- Posterior commissure
Infobox Brain
Name = PAGENAME
Latin = commissura posterior
GraySubject = 189
GrayPage = 812
Caption = Mesal aspect of a brain sectioned in the median sagittal plane. (Posterior commissure labeled at upper right.)
Caption2 = Median sagittal section of brain. The relations of thepia mater are indicated by the red color. (Label for posterior commissure is at center top.)
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Vein =
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BrainInfoType = hier
BrainInfoNumber = 475
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DorlandsPre = c_49
DorlandsSuf = 12251723
The posterior commissure is a rounded band of white fibers crossing the middle line on the dorsal aspect of the upper end of thecerebral aqueduct . It is important in the bilateralpupillary light reflex .Its fibers acquire their medullary sheaths early, but their connections have not been definitely determined. Most of them have their origin in a nucleus, the "nucleus of the posterior commissure" (nucleus of Darkschewitsch), which lies in the central gray substance of the upper end of the cerebral aqueduct, in front of the
nucleus of the oculomotor nerve .Some are probably derived from the posterior part of the
thalamus and from thesuperior colliculus , whereas others are believed to be continued downward into themedial longitudinal fasciculus .The posterior commissure interconnects the pretectal nuclei, mediating the consensual pupillary light reflex.
ee also
*
anterior commissure External links
* [http://www.mrc-cbu.cam.ac.uk/Imaging/Common/antcomm.shtml Overview at www.mrc-cbu.cam.ac.uk]
*
* http://isc.temple.edu/neuroanatomy/lab/atlas/papc/
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