe; Vega-Zuniga, Tomas; Karten, Harvey et al. (2012) Bilateral and ipsilateral ascending tectopulvinar pathways in mammals: a study in the squirrel (Spermophilus beecheyi). J Comp Neurol 520:1800-18
Wang, Yuan; Brzozowska-Prechtl, Agnieszka; Karten, Harvey J (2010) Laminar and columnar auditory cortex in avian brain. Proc Natl Acad Sci U S A 107:12676-81
Wang, Yuan; Karten, Harvey J (2010) Three subdivisions of the auditory midbrain in chicks (Gallus gallus) identified by their afferent and commissural projections. J Comp Neurol 518:1199-219
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Wang, Yuan; Major, Daniel E; Karten, Harvey J (2004) Morphology and connections of nucleus isthmi pars magnocellularis in chicks (Gallus gallus). J Comp Neurol 469:275-97
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Major, Daniel E; Rodman, Hillary R; Libedinsky, Camilo et al. (2003) Pattern of retinal projections in the California ground squirrel (Spermophilus beecheyi): anterograde tracing study using cholera toxin. J Comp Neurol 463:317-40
Wu, C C; Russell, R M; Nguyen, R T et al. (2003) Tracing developing pathways in the brain: a comparison of carbocyanine dyes and cholera toxin b subunit. Neuroscience 117:831-45
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