Abnormalities in how the nucleus accumbens, highlighted here, processes dopamine have been found in individuals with psychopathic traits and may be linked to violent, criminal behavior.
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.
“The really striking thing is with these two very different techniques we saw a very similar pattern — both were heightened in individuals with psychopathic traits,” Zald said.
Study volunteers were given a personality test to determine their level of psychopathic traits. These traits exist on a spectrum, with violent criminals falling at the extreme end of the spectrum. However, a normally functioning person can also have the traits, which include manipulativeness, egocentricity, aggression and risk taking.