Parietal transcranial random noise stimulation improves long-term visual acquisition of foreign vocabulary

Official URL: http://www.perceptionweb.com/ecvp/ecvp14.pdf

The acquisition of a foreign language is a complex task and previous research investigated which learning method could yield the best results in terms of long-term acquisition. In particular, past studies stressed the importance of the testing phase for memory consolidation. There is evidence that a fronto-parietal circuitry is involved in language processing and comprehension, but it is still unknown which specific portion is crucial for foreign vocabulary acquisition, and this has never been directly assessed by using transcranial random noise stimulation, or tRNS. This type of neural stimulation enhances activity in the underlying cortex. In our study we tested the acquisition of visually presented Swahili vocabulary while three groups of participants were stimulated by tRNS over frontal or parietal lobes, plus a placebo condition. Vocabulary acquisition was tested both immediately and after seven days. We found that parietal, but not frontal, stimulation significantly improved the memory performance compared to the placebo condition both immediately and in the long-term. These results suggest that the parietal cortex is more directly involved in the consolidation of memory for foreign vocabulary than would have been previously expected.