LANGUAGE-RELATED FIELD POTENTIALS IN THE ANTERIOR-MEDIAL TEMPORAL-LOBE .1. INTRACRANIAL DISTRIBUTION AND NEURAL GENERATORS

Field potentials were recorded from intracranial electrodes in humans to study language-related processing. Subjects viewed sentences in whi ch each word was presented successively in the center of a video monit or. Half of the sentences ended normally, while the other half ended w ith a semantically anomalous word. The anomalous sentence-ending words elicited a large negative field potential with a peak latency near 40 0 msec, which was focally distributed bilaterally in the anterior medi al temporal robe (AMTL), anterior to the hippocampus and near the amyg dala. Subdural electrodes positioned near the collateral sulcus just i nferior and lateral to the amygdala recorded a positive field potentia l at the same latency. This spatial distribution of voltage suggested that this language-sensitive field potential was generated in the neoc ortex near the collateral sulcus and anterior fusiform gyrus. Addition al task-related field potentials were recorded in the hippocampus. The AMTL field potential at 400 msec shares characteristics with the N400 potential recorded from scalp electrodes that has been associated wit h semantic processing.