A box of mirrors can trick your brain into unclenching a limb that isn't there

Amputees often feel their missing limb frozen in a painful position. Neuroscientist V. S. Ramachandran had patients place their remaining hand behind a mirror angled to create the visual illusion of the missing limb — and watching the reflection 'move' let many patients finally relax phantom pain that had lasted years.

— V. S. Ramachandran & Sandra Blakeslee, Phantoms in the Brain — William Morrow, 1998
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