Long arcuate fascicle in wild and captive chimpanzees as a potential structural precursor of the language network
Abstract
Abstract The arcuate fascicle (AF) is the main fibre tract in the brain for human language. It connects frontal and temporal language areas in the superior and middle temporal gyrus (MTG). The AF’s connection to the MTG was considered unique to humans and has influenced theories of the evolution of language. Here, using high-resolution diffusion MRI of post-mortem brains, we demonstrate that both wild and captive chimpanzees have a direct AF connection into the MTG, albeit weaker than in humans. This finding challenges the notion of a strictly human-specific AF morphology and suggests that language-related neural specialisation in humans likely evolved through gradual evolutionary strengthening of a pre-existing connection, rather than arising de novo. It is likely that this neural architecture supporting complex communication was already present in the last common ancestor of hominins and chimpanzees 7 million years ago, enabling the evolution of language processes in the human lineage.
Article Details
Authors (55)
Yannick Becker
Cornelius Eichner
Michael Paquette
Christian Bock
Cédric Girard-Buttoz
Carsten Jäger
Tobias Gräßle
Tobias Deschner
Bala Amarasekaran
Caroline Asiimwe
Daniel Aschoff
Martina Bleyer
Julian Chantrey
Pawel Fedurek
Karina Flores
Zoro Bertain Gone Bi
Jennifer E. Jaffe
Susan Hambrech
Daniel Hanus
Daniel Haun
Evgeniya Kirilina
Kathrin Kopp
Fabian H. Leendertz
Matyas Liptovszky
Patrice Makouloutou-Nzassi
Kerstin Mätz-Rensing
Richard McElreath
Matthew McLennan
Zoltan Mezö
Sophie Moittié
Torsten Møller
Markus Morawski
Karin Olofsson-Sannö
Simone Pika
Andrea Pizarro
Kamilla Pléh
Jessica Rendel
Alejandra Romero Forero
Jonas Steiner
Mark F. Stidworthy
Lara Southern
Claudia A. Szentiks
Tanguy Tanga
Reiner Ulrich
Steve Unwin
Sue Walker
Nikolaus Weiskopf
Gudrun Wibbelt
Kim Wood
Klaus Zuberbühler
Philipp Gunz
Roman M. Wittig
Catherine Crockford
Angela D. Friederici
Alfred Anwander