Several researchers, such as Adrian Raine, have done work studying the brains and neurological responses of children who exhibit traits often found in psychopaths and today we look at another such researcher.

Abigail Marsh is an assistant professor of psychology at Georgetown University who directs the school’s Laboratory on Social and Affective Neuroscience. This lab uses cognitive neuroscience methods to explore, among other things, the roots of empathy.

Marsh’s path to interest in this topic is, as is true for many of us who have been drawn to it, a compelling one. As she explains in her profile on her lab’s website, when she was 20 years old, she was in an accident, after which a stranger saved her life. And, as she explains in another interview, a few years later, a different stranger punched her in the face, breaking her nose.

Events like these led her to wonder why some people help others and some harm others. Her quest for answers led her to earn a Ph.D. in Social Psychology from Harvard and to do post-doctoral work with James Blair, another leader in the field who has done great work on these subjects.

As described by Georgetown University News, Marsh’s latest research – which also involved the National Institutes of Health, the Center for Disease Control and Prevention and several other researchers including Blair – showed that “young people with conduct problems and psychopathic traits such as callousness and remorselessness show less activity in the regions of the brain associated with empathy.”

Specifically, functional magnetic resonance imaging (fMRI) was used to measure brain activity as two different groups of adolescents looked at photographs of other people experiencing pain-inducing injuries while imagining either that the body in the photo was their own or someone else’s.

The first group consisted of adolescents with both:

• Psychopathic Traits
• Conduct Disorder or Oppositional Defiant Disorder

The second group was a control group of youngsters of matched age, gender and intelligence.

The study found that:

• As the injuries depicted became more painful, the youngsters with psychopathic traits showed reduced activity in the rostral anterior cingulate cortex, ventral striatum (putamen), and amygdala, all of which are brain regions associated with the experience of empathic pain.
• Amygdala activity was especially reduced when perceiving the injury as happening to another person rather than oneself.
• Youngsters whose scores on the PCL:YV (the Youth Version of the Hare Psychopathy Checklist) were higher, indicating more severe psychopathic traits, showed less activity in the amygdala and rostral anterior cingulate cortex, specifically.

The researchers also discovered that, in the group with psychopathic traits, lower responsiveness was predictive of psychopathic symptom severity.

The formal title of the study is “Empathic responsiveness in amygdala and anterior cingulate cortex in youths with psychopathic traits.” It is published in the March 12, 2013 issue of the Journal of Child Psychology and Psychiatry.

In the Georgetown University News piece, Abigail Marsh says that, in her future work, she hopes to help tease out even more fully the various types of different mechanisms underlying helpful and harmful behavior. She explains, “I will continue to use brain imaging, genetic and behavioral research paradigms in healthy adults and adolescents as well as adolescents with conduct problems to try to understand the origins of empathy, aggression, and altruism.” Such important goals position her work squarely in the realm of ponerology.

Well there is actually a research journal by that very name. And that journal, Social Neuroscience, has recently honed in on topics at the very heart of ponerology. Its latest issue – Volume 8, Issue 2 – is a special issue focusing on aggression and violence.

It features an editorial entitled “The social cognitive neuroscience of aggression, violence, and psychopathy” followed by six studies that consider the links between neurological markers and responses and harmful behavior.

Here is a summary of the six studies in this special issue.

Affective startle potentiation in juvenile offenders: The role of conduct problems and psychopathic traits

• Exposed male juvenile offenders and controls to aversive sounds to compare emotion processing via measuring their startle reflexes.
• Found that juvenile offenders have fewer blinks in response to the startling sounds and the number of blinks decreases as their level of conduct disorder symptoms and psychopathic traits increases.

The neural signatures of distinct psychopathic traits

• Looked at and documented a relationship between young adults’ measures in several categories of psychopathic traits, their amygdala reactivity in response to threats and their ventral striatum reactivity in response to potential rewards.

Neural correlates of risk taking in violent criminal offenders characterized by emotional hypo- and hyper-reactivity

• Had antisocial criminals and healthy non-criminals make financial decisions involving different levels of risk while under functional magnetic resonance imaging (fMRI).
• Found that offenders with lower emotional reactivity had less rostral anterior cingulate cortex activity than healthy people when uncertain, as well as less prefrontal cortex activity when trying to control their responses accordingly so as to make safe choices.
• This indicates that the offenders have difficulty emotionally representing uncertainty or anticipating punishment.

Vasopressin modulates neural responses during human reactive aggression

• Administered vasopressin, which is known to modulate mammalian aggressive behavior, or placebo to healthy men, who then performed in a competitive reaction time task while under fMRI.
• The men who received vasopressin displayed more activity in the right superior temporal sulcus while making decisions under threat of punishment if they lost the competition, but no behavioral differences were recognized between the two groups.

Endogenous testosterone and cortisol modulate neural responses during induced anger control

• Healthy Asian males were asked to control their anger while being insulted under fMRI monitoring to study the relationship and influence of testosterone and cortisol levels.
• Found that testosterone level correlated positively with dorsolateral prefrontal cortex (DLPFC) and thalamus activity when cortisol levels were low, but not when cortisol levels were high.
• Also found greater functional connectivity between the amygdala and a top-down prefrontal cortical control network while subjects tried to control their anger and that this connectivity was greatest in those with high testosterone and low cortisol.
• All of this suggests a possible mechanism where testosterone and cortisol modulate anger control neurally.

Asymmetry in the dorsolateral prefrontal cortex and aggressive behavior: A continuous theta-burst magnetic stimulation study

• Randomly applied vs. did not apply continuous theta-burst magnetic stimulation (cTBS), an inhibitory procedure, to study the role of the right and left dorsolateral prefrontal cortex (DLPFC) – which typically help inhibit impulse control – in aggression. After real or sham cTBS application, subjects engaged in a monetary task designed to assess proactive and reactive aggression.
• Found that targeting the left DLPFC with cTBS increased both proactive and reactive aggressive responses more than targeting the right, indicating the left DLPFC is more involved in modulating aggression.

As the introductory editorial describes, this issue is a reflection of the shift in the mid-90’s from a focus on attentional differences in the aggressive and psychopathic to a focus on their neurobiological and emotional dysfunctions, even though attentional differences also play an important role. It says the included studies, as a whole, demonstrate three themes:

1. “That there are different neurobiological risk factors for an increased risk for aggression and antisocial behavior.” – The risk factors associated with psychopathy differ from those associated with threat/frustration based reactive aggression, for example.
2. A relationship between reinforcement processing – processing of potential risk and rewards – and psychopathy
3. A potential relationship between brain areas associated with top-down attention and response control and “an increased risk for predominantly reactive aggression.”