At thirty-eight, Kiehl is one of the world’s leading younger investigators in psychopathy, the condition of moral emptiness that affects between fifteen to twenty-five per cent of the North American prison population, and is believed by some psychologists to exist in one per cent of the general adult male population. (Female psychopaths are thought to be much rarer.) Psychopaths don’t exhibit the manias, hysterias, and neuroses that are present in other types of mental illness. Their main defect, what psychologists call “severe emotional detachment”—a total lack of empathy and remorse—is concealed, and harder to describe than the symptoms of schizophrenia or bipolar disorder. This absence of easily readable signs has led to debate among mental-health practitioners about what qualifies as psychopathy and how to diagnose it. (…)

In January of 2007, Kiehl arranged to have a portable functional magnetic-resonance-imaging scanner brought into Western—the first fMRI ever installed in a prison. So far, he has recruited hundreds of volunteers from among the inmates. The data from these scans, Kiehl hopes, will confirm his theory, published in Psychiatry Research, in 2006, that psychopathy is caused by a defect in what he calls “the paralimbic system,” a network of brain regions, stretching from the orbital frontal cortex to the posterior cingulate cortex, that are involved in processing emotion, inhibition, and attentional control. (…)

The inmate was being shown a series of words and phrases, and was supposed to rate each as morally offensive or not. There were three kinds of phrases: some were intended as obvious moral violations, like “having sex with your mother”; some were ambiguous, like “abortion”; and some were morally neutral, like “listening to others.” The computer software captured not only the inmate’s response but also the speed with which he made his judgment. The imaging technology recorded which part of the brain was involved in making the decision and how active the neurons there were. (…)

Neurons in the brain consume oxygen when they are “firing,” and the oxygen is replenished by iron-laden hemoglobin cells in the blood. The scanner’s magnet temporarily aligns these iron molecules in the hemoglobin cells, while the imaging technology captures a rapid series of “slices”—tiny cross-sections of the brain. The magnet is superconductive, which means it operates at very cold temperatures (minus two hundred and sixty-nine degrees Celsius). The machine has a helium cooling system, but if the system fails the magnet will “quench.” Quenches are an MRI technician’s worst fear; a new magnet costs about two million dollars.

{ The New Yorker | Continue reading | Read more: The Disconnection of Psychopaths }

neurosciences, psychology | December 19th, 2011