The interstitial nucleus of Cajal is a collection of neurons in the mesencephalon (midbrain) which are involved in integrating eye position-velocity information in order to coordinate head-eye movements - especially those related to vertical and torsional conjugate eye movements (gaze).
[1]: 156 [2]: 241 [3]: 458.e1 The interstitial nucleus of Cajal is a diffuse collection of mid-sized, parvalbumin-containing premotor neurons of the midbrain reticular formation.
It forms connections with the ipsilateral rostral interstitial nucleus of medial longitudinal fasciculus.
[3]: 502 It receives afferents (in fact, forms reciprocal connections) with the vestibular nuclei (via the MLF), and the nucleus prepositus hypoglossi.
[3]: 458.e1 It projects descending efferents through the medial longitudinal fasciculus to (all levels of) the spinal cord (via the interstitiospinal tract), the ipsilateral superior and medial vestibular nuclei, the nucleus prepositus hypoglossi, and reticular formation.