Research is still being done on the olivary bodies.
Sometimes called "olives," olivary bodies are a pair of distinct, oval structures, situated one on each side of the anterior (front) surface of the medulla oblongata. The medulla oblongata is the lower part of the brain stem. The brain stem assists in the management of certain senses and the regulation of the cardiac (heart) and respiratory centers. It also controls import aspects of sleep.
The medulla oblongata contains the respiratory, vomiting, and vasomotor centers, which control the size of blood vessels. It deals with involuntary functions such as breathing, blood pressure, and heart rate. The olivary body works specifically in the areas of motor (movement) learning function, as well as auditory (sound) perception.
The olivary bodies are composed of nerve tissue and measure about 1.25 cm in length. The inferior olivary nucleus is the part of the olivary body that assists in cerebellar motor learning and functioning. The cerebellum is located in the lower, back part of the brain. The superior olivary nucleus is the part of the olivary body that belongs to the auditory system and assists with sound perception.