Figure 1. Psychophysical task paradigm and intracranial stimulation locations.

1A: Pain stimuli of varying intensity were applied to the hand's palmar surface in patients with intracranial electrodes. The intensity of the stimulus was adjusted in each trial. One trial constituted having the hand on the stimulus for 10 seconds (top screen). Stimulation was applied in a pseudo-random order. The patient removed their hand from the device. After removing their hand, the patient responded to the question, "Was that painful?" on the touchscreen desktop. After answering "yes" or "no," the patient filled out how painful, hot, or cold the stimulus felt on a scale of 0-10 (bottom right screen). After submitting their answers, the stimulus was adjusted, and the sequence was repeated.

1B: Four different patients underwent stimulation of their cingulate cortex. While many more electrodes were implanted in each patient's brain, we only show the ones stimulated for a psychophysical effect. Electrode locations are displayed according to the coordinates in MNI space. Two spheres represent bipolar stimulation performed with Patient 2, 3, and 4. Monopolar stimulation was performed in Patient 1.

1C: Location of stimulation electrodes overlayed on patients’ preoperative MRI and postoperative CT. Electrode locations were visualized in the LeGUI software, following the method in Electrodes.