Plasticity in the neural representation of language: Insights from hearing infants with Deaf mothers

Mercure, E. 1 , Lloyd-Fox, S. 2 , Johnson, M. H. 2 & MacSweeney, M. 1

1 UCL Institute of Cognitive Neuroscience
2 Birkbeck College, University of London

Hearing infants with Deaf parents (HoD) have a very different experience of language to that of hearing infants with hearing parents (HoH). They are generally exposed to language both in the auditory and visual modality, and are likely to experience a reduction in auditory spoken language. This study investigates the impact of language experience on brain representation for spoken and sign language in infancy. Three groups of hearing infants (4-7 months) were recruited: 31 HoD infants, 34 monolingual HoH infants and 28 bilingual HoH infants. Functional near infrared spectroscopy (fNIRS) was used to study brain activation in response to sentences in infant-directed English and French (familiar and unfamiliar spoken languages), BSL and French Sign Language (familiar and unfamiliar sign languages). Results suggest strong activation to spoken language in the temporal cortex, which is influenced by language experience. In general spoken language elicit stronger/more left lateralised activation in monolinguals than HoD and HoH bilinguals, with a familiar language eliciting a stronger response than an unfamiliar language. Activation to sign language was found in a more restricted area of the temporal cortex and was also influenced by experience. These results suggest early experience-dependent plasticity in the neural representation of language.