Hypothalamus in the brain. Computer illustration showing the location of the hypothalamus (glowing) in a normal human brain. The hypothalamus is a complex area with a number of important functions. One of the most important is to link the nervous system to the endocrine system via the pituitary gland. It is responsible for certain metabolic processes and other activities of the autonomic nervous system. It synthesises and secretes neurohormones, which in turn stimulate or inhibit the secretion of pituitary hormones. The hypothalamus also plays a role in controlling body temperature, hunger, thirst, fatigue and circadian cycles.