Design of the mirror experiment.

<p>The photos show the four conditions of the 2 x 2 factorial design. The two conditions (A,B) with direct view on both forearms are shown in the top row. The two mirror conditions (bottom row) in which the participant visually perceives the non-itching (left) forearm in place of the itching (right) forearm (C) and in which the subject’s view on the scratching of the itching (right) forearm is prevented by the mirror (D). The injection site is masked by red color patches at homologue skin sites on both forearms to prevent visual identification of the itching forearm. The lightning symbol indicates the itching (right) forearm. S-: scratching at the non-itching (left) forearm; S+: scratching at the itching (right) forearm; V-: visual percept that the non-itching (left) forearm is being scratched; V+: visual percept that the itching (right) forearm is being scratched.