In the light pupillary reflex, where does the signal travel after the pretectal nucleus?

In the light pupillary reflex, the pathway of the signal after the pretectal nucleus is crucial for understanding how the reflex is mediated. Once the signal reaches the pretectal nucleus, it then synapses with neurons that project to the Edinger-Westphal (EW) nucleus.

The Edinger-Westphal nucleus is responsible for the parasympathetic innervation of the iris sphincter muscle, ultimately leading to constriction of the pupil in response to light. This pathway is part of a reflex arc that activates the efferent fibers of the parasympathetic system, which travel along the oculomotor nerve to reach the iris.

The other options involve areas and structures that do not play a direct role in the light reflex pathway after the pretectal nucleus. The optic nerve is involved in sending visual information to the brain but does not directly convey the signal for pupil constriction from the pretectal nucleus. The temporal and occipital lobes are associated with higher visual processing and perception, not with the immediate reflex response of pupil constriction. Therefore, the correct answer accurately reflects the next step in this critical neurological pathway.