neu·ro·psy·chol·o·gy (nŏŏr'ō-sī-kŏl'ə-jē, nyŏŏr'-) n. The branch of psychology that deals with the relationship between the nervous system, especially the brain, and cerebral or mental functions such as language, memory, and perception. neu'ro·psy'cho·log'i·cal (-sī'kə-lŏj'ĭ-kəl) adj., neu'ro·psy·chol'o·gist n.