Neural language processing in adolescent first-language learners.
The relation between the timing of language input and development of neural organization for language processing in adulthood has been difficult to tease apart because language is ubiquitous in the environment of nearly all infants. However, within the congenitally deaf population are individuals who do not experience language until after early childhood. Here, we investigated the neural underpinnings of American Sign Language (ASL) in 2 adolescents who had no sustained language input until they were approximately 14 years old. Using anatomically constrained magnetoencephalography, we found that recently learned signed words mainly activated right superior parietal, anterior occipital, and dorsolateral prefrontal areas in these 2 individuals. This spatiotemporal activity pattern was significantly different from the left fronto-temporal pattern observed in young deaf adults who acquired ASL from birth, and from that of hearing young adults learning ASL as a second language for a similar length of time as the cases. These results provide direct evidence that the timing of language experience over human development affects the organization of neural language processing.
['Ferjan Ramirez|Naja|N|', 'Leonard|Matthew K|MK|', 'Torres|Christina|C|', 'Hatrak|Marla|M|', 'Halgren|Eric|E|', 'Mayberry|Rachel I|RI|']
D000293:Adolescent D000328:Adult D000367:Age Factors D002540:Cerebral Cortex D003423:Critical Period, Psychological D003638:Deafness D005260:Female D007839:Functional Laterality D006801:Humans D007804:Language Development D007858:Learning D015225:Magnetoencephalography D008297:Male D012660:Semantics D012813:Sign Language D055815:Young Adult
language processing sign language anatomically constrained magnetoencephalography age of acquisition critical period