Different brain areas activated during imagery of painful and non-painful 'finger movements' in a subject with an amputated arm

The purpose of the present study was to investigate differences in brain ac tivation with functional magnetic resonance imaging (fMRI) during imagery o f painful and non-painful 'finger movements' and 'hand positioning' in a su bject with an amputated arm. The subject was a right-handed man in his mid- thirties who lost his right arm just above the elbow in a car-train acciden t. MRI was performed with a 1.5 T Siemens Vision Plus scanner. The basic de sign involved four conditions: imagining 'painful finger movements', 'non-p ainful finger movements', 'painful hand positioning', 'non-painful hand pos itioning'. Imagery of finger movements uniquely activated the contralateral primary motor cortex which contains the classic 'hand area'. The lateral p art of the anterior cerebellar lobe was also activated during imagery of fi nger movements. Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior later al nucleus of the thalamus. It is suggested that the insula and thalamus ma y involve neuronal pathways that are critical for mental processing of pain -related experiences, which may relate to a better understanding of the neu robiology of phantom limb pain.