The main hypothesis of this study is that the alteration of the reward circuitry underlying the motivational deficit in chronic pain patients compared to healthy subjects results in a decrease in the capacity for reward learning. The fMRI studies have shown that this type of learning depends on the dopaminergic system innervating key regions of the reward system.

Inclusion Criteria:

• For cases: patients managed in the neurosurgery department or at CETD for chronic neuropathic pain, of central or peripheral origin.
• For controls: matched to a case on age (±5 years) and sex

Exclusion Criteria:

• Neurodegenerative or inflammatory neurological pathology
• Clinical depressive syndrome
• High doses of opioid treatment (greater than 100 mg/day of morphine equivalent)
• Impaired judgment or inability to receive information that does not allow the performance of behavioral tasks
• Absolute contraindication to MRI (e.g. pacemaker, implantable pacemaker, metallic intra-orbital foreign body)

The study will be proposed to patients followed at the pain treatment center or in neurosurgery for chronic neuropathic pain, of peripheral or central origin.

Controls will be recruited among the patients' companions and the staff of the Adolphe de Rothschild Foundation Hospital.