As any fan of the TV series “Sherlock” or “Dexter” knows, a lack of empathy is a hallmark of psychopathy.

However, as researchers Jean Decety, Laurie R. Skelly and Kent A. Kiehl explain in their study published in the Journal of the American Medical Association, the neural processes associated with empathetic processing have not been directly examined in the mental condition, especially in regards to perceiving others’ pain and distress.

That is, until now.

In a case-control study, 80 incarcerated men classified on the Hare Psychopathy Checklist-Revised as having high, medium or low levels of psychopathy were scanned on the grounds of a correctional facility using the Mind Research Network’s mobile 1.50-T magnetic resonance imaging system.

The participants were shown depictions of people being harmed as well as facial expressions of pain while the researchers measured their brain activation patterns.

What they found was telling.

“In response to pain and distress cues expressed by others, individuals with psychopathy exhibit deficits in the ventromedial prefrontal cortex and orbitofrontal cortex regardless of stimulus type and display selective impairment in processing facial cues of distress in regions associated with cognitive mentalizing,” the researchers wrote.

Knowing this, the team said, can only help to better inform intervention programs.

The study, while the first to examine the difference in brain activation in relation to empathy, is not the first to examine the difference between psychopathic and non-psychopathic brains.

Last year, researchers based at King’s College London’s Institute of Psychiatry found that psychopathic individuals actually had less grey matter in the areas of the brain important for understanding other peoples’ emotions.

This distinguishing characteristic, Essi Viding, a professor in psychology and language at University College London, told Reuters, offers “weighty new evidence” as to the importance of distinguishing psychopathic and non-psychopathic individuals from one another, especially in terms of prosecution within the justice system as it raises the strength of the former’s group claim on insanity.