Poster A33, Tuesday, August 20, 2019, 10:15 am – 12:00 pm, Restaurant Hall
Spatio-temporal dynamics of noun and verb naming in early bilinguals
Shuang Geng1, Lucia Amoroso1,2, Nicola Molinaro1,2, Manuel Carreiras1,2,3;1BCBL, Basque Center on Cognition, Brain and Language, 2Ikerbasque, Basque Foundation for Science, 3University of the Basque Country UPV/EHU
Despite decades of research, the question of how conceptual knowledge is represented and retrieved from memory remains controversial. In particular, there is still an ongoing debate on whether words representing objects (nouns) and words representing actions (verbs) recruit different or similar functional networks in the brain. Furthermore, within this context, little is known about how words from different languages are represented and accessed in bilingual speakers. Here, we aimed to shed light on these two aspects by analyzing brain oscillations during picture naming of nouns and verbs in a group of early Spanish-Basque bilinguals. We recorded neuromagnetic signals with a 306-sensor Elekta Neuromag system while 20 early high-proficient Spanish-Basque bilinguals performed a noun and verb picture-naming task in both languages (i.e., separate blocks). We performed time–frequency analysis to examine how power varied based on category and language. Differences between conditions were assessed using cluster-based permutation tests and sensor-level effects were source-reconstructed using Beamforming techniques. The analysis revealed power increases for verbs as compared to nouns in the theta (4-8Hz), alpha (8-12Hz) and beta (13-28 Hz) frequency-bands. However, when comparing categories across languages no differences were observed neither for noun nor verb naming. Source reconstruction of the sensor level effects showed the involvement of different neural networks for nouns and verbs depending on frequency-band. Briefly, theta differences between categories were mainly located in inferior occipito-temporal regions, while alpha and beta differences were localized in the angular gyrus, the posterior middle temporal gyrus, the anterior temporal pole and ventral premotor regions. In this study, we aimed to address how oscillatory dynamics mediate the lexico-semantic retrieval of nouns and verbs and whether this process differed or not across languages. Overall, our results suggest the recruitment of partially different networks during noun and verb processing. Interestingly, our findings support the existence of common brain networks and similar oscillatory dynamics across languages in early bilinguals.
Themes: Meaning: Lexical Semantics, Multilingualism
Method: Electrophysiology (MEG/EEG/ECOG)