Sunday, March 14, 2010

Psychopaths blind to consequences in search for reward

The brains of psychopaths appear to be wired to keep seeking a reward at any cost, new research from Vanderbilt University finds.
To examine the relationship between dopamine and psychopathy, the researchers used positron emission tomography, or PET, imaging of the brain to measure dopamine release, in concert with a functional magnetic imaging, or fMRI, probe of the brain's reward system.

In the first portion of the experiment, the researchers gave the volunteers a dose of amphetamine, or speed, and then scanned their brains using PET to view dopamine release in response to the stimulant. Substance abuse has been shown in the past to be associated with alterations in dopamine responses. Psychopathy is strongly associated with substance abuse.

"Our hypothesis was that psychopathic traits are also linked to dysfunction in dopamine reward circuitry," Buckholtz said. "Consistent with what we thought, we found people with high levels of psychopathic traits had almost four times the amount of dopamine released in response to amphetamine."