IF SOME OF Feinberg's cases have an inherent spookiness, some of Farah's almost have a comical aspect -- and not just because the patients she sees are usually in less dire circumstances. She gets her cases in two basic ways, she explains. Usually she tells her colleagues at the Medical Center that she's looking for patients who cannot recognize faces or printed words. (One patient Farah has seen can write -- but then is unable to read what he's just written!) But occasionally she hears of cases by chance -- and with those, she says, "you stand to learn a lot" and stretch a little bit as a scientist. She proceeds to offer "a pretty wild example" of just such a serendipitous case, referred by a speech therapist who was helping a patient with his reading problems.
   When Farah and one of her graduate students, Marcie Wallace, began showing the new patient a series of cards with pictures of everyday objects, he seemed to recognize the pictures, occasionally fretting for the right word. But then they noticed something odd: the man had a particularly difficult time naming the picture of a carrot. His pause, says Farah, was agonizing; he waved his hands, listing several properties of a carrot while at a loss to name it. Since Farah's main interest has been in vision and the interface between vision and thought -- her previous book was Visual Agnosia: Disorders of Object Recognition and What They Tell Us about Normal Vision (1990) -- she had approached the new patient with an eye toward the visual-processing aspects, those involved in reading. But this patient could visually process -- it was coming up with the name that was the problem.
   While that kind of block is not unusual in patients with brain damage, Farah and Wallace discovered a pattern: either he could not name any of the fruits and vegetables in the deck of cards, or it would take him more than 10 seconds of evident struggle. By coincidence, the researchers had just read about a similar problem in a scientific journal -- which they had both initially dismissed as impossible! As Farah puts it, how could the brain be so organized that a lesion affected only a person's ability to name fruits and vegetables? Given their own skepticism about the earlier study, Farah and Wallace were cautious.
   First they ruled out "potential confounds that had been in the original report" -- factors that might have provided other possible explanations for the man's condition. Then, to determine whether it was the pictures and not the fruits and vegetables themselves that the patient could not name, Farah and Wallace bought a couple of bags of groceries and had him try to identify the real things. "It didn't matter what the input modality was," says Farah. The patient's brain continued to stumble in this highly restricted area.
   The condition, which came after the patient suffered a stroke, baffled him as much as it did the researchers. Their studies convinced Farah that the brain's naming system is semantically organized -- by categories of meaning -- and implemented in the brain "in such a way that different little localized bits of tissue evidently represent names from different categories." And all it takes, she says, is "just the right kind of lesion coming along in just the right place [to] knock out your ability to retrieve names from that category." It could almost be an absurdist skit by Steve Martin, Farah's "idol": the brain's fruits-and-vegetables naming-site located right next door to the site for naming farm animals.
   Another unusual disorder that Farah studies is prosopagnosia, the inability to recognize faces. It is caused by damage to two very specific areas located symmetrically on either side of the brain, on its inferior surface. "The most astonishing thing about these people is that they can recognize most everything else," says Farah. A patient she studied for years, L. H., had been in an accident. Despite brain damage, he got on with his life so successfully that he finished college and earned two master's degrees. With one significant change: he can walk right past family members and not recognize them. Often, he must identify them by characteristic clothing. But that's not always possible. Farah reports that L. H. coached soccer after his accident -- and when his own children were in uniform, he could not tell them from others on the team. And at a party once, he offended a woman by walking up to her and saying, "Come on, honey, let's go home." She was not his wife. While that may not seem quite as dramatic a misidentification as that made by the title character in Oliver Sacks's The Man Who Mistook His Wife for a Hat, Farah expresses great sympathy and admiration for this person who looks in the mirror "and sees an unfamiliar-looking face there." Despite his brain damage, she reports, the man retains a high IQ and a good memory and has a career in the mental-health field. He's also highly adept at "visual-spatial processing," such as reading maps and solving mental "rotation" tests.
   Another memorable patient, C.T., had suffered a head injury in a motorcycle accident and appeared not to recognize faces. Eventually, however, Farah's team discovered that he could recognize some famous faces from before his injury. In fact, he could identify photos of the young Michael Jackson taken before the time of C.T.'s brain injury -- which showed the singer with a broad nose and an Afro hairstyle -- but he could not identify photos of Jackson taken after his cosmetic makeover!
   According to Farah, the parts of the brain that originally do the work of perceiving faces are certain areas of the inferior temporal cortex. That perceptual information is then projected to the hippocampus and surrounding structures, where it is processed in a way that remains, in Farah's word, "mysterious." That processing enables the information to take a permanent form back in the area where the original analyzing took place, the inferior temporal cortex. Given that division of labor, if there were an anatomical disconnection as the result of trauma, the brain would be able to perceive new faces, but not remember them; yet it would be able to perceive and remember everything that is not a face. In tests, C.T. fared very well on recognizing objects and "old" faces, but with faces from after his accident, he was "just terrible." Farah dubbed it a case of prosopamnesia -- amnesia of faces -- the first one ever recorded. Continued...
March Contents | Gazette Home
Copyright 1998 The Pennsylvania Gazette Last modified 3/13/98