Figure 7.

Decoding accuracy and the location of the hybrid electrode. Each circle represents the center of each hybrid electrode, which was automatically overlaid on the Montreal Neurological Institute normalized brain (Electrodes on the right hemisphere was inverted and overlaid onto the left hemisphere). The color map indicates the decoding accuracy averaged across five vowels for the optimal feature combination. The population map revealed that the highest performance was achieved when the electrode center was at the MNI coordinate of [X, Y, Z] = [−59, 5, 13] (left hemisphere of Subject 3), which is compatible with the lip/tongue area proposed by previous studies using electrical stimulation.