The rTMS findings of van Honk and colleagues is intriguing for several reasons, not the least of which is the fact that it seems to be the first report of reduced electrodermal activity following selective functional inactivation of the orbitofrontal cortex in humans. Because rTMS deactivates gray matter, and because it reduces skin conductance but not heart rate, this result further supports our recent finding that a subgroup of individuals with APD with particularly reduced prefrontal gray volume also have reduced skin conductance but not reduced heart rate.1 The observation of van Honk and coauthors would make the prediction that it is the orbitofrontal subregion of the prefrontal cortex that is structurally impaired in our sample, a prediction that needs to be further tested as we did not segment into subregions the prefrontal cortex.
Raine A. Repetitive Transcranial Magnetic Stimulation at the Frontopolar Cortex Reduces Skin Conductance but Not Heart Rate: Reduced Gray Matter Excitability in Orbitofrontal Regions—Reply. Arch Gen Psychiatry. 2001;58(10):974. doi: