Research Journal Social Neuroscience Dedicates Special Issue to Brain Studies of Aggression, Violence & Psychopathy
One of the most important aspects of ponerology – a crucial one in seeking answers regarding why people act (or fail to act) in ways that do harm to others – is investigation into what goes on in the brain when people relate with each other in various ways. We might term such investigation “social neuroscience.”
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.
- 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.
- 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.
- 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:
- “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.
- A relationship between reinforcement processing – processing of potential risk and rewards – and psychopathy
- A potential relationship between brain areas associated with top-down attention and response control and “an increased risk for predominantly reactive aggression.”
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Tags: aggression, amygdale, anger, attention, brain, brain scans, conduct disorder, cortisol, criminals, dorsolateral prefrontal cortex, emotional processing, fmri, impulse control, juvenile offenders, neurology, neuroscience, prefrontal cortex, psychopathy, reinforcement processing, social neuroscience, startle reflexes, superior temporal sulcus, testosterone, thalamus, theta-burst magnetic stimulation, vasopressin, ventral striatum, violence
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