Neural Systems of Ingestive Behavior

描述（由申请人提供）：肥胖是一种全国性的流行病。在其他疾病中，肥胖是大多数2型糖尿病和高血压的主要诱因。肥胖的发生是因为个体摄入的卡路里多于消耗的卡路里。当食物的奖励值大于肠道中产生的饱腹感信号的总和时，就会发生这种情况。这项研究的目的是了解控制进食或拒绝口腔内容物的决定的神经机制，这是进食行为的基本行为。这个决定的神经基础在脑干中是完整的。指导摄食行为的口腔触觉、热和味觉传入活动首先通过脑桥和髓质到达大脑。产生摄食行为的运动神经元也位于脑干。这些口腔刺激引起的反应可以通过迷走神经内脏活动从摄取转变为排斥，这种活动首先到达髓质的中枢神经系统。然而，控制进食需要前脑与脑干之间的连接，因为切断前脑与脑干之间的连接会消除随意进食。利用行为学、神经解剖学、神经化学和电生理分析，该项目将测试关于味觉和其他口腔刺激的奖励价值如何在大脑中得到阐述的假设。具体的实验检验了(1)味觉感觉活动如何影响被认为与产生奖励有关的大脑区域，(2)这些奖励感觉效应的神经通路，(3)其他奖励性的口腔刺激，如温度和质地，在享乐领域与味觉有何不同。这些问题的答案将帮助我们理解，正常情况下受到良好监管的行为，比如饮食，是如何偏离到导致流行病的程度的。

DESCRIPTION (provided by applicant): Obesity is a national epidemic. Among other maladies, obesity underlays most type 2 diabetes and a significant proportion of hypertension. Obesity occurs because individuals ingest more calories than they expend. This takes place when the reward value of the food is greater than the sum of the satiety signals arising in the gut. The goal of this research is to understand the neural mechanisms that govern the decision to ingest or reject the contents of the oral cavity, the fundamental act of feeding behavior. The neural substrates for this decision are complete in the brainstem. The oral tactile, thermal, and gustatory afferent activity that guides ingestive behavior first reaches the brain in the pons and medulla. The motor neurons that produce ingestive behavior also are located in the brainstem. The response elicited by these oral stimuli can be switched from ingestion to rejection by vagal visceral activity that first reaches the CNS in the medulla. Nevertheless, control of ingestion requires connections to and from the forebrain because disconnecting it from the brainstem eliminates voluntary eating. Using behavioral, neuroanatomical, neurochemical, and electrophysiological analysis, this project will test hypotheses about how the reward value of gustatory and other oral stimuli are elaborated in the brain. Specific experiments examine (1) how the gustatory sensory activity influences brain areas thought to be involved in producing reward, (2) the neural pathways for these rewarding sensory effects and (3) how other rewarding oral stimuli, such as temperature and texture, differ from taste in the hedonic domain. The answers to these questions will help us understand how a normally well regulated behavior, such as eating, can go so far awry as to cause an epidemic.