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Topic

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Anterior commissure

The anterior commissure is a compact bundle of white matter fibers in the brain that plays a crucial role in interhemispheric communication. Situated at the anterior wall of the third ventricle, it connects the two temporal lobes, including parts of the olfactory bulbs and amygdaloid complexes. Although much smaller than the corpus callosum, the anterior commissure is vital for certain sensory and memory pathways, especially those related to the olfactory and temporal regions.

Synonyms

  • Precommissural commissure

  • Commissura anterior (Latin)

  • White commissure of the anterior wall of third ventricle

Arterial Supply

  • Supplied primarily by branches of the anterior cerebral artery (ACA), particularly:

    • Perforating branches from the anterior communicating artery

    • Occasional small contributions from the anterior choroidal artery

Venous Drainage

  • Drained by small venules that empty into the deep cerebral veins:

    • Internal cerebral veins

    • Basal veins of Rosenthal

Function

  • Interconnects the temporal lobes of both hemispheres

  • Facilitates interhemispheric transfer of olfactory information

  • Connects parts of the amygdaloid complex, playing a role in emotional processing and memory

  • Contributes to pain perception pathways

MRI Appearance

  • T1-weighted imaging: Appears bright (hyperintense) due to its high myelin content

  • T2-weighted imaging: Appears dark (hypointense) because of dense myelination

  • FLAIR imaging: Not well visualized; remains dark or iso-intense to surrounding white matter

CT Appearance

  • Appears as a subtle linear hypodensity (difficult to distinguish from adjacent white matter)

MRI images

Anterior commissure mri 3t axial image

MRI images

Anterior commissure mri 3t sagittal image