Distinct hemispheric specializations for native and non-native languages in one-day-old newborns identified by fNIRS

This study assessed whether the neonatal brain recruits different neural networks for native and non-native languages at birth. Twenty-seven one-day-old full-term infants underwent functional near-infrared spectroscopy (fNIRS) recording during linguistic and non-linguistic stimulation. Fourteen newborns listened to linguistic stimuli (native and non-native language stories) and 13 newborns were exposed to non-linguistic conditions (native and non-native stimuli played in reverse). Comparisons between left and right hemisphere oxyhemoglobin (HbO2) concentration changes over the temporal areas revealed clear left hemisphere dominance for native language, whereas non-native stimuli were associated with right hemisphere lateralization. In addition, bilateral cerebral activation was found for non-linguistic stimulus processing. Overall, our findings indicate that from the first day after birth, native language and prosodic features are processed in parallel by distinct neural networks.