My students and I study how the brain processes information. We have a deep interest in sensory coding – how the brain takes in and “maps” sensory input to give rise to perception and behavior. Our model system is the sense of taste. Taste is a component of flavor, which also involves mouthfeel (touch, temperature) and smell. Taste and flavor critically guide ingestive decisions that impact nutritional status and well being in diverse animals, humans included. We study taste and sensory information processing in the brain using a collection of approaches, including neurophysiology, math, animal behavior, and genetics. Our research is funded by the National Institutes of Health, U.S. Department of Health & Human Services.
Some of the ongoing experiments in the lab are centered on delineating the receptive range of taste-sensitive neurons – what are the sensations conveyed by these cells? At first glance, the answer to this question may seem obvious – taste neurons convey one of the five human taste categories of “sweet”, “salty”, “sour”, “bitter”, or “umami”, which is the taste of MSG. However, recent, and also early, advances in gustatory neurobiology challenge the assumption that taste-sensitive neurons detect and register solely five tastes. For instance, published data from several labs, ours included, have revealed that different stimuli from the “bitter” category can induce very different patterns of neural activity. This raises the possibility that the nervous system can register differences between stimuli classified as “bitter”, which questions the singularity of this taste category. We are continuing to explore this issue.
What is more, cells in the brain responsive to taste chemicals have been classically defined as “gustatory” neurons, albeit many of these cells do not show selective tuning to only taste. Taste-sensitive neurons can also respond to oral somatosensation, which includes touch and temperature stimulation inside the mouth. This feature positions “gustatory” neurons to function as integrators of taste and oral cutaneous sensation, a process of generating flavor. We are studying the details of this integration in brain stem circuits.