Neural representation of goal direction in the monarch butterfly brain

ABSTRACT Neural processing of a navigational goal requires the continuous comparison between the current heading and the intended goal direction. While the neural basis underlying the current heading is well-studied in insects, the coding of the goal direction is completely unexplored. Here, we identify for the first time neurons that encode goal direction in the brain of a navigating insect, the monarch butterfly. The spatial tuning of these neurons accurately correlates with the animal’s goal direction while being unaffected by compass perturbations. Thus, they specifically encode the goal direction similar to goal neurons described in the mammalian brain. Taken together, a navigation network based on goal-direction and heading-direction neurons generates steering commands that efficiently guides the monarch butterflies to their migratory goal.