Studies have shown that fear memory involves an extensive neural network including some limbic and cortical structures. Observation learning of fear suggests contribution of social interaction to knowing environmental danger, but underlying neural basis remains unclear. We have shown that a rat could acquire fear to environmental danger in various tasks by observing other’s behavior. Further, learning from a naïve model benefited the observer more than an expert model. Such findings imply that sensing the contingency between the model’s reaction to the signal and its emotion changes, which may be better explicated in a naïve model, is crucial for observation learning. Our data indeed showed that rats displayed empathetic/prosocial behavior to another rat in pain. We thus explored the neural correlates of reaction to other’s pain as it is a prerequisite for social learning. Ensemble unit activity was recorded in the anterior cingulate (ACC), insular (InC) and other cortex of a rat when it self or a companion was stressed. We found some ACC and InC units responding not only to one’s own but also to others’ pain; some of them shared the same excitatory responses to self and other’s pain, some had opposite responses: activated by one’s own pain but inhibited by other’s pain, or vice versa. In a task for prosocial behavior, some ACC and InC units increased activity shortly prior to altruistic behavior. Shared-response units in the empathetic task increased their ensemble activity as rats performed an altruistic act, and units related to altruistic behavior also increased their ensemble activity to other’s pain, indicative of circuitry overlapping in the two behaviors. Given the involvement of medial frontal cortex and InC in observation learning from our preliminary human data, the role of ACC and InC units in social learning of rodents should be better pursued in the future.