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


Hôpital le Vinatier






Procedure: Transcranial alternative current stimulation (tACS) at alpha frequency
Procedure: Sham stimulation

Study type


Funder types




Details and patient eligibility


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

Full description

The study will focus on the effect of tACS at alpha frequency (α-tACS), delivered on the dorsolateral prefrontal cortex, on the response to a stress factor. In this study, while receiving a single α-tACS session, the participants will complete a standardized stress test combining cognitive stress (mental calculation) and physical stress (cold pressure): the Maastricht Acute Stress Test. The main objective aims at assessing the effect of a single session of tACS at alpha frequency, delivered on the dorsolateral prefrontal cortex, on the cortisol reactivity in healthy stressed subjects. In that study, the influence of α-tACS on other biological ; electrophysiological, neuropsychological parameters relevant for the stress response will be assessed also.


40 estimated patients




18 to 45 years old


Accepts Healthy Volunteers

Inclusion criteria

  • Right-handed Men and Women aged between 18 and 45
  • If woman, hormonal contraception required
  • Having given their written informed consent
  • Affiliated with a social security scheme
  • French speakers and readers

Exclusion criteria

  • Contraindication to the exposure to exposure to tACS
  • Current psychiatric disorder as classified in the DSM-5
  • Regular intake of any psychotropic drug or Beta Blocker
  • Recent exposure to a traumatic event
  • Any debilitating condition making the experimental procedure not feasible
  • Pregnancy

Trial design

Primary purpose

Basic Science



Interventional model

Parallel Assignment


Triple Blind

40 participants in 2 patient groups, including a placebo group

Active tACS stimulation
Experimental group
Transcranial alternative current stimulation (tACS) at alpha frequency Single session of tACS : 30 minutes, 2mA, frequency = 10Hz, both electrodes located on the dorsolateral prefrontal cortex (left and right)
Procedure: Transcranial alternative current stimulation (tACS) at alpha frequency
Sham stimulation
Placebo Comparator group
Single session of tACS sham stimulation : both electrodes located on the dorsolateral prefrontal cortex (left and right) ; real current delivered for the first and last 30s of the total stimulation time (ramp-in and ramp-out)
Procedure: Sham stimulation

Trial contacts and locations



Data sourced from clinicaltrials.gov

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