The bilateral Left Cerebrum.Sub-lobar.Extra-Nuclear.White Matter.Anterior Commissure region in the Talairach 1 mm atlas corresponds to the anterior commissure, a compact bundle of myelinated interhemispheric fibers located in the sub-lobar white matter anterior to the third ventricle and beneath the anterior columns of the fornix. This tract connects primarily the anterior temporal lobes, including parts of the amygdala and temporal association cortices, and also carries some fibers related to olfactory and limbic structures, thereby contributing to interhemispheric integration of emotional, mnemonic, and sensory information. It is especially prominent in the ventral pathway for temporal lobe connectivity and serves as an alternative interhemispheric route alongside the corpus callosum, particularly for temporal and limbic networks. Anterior commissure
The anterior commissure’s white matter, part of the bilateral left sublobar extra-nuclear region in the Talairach 1 mm atlas, has been implicated in several genetically influenced traits and disorders, though often indirectly via broader callosal/commissural or limbic pathways rather than this label specifically. Imaging–genetics and GWAS of brain connectivity and white matter microstructure (e.g., diffusion tensor imaging measures such as fractional anisotropy) have linked common variants affecting axon guidance, myelination, and neural development—frequently in genes such as NRG1/ERBB4, CNTNAP2, ROBO/SLIT family members, and oligodendrocyte-related genes—to interhemispheric tracts that include the anterior commissure, with downstream associations to schizophrenia, autism spectrum disorder, bipolar disorder, and major depression. Polygenic risk scores for these psychiatric conditions have been associated with altered interhemispheric connectivity patterns, while rare variants and copy number variants affecting midline crossing and commissural formation sometimes produce agenesis or hypoplasia of the corpus callosum accompanied by anterior commissure abnormalities. GWAS of pain sensitivity, olfaction, and limbic-related traits (e.g., emotional processing, addiction vulnerability) occasionally highlight loci in pathways supporting temporal and amygdalar connectivity in which the anterior commissure is a key conduit, though effect sizes are modest and findings rarely isolate this tract alone. Overall, genetic associations for the Talairach-defined anterior commissure white matter region are best viewed as part of a broader, polygenic architecture influencing interhemispheric connectivity, limbic circuitry, and susceptibility to major neuropsychiatric disorders rather than as region-specific effects.
Overview generated by GPT-4o (2026).
Region ID: 504
Hemisphere: bilateral
Atlas: Talairach labels 1mm
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Full Quality Version: Download MP4
Wali Sidiqyar*, Gaurav Rudravaram*, Elyssa M. McMaster, Trent M. Schwartz, Adam M. Saunders, Kurt G. Schilling, Bennett A. Landman "Introducing SPINS: A Shared Public Visualization Library of Neuroanatomical Structures." Medical Imaging with Deep Learning- short paper
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