Comparison of Time–Frequency Responses and the Event-Related Potential to Auditory Speech Stimuli in Human Cortex


American Physiological Society


We recorded the electrocorticogram directly from the exposed cortical surface of awake neurosurgical patients during the presentation of auditory syllable stimuli. All patients were unanesthetized as part of a language-mapping procedure for subsequent left-hemisphere tumor resection. Time–frequency analyses showed significant high-gamma (γhigh: 70–160 Hz) responses from the left superior temporal gyrus, but no reliable response from the left inferior frontal gyrus. Alpha suppression (α: 7–14 Hz) and event-related potential responses exhibited a more widespread topography. Across electrodes, the α suppression from 200 to 450 ms correlated with the preceding (50–200 ms) γhigh increase. The results are discussed in terms of the different physiological origins of these electrocortical signals.

Documentos Relacionados