Poster Slam Session B, Tuesday, August 20, 2019, 3:00 – 3:15 pm, Finlandia Hall, Angela Grant
The influence of the prenatal linguistic environment on the newborn cerebral language processing: A fNIRS study
Laura Caron-Desrochers1,2,3, Phetsamone Vanassing1,2, Julie Tremblay1,2, Sarah Kraimeche1,2,3, Ioana Medeleine Constantin1,2,3, Kassandra Roger1,2,3, Sarah Provost1,2,3, Catherine Taillefer2,3, Isabelle Boucoiran2,3, Anne Gallagher1,2,3;1Neurodevelopmental Optimal Imaging Laboratory (LIONLAB), 2Sainte-Justine University Hospital Center, 3University of Montreal
From birth, the newborn brain reacts differently to familiar sounds, such as its mother’s voice or native language. For instance, hearing its native language triggers a left-hemisphere dominant neuronal response in temporal and frontal regions that differs from the right-dominant response to a foreign language. While it suggests that brain development can already be modulated by the fetus’ surrounding environment, the current knowledge is mainly based on postnatal correlational studies. The present study aimed to investigate the impact of a repeated prenatal exposure to a foreign language on the brain activation patterns at birth. METHODS: The preliminary sample included 31 healthy pregnant women recruited during their last trimester of pregnancy. They were randomly assigned to either the control group (n=11, no prenatal exposure) or one of the two experimental groups with a prenatal exposure to a foreign language, either German (n=10) or Hebrew (n=10). Between 35 weeks of gestation and birth, fetuses in the experimental groups were exposed daily to a children’s story. It was repeated twice in both their native (French) and a foreign language (German or Hebrew) using headphones placed on the mother’s abdomen. Thus, they heard each version 52 ± 14 times on average. In the first days after birth (average of 26 ± 11 hours after birth), the newborns undertook a brain imaging recording using functional near-infrared spectroscopy (fNIRS) while listening to the very same story. The story was presented in the three languages (French, German and Hebrew). fNIRS is a non-invasive technique that allows to indirectly measure cortical activity based on neurovascular coupling and hemoglobin concentration changes. The newborns’ fNIRS data were preprocessed offline – including normalization, segmentation, artifact correction, and estimation of concentration changes in oxy- and deoxy-hemoglobin based on the modified Beer-Lambert law. The signal was averaged across participants, groups and language conditions. RESULTS: Results from the preliminary sample revealed a significant increase in hemodynamic concentration in bilateral temporal lobes for all conditions (p<.05). More specifically, the native language elicited a left-hemisphere dominant activation, while both foreign languages elicited a right-dominant activation. We then performed comparisons between brain responses to familiar (exposed prenatally) and unfamiliar (unexposed) foreign languages in the experimental groups. Interestingly, hemispheric dominance patterns differed across both foreign languages when taking to account the newborns’ familiarity. Cerebral response to the familiar language showed significant dominance in the left posterior temporal region compared to the unfamiliar language that elicited a right-dominant activation (p=.043). CONCLUSION: Our results suggest that newborns as young as one-day old process their native syllable-timed language differently from various stress-timed foreign languages. The brain shows a left-dominant processing regarding their native language, contrarily to both foreign languages. Moreover, our results imply that a repetitive prenatal exposure to new speech stimuli during the last month of pregnancy modulates the brain functional organization in a way that resembles the native language brain processing. It provides preliminary evidence of prenatal experience-dependent auditory and linguistic learning.
Themes: Development, Multilingualism
Method: Functional Imaging
Poster B14