The arcuate fasciculus has no 3D representation in the rendered atlas yet. Its course arches above the lateral fissure and would require sourcing streamline data from a diffusion-MRI atlas (AFQ, DSI Studio HCP842, or similar) and rendering tube geometry around the centroid spline. That work is on the v1.1 roadmap.

The arcuate fasciculus has been studied since Carl Wernicke proposed in 1874 that conduction aphasia (then called Leitungsaphasie) would arise from a lesion disconnecting the auditory word-form area in the superior temporal gyrus from the motor speech area in the inferior frontal gyrus. Geschwind’s 1965 disconnexion-syndrome review revived this framework after a long mid-twentieth-century period when disconnection accounts of aphasia had fallen out of favour.

Diffusion-MRI tractography over the last two decades has consistently resolved the arcuate into multiple parallel pathways. The long direct fronto-temporal segment is the canonical “arcuate”, but the two indirect segments (parieto-temporal and fronto-parietal) carry substantial fibre volume and contribute to the integration of phonological, syntactic, and semantic processing across the perisylvian network.

Right-arcuate-fasciculus differences underlie much of the cortical asymmetry in language lateralisation. The left arcuate is reliably larger and more myelinated than the right in right-handed subjects; this asymmetry develops in early childhood and tracks language acquisition milestones.