Noun | 1. | ![]() brain cell - a nerve cell in the brain cerebral cortex, cerebral mantle, cortex, pallium - the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum medulla spinalis, spinal cord - a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain; a long tubelike structure extending from the base of the brain through the vertebral canal to the upper lumbar region |