ENVIRONMENTAL INFLUENCES ON BRAIN PLASTICITY

描述(摘自申请者的摘要)：本研究涉及 决定行为变异的根本问题是什么。许多 环境变量可以对表型产生可预测的影响。一 许多爬行动物的卵孵化温度就是这样的变量。在……里面 豹壁虎，胚胎变成雄性或雌性取决于它们的 发育过程中的温度。此外，男女之间以及 可归因于孵化温度的性别差异 在形态、分泌和对类固醇激素的敏感性中发现， 社会性行为，生殖成功，以及在神经解剖学和 调节社会性行为的大脑区域的代谢活动。这些 环境影响类似于宫内影响。 哺乳动物的环境，包括人类。在给定的同源性下 在脊椎动物的内分泌和神经系统中，重要的是 确定同源机制是否构成这些类似效应的基础 行为。如果环境对行为影响的潜在机制 豹壁虎是保守的(即通过性类固醇)，这项研究将 为性别分化的进化提供了新的见解，因为 依赖温度的性别决定被认为是进化的 基因决定性别的先驱(存在于鸟类和哺乳动物中)和 因为爬行动物是鸟类和哺乳动物的祖先。如果 机理不同(即直接的温度效应)，本研究 将阐明一个新的性别分化过程，这一过程也可能是 存在于鸟类和哺乳动物中，但由于恒温，它是被遮盖的。这 后一种可能性尤其重要，因为年轻的鸟类和哺乳动物 不能像成年人那样调节体温。拟议的研究 大致分为三类：体温调节及其关系 对社会性行为的影响(即，神经底物 调节体温调节和社会性行为重叠)， 这些脑区的神经表型和激素的发育 环境，以及发育和发育过程中激素调控的影响 成年期对体温调节和社会性的神经操作 行为。最后一类实验尤其重要，因为 它将辨别孵化温度的影响是直接的还是 间接的。

DESCRIPTION (Adapted from applicant's abstract): This research addresses the fundamental question of what determines behavioral variation. Many environmental variables can produce predictable effects on phenotype. One such variable is the incubation temperature of eggs in many reptiles. In the leopard gecko, embryos become male or female depending upon their temperature during development. In addition, between-sex as well as within-sex differences attributable to incubation temperature have been found in morphology, secretion of and sensitivity to steroid hormones, sociosexual behavior, reproductive success, and in the neuroanatomy and metabolic activity of brain areas that mediate sociosexual behaviors. These environmental effects are analogous to the effect of intrauterine environment in mammals, including humans. Given the homology of the endocrine and nervous systems across vertebrates, it is important to determine if homologous mechanisms underlie these analogous effects on behavior. If the mechanism underlying environmental effects on behavior in the leopard gecko is conserved (i.e., via sex steroids), this research will lend new insight into the evolution of sexual differentiation because temperature-dependent sex determination is thought to be the evolutionary precursor to genotypic sex determination (present in birds and mammals) and because reptiles are the ancestors of both birds and mammals. If the mechanism is different (i.e., direct temperature effects), this research would elucidate a novel process of sexual differentiation that may also be present in birds and mammals but, because of homeothermy, is masked. This latter possibility is especially important because young birds and mammals cannot regulate their body temperature as do adults. The proposed research is broadly categorized into three groups: thermoregulation and its relation to sociosexual behaviors (i.e., the degree to which the neural substrates mediating thermoregulatory and sociosexual behavior overlap), the development of the neural phenotypes of these brain regions and hormone milieus, and the effects of hormonal manipulations during development and neural manipulations in adulthood on thermoregulatory and sociosexual behaviors. The final category of experiments is particularly important as it will discern whether the incubation temperature effects are direct or indirect.