Final answer:
The Edinger-Westphal nucleus is a group of parasympathetic neurons located in the midbrain, responsible for controlling the muscles involved in pupil constriction and lens adjustment for near vision.
Step-by-step explanation:
The Edinger-Westphal nucleus is located in the midbrain and is composed of parasympathetic neurons. These neurons are involved with the pupillary light reflex and adjusting the lens for near vision by controlling the ciliary muscles. The Edinger-Westphal nucleus is an important component of the oculomotor nerve (cranial nerve III) and is part of the efferent branch of a reflex arc. The central neurons in this nucleus project to the ciliary ganglion, which ultimately affects the muscles of the iris and lens. As a parasympathetic central neuron destination, activation of this area leads to the contraction of the pupillary sphincter muscle, resulting in miosis or the constriction of the pupil.