Motor Cortex Causally Contributes to Vocabulary Translation following Sensorimotor-Enriched Training

Abstract

The role of the motor cortex in perceptual and cognitive functions is highly controversial. Here, we investigated the hypothesis that the motor cortex can be instrumental for translating foreign language vocabulary. Human participants of both sexes were trained on foreign language (L2) words and their native language translations over 4 consecutive days. L2 words were accompanied by complementary gestures (sensorimotor enrichment) or pictures (sensory enrichment). Following training, participants translated the auditorily presented L2 words that they had learned. During translation, repetitive transcranial magnetic stimulation was applied bilaterally to a site within the primary motor cortex (Brodmann area 4) located in the vicinity of the arm functional compartment. Responses within the stimulated motor region have previously been found to correlate with behavioral benefits of sensorimotor-enriched L2 vocabulary learning. Compared to sham stimulation, effective perturbation by repetitive transcranial magnetic stimulation slowed down the translation of sensorimotor-enriched L2 words, but not sensory-enriched L2 words. This finding suggests that sensorimotor-enriched training induced changes in L2 representations within the motor cortex, which in turn facilitated the translation of L2 words. The motor cortex may play a causal role in precipitating sensorimotor-based learning benefits, and may directly aid in remembering the native language translations of foreign language words following sensorimotor-enriched training. These findings support multisensory theories of learning while challenging reactivation-based theories.

A Bibliometric and Visualization Analysis of Motor Learning in Preschoolers and Children over the Last 15 Years

“…It not only improves children’s motor-learning abilities, performance, and tolerance, but it also aids in the rehabilitation of children with cerebral palsy and developmental delay [ 41 ]. Furthermore, based on the evidence, TMS has potential benefits for fine-motor-skills rehabilitation in CP [ 42 ], induces foreign language learning within the primary motor cortex, and has behavioral benefits [ 43 ]. Overall, VR, tDCS, and TMS have the potential to be promising technological tools for children with motor deficits, even though the underlying brain mechanisms are largely unknown.…”

Motor imagery training to improve language processing: What are the arguments?

“…This study suggested that the motor system could be involved in action-verb encoding and representation. More recently, Mathias et al (2021) employed another neuromodulation protocol: offline, inhibitory continuous theta burst stimulation (cTBS) combined with repetitive TMS (rTMS). The experiment involved sensorimotor-enriched training for foreign-language learning.…”

Production benefits on encoding are modulated by language experience: Less experience may help

“…The mechanisms underlying these learning effects are not yet well understood. One candidate mechanism may be motor-to-sensory predictions: performing movements is thought to elicit predictions of resulting sensory feedback (Mathias et al, 2021 ; Miall & Wolpert, 1996 ). Because accurate prediction depends on prior learning (Bar, 2007 ; Bubic et al, 2010 ), the benefit of movement on encoding may also depend on experience.…”

“…One such robust phenomenon in the language domain, known as the production effect , occurs when participants first study lists of words by speaking them out loud or silently reading (or hearing) them, and subsequently show increased recognition accuracy for the spoken words compared to the silently studied words (Forrin et al, 2012 ; MacLeod et al, 2010 ; Mama & Icht, 2016 ; Murray, 1965 ; Ozubko et al, 2012 ). Notably, other types of production (i.e., movement) such as writing, typing, whispering, and gesturing, also appear to benefit word recognition compared to perceptual learning conditions involving either reading or hearing words (Forrin et al, 2012 ; Mama & Icht, 2016 ; Mathias et al, 2021 ). Movement has also been associated with memory enhancements in other contexts, involving different types of movements when learning different types of items.…”

“…The question remains: by what mechanisms could movement improve memory? Applying frameworks for action (movement) – perception coupling – one can assume that performing a movement should activate the corresponding percept that normally results from that movement, via motor-to-sensory predictions (Mathias et al, 2021 ; Miall & Wolpert, 1996 ). Reciprocal action-perception associations should additionally allow percepts, such as words or objects, to activate corresponding motor associations (Hommel, 2009 ; Koch et al, 2004 ; Pfister, 2019 ; Shin et al, 2010 ).…”