Design: Three planned studies use a within-subject, repeated measures design. The MEG studies will be conducted before patients have subdural electrodes implanted for intracranial mapping. The MEG studies and connectivity analyses will be performed at NIH. The ECoG studies will take place at Johns Hopkins Hospital. Data will be acquired using the same auditory stimuli and tasks for both the MEG and ECoG parts of the study. The same functional connectivity analyses will be performed on the two data sets.