Neural bases of infants’ language ability

Abstract: Language processing relies in adults on precise and specialized networks, located primarily in the left hemisphere, around the sylvian fissure. Although different human languages use different sounds, words and syntax, most children acquire their native language without difficulties following the same developmental path. How can the early organization of the human brain explain this calendar? Thanks to the development of brain imaging, we can now study early functional brain organization and understand the neural biases favoring speech learning in human infants. Results obtained during the first months of life with functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) show that the neuronal networks engaged when infants listen to speech are close to those described in adults and comprise multiple brain areas that are involved in phonological representations, lexical storing, memory and attention in adults. Furthermore, as in adults a significant left-right functional and structural asymmetry is observed at the level of the planum temporale. Quantified measures of gray and white matter maturation reveal the complex development of left and right, frontal and temporal areas. The dorsal pathway between area 44 and the posterior temporal areas via the arcuate is efficient very early on suggesting that frontal areas contribute to speech learning earlier than expected. These similarities between preverbal infants and adults, expert in their native language, suggest continuity in the functional and anatomical structures that underlie language processing. Language development appears thus to rely on a very complex and particular organization of the perisylvian areas in the human species.

Bio: Ghislaine Dehaene-Lambertz, Ph.D., originally qualified as a paediatrician, is a full-time associate researcher at Institut national de la santé et de la recherche médicale (INSERM) U992, Paris, France, where she investigates the development of cognitive functions in children using brain imaging techniques. She is the director of the developmental brain imaging program in Neurospin, Saclay, a new imaging center dedicated to brain research near Paris (France). She published pioneering work using high-density event-related potentials (Nature, 1994), functional magnetic resonance imaging (Science, 2002) and optical topography (PNAS, 2003-2013) to study language acquisition. The goal of her research is to study the brain functional organization at the beginning of life in order to understand how complex cognitive functions, such as language, music, mathematics, etc… emerge in the human brain.