Abstract
We engineered a transdermal neuromodulation approach that targets peripheral (cranial and spinal) nerves and utilizes their afferent pathways as signaling conduits to influence brain function. We then investigated the effects of this transdermal electrical neurosignaling (TEN) method on sympathetic physiology in response to acute stress induced by classical fear conditioning and a series of time-pressured cognitive tasks. The TEN approach involved delivering high-frequency, pulse-modulated electrical currents to the ophthalmic and maxillary divisions of the right trigeminal nerve and cervical spinal nerve afferents (C2/C3). Compared to active sham stimulation of the same anatomical targets, TEN treatment significantly suppressed sympathetic activity in response to acute stress without impeding cognitive performance. This sympatholytic action of TEN was indicated by significant suppression of heart rate variability changes, galvanic skin responses, and salivary α-amylase levels in response to experimentally induced stress. Our observations are consistent with the hypothesis that TEN acts partially by modulating afferent activity in the locus coeruleus and subsequent noradrenergic signaling. Dampening sympathetic tone using TEN in such a manner represents a promising approach to managing daily stress and improving brain health.
