A reflex arc is an involuntary reaction to a stimulus mediated by an afferent nerve, a central integrator, and an efferent nerve. The relevant reflexes are:
Retina \(\to\) optic nerve (ipselateral retinal info) \(\to\) optic tract (contralateral field info) \(\to\) ipselateral pretectal nucleus \(\to\) bilateral Edinger-Westfall nuclei \(\to\) bilateral CNIII \(\to\) ciliary ganglion \(\to\) bilateral pupillary constriction
Light touch receptors in cornea \(\to\) CN V1 \(\to\) spinal trigeminal nucleus (light touch information of ipselateral face) \(\to\) facial motor nucleus \(\to\) CN VII \(\to\) orbicularis oculi \(\to\) blink
\(\Delta\) head angular momentum \(\to\) \(\Delta\)Flow in semicircular canals \(\to\) CN IIX \(\to\) vestibular nucleus \(\to\) ipselateral and contralateral medial longitudenal fasciculus \(\to\) oculomotor, trochlear, and abducens nuclei \(\to\) extraoocular muscles to keep gaze fixed as head moves
Light touch receptors in pharynx \(\to\) CN IX \(\to\) spinal nucleus of V (ipselateral facial light touch) \(\to\) Nucleus ambiguus \(\to\) CN X \(\to\) soft palate elevation, pharyngeal constriction