Gray matter, also known as the gray substance, is the darker tissue of the human brain and spinal cord that contains nerve cell bodies and unmyelinated axons. Synonyms for gray substance are cerebral cortex, neocortex, temporal lobe, and basal ganglia. The cerebral cortex is responsible for higher brain functions including perception, thought, and consciousness. The neocortex controls sensory inputs and is the most recently evolved part of the brain. The temporal lobe processes sound, memory, and facial recognition. The basal ganglia regulates voluntary movement and learning. Understanding the synonyms for gray substance can assist in interpreting the complex functions and structures of the human brain.