There are large sex difference in the structure and function of brain regions controlling song in passerine birds. These sex differences develop under the control of gonadal steroids. The long term objectives are to understand the cellular mechanisms by which gonadal steroids influence the development of these neural circuits that control a complex learned motor pattern. By gaining knowledge of these cellular mechanisms, we will also shed light on the neural mechanisms responsible for song learning and for the limitation of learning to an early critical period. Using castration and various treatments with steroid hormones and antihormones, we will examine which steroids act singly or in combination to alter the morphological development of the song system (numbers and sizes of neurons). Other experiments will measure steroid accumulation and projections of steroid sensitive neurons to clarify possible sites of steroid action in the control of neural development. Using thymidine autoradiography, we will assess when song system neurons undergo their last mitotic division, and manipulate steroid levels to determine if steroids regulate neuron number by altering the processes of proliferation or migration of neurons. Anatomical tract tracing techniques will map the ontogeny of interconnections between song system neurons to suggest possible times at which these neurons can have trophic interactions regulated by steroids.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC000217-07
Application #
3216144
Study Section
Neurology B Subcommittee 2 (NEUB)
Project Start
1983-07-01
Project End
1992-06-30
Budget Start
1990-07-01
Budget End
1991-06-30
Support Year
7
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Schools of Arts and Sciences
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Burgoyne, Paul S; Arnold, Arthur P (2016) A primer on the use of mouse models for identifying direct sex chromosome effects that cause sex differences in non-gonadal tissues. Biol Sex Differ 7:68
Itoh, Yuichiro; Arnold, Arthur P (2014) X chromosome regulation of autosomal gene expression in bovine blastocysts. Chromosoma 123:481-9
Arnold, Arthur P; Chen, Xuqi; Link, Jenny C et al. (2013) Cell-autonomous sex determination outside of the gonad. Dev Dyn 242:371-9
Arnold, Arthur P (2012) The end of gonad-centric sex determination in mammals. Trends Genet 28:55-61
Arnold, Arthur P; Itoh, Yuichiro (2011) Factors causing sex differences in birds. Avian Biol Res 4:
McCarthy, Margaret M; Arnold, Arthur P (2011) Reframing sexual differentiation of the brain. Nat Neurosci 14:677-83
Itoh, Yuichiro; Kampf, Kathy; Arnold, Arthur P (2011) Possible differences in the two Z chromosomes in male chickens and evolution of MHM sequences in Galliformes. Chromosoma 120:587-98
Naurin, Sara; Hansson, Bengt; Hasselquist, Dennis et al. (2011) The sex-biased brain: sexual dimorphism in gene expression in two species of songbirds. BMC Genomics 12:37
Itoh, Yuichiro; Kampf, Kathy; Balakrishnan, Christopher N et al. (2011) Karyotypic polymorphism of the zebra finch Z chromosome. Chromosoma 120:255-64
Itoh, Yuichiro; Arnold, Arthur P (2011) Zebra finch cell lines from naturally occurring tumors. In Vitro Cell Dev Biol Anim 47:280-2

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