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.