phren-
phren- (fren- or frēn-) , noun
[Greek frh`n, freno`s, the midriff, or diaphragm, the heart (as the seat of emotions), the mind.]
(Anatomy) A combining form meaning, of or pertaining to the diaphragm, the mind, or the brain; frenic. — Stedman
Also: phrenico-, phreni-, phreno-