Fig. 1.

Data from patient with intractable facial pain (black) and patient with epilepsy (gray). Data from patients with intractable facial pain and no history of seizures serve as control recordings for quantitative comparison with epileptic cortex. A: sample signals from 2 electrodes of the control brain recording. B: the correlation magnitudes (solid lines) and mean phase coherence (dashed lines) of the signal pairs in A and C. Both the correlation and mean phase coherence (MPC) show significant temporal variability over the course of 60 s with values primarily ranging from 0.2 to 0.7. C: sample signals from 2 electrodes in epileptic cortex inside the seizure onset zone. D: a sample layout of the bipolar reference pair measurement. The distance d between 1 corresponding pair of electrodes 1 and 3 is equal to the distance between the other pair, electrodes 2 and 3, and this is the distance referenced in our bipolar measurements (Fig. 3).