TY - JOUR

T1 - Cortical motor systems are involved in second-language comprehension

T2 - Evidence from rapid mu-rhythm desynchronisation

AU - Vukovic, Nikola

AU - Shtyrov, Yury

PY - 2014/11/5

Y1 - 2014/11/5

N2 - Understanding neurocognitive mechanisms supporting the use of multiple languages is a key question in language science. Recent neuroimaging studies in monolinguals indicated that core language areas in human neocortex together with sensorimotor structures form a highly interactive system underpinning native language comprehension. While the experience of a native speaker promotes the establishment of strong action-perception links in the comprehension network, this may not necessarily be the case for L2 where, as it has been argued, the most a typical L2 speaker may get is a link between an L2 wordform and its L1 translation equivalent. Therefore, we investigated, whether the motor cortex of bilingual subjects shows differential involvement in processing action semantics of native and non-native words. We used high-density EEG to dynamically measure changes in the cortical motor system's activity, indexed by event-related desynchronisation (ERD) of the mu-rhythm, in response to passively reading L1 (German) and L2 (English) action words. Analysis of motor-related EEG oscillations at the sensor level revealed an early (starting ~. 150. ms) and left-lateralised coupling between action and semantics during both L1 and L2 processing. Crucially, source-level activation in the motor areas showed that mu-rhythm ERD, while present for both languages, is significantly stronger for L1 words. This is the first neurophysiological evidence of rapid motor-cortex involvement during L2 action-semantic processing. Our results both strengthen embodied cognition evidence obtained previously in monolinguals and, at the same time, reveal important quantitative differences between L1 and L2 sensorimotor brain activity in language comprehension.

AB - Understanding neurocognitive mechanisms supporting the use of multiple languages is a key question in language science. Recent neuroimaging studies in monolinguals indicated that core language areas in human neocortex together with sensorimotor structures form a highly interactive system underpinning native language comprehension. While the experience of a native speaker promotes the establishment of strong action-perception links in the comprehension network, this may not necessarily be the case for L2 where, as it has been argued, the most a typical L2 speaker may get is a link between an L2 wordform and its L1 translation equivalent. Therefore, we investigated, whether the motor cortex of bilingual subjects shows differential involvement in processing action semantics of native and non-native words. We used high-density EEG to dynamically measure changes in the cortical motor system's activity, indexed by event-related desynchronisation (ERD) of the mu-rhythm, in response to passively reading L1 (German) and L2 (English) action words. Analysis of motor-related EEG oscillations at the sensor level revealed an early (starting ~. 150. ms) and left-lateralised coupling between action and semantics during both L1 and L2 processing. Crucially, source-level activation in the motor areas showed that mu-rhythm ERD, while present for both languages, is significantly stronger for L1 words. This is the first neurophysiological evidence of rapid motor-cortex involvement during L2 action-semantic processing. Our results both strengthen embodied cognition evidence obtained previously in monolinguals and, at the same time, reveal important quantitative differences between L1 and L2 sensorimotor brain activity in language comprehension.

KW - Electroencephalography (EEG)

KW - Embodied cognition

KW - Event-related desyncronisation (ERD)

KW - Lexical semantics

KW - Motor cortex

KW - Mu rhythm

KW - Second-language processing (L2)

UR - http://www.scopus.com/inward/record.url?scp=84907160933&partnerID=8YFLogxK

U2 - 10.1016/j.neuroimage.2014.08.039

DO - 10.1016/j.neuroimage.2014.08.039

M3 - Article

C2 - 25175538

AN - SCOPUS:84907160933

VL - 102

SP - 695

EP - 703

JO - NeuroImage

JF - NeuroImage

SN - 1053-8119

IS - P2

ER -