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Others, too, are interested in solving that mystery. Robert Galambos, 59, a professor of neurosciences at the University of California at San Diego, is at tempting to track auditory impulses from the ear, through the brain stem and into the cortex. He is studying several brain-wave patterns, including what is called the "Aha wave," which the brain generates when it finds what it is looking for.
Hugh Christopher Longuet-Higgins of the University of Edinburgh is trying to make computer models of the way people produce sentences and understand language. Floyd Bloom, 37, chief of the laboratory of neuropharmacology at the National Institute of Mental Health in Bethesda, Md., and Walle Nauta, 57, of M.I.T., are using special staining techniques to trace the brain's neuronal pathways. "We have a long way to go," says Bloom, "but every little piece of information we gather leads us toward a better understanding of the way that the brain reacts to the outside world."
Twin Mysteries. In their work, all of these researchers are striving toward two major goals: explaining learning and memory. Anatomically, there is no specific learning center in the brain, and there is no explanation for learning. "There is no known basis for learning; it cannot take place," says Teuber. "In fact," he adds jokingly, "as a teacher, I sometimes wonder if it does."
But learning does occur, and most researchers believe that a crucial factor in the process is protein synthesis—the creation of complex molecules. Steven Rose, 35, a professor at Britain's Open University, has found that as chicks were trained to master certain simple skills, certain brain proteins increased.
Sweden's Holger Hyden, 56, director of the Institute of Neurobiology at the University of Goteborg, has found even more convincing evidence that proteins play a role in learning. Hyden (pronounced he-dayn) trained rats and then killed them so that their brains could be studied. He found that certain nervous-system proteins were produced in greater amounts during the first part of learning, when the animals were striving to cope with a new problem; overtraining the animals produced no higher levels of the substances. Hyden then injected animals with antibodies against the protein, which is called S-100. The injection, which blocked the protein's activity, also caused the animals' learning rate to lessen markedly. Other findings tend to reinforce this conclusion. Protein-deficient rats learn much more slowly than well-fed animals. Also, protein-deficient children from poor families habitually trail better-fed, middle-class children in intellectual development, even when the children receive the same education.