Taste memory formation: latest advances and challenges.

Taste memory has been a useful model for studying memory formation; using different approaches ranging from lesion studies, analysis of receptor and neurotransmitter activity, and measurement of intracellular signaling mechanisms or gene expression, it has been possible to describe processes which may be involved in several types of memory. Taste memory includes the recognition of a taste as well as its characteristics related to the hedonic value, degree of familiarity, and the nutritive or toxic properties associated with that taste. In terms of evolutionary adaptation, taste memory is necessary for the proper identification of available nutritive foods and, of course, is essential to avoid deadly toxins. This review summarizes the current knowledge of taste memory, describing the evidence obtained using non-associative and associative taste learning models by manipulating the different structures involved in the formation and expression of taste memory. Pharmacological, biochemical, and molecular data are shown for each structure and subsequently current theories are presented about possible inter-structural interactions taking part in taste memory formation. Finally, we describe how the study of taste memory can reveal basic mechanisms of learning, raising issues that might apply to learning processes in general. Copyright 2009 Elsevier B.V. All rights reserved.