nucleus abducentisnucleus of abducens nerve a group of motor neurons in the lower part of the pons, innervating the ipsilateral lateral rectus muscle of the eye; unique among motor cranial nerve nuclei in that it consists of two distinct populations of neurons: neurons that give rise to fibers forming the abducens nerve root and those internuclear neurons the processes of which cross the midline, ascend in the opposite medial longitudinal fasciculus, and terminate on specific oculomotor neurons; considered a primary center for mechanisms controlling conjugate horizontal gaze. SYN: nucleus nervi abducentis [TA].