Figure 4. Correlation between LF/HF differences during tVNS and NWR thresholds.
A significant negative correlation was found between LF/HF changes during tVNS and the NWR threshold change at Post 10 and Post 30, indicating that subjects whose LF/HF significantly decreased during tVNS, that is, those whose parasympathetic activity increased during tVNS stimulation, tended to have larger increases in NWR threshold at Post 10 and Post 30. No such correlation was observed at Post 0 (p > 0.05).