Fig. 10.
A schematic diagram of the mean onset and offset times of gamma activity relative to the task events. During the presentation of the tones and words, the onset of gamma activation was close to the onset of the stimulus, but lasted longer than the auditory event. When the patient repeated the word, the onset of gamma activation from electrodes over the temporal lob was similar to hearing the tone and word. Over the frontal lobe the onset of gamma activation associated with repeating the words started before voice-onset time, suggesting preparation to speak.