ABSTRACT
Paul Donald MacLean is best known for identifying the limbic system with "visceral" emotional behaviour and for his theory that the mammalian brain has three evolutionary distinct anatomical parts, each with their own behavioural repertoire. MacLean began a research project assessing the bioelectrical activity of the anterior medial temporal lobe region that includes the hippocampus. MacLean was particularly interested in establishing what parts of the temporal lobes were triggering these emotions and designed nasopharyngeal electrodes that could be slipped up the sides of the nose, which lay only about 2 cm from the tissue of the anterior medial temporal lobe. These electrodes would show the seizure activity and emotionally charged auras most often arose from areas surrounding the hippocampal formation. In 1948, MacLean managed to spend a few days learning neuroanatomy in Papez's Cornell University laboratory – a visit he would describe as life-changing.
