Monolingual and bilingual infants rely on the same brain networks: Evidence from resting-state functional connectivity

Abstract

15This study examines whether bilingual exposure has a profound effect on the functional organization of the 16 developing human brain during infancy. Recent behavioural research attests that monolingual vs. bilingual 17 experience affects cognitive and linguistic processes already during the first months of life. However, to what 18 extent the intrinsic organization of the infant human brain adapts to monolingual vs. bilingual environments is 19 unclear. We measured spontaneous hemodynamic brain activity using functional near-infrared spectroscopy 20 (fNIRS) in a large cohort (N=99) of 4-month-old monolingual and bilingual infants. We implemented well-21 established analysis approaches of functional brain imaging that enabled us to reveal the functional organization 22 of the infant brain in large-scale cortical networks, and to perform group-level comparisons (i.e., monolingual 23 vs. bilingual groups) in a reliable manner. Our results revealed no differences between the intrinsic functional 24 organization of the developing monolingual and bilingual infant brain at 4 months of age. 26Keywords: Functional connectivity, functional near-infrared spectroscopy, brain development, language 27 acquisition, bilingualism, independent component analysis, connectome . 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 85 profound effect on the developing human brain, such as its functional organization, is currently unknown. 86Measuring RSFC in monolingual and bilingual infants can reflect whether bilingual experience during the first 87 months of life leads to specific adaptations in the intrinsic properties of brain's function that are observable in 88 the absence of any task or stimuli (i.e., at rest). Testing whether functional adaptation to a bilingual context is 89 evident at the earliest stages of human development is crucial for our understanding of how bilingualism interacts 90 with general brain maturation patterns beyond task-specific language and cognitive processing. There is evidence 91 that long-term exposure to two languages might alter the brain's functional (Parker Jones et al., 2011; Berken 92 et al., 2016) and structural organization (Mechelli et al., 2004; García-Pentón et al., 2014; Mohades et al., 93 2015), as demonstrated by MRI studies in adults. For instance, stronger functional connectivity in bilingual 94 adults as compared to monolinguals has been observed in long-range bilateral and anterior-posterior connections 95 on both hemispheres (Luk et al., 2011), and in brain networks associated with language and executive control 96 processes (Grady et al., 2015; Berken et al., 2016). The aim of the current study is to assess whether the brain's 97 functional architecture begins to adapt to a bilingual environment as early as 4 months of age, by the time neural 98 and behavioural responses to external stimuli often differ across monolinguals and bilinguals. Specifically, the 99 current goal is to contrast the RSFC across monolingual and bilingual 4-month-old infants using fun...

Gender difference in functional activity of 4-months-old infants during sleep: A functional near-infrared spectroscopy study

“…The dataset used in this study is high-quality fNIRS data collected from a large sample of participants, which accurately describes large-scale patterns of functional connectivity at the population level in 4-month-old infants ( 20 ). The sample in the dataset consisted of 104 participants who were recorded during natural sleep for relative changes in HbO and HbR in the cerebral cortex.…”

“…Most of these studies, like those studying children, have focused on the effects of the early language environment on changes in HbR and HbO levels and have not thoroughly examined gender differences in early development. In addition, most early infant studies define cortical activation based on HbO signaling only ( 20 ) and do not consider HbR signaling either before or after data analysis. However, the fNIRS community has raised awareness of the importance of assessing HbO and HbR (and possibly HbT) in order to draw solid scientific conclusions, and most publications now report results for both parameters.…”