Pairing tVNS with feedback after correct responses does not enhance speech category learning, suggesting the enhancement is not driven by a reward signal¶

Claim · All claims
Evidence · 1 study · causal r2 · q3
Currency · newest study 2020 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q3 i? In a supplementary condition synchronizing tVNS with correct-response feedback, the trial-by-group interaction was not significant, unlike the tVNS-easy condition. → Llanos 2020

Evidence¶

Llanos 2020¶

Llanos, F., McHaney, J. R., Schuerman, W. L., Yi, H. G., Leonard, M. K. and Chandrasekaran, B. (2020). Non-invasive peripheral nerve stimulation selectively enhances speech category learning in adults. npj Science of Learning. https://doi.org/10.1038/s41539-020-0070-0

q3 · i? · causal · r2

Supplementary experimental condition (tVNS-feedback) in a shorter version of the training task, compared against tVNS-easy and Control via logit mixed-effects modeling. The tVNS-feedback interaction was non-significant (p = 0.55) while tVNS-easy was significant (β = 0.006, z = 2.8, p < 0.005).

"In contrast, the interaction of trial-by-group for the tVNS-feedback group was not significant (β = 0.001, z = 0.59, p = 0.55). These results indicate that pairing stimulation with positive feedback (i.e., feedback following correct responses) did not enhance learning."

Discussion¶

Related Claims¶

• Brief tVNS paired with speech training produces no measurable change in the sensory representation of non-native pitch as indexed by frequency-following responses — related
• Sub-perceptual-threshold tVNS evokes brainstem vagal potentials consistent with peripheral nerve engagement, and the pulse-evoked response follows an inverted-U function of stimulation intensity — related
• Pairing sub-perceptual tVNS with easier-to-learn Mandarin tone categories improves trial-by-trial speech category learning faster than training alone, and the enhancement is specific to the stimulated categories — related
• The tVNS-easy group's performance falls outside the normal range of individual learning variability observed across 678 comparable unstimulated learners — related
• tVNS paired with easier-to-learn categories increases retention of correct stimulus-response associations between training blocks — related
• tVNS-enhanced speech category learning generalizes to new talkers' exemplars without accompanying stimulation or feedback — related
• Feedback-stage reward prediction errors, signed or unsigned, do not modulate memory in either learning condition — related