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Dramatic Discoveries Mark End of the "Decade of the Brain "

By Elaine Cassel

Congress designated the 1990s "The Decade of the Brain." As we enter a new millenium, several recent findings challenge long-held beliefs about the brain and provide new insight into two of the most devastating brain disorders, Parkinson's disease and schizophrenia.

It has long been thought that we are born with all the brain cells we will ever have, and that when disease or injury destroys cells, they do not regenerate. But Princeton University biologists Elizabeth Gould and Charles Gross injected macaque monkeys with a chemical that is incorporated into new DNA formed when a cell divides. In October, 1999, they reported that new neurons were generated in the area of the brain that is home to the brain's stem cells (the mother cells from which all of an organ's variety of cells originate) and migrated to areas of the cerebral cortex involved in decision-making and visual recognition. The findings suggest that the new cells might be sensitive to recording experiences from specific times. Although the research has yet to be confirmed in humans, further efforts could lead to greater understanding of long-term memory.

Also in October, Rodolfo Llinas and his colleagues at New York University School of Medicine published the results of magnetoencephalography studies of the electrical firings of the brains of nine healthy people, compared with the brains of people suffering from Parkinson's disease and depression. The people with brain problems showed a distinctive abnormal pattern of electrical activity between the thalamus, an area deep inside the brain that is a relay station for incoming information, and the cerebral cortex, the part of the brain involved in perception, thought, and recognition of information. The researchers believe that the misfirings may result in scrambled brain messages. Depending upon where in the thalamus the misfiring occurs, the result may be associated with depression, Parkinson's disease, and even schizophrenia. Further research may indicate that the misfiring can be alleviated with drugs or by implanting electrodes in the brain to regulate the electrical firings, much as a pacemaker modulates irregular heart rhythm.

Renowned schizophrenia researcher E. Fuller Torrey and colleagues presented findings on the possible role of viruses in schizophrenia at a symposium held at the Johns Hopkins University School of Medicine in the first week of November. Using frozen blood samples collected from pregnant women at hospitals around the country in the 1950s and 1960s, they found that the blood of mothers of children who developed schizophrenia had significantly higher levels of antibodies (that indicated infections during pregnancy) to the type 2 herpes virus sometimes known to cause severe brain damage in newborn infants. This type of virus is known as an "endogenous retrovirus"—endogenous, because it’s passed on from parent to child; "retro" because it lies dormant for a period of time before producing symptoms. Schizophrenia symptoms appear for the first time in late adolescence or early adulthood.

Researchers have learned more about the brain in the last ten years then they have in the short history of neuroscience, which began only 30 years ago. In the 21st century, we can expect that increasingly sophisticated brain imagining techniques and advances in molecular biology, including mapping the human genome, will continue to unlock the brain's secrets and lead to enhanced therapeutic and preventive interventions.

Susan Okie. "A Viral Source for Schizophrenia? New Evidence Gives Credence to an Old Theory." The Washington Post, Health Section, November 9, 1999, pp. 7, 10.

Rob Stein. "Brain Ailment Breakthrough?" The Washington Post, November 1, 1999, p. A13.

Nicholas Wade. "Brain May Grow New Cells Daily." The New York Times, October 15, 1999, p. 1A.

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