The implication of the second somatosensory area (SII) and the insular cortex in the processing of somatosensory inputs is now well established. However the functional anatomy of these areas hidden in the depth of the sylvian scissure remain mostly unknown.

The aim of this fMRI study is to determine the functional cartography of SII and insula. The localization of responses to different somatosensory stimuli (slight touch, warm, cold, heat pain and arthrokinesia) applied on the left hand of 25 healthy volunteers, will be compared.

Aims : Demonstrate that localization of the several types of somatosensory stimuli is different into SII and into insula. If possible, we'll determine a functional cartography of these areas.

Inclusion Criteria:

• 25 healthy volunteers will be included ranging in age from 18 to 50 years
• contraception needed for women
• right handed
• All the subjects have to give their written informed consent.

Exclusion Criteria:

• pregnancy
• neurological or psychiatric disease
• drugs taken <12h before fMRI
• contra-indications to fMRI : pacemaker, clip, metallic device
• Refusing to be informed of the presence of a cerebral abnormality, detected during MRI.