Poster E62, Saturday, August 18, 3:00 – 4:45 pm, Room 2000AB

Neural plasticity of language production networks associated with language learning

Kshipra Gurunandan1, Manuel Carreiras1,2, Pedro M. Paz-Alonso1;1BCBL - Basque Center on Cognition, Brain and Language, San Sebastián, Spain, 2Ikerbasque - Basque Foundation for Science, Bilbao, Spain

Verbal fluency (VF) tasks have long been used to study cognitive-linguistic processing and its impairments. However, the study of the functional networks underlying VF task performance is more recent, and few fMRI studies have looked at bilingual language production networks and their modulating factors using this task. A study with high proficient early bilinguals (Perani et al., 2003) found an effect of the age of acquisition of a second language (L2) in the activation patterns, but while proficiency is known to play an important role in language organization, it is as yet unknown what effect L2 proficiency has on the language production networks. Our previous study on language learning in adulthood found considerable neural plasticity of speech and reading networks as a function of L2 proficiency and here we looked at whether or not the same principle and result profiles apply to the production networks. Our study was aimed at investigating the differences in language production networks in adults at different stages of acquiring a L2. We examined 1) regional patterns of task activation during production, 2) laterality of the language production networks, and 3) the effect of increasing task difficulty on these two groups. Thirty-four adult (mean age = 46.5 years, 17 male) native speakers of Spanish (L1), either at the intermediate or advanced levels of learning Basque, underwent functional MRI scanning while performing semantic and phonological verbal fluency tasks in their L1 and L2. Behavioral results showed a group by language interaction, with similar performance in the L1 and differential performance in the L2 between the intermediate and advanced language-learning groups. fMRI results revealed 1) stronger engagement of right-hemispheric regions for phonological versus semantic VF tasks in the advanced group across languages; 2) no significant changes in the laterality of L2 production networks with increasing L2 proficiency; and 3) widening group differences in the recruitment of the L2 production network as a function of task difficulty. In conclusion, our study revealed less proficiency-dependent plasticity of the language production networks compared to speech and reading comprehension, in line with previous speculations of the fixedness of language production networks (Gaillard et al., 2000) now extended to L2 acquisition.

Topic Area: Multilingualism