The rostral interstitial nucleus of medial longitudinal fasciculus (riMLF) is a collection of neurons in the medial longitudinal fasciculus in the midbrain.

[3]: 122  It mostly projects efferents to the ipsilateral oculomotor and trochlear nuclei.

[2]: 458.e1 To mediate downgaze, it projects efferents to the ipsilateral oculomotor nucleus and trochlear nucleus; mediate upgaze,[2]: 777-778  it projects efferents to the contralateral aforementioned nuclei[3]: 122 [additional citation(s) needed] through the posterior commissure.

[2]: 1464.e17 It is situated at the caudal extremity of the mesencephalon[1] at its junction with the telencephalon,[3]: 156  at the level of the superior colliculus.

[2]: 778  Lesions of the posterior commissure meanwhile disrupt upgaze.