Shining new light on the brain’s “bilingual signature”: a functional near infrared spectroscopy investigation of semantic processing. Neuroimage 39:1457–1471

Decades of research have shown that, from an early age, proficient bilinguals can speak each of their two languages separately (similar to monolinguals) or rapidly switch between them (dissimilar to monolinguals). Thus we ask, do monolingual and bilingual brains process language similarly or dissimilarly, and is this affected by the language context? Using an innovative brain imaging technology, functional Near Infrared Spectroscopy (fNIRS), we investigated how adult bilinguals process semantic information, both in speech and in print, in a monolingual language context (one language at a time) or in a bilingual language context (two languages in rapid alternation). While undergoing fNIRS recording, ten early exposed, highly proficient Spanish-English bilinguals completed a Semantic Judgment task in monolingual and bilingual contexts and were compared to ten English monolingual controls. Two hypotheses were tested: the Signature Hypothesis predicts that early, highly proficient bilinguals will recruit neural tissue to process language differently from monolinguals across all language contexts. The Switching Hypothesis predicts that bilinguals will recruit neural tissue to process language similarly to monolinguals, when using one language at a time. Supporting the Signature Hypothesis, in the monolingual context, bilinguals and monolinguals showed differences in both hemispheres in the recruitment of DLPFC (BA 46/9) and IFC (BA 47/11), but similar recruitment of Broca's area (BA 44/45). In particular, in the monolingual context, bilinguals showed greater signal intensity in channels maximally overlaying DLPFC and IFC regions as compared to monolinguals. In the bilingual context, bilinguals demonstrated a more robust recruitment of right DLPFC and right IFC. These findings reveal how extensive early bilingual exposure modifies language organization in the brain-thus imparting a possible "bilingual signature." They further shed fascinating new light on how the bilingual brain may reveal the biological extent of the neural architecture underlying all human language and the language processing potential not fully recruited in the monolingual brain

“One glove does not fit all” in bilingual reading acquisition: Using the age of first bilingual language exposure to understand optimal contexts for reading success

In teaching reading, educators strive to find the balance between a code-emphasis approach and a meaning-oriented literacy approach. However, little is known about how different approaches to literacy can benefit bilingual children’s early reading acquisition. To investigate the novel hypothesis that children’s age of first bilingual exposure can interact with different approaches to literacy, we tested 56 Spanish-English bilingual children (ages 7–9), with birth exposure to Spanish and either early (before age 3) or late (3–4) age of first bilingual exposure to English. The children attended reading programs identified with either phonics or whole language emphasis. Consistent with our hypothesis, differential outcomes were linked to different ages of first bilingual exposure. Early bilingual exposure to English was associated with more advanced reading abilities under whole language emphasis, while later (ages 3–4) exposure was associated with better decoding and reading abilities under phonics emphasis. The findings show that knowing the age of a child’s first bilingual language exposure, as it corresponds to different periods in child development, may contribute to an educator’s design of reading instruction that best accommodates young bilingual learners

Exploring Cognitive Functions in Babies, Children & Adults with Near Infrared Spectroscopy

An explosion of functional Near Infrared Spectroscopy (fNIRS) studies investigating cortical activation in relation to higher cognitive processes, such as language1,2,3,4,5,6,7,8,9,10, memory11, and attention12 is underway worldwide involving adults, children and infants 3,4,13,14,15,16,17,18,19 with typical and atypical cognition20,21,22. The contemporary challenge of using fNIRS for cognitive neuroscience is to achieve systematic analyses of data such that they are universally interpretable23,24,25,26, and thus may advance important scientific questions about the functional organization and neural systems underlying human higher cognition