Dose‐dependent response of prefrontal transcranial direct current stimulation on the heart rate variability: An electric field modeling study

• Published in: Psychophysiology 2024-07, Vol.61 (7), p.e14556-n/a
• Main Authors: Razza, Laís B., De Smet, Stefanie, Cornelis, Xander, Nikolin, Stevan, Pulopulos, Matias M., De Raedt, Rudi, Brunoni, Andre R., Vanderhasselt, Marie‐Anne
• Format: Article
• Language: English
• Subjects: Amygdala; Autonomic nervous system; Brain; Cortex (cingulate); dose‐dependency; electric field; Electric fields; Electrical stimulation of the brain; ESB; Heart rate; heart rate variability; Nervous system; Prefrontal cortex; transcranial direct current stimulation
• ISSN: 0048-5772; 1469-8986; 1469-8986; 1540-5958
• DOI: 10.1111/psyp.14556

Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) modulates the autonomic nervous system by activating deeper brain areas via top‐down pathway. However, effects on the nervous system are heterogeneous and may depend on the amount of current that penetrates. Therefore, we aimed to investigate the variable effects of tDCS on heart rate variability (HRV), a measure of the functional state of the autonomic nervous system. Using three prefrontal tDCS protocols (1.5, 3 mA and sham), we associated the simulated individual electric field (E‐field) magnitude in brain regions of interest with the HRV effects. This was a randomized, double‐blinded, sham‐controlled and within‐subject trial, in which healthy young‐adult participants received tDCS sessions separated by 2 weeks. The brain regions of interest were the dorsolateral PFC (DLPFC), anterior cingulate cortex, insula and amygdala. Overall, 37 participants were investigated, corresponding to a total of 111 tDCS sessions. The findings suggested that HRV, measured by root mean squared of successive differences (RMSSD) and high‐frequency HRV (HF‐HRV), were significantly increased by the 3.0 mA tDCS when compared to sham and 1.5 mA. No difference was found between sham and 1.5 mA. E‐field analysis showed that all brain regions of interest were associated with the HRV outcomes. However, this significance was associated with the protocol intensity, rather than inter‐individual brain structural variability. To conclude, our results suggest a dose‐dependent effect of tDCS for HRV. Therefore, further research is warranted to investigate the optimal current dose to modulate HRV. By dissecting the effects of different tDCS protocols on HRV and linking them to individual brain anatomy, we have uncovered a dose‐dependent relationship between tDCS dose and HRV modulation. These findings underscore the importance of optimizing tDCS for HRV modulation, advancing our understanding of neurostimulation's potential in autonomic nervous system regulation.