As a rat feeds, information about the food on the tongue both its taste and its texture is transmitted to populations of multimodal neurons in the gustatory cortex (GC), amygdala (AM), and elsewhere. Little is known about how this information is processed and interpreted, but recent findings suggest that somatosensory, chemosensory, and hedonic sources of GC activity can be pulled out of single-neuron responses via examination of the responses' temporal and spectral properties. The proposed research will extend this basic understanding of the mechanisms of gustatory response in two ways: 1) we will analyze when and how AM activity, thought to be involved in the processing of palatability, influences GC responses; and 2) we will examine how the various influences on GC activity change with associative learning. Chronic recordings will be taken from small ensembles of GC and AM neurons in rats trained to accept controlled doses of tastes ranging from bitter to sweet. It is expected that certain facets of GC activity, identified via time-series analysis, will be attributable to input from the ipsilateral AM; these facets will characterized with regard to their relationship to the palatability of the administered taste. Furthermore, the relationship between AM and GC activity is expected to change with induction of an aversion to a formerly preferred taste. The sources and behavioral relevance of these patterns will be examined by temporarily inactivating AM during stimulus exposure, which should inhibit both learning and any learning-related patterns expected during post-training trials. This project will expand our understanding of gustatory (and general perceptual) processing in new directions.
| Fontanini, Alfredo; Katz, Donald B (2005) 7 to 12 Hz activity in rat gustatory cortex reflects disengagement from a fluid self-administration task. J Neurophysiol 93:2832-40 |
| Stone, Martha E; Grimes, Brandon S; Katz, Donald B (2005) Hippocampal inactivation enhances taste learning. Learn Mem 12:579-86 |
