Figure 3. Mirth induced by acute cingulum stimulation in the index patient.

Continuous intracranial EEG record and associated sequential still images of patient’s face showing temporal progression of facial expression (smiling, laughter) during a 6-second period of acute cingulum bundle stimulation (3.0 mA, 130 Hz, 300-μs pulse width marked by stimulation artifact). No epileptiform after-discharges from cingulum stimulation were detected in any channel. The patient described the experience as follows: “I just feel my face smile and I feel happy. [The happiness] lingers for a while and then it kind of slows down a little and I just feel happy and relaxed.”