Can low-intensity tACS genuinely entrain neural activity in vivo?

Transcranial alternating current stimulation (tACS) was introduced about a decade ago as a non-invasive brain stimulation method to modulate neural oscillations in a relatively safe manner in humans. However, the possibility to induce genuine neural entrainment with low current intensities has been questioned. In a recent study, Johnson and colleagues provide direct evidence for the efficacy of low-intensity tACS to induce neural entrainment in awake monkeys. These findings have important translational implications for human non-invasive neuromodulation research.