The Arcuate Fasciculus disentangled: Different conceptions are depicting different evolutionary trajectories

Yannick Becker (1) , Olivier Coulon (2) , Adrien Meguerditchian (1, 3, 4)

1 LPC - Laboratoire de psychologie cognitive
2 INT - Institut de Neurosciences de la Timone
3 ILCB - Institute of Language, Communication and the Brain
4 SP - Station de primatologie

Of all brain connections, the Arcuate Fasciculus is of considerable interdisciplinary interest, because of its major implication in language processing. The more peculiar is that its exact course and terminations remain inaccurately defined in the literature. Additionally, its appellation has been confused with the Superior Longitudinal Fasciculus and the Dorsal pathway. This morphological inconsistency led to diverging evolutionary accounts, which becomes visible in the recent renewed interest for the Arcuate Fasciculus across primate species. Historical knowledge about the Arcuate Fasciculus originated from human blunt dissections and later from tract tracing studies in the monkey brain. Contemporary diffusion weighted MRI studies reinvestigate the fasciculus’ morphologybut remain heavily bound to unclear anatomical priors and methodological limitations.While reviewing the three epistemological steps chronologically, we try to disentangle the major fibre bundle for language processing and highlight how each conception influenced current views about theevolution of language.

Mots clés: frontal terminations; temporal terminations; discontinuity; continuity; lateralization; nomenclature; terminology; hemispheric specialization; Comparative anatomy; White matter; Tractography; language network; language evolution

Domaines: Neurosciences

Yannick Becker, Olivier Coulon, Adrien Meguerditchian. The Arcuate Fasciculus disentangled: Different conceptions are depicting different evolutionary trajectories. 2021. ⟨hal-03255234v1⟩