Neuroendocrine Regulation of Behavioral Differences

生殖行为的性别和季节差异往往伴随着控制这些行为的结构的形态差异。虽然这种二形性是许多脊椎动物的基本特征，但其中涉及的机制似乎各不相同。类固醇荷尔蒙通常同时调节解剖和功能，但生物体在哪种荷尔蒙是重要和关键的年龄以及它在哪种性别中起作用的方面有所不同。其中一些差异可能反映了动物或其环境施加的限制，但其他差异可能反映了系统的类型(例如，求偶或交配)。拟议中的实验研究了绿色变态蜥蜴协调一系列雄性生殖行为所需的两个神经肌肉系统。雄性伸展喉扇(露水)来向雌性求爱，控制这种显示的运动神经元和肌肉有几个偏向男性的特征。类固醇激素调节这些结构分化的假设将得到检验，并将确定具体涉及的激素，从而确定它们何时何地起作用。雄性在交配时也使用两个半月板中的一个，由两对肌肉控制。成年雌性没有这些结构。相关的脊髓运动神经元在男性更大，数量更多。与成年时看起来稳定的露垂系统不同，初步结果表明，至少成年男性的交配肌肉是可塑性的。实验将调查交配肌肉和运动神经元在繁殖季节和非繁殖季节之间是否在形态上发生变化，以及这些变化是否可以由睾酮诱导。然后，至于露水系统，性腺激素在交配神经肌肉结构的性别分化中的作用将被评估。在幼体中求偶系统是不同的，而交配系统在孵化时是性别二态的。这项提议将解决一个重要的问题，“为什么有些系统在发育和成年期间失去了对性腺激素的反应，而另一些系统则保持可塑性？”这项拟议工作的更广泛影响包括通过增加对神经系统和肌肉结构塑造机制的了解来推进科学发现，无论是在发育组织中还是在成人的可塑性中。同时，促进教学、培训和学习，鼓励代表不足的群体参与实验室工作，及时传播科学成果，加强大学神经内分泌研究的基础设施

Gender and seasonal differences in reproductive behaviors are often paralleled by differences in the morphology of structures controlling them. Although such dimorphisms are fundamental characteristics of numerous vertebrates, the mechanisms involved appear to vary. Steroid hormones often mediate both anatomy and function, but organisms differ in which hormone is important and critical age and in which sex it acts. Some of these differences may reflect constraints imposed by the animals or their environments, but others may reflect the type of system (e.g., courtship or copulatory). The proposed experiments investigate two neuromuscular systems required to coordinate a suite of masculine reproductive behaviors in green anole lizards. Males extend a throat fan (dewlap) to court females, and the motoneurons and muscles controlling this display have several male-biased characteristics. The hypothesis that steroid hormones regulate differentiation of these structures will be tested, and hormones specifically involved will be identified, thus determining when and where they act. Males also use one of two hemipenes during copulation, which are controlled by two pairs of muscles. Adult females do not have these structures. Relevant spinal motoneurons are larger and more numerous in males. Unlike the dewlap system, which appears stable in adulthood, preliminary results suggest that at least the copulatory muscles are plastic in adult males. Experiments will investigate whether the copulatory muscles and motoneurons change morphologically between the breeding and non-breeding seasons, and whether these changes can be induced by testosterone. Then, as for the dewlap system, the role of gonadal hormones in sexual differentiation of the copulatory neuromuscular structures will be assessed. The courtship system differentiates in juveniles, whereas the copulatory system is sexually dimorphic at hatching. This proposal will address the important question, "Why do some systems loose their responsiveness to gonadal hormones while others remain plastic during development and into adulthood ?".The broader impacts of the proposed work involve advancing scientific discovery by increasing the understanding of mechanisms involved in sculpting the structure of the nervous system and muscles, both in developmental organization and adult plasticity. At the same time teaching, training, and learning will be promoted, the participation of underrepresented groups in lab work will be encouraged, scientific result will be disseminated in a timely fashion, and the infrastructure for neuroendocrine research at this university will be enhanced