What is Pretectal nucleus?
The olivary pretectal nucleus is a primary visual centre sensitive to luminance changes. It is involved in the pupillary light reflex, the consensual pupillary light reflex and related reflexes, such as the lid closure reflex whereby pupillary constriction takes place.
Where is the Olivary Pretectal nucleus?
midbrain
The pretectal complex is part of the subcortical visual system located in the midbrain. It is divided into five nuclei [1], among which is the olivary pretectal nucleus (OPN). The OPN receives dense retinal innervation [2], [3] and is the first nucleus in the arch of the pupillary light reflex [4].
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).
What is the Pretectal area?
The pretectum is a bilateral group of highly interconnected nuclei located near the junction of the midbrain and forebrain. The pretectum is generally classified as a midbrain structure, although because of its proximity to the forebrain it is sometimes classified as part of the caudal diencephalon (forebrain).
What is the red nucleus?
The red nucleus is a large structure located centrally within the tegmentum that is involved in the coordination of sensorimotor information. Crossed fibres of the superior cerebellar peduncle (the major output system of the cerebellum) surround and partially terminate in the red nucleus.
What Innervates the Edinger Westphal nucleus?
The Edinger–Westphal nucleus (accessory oculomotor nucleus) is the parasympathetic pre-ganglionic nucleus that innervates the iris sphincter muscle and the ciliary muscle….
| Edinger–Westphal nucleus | |
|---|---|
| NeuroLex ID | birnlex_822 |
| Anatomical terms of neuroanatomy |
Where is the Edinger Westphal?
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 Pretectal mean?
Medical Definition of 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.
What does the superior colliculus do?
The superior colliculus (SC) is a midbrain area where visual, auditory and somatosensory information are integrated to initiate motor commands. The SC plays a central role in visual information processing in the mouse; it receives projections from 85% to 90% of the retinal ganglion cells (RGCs).
What happens if the red nucleus is damaged?
The red nucleus is traversed by fibers of the oculomotor nerve rostrally and the fibers of the superior cerebellar peduncle caudally. The red nucleus is connected with the cerebellum, cerebral cortex, and spinal cord. Lesions of the red nucleus usually result in contralateral tremor, ataxia, or choreiform movements.
Why red nucleus is called Red?
The red nucleus is pale pink, which is believed to be due to the presence of iron in at least two different forms: hemoglobin and ferritin. The structure is located in the tegmentum of the midbrain next to the substantia nigra and comprises caudal magnocellular and rostral parvocellular components.
Where is the Edinger Westphal located?
What are the function of neurons in the pretectal area?
As part of the subcortical visual system, neurons within the pretectal nuclei respond to varying intensities of illuminance and are primarily involved in mediating non-conscious behavioral responses to acute changes in light.
Is the pretectal area part of the subcortical system?
[edit on Wikidata] The pretectal area, or pretectum, is a midbrain structure composed of seven nuclei and comprises part of the subcortical visual system.
Where does the pretectal area of the retina receive input?
The pretectum receives significant binocular input from photosensitive ganglion cells in the retina. In primates these afferents are bilateral while in rodents they project from the contralateral retina.
Is the pupillary reflex mediated by the pretectum?
Pupillary constriction resulting from the pupillary light reflex is mediated by the olivary and posterior pretectal nuclei. The pupillary light reflex is mediated by the pretectum. This reflex is responsible for the constriction of the pupils upon light’s entering the eye.