The role of brain oscillations in bilingual language processing: insights from tACS and EEG
Dr Walter van Heuven
Dr JeYoung Jung
Dr Yun Wen
This PhD project investigates the causal link between brain oscillations and bilingual language processing through transcranial alternating current stimulation (tACS), which is a non-invasive brain stimulation technique. Brain oscillations at specific frequency bands observed with electroencephalography (EEG) have been associated with specific aspects of bilingual language processing. For example, Wen et al. (2018) reported gamma-band oscillations that were modulated differently by repetition of Chinese sounds (phonemes/tones) when Chinese-English bilinguals read pairs of Chinese (L1) words, and when they read the English (L2) translation of these L1 words. Furthermore, Perez et al. (2022) investigated forward translation (from L1 to L2) and backward translation (from L2 to L1) and reported theta power differences between forward and backward translation.
The first year of the project will focus first on how modulation of oscillations through tACS impacts forward and backward translation using a behavioural masked translation priming paradigm. The second year will focus on automatic translation in a purely L2 context. EEG data has revealed that L1 translations are automatically activated when bilinguals read in their L2 (Thierry & Wu, 2007). Further research has shown that gamma oscillations were modulated when L1 translations activated by the L2 had repeated sounds (Wen et al., 2018). Therefore, tACS targeting gamma band oscillations will be applied in a behavioural experiment to investigate the behavioural impact on automatic translation using a similar design as Wen et al. (2018). Additional experiments will involve both EEG and tACS to investigate the effectiveness of tACS to modulate oscillatory brain activity in bilinguals.
G. Pérez et al., Neuroscience 481, 134 (2022).
G. Thierry, Y. J. Wu, Proc Natl Acad Sci U S A 104, 12530 (2007).
Y. Wen, W. J. B. van Heuven, Psychon Bull Rev 24, 879 (2017).
Y. Wen, R. Filik, W. J. B. van Heuven, Sci Reports 6869, 1 (2018).