Céline Amiez (SBRI) is delighted to have Adrien Meguerditchian from the Cognitive Psychology Lab (Rousset) to come and give a conference:
On the origin of hemispheric specialization for language: hand & brain asymmetries using MRI in baboons (papio anubis)
Language is an unique system of communication in humans and involve complex hemispheric specialization of the brain. Given the phylogenetic proximity between humans and nonhuman primate species, the investigation of the lateralization of communicative system as well as the cortical organization in apes and monkeys within a comparative approach might enable detecting the potential precursors of hemispheric specialization for language processing in our common ancestors. In previous studies we found that both chimpanzees and baboons - a non-hominid Old World monkey species - showed a robust predominance of right-hand use for communicative manual gestures specifically, indicating that the left-hemisphere might be dominant for the control of gestural communication. In the present brain studies using MRI at the Centre IRMf of Marseille, we investigate the anatomical brain asymmetries of some of key-cortical regions for language in olive baboons (Papio anubis) among 96 subjects housed in social groups at the Station de Primatologie CNRS. We found, for the first time in a non-hominid species, human-like significant neuroanatomical asymmetries toward the left hemisphere for the planum temporale surface and toward the right hemisphere for a specific portion of the Superior Temporal Sulcus's and of the Arcuate's depth. Interestingly, inter-hemispheric asymmetries of the central sulcus depth were shown to be significantly driven by the contralateral direction of handedness (i.e., left- or right-hand), which were previously assessed in those individuals using a bimanual coordinated task. These collective findings suggest that the continuity of hemispheric specialization between apes and humans extend to baboons for key structures of language and handedness. These findings argue that prerequisites of hemispheric specialization for language and handedness might be dated back to the common ancestor of Catarrhini at 30-40 million years ago.
SBRI conference room, May 23rd from 11am