Cortical representation of the digits and the lower lip before and after brachial plexus blockade in a unilateral upper extremity amputee with phantom limb pain who experienced complete pain relief attributable to the regional anesthesia. The location of the representation of the fifth digit (D5) of the intact hand before anesthesia is indicated by the red filled square, and the locations of the representations of the lip of the intact side and of the amputated side by the green filled squares (pre anesth. lip). The mirror images of the intact digit and the intact lip projected onto the amputation-side hemisphere are marked by open squares of the same colors. These locations refer to the period before anesthesia. The location of the representation of the amputation-side lip after anesthesia (post anesth. lip) is indicated by the yellow filled square. The central sulci on both sides are marked in blue. Note that before brachial plexus blockade, the lip on the amputated side (green square) had shifted into the region occupied by the representation of the fingers on the intact side (mirror D5). Twenty minutes after amputation stump anesthesia, the phantom pain was almost eliminated; at the same time there was a dramatic shift of the amputation-side lip back toward the position occupied by the lip representation on the intact side (mirror lip, open green square). The white dots are the vitamin E capsules marking the electrode positions.