University of Wisconsin-Madison School of Medicine and Public Health
This study found reduced connectivity between an area of prefrontal cortex (PFC, red) and the amygdala (blue). The white matter pathway connecting the two structures (the uncinate fasciculus) is shown in green.
The Koenigs Lab, an appendage of the University of Wisconsin Department of Psychiatry, says something about the multidisciplinary nature of neuroscience. Named for Michael Koenigs, an assistant professor of psychiatry, the lab includes a postdoctoral researcher with degrees in psychology and comparative religion, graduate students with backgrounds in biology, philosophy and English, and a scientist trained in applied math.
Centered on the mind and nervous system, neuroscience is exploding, and there's practically no topic it won't take on, be it Shakespeare, meditation or consciousness itself. Or psychopathy.
In a paper to be published in the Nov. 30 Journal of Neuroscience, Koenigs, along with veteran UW psychopathy researcher Joseph Newman, will unveil new evidence of a physical basis for the disorder.
In the study, Koenigs and Newman use brain scans of 40 inmates (20 psychopaths and 20 others) from Fox Lake Correctional Institution in Fox Lake, Wisconsin. In the scans of psychopathic brains, the researchers discovered poor connections between an important brain segment -- the "ventromedial prefrontal cortex" (VMPFC) -- and another crucial to emotional processing, the almond-shaped amygdala.
The study will be the largest yet published that examines this link, according to Koenigs. Researchers used two types of brain scans: one testing the integrity of "white matter" structures connecting the VMPFC and the amygdala, and another tesing how well they communicate. Both types of scans found a weakened link in the brains of psychopaths.
Better understanding such abnormalities could, one day, reorder how the justice system responds to criminals who have them. "Can we hold them as accountable as someone who doesn't have these abnormalities?" Koenigs asks.
Scientists have studied the connection between the VMPFC and amygdala before. In one experiment using rodents, scientists found that stimulating the VMPFC suppressed the amygdala.
Koenigs primarily studies brain injuries, particularly those in the VMPFC, where the brain is believed to regulate emotion, process threats, guide decision-making and direct social behavior. Damage to this segment, located just behind the forehead in the frontal lobes, tends to make patients more aggressive, irritable and less sensitive to others.
"They're not the same person they used to be," Koenigs says. "They develop very striking personality changes reminiscent of psychopathy."
Is a VMPFC deficiency to blame for psychopathy? It's not clear. And scientists don't know if the VMPFC is failing to regulate the amygdala or if the amydala is failing to send crucial emotional feedback to the VMPFC.
"Normally, considering a decision [to rob someone] and the harm you would inflict would be marked with a negative emotional state," says Koenigs. But in psychopaths, this affect is flat.
To do their study at Fox Lake, Koenigs and Newman enlisted a mobile MRI lab run by Kent Kiehl, an associate professor of psychology at the University of New Mexico. The lab, pulled by a tractor trailer, brings the scanner to the inmates.
Across the field of neuroscience, researchers are rapidly exploiting the powers of MRI scanning, particularly "functional" scanning, which tracks blood flow in the brain. This flow, because it is directed to busy neurons, is a precise indicator of brain activity.
The new study is Newman's first foray into brain imaging. "There's a very strong bias toward using brain measurements," he says, "and there's been a lot of wonderful progress. People want to see how far we can go."
Psychopathy is not as rare as some might believe. According to researchers, psychopaths make up an estimated 1% of the U.S. population and between 10% to 20% of the country's prisoners.
In his 30 years of studying psychopathy, Newman has theorized the existence of an "attention bottleneck" in the psychopathic mind that prevents it from fully receiving emotional and other inhibitory signals that say, "Stop! Reconsider! Reevaluate!"
The conventional theory on psychopaths is that they lack emotion, be it fear, empathy or guilt, that would otherwise inform decision-making. Newman doesn't deny that but insists on the importance of attention.
"It feels like I'm trying to identify a learning disability," he says.
Our minds unconsciously monitor us. It happens in secret. Our conscious minds don't know of it until the unconscious sounds an alarm -- such as when a nagging suspicion of "having forgotten something" turns out to be true (the oven is still on; the keys were left on the car seat).
The psychopathic brain may be very bad at automatically diverting attention to these types of cues if the psychopath is locked into "goal-driven" behavior, a kind of tunnel vision.
Such an impairment, if it exists, doesn't necessarily lead to crime. "Environmental factors are critical," says Newman. They could be parental abuse, substance abuse or socioeconomic disadvantage. But once classified as a psychopath, an offender is two to five times more likely to reoffend than one who isn't.
Newman tested his "attention bottleneck" theory in a study published earlier this year.
In that study, 87 maximum-security inmates, some classified as psychopaths, sat down in front of computers. Two things appeared on the screen: a square, either red or green, and a letter, either uppercase or lowercase.
In some of the trials, researchers startled inmates with a low-intensity shock after showing a red square. (Prisoners were told of the mild "buzzes" before they volunteered.) Each was shocked a total of 24 times, always after a red square. Then, to conclude the trials, the computer asked the prisoners to identify either the case of the letter or the color of the box.
The human body, when conditioned to fear something, will startle at its appearance. This is called "fear-potentiated startle." In the experiment, the red box primed the inmates to startle upon receiving the shock, and they did -- with one major exception. In trials where psychopaths first saw the letter, followed by a red square, their startle was greatly diminished.
Newman and the other researchers, Arielle Baskin-Sommers, a graduate student at UW-Madison, and John Curtin, a psychology professor, concluded that by presenting the letter first -- thereby making the red square "secondary information that is not goal relevant" -- the psychopaths fell victim to the "attention bottleneck" as theorized by Newman. They saw the square, but its meaning was not fully absorbed because the letter (and its case) had already won their attention.
There's growing speculation today that neuroscience could revolutionize the U.S. criminal justice system, overthrowing the old precept of culpability.
One indication of the promise of this growing field is a new dual degree program at UW-Madison that will train students in both neuroscience and the law. The "Neuroscience and the Law" track, part of the broader Neuroscience & Public Policy program, will allow students to earn a J.D. degree in law and a Ph.D. degree in neuroscience.
Applications to join the new track's first class come due this December. Professor Ron Kalil, a neuroscientist who studies brain injuries and the brain's innate ability to repair itself, says the new program grew out of a 2010 meeting he had, over coffee, with Pilar Ossorio, an associate professor of law and bioethics. The two left with a "let's do this" attitude, according to Kalil, but getting university approval for the new track didn't happen overnight. To make the program official, they needed the approval of four university committees.
They succeeded, adding "Neuroscience and the Law" to the existing tracks combining neuroscience and public policy and neuroscience and international public policy.
Of neuroscience's broad range, Kalil says, "At one end you have the study of molecules and proteins that make up parts of neurons, and at the other, the field tries to wrestle with issues that have been on the table since people started to think of themselves as human."
One of these is how to respond to crime, and what punishment is appropriate. "There are a lot of people who are not insane, but they're not normal," he says. "Where do we draw the line?"