PT  - JOURNAL ARTICLE
AU  - Ivan Alekseichuk
AU  - Miles Wischnewski
AU  - Alexander Opitz
TI  - A minimum effective dose for (transcranial) alternating current stimulation
AID  - 10.1101/2022.07.06.499054
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.07.06.499054
4099  - http://biorxiv.org/content/early/2022/08/09/2022.07.06.499054.short
4100  - http://biorxiv.org/content/early/2022/08/09/2022.07.06.499054.full
AB  - Transcranial alternating current stimulation (tACS) is a popular method for non-invasive neuromodulation in human research and therapy. However, what constitutes an effective dose in tACS applications is still a matter of investigation and debate. Here, we examined available literature data regarding the effects of alternating current (AC)-induced electric fields on cellular-level neural activity. The literature search identified 16 relevant experimental reports that utilized brain slices, anesthetized rodents, and awake/behaving animal models. We implemented a probabilistic meta-analysis to estimate the minimum effective dose (MED) required for inducing detectable significant neural changes with AC stimulation. The results showed that AC stimulation at 0.3 mV/mm in awake/behaving mammals leads to an 80% probability of inducing minimum neural effects. A similar level of effectiveness in brain slices and anesthetized mammals required 0.7 mV/mm. In conclusion, (transcranial) alternating current stimulation is significantly more effective in awake than in anesthetized brains. The proposed dose targets can serve as a practical guideline for tACS in humans.Competing Interest StatementThe authors have declared no competing interest.