Primate auditory prototype in the evolution of the arcuate fasciculus

Balezeau et al. find a primate homolog of the human language pathway within the auditory system of monkeys and apes. This discovery pushes back the human language pathway's origin by about 20 million years and illuminates its remarkable evolutionary transformation. The human arcuate fasciculus pathway is crucial for language, interconnecting posterior temporal and inferior frontal areas. Whether a monkey homolog exists is controversial and the nature of human-specific specialization unclear. Using monkey, ape and human auditory functional fields and diffusion-weighted MRI, we identified homologous pathways originating from the auditory cortex. This discovery establishes a primate auditory prototype for the arcuate fasciculus, reveals an earlier phylogenetic origin and illuminates its remarkable transformation.