Neuroendocrine control of sound production and of sexually dimorphic nuclei, clusters of neurons in the CNS, of toadfish, frogs, birds and mammals are important avenues for understanding neural control of behavior. The stereotypy and simplicity of the male toadfish's mating call, which is determined by rate and duration of sonic muscle contraction, make the call an attractive model for neuroendocrine and physiological control of sexually-related vocal behavior. Fruitful exploitation of this model requires more detailed knowledge of sonic neuroanatomy, a major goal of this proposal. Demonstration in our laboratory of a multiyear four fold increase in number and size of neurons in the sonic motor nucleus (SMN), a likely homologue of the hypoglossal nucleus, has implications for neuroplasticity and CNS regeneration, since neuron number and size are fixed pre- or perinatally in mammals. Additionally, we have divided toadfish into 2 classes based on SMN neuron size: (1) females and males with small neurons and (2) males with large neurons. This intrasexual dimorphism suggests hypotheses which will allow correlation of neuron morphology with social behavior. Using primarily anatomical methods, this proposal has 3 major related foci: (1) morphological basis for ontogeny and sexual dimorphism of sonic muscles (hypertrophy and hyperplasia of muscle fibers); (2) morphology, histochemistry, ontogeny, and sexual dimorphism of the SMN in embryonic and adult toadfish and correlates with social behavior; and (3) identification of sonic pathways from the preoptic area to the SMN with HRP, and the comparison of sonic nuclei with nuclei containing 3H steroid concentrating neurons, which will be established by autoradiography.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH038921-02
Application #
3376999
Study Section
(BPNB)
Project Start
1984-01-01
Project End
1986-12-31
Budget Start
1985-01-01
Budget End
1985-12-31
Support Year
2
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Virginia Commonwealth University
Department
Type
Schools of Arts and Sciences
DUNS #
City
Richmond
State
VA
Country
United States
Zip Code
23298
Fine, M L; Keefer, D A; Russel-Mergenthal, H (1990) Autoradiographic localization of estrogen-concentrating cells in the brain and pituitary of the oyster toadfish. Brain Res 536:207-19
Fine, M L; Mosca, P J (1989) Anatomical study of the innervation pattern of the sonic muscle of the oyster toadfish. Brain Behav Evol 34:265-72
Fine, M L (1989) Embryonic, larval and adult development of the sonic neuromuscular system in the oyster toadfish. Brain Behav Evol 34:13-24
De Rosa, F; Fine, M L (1988) Primary connections of the anterior and posterior lateral line nerves in the oyster toadfish. Brain Behav Evol 31:312-7
Fine, M L; Horn, M H; Cox, B (1987) Acanthonus armatus, a deep-sea teleost fish with a minute brain and large ears. Proc R Soc Lond B Biol Sci 230:257-65
Galeo, A J; Fine, M L; Stevenson, J A (1987) Embryonic and larval development of the sonic motor nucleus in the oyster toadfish. J Neurobiol 18:359-73
Fine, M L; Pennypacker, K R (1986) Hormonal basis for sexual dimorphism of the sound-producing apparatus of the oyster toadfish. Exp Neurol 92:289-98
Pennypacker, K R; Fine, M L; Mills, R R (1985) Sexual differences and steroid-induced changes in metabolic activity in toadfish sonic muscle. J Exp Zool 236:259-64