The uncinate fasciculus has no 3D representation in the rendered atlas yet. Like the arcuate and superior longitudinal fasciculi, sourcing streamline data and rendering tube geometry is on the v1.1 roadmap.

The uncinate is the slowest-developing major white-matter tract in the human brain, with fractional anisotropy continuing to increase into the third decade of life. This protracted maturation parallels the slow development of executive function and emotional regulation, which both depend on the temporal-prefrontal integration the uncinate supports.

Semantic-variant primary progressive aphasia is the canonical syndrome demonstrating uncinate function. Patients lose specific word meanings (loss of the meaning of “dog” not just the word) while their syntax, articulation, and perception remain intact. Atrophy is densest in the left temporal pole and the uncinate fasciculus underneath, with the dorsal language stream and frontal cortex relatively spared in early disease.

The uncinate is also implicated in psychopathology. Decreased uncinate integrity has been reported in social anxiety disorder, antisocial personality disorder, and the negative symptoms of schizophrenia, in each case interpretable as disrupted integration between temporal limbic representations and prefrontal evaluative control.