HSE Scientists Test New Method to Investigate Mechanisms of New Word Acquisition
Researchers at the HSE Centre for Language and Brain were among the first to use transcranial alternating current stimulation to investigate whether it can influence the acquisition of new words. Although the authors of the experiment have not yet found a link between brain stimulation and word acquisition, they believe that adjusting the stimulation parameters may yield different results in the future. The study has been published in Language, Cognition and Neuroscience.
The ability to acquire and appropriately use new words is essential for effective human communication. Throughout life, people continue to learn new words in their native language and also master foreign languages. Acquiring new words is a complex cognitive process, and its underlying mechanisms remain poorly understood.
Modern neuroimaging techniques—such as electroencephalography, magnetic resonance imaging, and magnetoencephalography—allow researchers to look inside the brain and observe which regions are activated during specific cognitive processes. However, it remains impossible to determine whether the relationship between stimulation and brain processes is causal or merely coincidental. The use of alternating current in experiments changes the approach: it allows for modulating rhythms at specific frequencies and tracking their role in neural processes.
Researchers at the HSE Centre for Language and Brain were among the first to investigate whether weak electrical stimulation of the brain at the theta frequency can help memorise new words. The scientists recruited 30 healthy volunteers and asked them to learn 80 pseudowords paired with Russian nouns. During the training, participants received low-current brain stimulation at theta rhythm frequencies (3.5–7.5 Hz) over the left frontotemporal regions of the brain, which are associated with speech and memory. The theta frequency band was deliberately chosen, because previous studies have shown that theta rhythms play a key role in transferring information from short-term to long-term memory.
After participants learned the words with stimulation, the researchers tested their memory retention. There was also a separate phase of learning and testing without stimulation to compare participants’ performance.
No improvement was observed in new word acquisition with stimulation compared to the control condition. The authors note that learning new words activates complex neural networks involving both the cerebral cortex and the hippocampus, which is difficult to stimulate noninvasively from the surface of the head.
Anna Komissarenko
'Although our study did not find a direct effect of alternating current stimulation on word acquisition, we still made an important step toward developing new methods to support language learning. We will continue our research in this direction, but future experiments will focus on other brain regions and types of stimulation,' explains Anna Komissarenko, Junior Research Fellow at the HSE Centre for Language and Brain and lead author of the paper.
In the future, the team plans to test different frequency bands and phases of electrical stimulation, change electrode placement, and expand the experiments to explore various cognitive functions. This can help deepen our understanding of how the brain’s electrical activity influences learning and memory, potentially leading to the development of accelerated language learning techniques, rehabilitation programmes for stroke and injury patients, and optimised neurostimulation methods to enhance memory.
