The Role of Hippocampus during Observational Learning

Observational learning is a fundamental cognitive ability present in several species, where a naive animal imitates a goal-directed behavior from the observation of a congener which acts as a demonstrator. Recent evidence in bat and rats suggests that hippocampal place cells of an observer may generate a spatial representation of the locations visited by a demonstrator, during spatial navigation. However, it is still unclear whether this hippocampal neural activity is critical for the process of observational learning or if the patterns of activity during observation differ from those emerging from the execution of a spatial memory task previously observed. To test this idea, we assess the role of the hippocampus by pharmacological reversible inactivation during the observation of a spatial learning task, demonstrating a critical role for this structure in observational learning. Then we recorded the neuronal activity of principal pyramidal cells of the same animal when it was observing or solving the memory task, and two different representation of the space emerged after observation or navigation. This evidences demonstrated that the hippocampus is necessary for observational learning and indicated that the observed and executed hippocampal representation are different, confirming the idea that the hippocampus could represent the position of others in the space, and use this information to improve his behavioral performance.