The central nervous system (CNS) consists of the brain and spinal cord. It develops from the ectoderm and neural tube. The brain regions include the forebrain, midbrain and hindbrain. The CNS contains gray matter with neuron cell bodies and white matter with axon tracts. It receives sensory input and directs motor neurons. Imaging techniques like CT, PET, and MRI are used to visualize the brain. The CNS coordinates sensory, motor, emotional and memory functions.