Interneuronal Dynamics in the Neural Code for Taste in the Brain Stem

Suny At Binghamton, Binghamton NY

Investigators

Abstract

The "taste world" of most mammals, including humans, can be divided into a small number of taste qualities, e.g. sweet, sour, salty, and bitter. Because most tastes in the natural world are a mixture of these taste qualities, it is the job of the brain to decide what qualities are present in each taste stimulus that we encounter. One of the ways that it might do this is to have different groups of cells that each respond to a different taste quality. In reality, it turns out that most cells in the brain respond to more than one taste quality, implying that they can't distinguish between them. The proposed project is designed to study how the brain can tease apart the various taste qualities that we encounter in food by using cells that are broadly responsive. The general approach will be to record the electrophysiological responses to taste stimuli that are bathed over the tongue from cells in the brain stem and from the taste nerves that innervate the tongue in anesthetized rats. In these experiments we will test the hypothesis that when a given taste stimulus is presented, it generates both excitation and inhibition in the brain and that it is this inhibition that allows the cells in the brain to focus their activity so that the components of that stimulus can be determined. We expect to confirm this hypothesis and to define the conditions under which this inhibitory influence is invoked. Further, we hope to determine the site, either in the brain or at the tongue, where these inhibitory effects originate. The impact of this project will be a better understanding of how different tastes are processed by the brain and moreover, how complex perceptions, tastes and otherwise, might be analyzed into their components.