Importantly, these differences have been observed across different imaging modalities such as electro- and magnetoencephalography, and functional near-infrared spectroscopy (fNIRS). Dissimilar patterns of brain activation have been observed in monolingual and bilingual 4-month-olds in a language discrimination/recognition task (Nacar-García et al., 2018) and when infants are presented with native and non-native speech sounds ( García-Sierra et al., 2011 Petitto et al., 2012 Ferjan Ramírez et al., 2017) or words ( Conboy and Mills, 2006). A bilingual environment has been shown to have consequences on infants’ brain responses and behaviour when cognitive functions and spoken language processing are considered. While bilingual infants’ overall language exposure should be comparable to that of monolinguals, bilingual infants likely receive less exposure to each of their languages –compared to their monolingual peers– because their exposure time is split between two inputs. In addition, differently from monolinguals, bilinguals need to discriminate between two languages. Therefore, the linguistic statistical regularities present in a bilingual environment are different than in a monolingual one. In a bilingual learning environment, infants are exposed to the linguistic regularities (e.g., speech sounds, words, grammar) of not one, but two inputs simultaneously. Language acquisition begins as soon as infants are able to hear spoken language, about 3 months prior to birth (e.g., Werker, 2018). Relevant to the current study, RSFC also reflects differences in neural adaptation associated with environmental factors, such as the caregivers’ education level or socioeconomic status ( Gao et al., 2015).Ī specific external factor is growing up in a bilingual environment. As measured by functional magnetic resonance imaging (fMRI) studies, premature and full-term infants show different RSFC patterns ( Damaraju et al., 2010 Smyser et al., 2010) moreover, the configuration and maturational course of functional connectivity differs across neurotypical infants and toddlers in comparison to those of high risk of developmental disorders, such as autism spectrum disorder ( Dinstein et al., 2011 Keehn et al., 2013). The intrinsic functional organization of the infant brain described by RSFC might show changes depending on various pre- and postnatal factors. RSFC can be measured in infants, children, and adults, thus providing a window into neural specialization across the life span ( Gao et al., 2017). RSFC reflects spontaneous but synchronized fluctuations in cerebral hemodynamic activity between brain regions that share a common role in supporting various, functionally relevant sensory and cognitive processes ( Fox and Raichle, 2007 Damoiseaux et al., 2006). One way to understand the intrinsic functional organization of the human brain is through the measurement of resting-state functional connectivity (RSFC). Our results revealed no differences between the intrinsic functional organization of the developing monolingual and bilingual infant brain at 4 months of age. We implemented well-established analysis approaches of functional brain imaging that enabled us to reveal the functional organization of the infant brain in large-scale cortical networks, and to perform group-level comparisons (i.e., monolingual vs. We measured spontaneous hemodynamic brain activity using functional near-infrared spectroscopy (fNIRS) in a large cohort (N=99) of 4-month-old monolingual and bilingual infants. However, to what extent the intrinsic organization of the infant human brain adapts to monolingual vs. bilingual experience affects cognitive and linguistic processes already during the first months of life. Recent behavioural research attests that monolingual vs. This study examines whether bilingual exposure has a profound effect on the functional organization of the developing human brain during infancy.
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