Figure 6.

a, Intraoperative image of a high-density 4 mm electrode grid. b, High-frequency oscillatory responses are shown for two adjacent electrodes during a 2 s epoch (raw traces filtered at 70–150 Hz). Electrode A responds selectively to external stimuli (speaker plotted in red), while electrode B responds predominantly to self-produced speech (microphone plotted in blue). c, Averaged event-related power changes locked to hearing (red) and speaking (blue) stimuli in the two adjacent electrodes.