Some aspects of the central nervous system of the rat during aging.

Literature pertaining to structural and functional changes in rat brain taking place with increasing age has been reviewed. For the most part, only young rats have been studied. Brain weight does not appear to change dramatically throughout the life span of rats beyond early development. Neuronal and neuropil elements appear to undergo age-related changes with respect to size, number, and intercellular relationships. Intracellular organelles show evidence of degeneration. Additional studies on central nervous system function in relation to age are required in order to ascertain the meaning of particular structure changes.