Neuroanatomy is a branch of neuroscience that studies the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defined nervous systems. Their neuroanatomy is therefore better understood. In vertebrates, the nervous system is segregated into the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the connecting nerves between them. Much of what has informed neuroscientists has come from observing how lesions (damage) to specific brain areas affects behavior or other neural functions.
For information about the composition of non-human animal nervous systems, see nervous system. For information about the typical structure of the human nervous system, see human brain, and peripheral nervous system.