WP1 Comparative asymmetries in baboons & humans
We found that, in both humans and baboons, unlike typical handedness measures, communicative gesturing’s hand preference is clearly related to markers of language-related hemispheric specialization. In contrast, handedness for manipulation in baboons was exclusively related to the cerebral asymmetry of the motor hand area within the depth of the central sulcus of the brain, just like human handedness.
These collective findings clearly speak for the evolutionary continuities of the gestural system with language lateralization, dating back – not to Hominidae – but to a much older common ancestor shared with old-world monkeys.
WP2 Functional brain lateralization using fNIRS
We successfully tested for the first time non-invasive optical fNIRS imaging (near infrared spectroscopy) on anesthetized baboons to infer hemispheric difference in functional activation of the brain for both arms movement in the motor cortex and audio stimulation in the temporal cortex. This critical development of this technique opened further data acquisition of brain activity for communication tasks in a more ecological environment by training monkeys to wear the device.
WP3 Longitudinal development
We found that, similarly than in human infants, baboon newborns shows leftward asymmetry for a key structure for language, the Planum Temporale, which increases with age and predict the future development on right-handedness for gestural communication once juveniles, suggesting this feature might be not human- or language-specific but related to a ancient prewired lateralized system for gesture inherited from our last common ancestor with monkeys.
In contrast, maternal baby cradling bias in baboons’ mother shape not only the early neuroanatomical asymmetry of the motor hand area in their baby but also the first manifestation of their early hand preference for reaching. Such an external maternal factor seems thus to shape the baby’s brain by plasticity, but finally disappears when the baboons is wean at 9 month old. At this age, their pattern of handedness further evolved independently from their mother, likely in relation to novel and more complex manipulative experience (bimanual coordination), which ultimately affect their central sulcus asymmetry.
WP4 Dissemination
35 published papers (+ 6 to be submitted + 5 in prep)
- 21 original research papers
- 9 review or theory chapters
- 5 science popularization article in French journals for the general public
95 communications
- 36 to international conf/workshops including 4 published abstracts & 13 invited
- 33 to francophone conf/workshops including 11 published abstracts & 19 invited
- 26 to general-public events (Schools, Theaters, Prison, Coffees, Festival, Social Center, Public Library or Museum)
