In Frankenstein monster movies from the 1930s to the 1990s, the big brute with the bad knees embodied the mystery surrounding the human brain and its thought processes. That strange globular organ floating in a liquid-filled jar looked harmless enough. But once Dr. Frankenstein gave the monster its brain, Boris Karloff and his successors broke free, smashed, burned and murdered. Sometimes the monster was pleasant. Usually though, his brain caused trouble, and no one knew why.
In the 1990s the brain may not be as mysterious or as threatening, but there are still many unanswered questions about it. One main question-"How does the human brain give rise to thought?"-is the focus of the Center for the Neural Basis of Cognition, a joint venture between Carnegie Mellon and the University of Pittsburgh. Center researchers build on existing information about the brain and use technology to find out more about the processes of learning, thinking, reading and speaking.
Purposely located at Mellon Institute between the campuses, the center, funded by the Richard King Mellon Foundation, brings together the strengths of both universities. "Carnegie Mellon is one of the best universities for the study of the human cognitive process and for computer science," says center co-director James L. McClelland of Carnegie Mellon's Psychology Department. "Pitt is extremely strong in its medical school and in neuroscience. They are trying to understand the biological mechanisms underlying mental disorders. And they have the world's most successful psychiatry department, measured in terms of funding."
McClelland works with codirector, Dr. Robert Y. Moore, chairman of Pitt's Department of Neurology.
Once at opposite ends of the spectrum, psychology and physiology-the mind and the brain-are moving closer together, says McClelland. "Until recently people studying human cognition paid no attention to the actual physical basis of the brain. The set-up in most universities reiterates this. The psychology department is separate from the medical school. Our center is about obliterating that and really understanding cognitive functions in terms of actual physical mechanisms."
Center scientists take four main approaches to their research. They study patients who have brain damage and cognitive disorders. They build computer models of the brain, damage those models and then rebuild them to understand how the brain learns and reacts to injury. They record the human brain in action, using functional MRI scans, taken while the patient works on a task. And they monitor neurons in the brains of monkeys, as they complete tasks.
The diagnostic diary
Marlene Behrmann, an assistant professor of cognitive neuroscience at Carnegie Mellon and a faculty member at the center, works with brain-damaged patients, but her study also has connections to the center's other three approaches. She studies a section of the brain called the parietal lobe and the changes that occur there after stroke or other damage. Researchers believe the parietal lobe is responsible for keeping track of where objects are located in a person's visual surroundings.
Behrmann's subjects ignore the entire side of physical space
opposite their brain damage, or lesion. "The standard definition,"
Behrmann says, "is that they are not aware, don't process and don't
use information on the side of space opposite the side of the lesion
in the brain. In most cases the lesion is on the right. Most things in
the brain work in that sort of crossed way. The right side of the
brain is responsible for processing information on the left side."
Behrmann works with patients at Pittsburgh area hospitals and rehabilitation institutes and gives them tests to determine the extent of brain damage to the parietal lobe. "If you ask patients to copy a daisy, they will only copy the right hand side and ignore the information on the left," she says of those with damage to a particular section of the right side of the brain. "If you give them a book, they read only the right hand page, and then if they read the right-hand page, they read only the words on the right side of the page and then maybe just the right side of each word."
What's most interesting about the patients, Behrmann says, is that they don't seem to notice that their flower is missing petals or that their book makes no sense. They don't feel compelled to complete the daisy because they are unaware it is inaccurate. Their neglect of the left side of their surroundings shows up in their personal care as well, Behrmann says. "They may only shave or apply makeup to the right side of their face. They will only dress the right side of their body or eat from the right side of the plate." She works with patients to learn about the normal system: how the parietal lobe sends information to the visual system and how health professionals can rehabilitate better.
Current rehabilitation practices teach patients to look for red dots and lines, used as anchors for their attention, to help them improve on checking to the left.
David Plaut, assistant professor of psychology at Carnegie Mellon and a center faculty member specializing in computer models, also works toward rehabilitating patients. But he has no contact with human subjects. Instead, he sits at his desk and builds brains. Plaut creates computer models of the human brain and then damages the models to see what happens and how the damage can be repaired. You may imagine him to have a crazy laugh and white matted hair, but he is very normal looking; tall with dark hair, not the least bit Frankensteinian. His office is normal, too. No brains floating in jars. Just a few plants and books.
Actually, Plaut's computer models don't look anything like the brain. A string of commands on a monitor and a small window reveal a large square divided into smaller squares that represent clusters of neurons. His models process information like groups of neurons, he says. "We can't develop computer simulations of the full complexity of human language and vision, but we can build models that have the important characteristics of human processing," he emphasizes.
Plaut and Behrmann collaborated to develop individual models that simulated the brain damage in Behrmann's patients and their performance when copying a daisy. To their delight, each computer model produced drawings very similar to individual patient's drawings. Models are easier to work with than patients, Behrmann says. "They allow a much more careful and systematic exploration of a whole range of deficits. In humans you don't have control over the lesion. A stroke is nature's experiment. You have to deal with whatever the patient comes with. In a model you can have all the manipulations you want." Watching the brain work On the imaging side of the center's research, center faculty member Jonathan Cohen, an assistant professor of psychology at Carnegie Mellon and of psychiatry at Pitt, uses high-powered magnets for magnetic resonance imaging on normal people while they complete small tests like recognizing repeated letters in a sequence. By watching the brain activity of people as they see a repeated letter and then asking them to say how far back in the sequence the letter first appeared, Cohen can see how sustained memory works. The imaging allows him to see which areas of the brain are active during the task, which in turn allows him to recognize areas that may be dysfunctional in disorders like schizophrenia.
In the center's fourth main approach to brain analysis, researchers work with rhesus monkeys. Carl Olson, director of the physiology laboratory at the center, watches the monkey's eye movements as they are prompted to look at the left or right side of an object. At the same time, Olson monitors neurons in an area of the animals' brains called the frontal cortex. Olson found that there are special neurons in the frontal cortex responsible for recognizing the right or left side of every object.
Since Olson's discovery, he and Behrmann are looking at normal people using magnetic resonance imaging with the hope of finding a specific pathway connecting the frontal cortex neurons with the parietal lobe. They know both areas are involved in recognizing objects and locating where those objects are. Behrmann describes their findings as crucial to understanding patients with brain damage who ignore one side of space. She sees applications ahead in patients with other brain disorders.
Behrmann, Plaut, Cohen and Olson's research represents a few of the projects underway at the center. Other faculty members and graduate students look at reading acquisition and disorders; learning and memory; schizophrenia; brain development; cognitive development; and working memory. The center's graduate program offers research training to postdoctoral and undergraduates students from both universities.
With every new discovery scientists get a little closer to understanding the mysterious brain that plagued the fictional Dr. Frankenstein and others like 17th century French philosopher Rene Descartes. Descartes proposed that the conscious, thinking mind and physical brain were separate parts connected by a mysterious gland.
McClelland likes to say that scientists are "awakening from the Cartesian dream. The mind is something to be understood in terms of actual mechanisms. We are pushing the frontiers of Descartes' insight. Once you stop thinking about insanity as being divorced from bodily processes, you start seeing something that is potentially addressable by chemical things. For example, the drugs used now to treat mental illness have had a big impact on this kind of thinking."
The Center for the Neural Basis of Cognition hopes to influence the development of new diagnostic and treatment methods, tools and resources for medicine and industry and to educate the public on brain activity. On the entertainment side, the center and artists from the Carnegie Mellon Studio for Creative Inquiry are creating a planetarium show that will give science center audiences around the world a 3-D tour of the brain.
Who knows, Dr. Frankenstein might have built a friendlier monster if only he had known what the center's scientists know these days.