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Hormone‐Dependent Neural Plasticity in the Juvenile and Adult Song System: What Makes a Successful Male?
Author(s) -
GAHR MANFRED
Publication year - 2004
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1298.025
Subject(s) - biology , forebrain , hormone , androgen , medicine , endocrinology , estrogen , neuroscience , sex hormone receptor , sexual differentiation , hypothalamic–pituitary–gonadal axis , estrogen receptor , central nervous system , luteinizing hormone , genetics , cancer , breast cancer , gene
A bstract : The sexual quality of adult song is the result of genetic and epigenetic mechanisms shaping the neural song system throughout life. Genetic brain‐intrinsic mechanisms determine the neuron pools that develop into forebrain song control areas independent of gonadal steroid hormones, androgens and estrogens. One fate of these neurons is the potential to express sex steroid receptors, such as androgen and estrogen receptors. Genetic brain‐intrinsic mechanisms, too, determine the activity of hypothalamic‐pituitary‐gonad (HPG) axis, i.e., the working range and responsiveness of HPG axis to produce gonadal hormones. The epigenetic action of gonadal steroid hormones (androgens and estrogens) on determined vocal neurons is required to maintain and increase the pool of determined vocal neurons and to complete the connections of the vocal system, i.e., to make it function motorically. The subsequent influence of environmental information, including both external (socio‐sexual and physical) and internal (body physiology) signals, specify the further neural phenotype of vocal areas either through acting on the HPG axis and differential release of gonadal hormones or through non‐gonadal hormone systems, both of which have target neurons in the functional vocal system. Despite the clear evidence of hormone dependency of the development of both the adult song phenotype and song system phenotype, their causal relation is complex.