TMS uncovers details about sub-regional language-specific processing networks in early bilinguals

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University of Helsinki
  • Åbo Akademi University
  • Aarhus University
  • Aalto University

Abstract

Despite numerous functional neuroimaging and intraoperative electrical cortical mapping studies aimed at investigating the cortical organisation of native (L1) and second (L2) language processing, the neural underpinnings of bilingualism remain elusive. We investigated whether the neural network engaged in speech production over the bilateral posterior inferior frontal gyrus (pIFG) is the same (i.e., shared) or different (i.e., language-specific) for the two languages of bilingual speakers. Navigated transcranial magnetic stimulation (TMS) was applied over the left and right posterior inferior gyrus (pIFG), while early simultaneous bilinguals performed a picture naming task with their native languages. An ex-Gaussian distribution was fitted to the naming latencies and the resulting parameters were compared between languages and across stimulation conditions. The results showed that although the naming performance in general was highly comparable between the languages, TMS produced a language-specific effect when the pulses were delivered to the left pIFG at 200 ms poststimulus. We argue that this result causally demonstrates, for the first time, that even within common language-processing areas, there are distinct language-specific neural populations for the different languages in early simultaneous bilinguals.

Details

Original languageEnglish
Pages (from-to)209-221
Number of pages13
JournalNeuroImage
Volume171
Publication statusPublished - 1 May 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • Bilingualism, Language-specific, Picture naming, TMS

ID: 18275863