Context-dependent representation of reinforcement in monkey amygdala

It has been reported that neurons in the amygdala respond to visual cues that predict reward and aversive outcomes. However, it remains unclear whether the representation of reinforcement in the amygdala depends on the relative preference for an outcome compared with another simultaneously available outcome. In this study, we introduced three reinforcements (juice, water, and electrical stimulus) and used two of them in one experimental block. Of 52 neurons that showed cue responses reflecting the outcome information, 23% of amygdala neurons coded preferred outcomes, whereas only one neuron coded nonpreferred outcomes. These proportions of amygdala were significantly different from those of the orbitofrontal cortex, which had both types of neurons.