Value-based decision making is the process of selecting actions from among several alternatives to maximize future possible rewards and minimize future possible punishers. Underlying this capacity are a number of distinct neural signals, which include: outcome value, chosen value, decision value and action value. This chapter considers each of these signals and evaluates evidence about the contribution of specific neural circuits to these functions. It briefly reviews evidence for the existence of comparison signals that resemble the outcome of such a decision process. The chapter talks about the post-decision value signals, which serve as an input for generating prediction error signals that are then subsequently used to update the value signals needed to compute future choice. Furthermore, it is likely that decisions emerge as a function of the interaction among a number of additional regions such as the amygdala, striatum, and intra-parietal cortex.