Research Summary

My laboratory studies the cellular and molecular control of brain nucleogenesis. We are particularly interested in the signals that govern cell-type specification in early brain development and the mechanisms that regulate how young neurons migrate to form nuclei of the appropriate size and shape. The focus of our current work is on the development of the ventral midbrain and the telencephalon.

Research Statement

I am interested in how the neurons and circuitries of the vertebrate central nervous system are specified during development. In vertebrate brains, neurons with similar long-distance connections are aggregated into neural centers known as nuclei. Dozens of nuclei can be distinguished in the brains of birds and mammals, and connections among neurons in these brains are in essence connections targeted to different nuclei. Viewed from this perspective, the problem of how neurons make the correct connections with one another in early development is, for studies of vertebrates, a problem of pattern formation: how are neurons allocated to different nuclear fates? and how are nuclei formed?

My laboratory employs cellular and molecular techniques to study this problem of brain nucleogenesis. This research is carried out in chicks and mice. The chick brain is accessible throughout development for fate mapping and cell lineage studies, experimental embryology including tissue transplants, and genetic manipulation by recombinant retrovirus infection and in ovo electroporation. Research on the mouse embryo offers a broad range of reverse genetic technologies and a number of established mutants.

My laboratory has also recently begun to explore two important related issues in evolutionary neurobiology, one on the origins of cerebral cortical cell types in amniotes, the other on the structure and development of large invertebrate brains.

Recent publications

Sanders, T.A., Lumsden, A. and Ragsdale, C.W. (2002) Arcuate plan of chick midbrain development. J. Neuroscience 22, 10742-10750.

Agarwala, S. and Ragsdale, C.W. (2002) A role for midbrain arcs in nucleogenesis. Development 129, 5779-5788.

Agarwala, S., Sanders, T.A. and Ragsdale, C.W. (2001) Sonic Hedgehog control of size and shape in midbrain pattern formation. Science 291, 2147-2150.

Assimacopoulos, S., Grove, E.A. and Ragsdale, C.W. (2003) Identification of a Pax6-dependent epidermal growth factor family signaling source at the lateral edge of the embryonic cerebral cortex. J. Neuroscience 23, 6399-6403.

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