Ventral pallidum encodes relative reward value earlier and more robustly than nucleus accumbens, challenging the existing model of information flow in the ventral basal ganglia

Ventral pallidum encodes relative reward value earlier and more robustly than nucleus accumbens. David Ottenheimer, Jocelyn M. Richard & Patricia H. Janak. Nature Communications, volume 9, Article number: 4350 (2018). https://www.nature.com/articles/s41467-018-06849-z

Abstract: The ventral striatopallidal system, a basal ganglia network thought to convert limbic information into behavioral action, includes the nucleus accumbens (NAc) and the ventral pallidum (VP), typically described as a major output of NAc. Here, to investigate how reward-related information is transformed across this circuit, we measure the activity of neurons in NAc and VP when rats receive two highly palatable but differentially preferred rewards, allowing us to track the reward-specific information contained within the neural activity of each region. In VP, we find a prominent preference-related signal that flexibly reports the relative value of reward outcomes across multiple conditions. This reward-specific firing in VP is present in a greater proportion of the population and arises sooner following reward delivery than in NAc. Our findings establish VP as a preeminent value signaler and challenge the existing model of information flow in the ventral basal ganglia.