"stimulate through the nerves," 1870, a back-formation from innervation "sending of a stimulus through the nerves" (1828), which is perhaps modeled on French innervation; see in- (2) "in" + nerve (n.) + -ate. Related: Innervated. Earlier in English the same word (but from the other in-) meant "to lose feeling or sensation" (1848), and, as an adjective, "without feeling" (1737). Innervation in psychology is from 1880, translated from German Innervationsgefühl.
