Systems Model of Cortical Organization: Positron Emission Tomography and Neuropsychological Test Performance

Positron Emission Tomography (PET) has a/lowed reseurchers toexamine in vivo br~~~-be~~vior ~~ationsh~ps. Correlations of metaboIie increases measured by PET with simple sensory tasks jn~~oIv~ng hear&g, vision, end tucti~e/motor re-sponses have genera&y produced metabolic changes in agreement with known neuronal pathways. However, complex neuropsychological tests such as Raven’s Matrices and Verbal Fluency have resulted in cortical activation of unexpected areas as well as ome negative correlations between test performance and metab-olism. These observations provide the first demonstration of complex relation-ships between neuropsychofogicai functioning and activation of the normal brain. Since PET technology offers (I means of computing the simultaneous proporiion~ ~ contribution of mufiiple brain regions, the issue of ‘focalization ” of neuropsyrhoiog~~~i test performff~ce might appropriately be considered for re-definition in terms of a “‘systems ” approach. in spite of the advances brought about by PE7; methodological probfems s7ill remain for researchers. Future studies will need to take into account he subtte regional effects of neuropsycho-logical paradigms. This articfe is based on the senior author’s PsyD dissertation. Presented in part at the meetin