The long term objective is to define and characterize the developmental mechanisms which direct the correct anatomical and functional organization of the mammalian neocortex and its connections. The neocortex processes visual, auditory and somatic sensation giving rise to perception, volitional motor responses, and to more complex phenomena such as learning and memory. These functions are performed by the functionally specialized areas of the neocortex, each characterized by unique connectivity and architecture. Thalamocortical input play a fundamental role in defining neocortical areas: in adult, the modality of thalamic input dictates an area's functional identity. During development, thalmocortical afferents are required for the proper differentiation of neocortical areas. A crucial issue in both cortical function and development is defining the mechanisms that control the pathfinding of thalamocortical axons from dorsal thalamus to neocortex, and the subsequent area-specific targeting of these axons to their appropriate cortical areas. The first three aims address these issues by testing hypotheses on mechanisms and molecules involved in the pathfinding and area-specific targeting of thalamocortical axons. Our goal is to define roles of attractant and repellant axon guidance molecules, including the chemoattractant Netrin-1 and the chemorepellant Sema III/D, in pathfinding of thalamocortical axons, and the roles of the regulatory genes EMx1, Emx2, and Pax6 in controlling the development of area-specific thalamocortical projections.
The fourth aim addresses hypotheses on the roles of Emx1, Emx2, and Pax6 in the genetic regulation of area identity of cortical output neurons in layers 6 and 5, focusing on their area-specific projections to targets in dorsal thalmus, or in the midbrain, hindbrain, and spinal cord, respectively. To accomplish these aims we will use complementary approaches, including in vivo and in vitro experiments to characterize axon guidance activities, loss of function analyses using knockout mice deficient for genes hypothesized to be involved, and gain of function studies using recombinant adenoviruses to express these genes in embryonic forebrain. Due to the conserved structural and functional homology of genes between rodents and humans, the mechanisms identified in the rodent model are anticipated to be similarly involved in human development.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS031558-07
Application #
6187759
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Finkelstein, Robert
Project Start
1993-12-15
Project End
2003-07-31
Budget Start
2000-08-01
Budget End
2001-07-31
Support Year
7
Fiscal Year
2000
Total Cost
$465,809
Indirect Cost
Name
Salk Institute for Biological Studies
Department
Type
DUNS #
005436803
City
La Jolla
State
CA
Country
United States
Zip Code
92037
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Perez-Garcia, Carlos G; O'Leary, Dennis D M (2016) Formation of the Cortical Subventricular Zone Requires MDGA1-Mediated Aggregation of Basal Progenitors. Cell Rep 14:560-571
Kawaguchi, Daichi; Sahara, Setsuko; Zembrzycki, Andreas et al. (2016) Generation and analysis of an improved Foxg1-IRES-Cre driver mouse line. Dev Biol 412:139-147
Perez-Garcia, Carlos G (2015) ErbB4 in Laminated Brain Structures: A Neurodevelopmental Approach to Schizophrenia. Front Cell Neurosci 9:472
Zembrzycki, Andreas; Perez-Garcia, Carlos G; Wang, Chia-Fang et al. (2015) Postmitotic regulation of sensory area patterning in the mammalian neocortex by Lhx2. Proc Natl Acad Sci U S A 112:6736-41
Pao, Gerald M; Zhu, Quan; Perez-Garcia, Carlos G et al. (2014) Role of BRCA1 in brain development. Proc Natl Acad Sci U S A 111:E1240-8
Hatori, Megumi; Gill, Shubhroz; Mure, Ludovic S et al. (2014) Lhx1 maintains synchrony among circadian oscillator neurons of the SCN. Elife 3:e03357
Del Barrio, Marta Garcia; Bourane, Steeve; Grossmann, Katja et al. (2013) A transcription factor code defines nine sensory interneuron subtypes in the mechanosensory area of the spinal cord. PLoS One 8:e77928
Kang, Ji-Yong; Kawaguchi, Daichi; Coin, Irene et al. (2013) In vivo expression of a light-activatable potassium channel using unnatural amino acids. Neuron 80:358-70
Chou, Shen-Ju; O'Leary, Dennis D M (2013) Role for Lhx2 in corticogenesis through regulation of progenitor differentiation. Mol Cell Neurosci 56:1-9

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