Taste Aversion Learning as a Tool for the Study of Hippocampal and Non-Hippocampal Brain Memory Circuits Regulating Diet Selection.

Diet selection is the result of different learning experiences that accumulate throughout the life of the organism. The acquisition of aversions to the taste of food followed by mild or severe visceral negative effects plays an important role in food selection. Current knowledge on the role of the critical brain areas (parabrachial area, insular cortex and amygdala) involved in the basic associative neural circuit of taste aversion learning is reviewed. In turn, as shown by a variety of learning phenomena, the development of new aversions to the taste of different types of food is profoundly modulated by the memory of previous learning experiences with the same or different tastes. Some of these phenomena may depend on memory brain systems independent of the basic circuit for taste aversion learning. This seems to be the case for contextual effects and conditioned blocking that depend on the hippocampal integrity. Experimental evidence on the neural basis of complex learning phenomena in taste aversion learning is reviewed. Thus, understanding the way in which taste aversion learning regulates diet selection in daily life requires the study of interactions between hippocampal and non-hippocampal dependent memory systems. Taste aversion learning is proposed as a useful behavioral tool in the investigation of different brain circuits that are critical for food selection.