Effect of Transcranial Alternative Current Stimulation at Alpha Frequency (α-tACS) on Stressed Healthy Subjects

stress. Notably, several studies reported that stress could alter impulsivity, source monitoring, and time perception. Several mechanisms are involved in the response to a stress factor, among them the hypothalamic-pituitary-adrenal (HPA) axis. The cortisol reactivity (it means the cortisol secretion after the exposure to a standardized stress factor) is a reliable tool to assess the function of HPA. Cortisol secretion is bidirectionally influenced by the prefrontal cortex (PFC), which is involved in the expression and regulation of stress as well. The asymmetry of the alpha band (AFα) is a well known electrophysiological parameter to assess the function of PFC. More precisely, AFα is arising a growing interest, as it is believed to be correlated with the cortisol reactivity. Modifying this asymmetry could influence the stress response. Transcranial Alternating Current Stimulation (tACS) consists in delivering a sinusoidal alternating current between two electrodes placed on the scalp at a predefined frequency. Previous studious reported that tACS, if delivered at the alpha frequency, increased the alpha band in the stimulated areas