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Cerebellar contributions to visuospatial learning Cerebellar contributions to visuospatial learningIn 1972, presidential candidate George McGovern’s running mate, Senator Thomas Eagleton of Missouri, was forced to drop out of the race when it became public knowledge that he had been hospitalized for depression.
That the stigma associated with many mental illnesses and mood disorders has declined in the past 30 years, and continues to do so, is due, in part, to the work of researchers like Kurtis Noblett. Noblett, whose doctoral dissertation deals with a common symptom of schizophrenia, is among a growing number of researchers studying the role of the cerebellum—the part of the brain that maintains balance and motor coordination—in functions of higher learning. Most people are able to understand visual representations and spatial relationships as part of the learning process. This ability, called visuospatial processing, is largely absent in schizophrenic individuals. After discovering research that suggested the cerebellum played a role in schizophrenic symptoms, Noblett decided to examine the cerebellum’s role in visuospatial processing.
“I was working with rodents, so I wanted to develop an animal model to test whether disruption of the cerebellum would, in fact, produce a similar spatial deficit in the rat,” he says. In his experiments, Noblett used control and experimental groups of rats. The experimental group had lesions in the areas of the cerebellum that tied in directly to the frontal lobes of the cerebral cortex, the site of most higher cognitive functions, including visuospatial processing. Of course, if the lesions were affecting the rats’ coordination, tests on their visuospatial processing abilities would be inconclusive. To ensure their coordination was unaffected, Noblett placed the rats on a narrow beam, and measured how much time the rats were able to spend with all four of their paws on the beam, and how much distance they were able to travel. Then came the main experiments, which examined higher brain function. The rats were put into a maze in which a platform was placed in a pool of water, either just above or below the surface. The entire pool was covered in foam peanuts. When the platform was above the surface, the rats could see it. If not, they had to learn where it was using environmental cues. All the rats were able to find the platform when it was above the surface of the water, but the rats in the experimental group had a much harder time when the platform wasn’t readily visible. “That was important,” Noblett says, “because it showed further evidence that the cerebellum is more than just a motor center in the brain, and that it can significantly influence cognitive abilities.” Noblett next set out to discover whether it was possible to reverse the effects of the brain damage in the experimental rats through training.
When the first sub-group of experimental rats was put back into the water maze, Noblett found that they were able to find the underwater platform as easily as the control group had. Experimental rats exposed to the maze but not trained improved less and experimental rats that had not seen the T-maze showed no improvement. Noblett says there could be several different reasons for the improvements, including the development of alternate pathways in the brain or the strengthening of existing pathways. He also postulated that the motor activity— swimming and navigating the maze—strengthened surviving neurons in the lesioned area. Neurochemical markers he used to identify changes in the pre-frontal cortex of the experimental rats indicated that significant changes occurred in response to both the lesions and the behavioral training. While more study needs to be done to discover the specific reasons for the improvement and its impact on schizophrenic individuals, Noblett says that the findings clearly provide evidence of rehabilitative potential for people who have suffered brain injuries resulting in cerebellar trauma. Noblett is currently a postdoctoral fellow at the University of Chicago. Caring for asthmatic children often a full-time jobAs a nurse at the Medical College of Wisconsin, Linda Gehring spent hours each day examining children from Milwaukee’s central city who had asthma. She quickly realized the impact of their caregivers— mostly mothers—on how well or poorly her young patients fared. As a result, when the time came to write her dissertation in nursing at UWM, Gehring chose to focus on what it’s like to care for a child with asthma.“It’s a major public health issue in the city,” Gehring says of the breathing disorder, which, accord ing to parent-reported statistics, affects one in every five central-city children, nearly twice the national average. Among her findings were that asthmatic children became the centerpiece of caregivers’ lives, and that ensuring their health and safety was a full-time and demanding job. Because asthma is a highly individualized condition, different things can trigger attacks. In one case, a child was hospitalized after an allergic reaction to the soap her mother used to clean the house. Caregivers found themselves having to make radical changes in their lives.
Learning to stand up for their children also meant standing up to doctors and educators, Gehring discovered. “Moms have to be assertive if their children are going to get appropriate care,” she says, adding that ensuring such care is frequently an uphill battle. Doctors willing to limit their practices to the central city are often paid only by Medicare. In order to make ends meet, they’re forced to spend less than five minutes with each patient. In addition, she says, the majority of the doctors are older and, as a result, not as conversant in what she described as the “nuances” of asthma. “In the last 15 years or so,” she says, “it’s been learned that asthma is an inflammatory disease and you need a steroid inhaler. But (when these doctors were in school), steroids got a bad name because of side effects.” In her research, Gehring discovered that 90 percent of the patients visiting Children’s Hospital’s emergency room for asthma attacks lived in the central city, and that a small number of physicians accounted for a majority of hospital admissions. One mother, who was a nurse practitioner, had been told repeatedly that her child’s illness wasn’t asthma. When the child finally ended up in the emergency room, the doctors there scolded the mother about it, Gehring says, adding that the daughter of another nurse practitioner she’d spoken to almost died because she was reluctant to stand up to the girl’s doctor. Gehring’s findings have translated into some concrete action. She’s working with Fight Asthma Milwaukee, a coalition dedicated to raising awareness about the disease and its treatment. Through another local program, Physician Asthma Care Education, she’s been able to put together evening in-service presentations on asthma for doctors, medical staff, and school personnel. “Schools in the state have had a law since 1992 that kids can carry inhalers with them if they know how to use them,” she says, adding that most children older than age 6 do. But school personnel often require that inhalers be kept in a locked central office, Gehring says, rendering them all but useless when a student has an attack on the playground or in gym class. Gehring plans to continue her work with caregivers, teachers, and doctors. In addition, she hopes to do a similar study, this time asking the children directly about their experiences with the disease.
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