Hering's law of equal innervation
Hering's law of equal innervation is used to explain the conjugacy of saccadic eye movement in stereoptic animals. The law proposes that conjugacy of saccades is due to innate connections in which the eye muscles responsible for each eye's movements are innervated equally.
Source: Wikipedia — Hering's law of equal innervation (CC BY-SA 4.0)