Reward perception is as equally as important for survival as aversion. A core region involved in attributing valence is the nucleus accumbens, that is mainly composed by medium spiny neurons (MSNs), expressing either dopamine receptor D1 or D2. Classically, D1-MSNs have been associated with positive reinforcement and reward, whereas D2-MSNs neurons are associated with negative reinforcement and aversion. However, recent evidence challenged this functional dichotomy hypothesis.
In this seminar, I will show that both D1- and D2-MSNs can drive reward and aversion. This bidirectional effect is dependent on the activation pattern of these neurons, and consequent electrophysiological effects in downstream regions, namely the VTA and ventral pallidum.
I will also present some data on the role of laterodorsal tegmentum inputs to nucleus accumbens in different aspects of reward-related behaviors.