Transcranial direct current stimulation (tDCS) is a non invasive, painless, harmless way to modulate cerebral cortex excitability. It was shown that anodal stimulation increases cortical excitability and the cathodal one decreases it (Nitsche and Paulus, 2000; Lang et al. 2004). To date, there is no data in the literature regarding the effect of tDCS on the corticodiaphragmatic pathways. This preliminary study aims to test and validate the modulating effect of tDCS on the excitability of the primary motor cortex dedicated to the hemi-diaphragms in a sample of healthy subjects, as a prelude to further large studies in patients with paretic hemi-diaphragms. Diaphragmatic motor evoked potentials will be assessed before and after applications of three different modalities of tDCS (anodal, cathodal and placebo).

We therefore expect to observe a significant increase of the mean values of the right hemidiaphragm's MEP's amplitudes after application of anodal tDCS compared to the baseline MEP obtained before this treatment.

Inclusion Criteria:

• Right handed,
• Healthy male volunteers
• Aged ≥ 18 and ≤ 35 years
• No history of neurological or respiratory disease
• BMI (body mass index < 30)

Exclusion Criteria:

• Female sex
• Vulnerable people as defined in the provisions relating to biomedical researches and described in the Code of Public Health.
• Recent or ongoing use of antibiotic drugs, antidepressants or psychotropic drugs.
• Recent hospitalization (within 3 months).
• No affiliation to a social security system.