What is Pretectal?
: occurring in or being the transitional zone of the brain stem between the midbrain and the diencephalon that is situated rostral to the superior colliculus and is associated especially with the analysis and distribution of light impulses.
Where is Edinger Westphal nucleus located?
midbrain
The EWpg is what is thought of as the classic ONC—sending parasympathetic nerve fibers towards the eye. It is located in the midbrain immediately dorsal to the oculomotor nucleus near the level of the superior colliculus, which is why it is often included in the overarching term oculomotor complex.
What does Edinger Westphal nucleus do?
The Edinger–Westphal nuclei provide preganglionic input to the ciliary ganglion mediating the pupillary light reflex and accommodation responses of the lens (i.e., the ciliary body).
Where is the posterior commissure?
The posterior commissure (also known as the epithalamic commissure) is a rounded band of white fibers crossing the middle line on the dorsal aspect of the rostral end of the cerebral aqueduct. It is important in the bilateral pupillary light reflex.
Where is Abducens nucleus?
The abducens nucleus is located internal to the facial colliculus and surrounded by the internal genu of the facial nerve (Fig. 14.1). This structure, in turn, is found in the floor of the rhomboid fossa just lateral to the median sulcus and rostral to the striae medullares of the fourth ventricle.
What is commissure in the brain?
Commissural fibers of the brain, also known as commissural tracts of the brain or commissures are a type of white matter tract that cross the midline, connecting the same cortical area in opposite hemispheres (right-left hemispheric connections 3).
What is the function of posterior commissure?
The posterior commissure is the inferior lamina or stalk of the pineal gland and is important in language processing and connects the language processing centres of both cerebral hemispheres. It is closely related in function to the splenium of the corpus callosum, and injury to it may lead to disorders such as alexia.
What structures are found in the pretectal region?
Pretectal Region. Transverse section through the pretectal region at the midbrain-diencephalon junction. The mesencephalic aqueduct is transitioning to third ventricle and subcommissural bodies are evident dorsally in the aqueduct. Midbrain structures are present ventrally. Dorsally, the pretectum, thalamus, and metathalamus can be seen.
What is the function of the pupillary pretectal area?
Pretectal area. The pretectal area, or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system. Through reciprocal bilateral projections from the retina, it is involved primarily in mediating behavioral responses to acute changes in ambient light such as the pupillary light reflex,…
What is the function of the pretectum?
Functionally, the pretectum is related primarily to the visual system and involved in visuomotor behaviors. Thus, the pretectal nuclei receive afferents from the retina and the optic tectum, and they are involved in modulating motor responses to visual input (reviewed in Butler and Hodos, 2005).
What is the function of the pretectal nucleus?
Thus, the pretectal nuclei receive afferents from the retina and the optic tectum, and they are involved in modulating motor responses to visual input (reviewed in Butler and Hodos, 2005 ).