Anterior commissure

Anterior commissure
Coronal cross-section of brain showing the anterior commissure. (left, third from bottom.)
Tractography of anterior commissure
Details
Identifiers
Latin	commissura anterior
MeSH	D066240
NeuroNames	205, 390
NeuroLex ID	birnlex_1557
TA98	A14.1.08.421
TA2	5613
FMA	61961
Anatomical terms of neuroanatomy [edit on Wikidata]

The anterior commissure (also known as the precommissure) is a white matter tract (a bundle of axons) connecting the two temporal lobes of the cerebral hemispheres across the midline, and placed in front of the columns of the fornix. In all but five species of mammal the great majority of fibers connecting the two hemispheres travel through the corpus callosum, which in humans and all non-monotremes is more than 10 times larger than the anterior commissure. Other routes of communication pass through the hippocampal commissure or, indirectly, via subcortical connections. Nevertheless, the anterior commissure is a significant pathway that can be clearly distinguished in the brains of all mammals.

The anterior commissure plays a key role in pain sensation, more specifically sharp, acute pain. It also contains decussating fibers from the olfactory tracts, vital for the sense of smell and chemoreception. The anterior commissure works with the posterior commissure to link the two cerebral hemispheres of the brain and also interconnects the amygdalae and temporal lobes, contributing to the role of memory, emotion, speech and hearing. It also is involved in olfaction, instinct, and sexual behavior.

In a sagittal section, the anterior commissure is oval in shape, having a long vertical axis that measures about 5 mm.