FUNCTION AND ORGANIZATION IN DYSGENIC CORTEX

Cerebral dysgenesis is a subject of interest because of its relationsh ip to cerebral development and dysfunction and to epilepsy. The author s present a detailed study of a 16-year-old boy who underwent surgery for a severe seizure disorder. This patient had dysgenesis of the righ t hemisphere, which was composed of a giant central frontoparietal nod ular gray matter heterotopia with overlying large islands of cortical dysplasia around a displaced central fissure. Exceptional insight into the function, biochemistry, electrophysiology, and histological struc ture of this lesion was obtained from neurological studies that reveal ed complementary information: magnetic resonance (MR) imaging, [(18)]f luoro-2-deoxy-D-glucose positron emission tomography (PET), functional PET scanning, proton MR spectroscopic (H-1-MRS) imaging, intraoperati ve cortical mapping and electrocorticography, in vitro electrophysiolo gy, and immunocytochemistry. These studies demonstrated compensatory c ortical reorganization and showed that large areas of heterotopia and cortical dysplasia in the central area may retain normal motor and sen sory function despite strikingly altered cytoarchitectonic organizatio n and neuronal metabolism. Such lesions necessitate appropriate functi onal imaging studies prior to surgery and cortical mapping to avoid cr eating neurological deficits. Integrated studies, such as PET, H-1-MRS imaging, cortical mapping, immunocytochemistry, and electrophysiology may provide information on the function of developmental disorders of cerebral organization.