The limbic system is a collection of interrelated structures that have been found to play a major role in human drives and emotions, such as homeostasis, eating, sleeping, sexual behavior, endocrine control, motivation, memory, and many other functions. It consists of of a network of neurons that form a ring around the upper part of the diencephalon, and includes parts of the thalamus, hypothalamus, hippocampus, amygdala, caudate nucleus, septum, and midbrain.