Central nervous system comprises two classes of cells; neurons and glia. Neurons are anatomic, functional, and trophic units of the brain. Despite great variability in size and shape, all neurons share common morphological features, the key elements of a highly complex communication network. Neurons are responsible for receiving sensory input from the external world; for sending motor commands to our muscles, and for transforming and relaying the electrical signals at every step in between. The human brain contains about 1 x 10^11 neurons, each being able to contact at least 10,000 other neurons. Rat Cortical Neurons provide an invaluable tool for understanding physiological and pathophysiological relevance in brain function and disease.