The brain's hidden agenda

Neuroimages can reveal physical explanations for violent, impulsive behavior. But does this technology have the power to excuse the accused?

     In the book, "The Man Who Mistook His Wife for a Hat," written by neurologist Oliver Sacks, a man suffering from a neurological disorder called visual agnosia tries to pull his wife's head off — thinking it's her hat. The story is true, its theme detailing a number of cases where brain damage was shown to have direct influence on behavior.

     Our notions of the so-called "loony bin," with patients in white shuffling through long hallways after having had a clandestine lobotomy, has evolved. Those "patients," we understand now, are individuals with documented illnesses — mental, physical or psychological. Sometimes they are rehabilitated, sometimes not. Rosemary Kennedy, sister of JFK, had undergone a lobotomy in the 1940s that rendered her more debilitated than she had been prior to the procedure. Fortunately, those days are gone.

     We know much more about the brain today, thanks to many areas of science working together. When a man tries pulling his wife's head off, we ask why (and come up with better answers). More recently, neuroscientists have found they can use neuroimages to link damaged areas of the brain to criminal activity and violence. At its best, these sharp pictures grant futuristic access into the dark recesses of the mind. Is this just high-tech phrenology? Or can such techniques offer another clue as to why a person might engage in impulsive crimes — even murder? How might it affect our perception of cause and accountability?

Random acts

     Dr. David Hartman is a forensic neuropsychologist who handles civil and criminal examinations of how people's brains work with respect to injury or dysfunction that might be reflected in claims of trauma or criminal indictments. He describes his job as like that of a mechanic. "[The mechanic] tests out various systems of the car, while it is working," says Hartman. "In a respect, I take the brain out for a drive; I evaluate its actual behavioral function and test out the emotional condition a person may have."

     The parts of the brain most associated with violence or lack of control are the frontal and temporal lobes. The frontal lobe is the anterior region located above the eye sockets. This most-evolved sector is considered to be the seat of working memory, and is responsible for high-order functions like planning and impulse-control.

     An ongoing dysfunction can reveal itself in many ways. Hartman recalls a recent patient of his — a professional from New York — who was booked for an appointment because he was becoming verbally abusive to his staff, and figured it was due to stress. During a day of evaluation Hartman found the man was unable to pay attention under distracting circumstances; he struggled with problem-solving in a way that someone of an executive position should not; he had trouble stifling his impulses. The man was referred to Hartman for a personality problem, but that wasn't the case.

     "I called back and said I think instead of calling this a psychiatric problem, you need to call it a neurological problem," recalls Hartman. Immediately, scans showed a brain tumor the size of a lemon had been growing behind the man's frontal lobe for years, but he was otherwise asymptomatic.

     "While he did not have any obvious indications of 'brain damage,' the tumor was slowly lobotomizing him," says Hartman. "His frontal lobe was being pushed out of commission."

(Brain) disorders in the court

     Head injury defenses are cropping up more frequently as a defense in violent crime cases. In the early 1990s Herbert Weinstein, a 65-year-old ad executive, was charged with strangling his wife to death and throwing her body out the window of their 12th floor Manhattan apartment. Weinstein's lawyer argued his client should not be held responsible, as scans showed Weinstein had an arachnoid cyst — a space occupying fluid-filled cavity the size of a baseball — surrounding his brain like a spider web. The cyst itself wasn't violent, but it pushed on part of the temporal lobe, both executive centers of introspection and self control as well as the center of emotional regulation.

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