Prevalence of neuropathic pain raise to 6.9 % in the general population and can reach more than 58 % for patients that carry a lesion of the spinal cord. This pathological condition stays a major health problem, particularly as the efficacity of available treatments is currently limited. Only 30 to 40% of patients are relieved of more than 50% of their pain by a pharmacological approach.

In case of failure, drug treatments or in addition of these ones, stimulation of the motor cortex is a therapeutic path proposed by Tsubokawa since the beginning of 1990s, but that found its place for neuropathic drug-resistant pain management only since a decade. Neurophysiologic mechanisms of the analgesic efficacity of the motor cortex stimulation are still little understood. This stimulation can be realised in a chronic and invasive way with implanted electrodes. This process allow a lasting relief for about half of operated persons, without the possibility to identify clinical selection criterion reliable for potentially responding patients for this technique.

Recently, two electrophysiological non invasive techniques have been developed, allowing to get an analgesic stimulation of the motor cortex: the repetitive transcranial magnetic stimulation (rTMS) and the direct current transcranial magnetic stimulation (tDCS).

The main goal of this study is to compare the importance of analgesic effect of tDCS in chronic drug-resistant neurophysiologic pains to the one get thanks to a reference method of stimulation non invasive of the motor cortex, the rTMS whose analgesic effect is already validated by data of the literature.

Inclusion Criteria:

• Persons affiliated to national social security.
• Patients that have given their signed free consent.
• Patients from 18 to 80 years, men or women, carriers of a chronic neuropathic pain (since more than a year ; EVN > 2during week S0) drug resistant, unilateral, involving at least the superior member and/or hemi-face, whose analgesic treatment is stable from at least one month.
• Patients whose drug resistance conduce their referent Algologist (specialist in pain medicine) to study the possibility to propose them alternative therapeutic solutions nonpharmacological and to start a pre-surgical examination.

Exclusion Criteria:

• History of drug addiction, migraine, epilepsy.
• Presence of ferromagnetic intracranial equipment or a stimulating implanted (pace-maker, stimulation of basal ganglia, vagus nerve stimulator).
• Introduction of a new analgesic treatment since at least a month.
• Pregnant, parturient or breastfeeding women. The absence of effective contraception during all the study for patients of childbearing age.
• Persons deprived of liberty by judicial or administrative decision, person under legal protection.
• Counter-argument to MRI.