Taste Experience Enhances Cortical Response Reliability during Latent Enhancement of Taste Aversion Learning

Abstract

AbstractLearning is not as simple as the association of paired stimuli in a vacuum. For example, benign experience with a taste stimulus weakens future conditioned taste aversions (CTA) to that taste—a phenomenon known as latent inhibition—and enhances later CTA to a novel taste (latent enhancement [LE]; Flores et al., 2016; Flores et al., 2018). Our recent investigations on how benign taste experience impacts cortical responses revealed an increase in the discriminability/salience of Gustatory Cortical (GC) responses to a new taste following experience offering a clue into potential underlying mechanisms for LE on CTA (Flores et al., 2022). Here, we predict that the previously reported increase in response discriminability following taste experience is associated with a reduction of variability that has been shown to promote learning. Our results support this prediction and reveal enhanced trial-to-trial consistency of single-neuron sucrose responses and coherent activity across ensemble neurons before CTA learning. Connecting this result to learning, we further show that the distinction between pre- and post-CTA sucrose responses are indeed greater in rats with prior benign taste experience. Overall, these results suggest that following benign experience, taste coding in GC becomes more reliable (at both the single-neuron and ensemble levels) providing a potential mechanism which may contribute to the stronger CTA acquisition seen in LE of learning.Significance StatementAnimals and humans readily learn the consequences of consuming a specific taste and react by changing their behaviors. We have shown that even seemingly inconsequential and benign taste experiences – which are arguably more common - can enhance taste behavior and learning. The work presented here is the first to evaluate how benign experience alters learning-related cortical processing dynamics usingin-vivoelectrophysiology in freely behaving rats. We report that benign taste experience alters cortical plasticity which underlies the enhancement of learning. This unravels a new area of chemosensory research and may shed light on how daily taste experiences impact the neural dynamics of future taste consumption and learning.