(a) Spatial layout of all 256 electrodes. The three sections outlined by the dashed lines, were designed for the medial wall (26 electrodes), the lateral surface (212 electrodes), and the supratemporal plane of the lateral sulcus (18 electrodes, STP array), respectively. A pair of electrodes designed for bipolar recording is magnified in the inset. The electrode diameter was 0.8 mm and the distance between the electrodes in the pair was 1.8 mm. The electrodes at the bottom of the lateral-surface section were designed for the ventrolateral surface, and the electrodes at the bottom of the medial-wall section were designed for the dorsolateral surface (See Fig. 6). (b) The four compartments (#1–4) of the array are each connected to a separate connector. Each compartment contains 56–70 electrodes.