Temporal Coding and Palatability in Gustatory Cortex

味觉皮层的时间编码和适口性

基本信息

批准号：
7383179
负责人：
Donald B Katz
金额：
$ 24.73万
依托单位：
BRANDEIS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-04-01 至 2011-03-31
项目状态：
已结题

项目摘要

When a taste is on an animal's tongue, behavior must soon follow--the substance must either be swallowed or expelled. This intimate coupling between stimulus and response implies that the function of gustatory neural circuits is to transform taste activity into response activity in 2-3 seconds; this in turn implies that neurons in these circuits may respond to tastes with temporal codes (i. e., responses that change through time) that reflect the perception-to-action transformation. My lab has begun to look for such content in taste- related temporal codes in cortex, identifying epochs of the neural responses in which "pure" chemosensory information seems to become imbued with emotional meaning in anticipation of consumption or rejection. The experiments proposed here will use large arrays of tastes, in association with chronic recordings of ensembles of GC single neurons, careful observation of rat taste-related behaviors, and pharmacological manipulation, to thoroughly explore features of the temporal codes that are related to taste identity, palatability/emotion, and the act of consuming or rejecting taste substances. First, we will look at responses to multiple tastes from each 'basic taste' category (sweet, salty, sour, and bitter), to determine how more and less similar tastes are distinguished by their associated temporal codes. Next, we will examine neural responses to, and preferences for, a range of taste concentrations-concentrations that should all be recognizable as the same taste, but that should vary widely in palatability and even in exact flavor; this should allow us to independently manipulate the palatability-related parts of the temporal codes. We will also manipulate the palatability of an individual tastant by increasing the rats' appetite for sodium, to test whether such changes are represented only in palatability-related parts of the temporal codes. Finally, we will inactivate the amygdala, thought to be the source of much of the palatability/emotional information in the brain, during tasting; if the amygdala truly imbues the taste with palatability, then this manipulation should only effect the palatability-related parts of cortical temporal codes. These experiments should greatly expand our understanding of how taste processing works in cortex, and as such should affect how we think about sensory processing in general.

当动物的舌头上有味道时，必须很快采取行动——该物质要么被吞下或被驱逐。刺激和反应之间的这种密切耦合意味着味觉的功能神经回路是在2-3秒内将味觉活动转化为反应活动；这反过来意味着这些回路中的神经元可能会通过时间代码对口味做出反应（即通过变化的反应）时间）反映了感知到行动的转变。我的实验室已经开始在品味中寻找这样的内容了—— 皮层中相关的时间编码，识别“纯”化学感应的神经反应时期在预期被消费或被拒绝的情况下，信息似乎变得充满情感意义。这里提出的实验将使用大量的味道，并与长期记录相结合。 GC单个神经元的集合，仔细观察大鼠味觉相关行为和药理学操纵，彻底探索与品味认同相关的时间代码的特征，适口性/情感，以及消耗或拒绝味道物质的行为。首先，我们将查看回复每个“基本味道”类别（甜、咸、酸、苦）中的多种味道，以确定更多不太相似的品味通过其相关的时间代码来区分。接下来，我们将检查神经对一系列味觉浓度的反应和偏好——这些浓度都应该是可以被识别为相同的味道，但在适口性甚至确切的风味上应该有很大差异；这应该允许我们独立地操纵时间代码中与适口性相关的部分。我们将还通过增加大鼠对钠的食欲来控制单个促味剂的适口性，以测试此类变化是否仅在时间代码的适口性相关部分中表示。最后，我们会使杏仁核失活，杏仁核被认为是食物中许多适口性/情感信息的来源大脑，在品尝过程中；如果杏仁核确实使味道变得可口，那么这种操作应该只影响皮质时间编码中与适口性相关的部分。这些实验应该大大扩大我们对味觉处理在皮层中如何运作的理解，因此应该会影响我们的思维方式关于一般的感觉处理。