The Specific Influence of Continuous Theta-Burst Stimulation of the Primary Motor Cortex on Novel Vocabulary Acquisition in Different Learning Environments

Human Physiology. 2023. Vol. 49. No. 3. P. 289–297.

Perikova E. I., Blinova E. N., Andriushchenko E. A., Blagoveshchensky E., Sherbakova O., Shtyrov Y.

Translator: А. Дерябина

The primary motor cortex takes part in various stages of language learning accompanied by human
motor activity. However, previous studies of causal relationships between the activation of the primary motor
cortex (M1) and the efficiency of language tasks reveal contradictory results, likely due to different learning
environments and specific movement patterns required by different experimental designs. The goal of this
research was to comprehensively investigate the effect of rhythmic theta-burst magnetic stimulation (rTMS)
of the primary motor cortex on the acquisition of new words while modulating the learning environment and
the motor response during the learning process. Following rTMS of the primary motor cortex or control conditions
(sham and active control rTMS), the subjects (n = 96) completed a novel word learning task, which
involved associating visually presented objects with spoken word forms using a virtual reality (VR) or conventional
computer monitor environment. In each environment, the subjects were exposed to eight novel words
embedded into questions about visual stimulus properties to prompt novel associations. Responses to these
questions could be performed either by distal or by proximal hand movements. The outcome of the word
acquisition was measured using a free recall task immediately after the training and on the next day. The
results showed significant differences in the success of recalling new words immediately after the learning session
and on the next day only in those subjects who received rTMS of the primary motor cortex; furthermore,
this effect was specific to proximal movements in both learning environments. The results suggest that the
motor cortex is directly involved in acquiring novel vocabulary during active interaction with the learning
material.

Keywords: language acquisition, motor cortex, word learning, virtual reality, embodiment cognition, rhythmic theta-burst magnetic stimulation