[TA] a round bundle of nerve fibers that crosses the midline of the brain near the anterior limit of the third ventricle. It consists of a smaller anterior part (pars anterior commissurae anterioris [TA]), the fibers of which pass in part to the olfactory bulbs, and a larger posterior part (pars posterior commissurae anterioris [TA]), which interconnects the left and right temporal lobes. SYN: commissura anterior [TA].