Scientists discover brain hack that improves language abilities by 13% - transcuteanous vagus nerve stimulation

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Article: https://www.inverse.com/innovation/neural-stimulation-language-device
Paper: https://www.nature.com/articles/s41539-020-0070-0#Sec10

Non-invasive peripheral nerve stimulation selectively enhances speech category learning in adults

Abstract
Adults struggle to learn non-native speech contrasts even after years of exposure. While laboratory-based training approaches yield learning, the optimal training conditions for maximizing speech learning in adulthood are currently unknown. Vagus nerve stimulation has been shown to prime adult sensory-perceptual systems towards plasticity in animal models. Precise temporal pairing with auditory stimuli can enhance auditory cortical representations with a high degree of specificity. Here, we examined whether sub-perceptual threshold transcutaneous vagus nerve stimulation (tVNS), paired with non-native speech sounds, enhances speech category learning in adults. Twenty-four native English-speakers were trained to identify non-native Mandarin tone categories. Across two groups, tVNS was paired with the tone categories that were easier- or harder-to-learn. A control group received no stimulation but followed an identical thresholding procedure as the intervention groups. We found that tVNS robustly enhanced speech category learning and retention of correct stimulus-response associations, but only when stimulation was paired with the easier-to-learn categories. This effect emerged rapidly, generalized to new exemplars, and was qualitatively different from the normal individual variability observed in hundreds of learners who have performed in the same task without stimulation. Electroencephalography recorded before and after training indicated no evidence of tVNS-induced changes in the sensory representation of auditory stimuli. These results suggest that paired-tVNS induces a temporally precise neuromodulatory signal that selectively enhances the perception and memory consolidation of perceptually salient categories.

 

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Interesting how they applied tVNS, specifically the TEMS electrodes to the subject's ears.

To stimulate the vagus nerve non-invasively, we targeted the cymba concha and cymba cavum of the outer ear, which have been shown to be innervated by the auricular branch of the vagus nerve49. We delivered current transcutaneously to these sites at amplitudes below each participant’s perceptual threshold. Sub-threshold stimulation avoids evoking somatosensory responses that alert participants to the timing of stimulation. Furthermore, animal models suggest that low-to-mid amplitude stimulation levels are more effective modulators of neural plasticity51.

The participant’s left ear was first cleaned with alcohol and abrasive gel using a cotton swab. Silicon putty was then molded to the shape of the participant’s ear. Two Ag-AgCl disc electrodes (4 mm diameter) were embedded in the putty at areas corresponding to the cymba concha (cathode) and cymba cavum (anode) and covered with a salt-free conductive gel. The mold was reinserted into the ear and pressed into place.

Instead of using specialized disc electrodes, at home you could poke the ends of the TEMS's connectors through the putty to the ear.