In 1937 Papez theorized that a circuit including the hippocampal formation constitutes the neural substrate of emotional behavior,[1] and Klüver and Bucy reported that, in monkeys, surgical removal of the hippocampal formation and the amygdaloid complex has a profound effect on emotional responses.[2][3] As a consequence of these publications, the idea that the hippocampal formation is entirely dedicated to olfaction began to recede.[4] (Today there is little support for the idea that the hippocampal formation is directly involved in emotion.) [citation needed]