Molecular neurobiology of ingestive behavior

The concepts and tools of molecular biology may be applied to almost any component of the animal involved in ingestion, but two categories of model system are particularly relevant for molecular analysis: homeostatic regulation of neuropeptide expression in the hypothalamus and neuronal plasticity underlying persistent changes in ingestive behavior. Molecular approaches to these models are reviewed, focusing on our strategy for analyzing conditioned taste aversion learning. Three questions must be answered: Where do the long-term changes occur within the distributed neural network that mediates feeding? This answer reveals the site of neuronal restructuring mediated by gene expression. When does the transition occur from short-term expression to long-term persistence of the change in behavior? This transition reveals the critical time of gene expression. What genes are expressed during the change in behavior? The expression of thousands of genes in discrete subpopulations of cells is likely to be required during critical periods of neuronal restructuring. The identification of these genes is a general challenge for molecular neurobiology. The analysis of ingestive behavior can profit from molecular tools, but ingestion also provides informative models that elucidate the principles of time- and neuron-specific gene expression mediating complex behaviors.