Inhibition Transcranial Random Noise Stimulation

Overview

Inhibition control deficits is a major risk factor in the transition to the act in suicidal patients. Neuroimaging studies have shown that this failure was associated with hypoactivity in the prefrontal cortex (PFC), a brain area involved in the control of impulsivity. It was recently shown that a noninvasive brain stimulation session applied on the PFC reduces transiently impulsivity in healthy volunteers. Noninvasive brain stimulation modulates the activity and connectivity of neural network connected to the stimulation site. The investigators assume that a repetition of noninvasive brain stimulation sessions on the PFC will allow a more intense and longer lasting effect on impulsivity and cognitive control in healthy volunteers compared to a single session and to placebo stimulation. The investigators assume that this behavioral change will be accompanied by a change in brain activity measured by resting EEG for the patients in the active group. A more intense and longer lasting effect is an essential step to transfer these results to patient populations. The main objective is to study the effect of bilateral stimulation of the PFC by transcranial random noise stimulation (tRNS) on the inhibition control measured by the cognitive motor inhibition capacity (Go NoGo test). The secondary objectives are to study the effect of tRNS on verbal inhibition (measured with the Hayling test); on anxiety (measured with the State-trait anxiety inventory (STAI)),on angry (measured with the State-trait anger expression inventory (STAXI)) on verbal and nonverbal inhibition (measured by the Stroop test), on impulsive behavior (measured by the Barrat impulsiveness scale (BIS 10)) and on the neuronal electrical activity measured by EEG.

Subjects are stimulated 3 times in a day. Each 20 minutes stimulation are separated by a period of at least 30 minutes. Before and after each stimulation, inhibition is evaluated by cognitive tests (Go Nogo test, Stroop test, Hayling test) and by the BIS 10 scale. During the stimulation, subjects compleat the STAXI and STAI scales. Cognitive tests are repeated 24 hours and 8 days after the stimulation to evaluate duration of the effect. Possible side effects will be notified throughout the protocol.