Inclusion Criteria:  Man or woman, aged 18 to 60 years old Right-handed Give an informed consent by signature Be part of the national health security system (registered to the Securité Sociale) do not confuse his right and his left  Specific of the non-sighted participants:  Loss of vision happened at birth or 3-to 5 years later in life Must have a visual acuity inferior or equal to 4/10 Be with a close relation for read information letter and sign the consent form if needed  Exclusion Criteria:  A person presenting an history of neurological, psychiatric or linguistic problems cannot be admitted Assumption of psychotropic drugs Pregnancy or breast-feeding woman A person under legal tutoring A person under care in other medical structure for reasons different from those of this research A person under administrative or judiciary contention  A person who is not eligible to a MRI-exam according to the following criteria cannot be admitted to the experiments including MR acquisitions :  Have a neurological, cardiac (battery) or defibrillator pacemaker Have a cardiac prosthesis (valve, stent...) or vascular prosthesis Have intracranial clips or clamps Carry a bypass of the cerebrospinal fluid Having metallic splinters in the eyes Wear metal prostheses (teeth, knees) Wear an infusion pump or system Be claustrophobic or have respiratory problems Have metal tattoos close to the head Have permanent make-up