The researchers will explore how the brain areas and mechanisms of brain plasticity are involved in the generation of thalamic CPSP, compared to other pain disorders, using structural and functional magnetic resonance imaging (MRI) at 3 Tesla. The functional magnetic resonance imaging (fMRI) will be also used to assess the cerebral processing of heat/cold stimuli in patients with thalamic pain compared to thalamic stroke patients without pain, to patients with migraine (other central pain disorder) and to normal controls. In addition the researchers want to assess the somatosensory profile of thalamic pain patients and compare it with thalamic stroke patients without pain, patients with migraine (pain control) and normal controls.