Uncinate fasciculus L

Overview

The bilateral Uncinate fasciculus L, as defined in the JHU ICBM labels 1mm Atlas, is a left-lateralized segment of a hook-shaped associative white matter tract that connects anterior temporal lobe structures, including portions of the temporal pole and amygdala, with the orbitofrontal and ventromedial prefrontal cortices. This tract courses ventrally and medially through the anterior temporal stem and insular region, curving around the lateral sulcus to reach the frontal lobe, and is composed of heavily myelinated fibers that support rapid cortico-cortical communication. Functionally, the uncinate fasciculus is implicated in emotional processing, social cognition, memory, and language, including semantic retrieval and affective components of decision making, with lateralization patterns suggesting potential specialization in verbal and emotional domains on the left. Microstructural properties of this region, commonly assessed via diffusion tensor imaging in the JHU atlas framework, show vulnerability in various neuropsychiatric and neurodegenerative conditions, highlighting its role in frontotemporal network integrity. Uncinate fasciculus

The bilateral uncinate fasciculus, a white matter tract connecting anterior temporal regions with the orbitofrontal cortex, has been implicated in multiple GWAS and imaging‐genetics studies, although findings are typically reported for tract-specific diffusion metrics rather than the JHU ICBM 1 mm label per se. Common variants in genes influencing axonal guidance, myelination, and neurodevelopment—such as CNTNAP2, NRG1, and DISC1—have been associated with microstructural variation in the uncinate fasciculus, particularly fractional anisotropy and mean diffusivity. Polygenic risk scores for schizophrenia, bipolar disorder, and major depressive disorder have shown correlations with uncinate fasciculus integrity, and risk alleles in neuregulin and glutamatergic signaling pathways have been linked to altered connectivity of this tract in psychosis. Imaging‐genetics work also connects APOE ε4 and other Alzheimer’s disease–related variants to degeneration and reduced anisotropy in the uncinate fasciculus, consistent with its role in frontotemporal and limbic networks affected by neurodegeneration. Additional GWAS and candidate‐gene studies have tied uncinate fasciculus microstructure to traits such as anxiety, callous–unemotional behavior, impulsivity, and language and social communication abilities, supporting its involvement as a genetically modulated substrate for emotional regulation, social cognition, and higher-order associative processing.

Overview generated by GPT-4o (2026).

Region ID: 46
Hemisphere: bilateral
Atlas: JHU ICBM labels 1mm

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