Given the task definition and input, reply with output. In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Whose pioneering work was released after 1930, but before 1951?, Context: Emotions are thought to be related to certain activities in brain areas that direct our attention, motivate our behavior, and determine the significance of what is going on around us. Pioneering work by Broca (1878), Papez (1937), and MacLean (1952) suggested that emotion is related to a group of structures in the center of the brain called the limbic system, which includes the hypothalamus, cingulate cortex, hippocampi, and other structures. More recent research has shown that some of these limbic structures are not as directly related to emotion as others are while some non-limbic structures have been found to be of greater emotional relevance.
Papez