FIGURE 3.

TOJ experimental setup. A pair of somatosensory stimuli were delivered non-invasively (orange) through mechanical tappers, and only in the POST_I session to the left severed limb invasively (blue) through intraneural electrodes. Stimuli were delivered, one to each limb, with a stimulus onset asynchronies (SOA) randomly assigned from 15 to 200 ms. The participant had to discern in which limb the first stimulus was delivered. The task was performed either with uncrossed and with the crossed arms. The solid lines are the probability to feel the right limb stimulated first depending on the SOA, fitted with a sigmoid function, when the task was performed by a healthy subject control group with the arms uncrossed (black) and crossed (gray). The point of subjective simultaneity (PSS) is the SOA where both limbs have the same probability to be perceived as firstly stimulated. The decrease of the slope of the curve from uncrossed to the crossed condition represents the worsening of esteem accuracy typical of the arm crossing effect. The esteem accuracy (EA) is computed through the SOA corresponding to half of the inverse of its derivate for PSS (black and gray segments for uncrossed and crossed hands, respectively); thus, the shorter the EA value is, the higher the accuracy is.