The daily headlines often focus on violent acts — and even President Obama has made over a dozen speeches about gun violence since he's been in office — but what if we could stem the tide with science? What if we could learn what happens to the brain when a person commits a violent act?

In fact, a recent Australian study has gotten closer to identifying how the brains of killers change. During the study, researchers did MRI (magnetic resonance imaging) scans on 48 people to detect how their brain patterns changed while they played three different video games in which they envisioned shooting an enemy soldier, an innocent civilian and shooting a weapon without injuring anyone. After the MRI, each person was asked to rate how guilty they felt in each scenario.

Turns out, our brain activity varies depending on whether or not we think the killing is seen as justified. For example, when the participants visualized shooting innocent civilians, there was more activity noted in the brain's lateral orbitofrontal cortex (OFC), a part of the brain that's involved in moral decisions. The more guilt each person felt about 'shooting' innocent citizens, the greater response was seen in this part of the brain.

This correlates to some of the things we already know about the brain and its impact on the behavior of killers.

"We're finding that violent individuals have reduced functioning in several parts of the brain," says John Mayer, a clinical psychologist in Chicago and leading expert on violent behavior. "These are all areas of the brain that control emotions, empathy, judgment, decision-making and impulse control."

At the same time, how does this jibe with the fact that we're all fundamentally wired for empathy and guilt?

"The normal brain functions with feeling toward others and guilt when we transgress," Mayer says. "However, new brain studies are showing us that what we suspected all along about psychopaths and sociopaths is true — that the areas responsible for these social emotions (i.e., empathy and guilt) aren't functioning at normal levels in those individuals."

However, this isn't the end of the story. There's way more to committing a violent act than the changes that might be occurring in our brains at the moment a trigger is pulled.

"We are just beginning to understand how the pressures of poverty, discrimination, concentrated trauma or violence and emotional abuse lead to stress on the brain," says Kim Gorgens, Ph.D., associate professor in the graduate school of professional psychology at the University of Denver. "The same is true of substance abuse, childhood neglect and poor nutrition."

All of these vulnerabilities are 'related' to aggression, but it remains unclear if these external cues can lead to a person becoming a coldblooded killer.

It helps to keep in mind that killing isn't a uniform entity, says James Giordano, Ph.D., a neuroscientist and chief of the neuroethics studies program at Georgetown University Medical Center in Washington, D.C.

"People kill for various reasons — premeditatively, emotionally or because we're looking to assert power and dominance," he says. "We can also kill out of things like greed."

In the end, empathy has many components and the relationship between behavior and brain circuitry is likely less straightforward than we think, Gorgens says.

"The question then becomes one of whether we should intervene when we recognize physiological abnormalities or do neuroimaging to predict violent behavior," she says. "Those questions and the related programs and policy are among the most controversial in neuroscience. That said, I believe that we'll soon get closer to the answers to these complex questions."

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