While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. It is the most energy-consuming organ of the body, and the most specialized, responsible for endocrine regulation, sensory perception, motor control, and the development of intelligence. The brain is the largest cluster of neurons in the body and is typically located in the head, usually near organs for special senses such as vision, hearing and olfaction. In vertebrates, a small part of the brain called the hypothalamus is the neural control center for all endocrine systems. The brain (or encephalon) is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.
