By MATTHEW TAYLOR - BBC NEWS - HEALTH
Added: Tue, 15 Nov 2011 17:41:39 UTC

Scans of serial killer Brian Dugan's brain showed limited activity in the area processing emotions

When Brian Dugan pleaded guilty to the brutal rape and murder of a seven-year-old girl, Jeanine Nicarico, he seemed to be the very sketch of a brutal serial killer.

She had been murdered in 1983, though Dugan only pleaded guilty in 2009. By then, he had also been convicted of rape several times over, and the murder of two others - another seven-year-old girl and a 27-year-old nurse whom he ran off the road before raping and killing her.

If the death sentence had not been withdrawn in Illinois, Dugan would have been executed.

Yet strikingly, he showed no remorse for any of his murders or crimes. Scientists now believe this lack of empathy may in fact be linked to the reason he committed these acts.

Neuroscientist Dr Kent Kiehl of the University of New Mexico scanned Dugan's brain, as part of a unique project to understand how anti-social behaviour is related to brain structure and function.

"He struggles to try and understand why people even care about what he did," says Kiehl, describing his time interviewing Dugan. "Clinically, it is fascinating."

Psychopathy
Dr Kiehl is seen as a pioneer in a cutting-edge area of behavioural neuroscience: the attempt to understand psychopaths' brain functions and use this to develop treatments for their condition.

It is controversial because for thousands of years, men like Dugan have been labelled not as ill, but as evil.

In literature and cinema, the term "psychopath" is not used for a diagnosis for which we might have sympathy, but rather as something we might fear.

Dr Kiehl has a different view: "I tend to see psychopaths as someone suffering from a disorder, so I wouldn't use the word evil to describe them."

So what exactly is a psychopath?

"Clinically, we define it as someone who scores high on traits such as lack of empathy, guilt and remorse," says Dr Kiehl.

"They are very impulsive: they tend not to plan or think before acting. They tend to get themselves in trouble by a very early age."

We have long known that many people in prisons display symptoms of psychopathy, but until now we have had little insight into their condition.

Brain scans
To address that using neuroscience, Dr Kiehl's lab has built a unique mobile brain scanner. It is equipped with the latest imaging technology but fitted into a truck he can drive into high-security prison facilities.

He used this to perform two types of analysis on Dugan's brain: looking at its density and its function.

"Brian's brain has very low levels of density in a system we call the para-limbic system," he explains.

The para-limbic system is a "behaviour circuit" of the brain, including brain regions known as the amygdala and pre-frontal cortex.

Scientists have long known that these areas are associated with the processing of emotions.

Over the past century or so, people with brain damage to these areas have been studied because their behaviour suddenly changed and became anti-social.

"Those systems, we think, didn't develop normally in Brian," says Dr Kiehl. Psychopathy seems to involve a lack of development in these regions - which may be genetically determined.

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You may also be interested in Nature's coverage of this story.

TAGGED: BIOLOGY, LAW, MORALITY, PSYCHOLOGY