Abstract
Laboratory rodents are typically raised in highly taste-impoverished environments,which means that these rodents enter into experiments remarkably “taste naïve.” Under the standard assumption that fundamental taste perception is innate and stable, this fact should be of little import–the first exposure to a taste should be processed “normally.” Recent behavioral and electrophysiological evidence, however, suggest that taste perception changes as animals grow familiar to taste stimuli, at least on the time scale of hours to days. Here, we leveraged our deep
understanding of gustatory cortical (GC) taste responses—not just which neurons respond, but the precise dynamics of ensemble responses in single trials—to investigate whether taste processing changes with exposure to novel tastes on an even shorter time scale, and whether any such changes depend on familiarization at longer time scales. We observed that these responses are in fact not innate: across initial exposures to novel battery of 4 (sweet, salty, sour, and bitter) tastes, they became more stereotyped and taste-specific. Lastly, we examine changes in taste-licking behavior across familiarization to the same battery of tastants and demonstrate that taste-familiarization impacts consumption behavior on a similar timescale as seen in electrophysiology. These experiments add to a growing literature indicating that exposure to even simple sensory stimuli is a “learning” experience and demonstrate that this learning process occurs across multiple time scales. As such, they reveal the danger of starting an experiment with a truly ‘taste-naïve’ subject.