SIGNALS TO FEED--BIOLOGICAL AND ASSOCIATIVE MECHANISMS

调节进食行为的模型通常假设动物（包括人类）进食并参与有助于获取食物的行为，以响应与其能量需求水平相关的内感受信号。因此，许多研究都致力于确定产生这些类型信号的代谢和激素事件，并确定与它们的检测和传递有关的神经基质。这项工作已经确定了各种促进或抑制食物摄入的生理和药理学操作。然而，很难将这些操作的潜在“饥饿”或“饱腹”信号特性与它们对适口性、学习、非特异性行为唤醒或其他机制的可能影响区分开来，这些机制即使在能量需求没有变化的情况下也会影响喂养。整合心理生物学和巴甫洛夫条件反射的方法和概念，提出的研究将开发和利用一种新的调节进食行为模型，该模型描述能量需求的内感受信号如何与食物线索（例如，食物的味道和其他感官特性）以及摄入后的摄食后果一起作用，以确定食欲和终性摄食行为的强度或概率。基于巴甫洛夫条件调节的研究，包括常规的听觉和视觉刺激，该模型假设能量状态信号通过调节食物相关刺激的能力来激活进食后食欲后果的记忆，从而影响摄食行为。研究人员提出了新的研究策略，以检查代谢、激素、膈下迷走神经和中枢神经系统机制在这一“记忆调节”过程中的参与。此外，一些实验将评估动物对它们所吃的食物所编码的信息的性质，以及与获取/激活这些信息有关的信号的性质。人类进食行为的紊乱模式似乎与能量状态信号的检测、利用或调节功能或食物信息编码有关。因此，拟议的研究可能对了解病因和开发这些疾病的有效治疗具有重要意义。

Models of regulatory feeding behavior often assume that animals (including humans) eat, and engage in behaviors that are instrumental to obtaining food, in response to interoceptive signals that are correlated with their level of energy need. Accordingly, much research has been devoted to specifying the metabolic and hormonal events that give rise to these types of signals and to specifying the neural substrates involved with their detection and transmission. This work has identified a variety of physiological and pharmacological manipulations that promote or suppress food intake. However, it has been difficult to separate the potential "hunger" or "satiety" signal properties of these manipulations from their possible effects on palatability, learning, nonspecific behavioral arousal or other mechanisms that are also known to influence feeding even in the absence of changes in energy need. Integrating methods and concepts from psychobiology and Pavlovian conditioning, the proposed research will develop and exploit a novel model of regulatory feeding behavior that describes how interoceptive signals of energy need act in conjunction with food cues (e.g., tastes and other sensory properties of food) and the postingestive consequences of intake to determine the strength or probability of appetitive and consummatory feeding behavior. Based on studies of Pavlovian conditioned modulation involving conventional auditory and visual stimuli, this model assumes that energy state signals influence feeding behavior by modulating the capacity of food-related stimuli to activate the memory of the appetitive postingestive consequences of intake. New research strategies are proposed to examine the involvement of metabolic, hormonal, subdiaphragmatic vagal, and central nervous system mechanisms in this "memory modulation" process. In addition, several experiments will assess the nature of the information that animals encode about the foods that they eat as well as the nature of the signals involved with the retrieval/activation of that information. It seems likely that disordered patterns of human feeding behavior involve impairments in the detection, utilization, or modulatory function of energy state signals or in the encoding of information about food. Thus, the proposed research may have important implications with respect to understanding the etiology and developing effective treatments for these disorders.