CS-Evoked Dopamine Neural Activity at Different Stages of Learning Reflect Cue-Punishment Association in the Medial Ventral Tegmental Area

Abstract

Past research has looked at how aversive associative learning is represented in dopamine neurons in the ventral tegmental area (VTA). How VTA dopamine neurons respond to cues and punishments depends on where the dopamine neurons project to. In addition, medial VTA dopamine neurons have been shown to encode reward prediction errors (RPEs). However, no studies have examined the specific changes in neural activity during the process of learning. Learning was divided into three stages: before, initial and late learning. Using eye-blink conditioning, this study sought to examine the dynamics of medial VTA dopamine neural activity from before learning to initial learning to late learning. Findings revealed that acquisition of the cue-punishment association was reflected by decreases in CS-evoked VTA activity across the learning stages, suggesting that learned aversive stimuli are represented by smaller amplitudes of CS-evoked neural activity. Omission of the aversive stimuli resulted in RPE signals, which supported medial VTA dopamine neurons’ role in aversive associative learning. This finding is consistent with the results from previous studies.