Figure 4 .

Intraoperative technical illustration: (A) transsulcal approach; (B) subdural strip of electrodes placed under preoperative nTMS and DTI guidance with stable responses at 7 mA; (C) docking of the BrainPath tubular retractor with positive responses of the anterior tibialis at 17 mA during the cannulation of the brain, insertion stopped at this point; (D) stimulation through the tube identified motor responses at 17 mA from lower limb muscles (tibialis anterior and abductor hallucis); (E) direct subcortical stimulation identified motor responses from upper and lower limb muscles at 7 mA; (F and G) Tumour subtotal resection stopped at 5 mA for the upper limb and 7 mA for the whole CST. The tumour demonstrated 5-ALA-induced fluorescence under the BLUE 400 filter; (H) activity from hand muscles at 5 mA threshold during removal of BrainPath tubular retractor before closure.