Brenowitz E A, Arnold A P, Loesche P
Department of Psychology, University of Washington, Seattle 98195,
J Neurobiol. 1996 Oct;31(2):235-44. doi: 10.1002/(SICI)1097-4695(199610)31:2<235::AID-NEU8>3.0.CO;2-C.
This study tested the hypothesis that the relative proportion of neurons that are hormone sensitive in avian song control nuclei is related to the basic motor ability to sing, whereas the absolute number of such neurons is related to the complexity of song behavior. Either [3H]testosterone (T) or estradiol (E2) was injected into male and female rufous and white wrens (Thryothorus rufalbus), a tropical species in which females sing duets with males but have smaller song repertoires than males. Autoradiographic analysis indicated that there were no sex differences in the proportions of T or E2 target cells in two song nuclei: the high vocal center (HVC) and the lateral portion of the magnocellular nucleus of the anterior neostriatum (IMAN). The density of labeled cells per unit volume of tissue did not differ between the sexes in either song nucleus. Males have larger song nuclei, however, which is consistent with their more complex song behavior, and therefore have a greater total number of hormone-sensitive neurons in these regions than do females. Comparison of these results with measures of hormone accumulation in zebra finches, canaries, and bay wrens supports the hypothesis presented.
在鸟类鸣唱控制核团中，对激素敏感的神经元的相对比例与鸣唱的基本运动能力有关，而此类神经元的绝对数量与鸣唱行为的复杂性有关。将[3H]睾酮（T）或雌二醇（E2）注射到雄性和雌性棕胁唧鹀和白眉唧鹀（棕胁唧鹀）体内，这是一种热带鸟类，其中雌性与雄性二重唱，但歌曲曲目比雄性少。放射自显影分析表明，在两个鸣唱核团：高级发声中枢（HVC）和新纹状体前部大细胞核的外侧部分（IMAN）中，T或E2靶细胞的比例没有性别差异。在这两个鸣唱核团中，单位体积组织中标记细胞的密度在两性之间没有差异。然而，雄性的鸣唱核团更大，这与它们更复杂的鸣唱行为一致，因此这些区域中激素敏感神经元的总数比雌性更多。将这些结果与斑胸草雀、金丝雀和湾唧鹀中激素积累的测量结果进行比较，支持了所提出的假设。
