Pubertal Development of Brain and Behavior

神经系统的主要功能是感知、解释和整合外部和内部刺激，并产生适当的行为反应。外部和内部刺激对神经系统和行为的影响在整个生命周期中发生变化。特别是，青春期是一个发育时期，在此期间，显著的神经和生理变化导致成年行为的出现。神经系统在青春期发育过程中的成熟导致成年后对外部和内部刺激的不同反应。这项研究的总体目标是了解青春期的发育事件，这些事件改变了行为神经回路中外部和内部刺激的整合。这个项目的重点是调节仓鼠雄性交配行为的神经回路的青春期成熟。对雌性嗅觉暗示的感知和循环中类固醇激素的存在都是该物种交配行为的必备条件。这些感觉和荷尔蒙刺激激活了成体一个特征明确的神经回路中的神经元，这些外部和内部线索的神经整合导致了交配行为的表达。以前的研究已经确定，嗅觉刺激和类固醇激素不会以同样的方式影响青少年男性的神经系统，因此不会表现出交配行为。这个项目将研究青春期类固醇受体和神经化学反应之间相互作用的变化。工作假设是，在成人神经系统中，感觉和激素信息整合的细胞基础包括通过神经递质或对女性嗅觉暗示做出反应而释放的神经肽来激活孕酮受体。我们假设，这种感觉/激素的整合在青春期之前没有完成，原因有两个：1)雌激素不会诱导幼年男性下丘脑神经元中的孕激素受体；2)女性嗅觉线索不会引发青春期前男性孕激素受体激活所需的神经递质或神经肽反应。实验旨在测试这一假说的两个方面，这一假说被认为是为了解释青少年女性无法表达交配行为。这个项目将有助于我们理解青春期成熟的细胞机制，青春期成熟是表达成人典型行为所需的感觉和激素刺激的神经整合。

The primary functions of the nervous system are to sense, interpret, andintegrate external and internal stimuli and to generate appropriatebehavioral responses. The influence of external and internal stimuli onthe nervous system and behavior changes across the life span. Inparticular, puberty is a period of development during which significantneural and physiological changes result in the emergence of adultbehaviors. Maturation of the nervous system during pubertal developmentresults in different responses to external and internal stimuli inadulthood. The overall objective of this research is to understanddevelopmental events during puberty that alter the integration of externaland internal stimuli within behavioral neural circuits. This project focuses on pubertal maturation of the neural circuit thatmediates male mating behavior in the hamster. The perception of olfactorycues from a female and the presence of circulating steroid hormones areboth obligatory for mating behavior in this species. These sensory andhormonal stimuli activate neurons within a well-characterized neuralcircuit in the adult, and the neural integration of these external andinternal cues leads to expression of mating behavior. Previous researchhas determined that olfactory stimuli and steroid hormones do not impactthe nervous system of juvenile males in the same way, and therefore matingbehavior is not expressed. This project will investigate pubertal changein the interactions among steroid receptors and neurochemical responses toolfactory cues. The working hypothesis is that in the adult nervoussystem, the cellular basis for the integration of sensory and hormonalinformation involves activation of progesterone receptors byneurotransmitters or neuropeptides released in response to female olfactorycues. We hypothesize that such sensory/hormonal integration is notaccomplished prior to puberty for two reasons: 1) estrogen does not induceprogesterone receptors in neurons of the hypothalamus of juvenile males;and 2) female olfactory cues do not elicit the neurotransmitter orneuropeptide responses needed for activation of the progesterone receptorin prepubertal males. Experiments are designed to test both aspects ofthis hypothesis, which is proposed to account for the inability of juvenilemales to express mating behavior. This project will contribute to ourunderstanding of the cellular mechanisms underlying pubertal maturation ofthe neural integration of sensory and hormonal stimuli required forexpression of adult-typical behaviors.