Understanding a brain area involved in starting movement

Inclusion criteria for patients who will be operated 1. Diagnosis of idiopathic Parkinson's disease (according to the criteria of the United Kingdom Parkinson's Disease Society Brain Bank) 2. Age between 18 and 70; 3. Motor complications in the form of fluctuations in motor state or dyskinesias induced by dopaminergic therapy, despite medical treatment optimum; 4. Other medical conditions that are stable or do not interfere with the procedure proposed; 5. Excellent responsiveness to levodopa (UPDRS motor score improvement greater than 50% in the acute levodopa test) 6. Brain MRI without abnormality 7. Normality of biological examinations 8. Person who has voluntarily and informedly agreed to participate in the study (signature of a written consent) 9. Patient with social health insurance Criteria for non-inclusion of Parkinsonian patients who will be operated 1. Contraindication to examinations necessary for inclusion 2. Evolutionary psychiatric pathology; 3. Dementia(MMS\<24/30); 4. Patients with a medical condition that makes surgery dangerous neuro-surgical; 5. Bleeding-promoting diseases and laboratory test abnormalities clotting; 6. Existence of contraindications to MRI (cardiac or neural pacemaker, clips ferromagnetic surgeries, implants and metal objects, foreign bodies intraocular, pregnancy, claustrophobia). 7. Taking drugs interfering with coagulation for 1 month before intervention. 8. Persons under guardianship, curatorship or any other administrative or judicial measure deprivation of rights and liberty Selection criteria for non-operated patients 1. Diagnosis of idiopathic Parkinson's disease (according to the criteria of the United Kingdom Parkinson's Disease Society Brain Bank); 2. Age between 18 and 70; 3. Other medical conditions that are stable or do not interfere with the proposed protocol; 4. Presence of axial signs (gait and/or balance disorders) no improved by antiparkinsonian treatment 5. Brain MRI without notable abnormality 6. Normality of biological examinations 7. Person who has voluntarily and informedly agreed to participate in the study (signature of a written consent) 8. Patient with social health insurance Criteria for non-inclusion of non-operated patients 1. Contraindication to examinations necessary for inclusion 2. Progressive psychiatric pathology; 3. Dementia (MMS\<24/30); 4. Existence of contraindications to MRI (cardiac or neural pacemaker, clips ferromagnetic surgeries, implants and metal objects, foreign bodies intraocular, pregnancy, claustrophobia). 5. Persons under guardianship, curatorship or any other administrative or judicial measuredeprivation of rights and liberty Inclusion criteria for group 3 patients (already operated) 1. Diagnosis of idiopathic Parkinson's disease (according to the criteria of the United Kingdom Parkinson's Disease Society Brain Bank); 2. Bilateral deep brain stimulation of the subthalamic nucleus for more than 1 year 3. Age between 18 and 70; 4. Person who has voluntarily and informedly agreed to participate in the study (signature of a written consent) 5. Patient with social health insurance Criteria for non-inclusion of Parkinsonian patients (already operated) 1. Contraindication to examinations necessary for inclusion 2. Evolutionary psychiatric pathology; 3. Dementia(MMS\<24/30); 4. Persons under guardianship, curatorship or any other administrative or judicial measure deprivation of rights and liberty Inclusion criteria for healthy subjects 1. Age between 18 and 70 years old 2. Normal neurological examination 3. Person who voluntarily and informedly agreed to participate in the study (signature of a written consent) 4. Patient with social health insurance Criteria for non-inclusion of healthy subjects 1. Persons under guardianship, curatorship or any other administrative or judicial measure of deprivation of rights and freedom 2. Existence of neurological, orthopedic or psychiatric history 3. Existence of contraindications to MRI (cardiac or neural pacemaker, ferromagnetic surgical clips, implants and metallic objects, foreign bodies intraocular, pregnancy, claustrophobia).