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Unformatted text preview: nd is characteristic of the later stages of Alzheimer's. The utility of imaging for diagnosis will depend on finding abnormalities that are specific to a certain disease or perhaps to a symptom complex that may occur as a component of one or more diseases. Furthermore, morphometric analysis of the human brain has proved to be challenging. Because the overall sizes and shapes of people's brains differ so much, researchers must employ complex computer algorithms to define normal values for various populations and compare the brains of individuals against those group norms. Moreover, the boundaries between brain structures may be very subtle. MRI atlases showing the anatomy of the normal human brain as it develops over the course of childhood and adolescence are only now becoming available. chart the progress of the disease. Early detection of schizophrenia could be a great boon to treatment. Researchers are now investigating whether early intervention in schizophrenia with antipsychotic drugs and stress management therapy can delay the onset of symptoms and reduce their severity. Functional neuroimaging may also find significant uses in diagnosis. In Alzheimer's, loss of brain function may precede the macroscopic atrophy of brain structures. Investigators are already trying to refine the diagnosis for Alzheimer's by linking cognitive testing with functional imaging using MRI or PET. A similar strategy could possibly be applied to schizophrenia, which is characterized by failures in working memory (the ability to keep information in mind and manipulate it). It is conceivable that cognitive tests combined with functional imaging of the prefrontal cortex-- a brain region that supports working memory-- could contribute to the di- NEUROIMAGING TOOLS may eventually play a role in diagnosis and in monitoring the EFFECTIVENESS OF TREATMENT.
Nevertheless, scientists have been able to use neuroimaging to shed some light on psychiatric illnesses. In 2001 teams led by Judith L. Rapoport of the National Institute of Mental Health and Paul Thompson and Arthur W. Toga of the David Geffen School of Medicine at U.C.L.A., produced an impressive study that found striking anatomical changes in the brains of adolescents with schizophrenia. The researchers focused on a relatively rare form of schizophrenia that begins in childhood. (The first signs of schizophrenia usually appear in the late teens or early 20s.) MRI scans of the brains of the affected children showed a remarkable loss of gray matter in the cerebral cortex--the brain structure responsible for higher thought--between the ages of 13 and 18 [see illustration on page 101]. As the disease progressed, the loss of gray matter intensified and spread, engulfing cortical regions that support associative thinking, sensory perception and muscle movement. The anatomical abnormalities mirrored the severity of the psychotic sympto...
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- Spring '10