SPATIAL ABILITY IN AFFECTIVE-ILLNESS - DIFFERENCES IN REGIONAL BRAIN ACTIVATION DURING A SPATIAL MATCHING TASK (H2O)-O-15 PET)

Previous studies have determined that mood disorder patients have decr eased spatial analysis skills and report subjective deficits in spatia l reasoning. We therefore wondered if regional cerebral blood flow (rC BF) activation patterns during a spatial matching task would differ in patients with recurrent mood disorders compared to controls. We image d 10 mood-disorder patients and 10 age- and sex-matched healthy contro ls with (H2O)-O-15 PET, while subjects performed tasks involving match ing for spatial relationships or, as a control, facial identity. In no rmal volunteer controls, spatial matching activated the temporoparieta l cortex bilaterally as well as the left prefrontal cortex. Mood disor der patients activated a significantly broader area of the temporopari etal cortex during this task, while failing to activate the left dorso lateral prefrontal cortex. In the mood-disorder group, lower self-rate d spatial skills significantly correlated with less activity in the le ft prefrontal cortex and more activity in the temporal lobes bilateral ly during the spatial task. Compared to healthy controls, mood-disorde red subjects activate a broader region of the temporoparietal lobes an d do not activate the left prefrontal cortex while performing a spatia l matching task. The more impaired the patients rated themselves in sp atial/navigational skills, the less they used their left prefrontal co rtex and the more they used the temporal lobes during a spatial task. These results provide a tentative functional neuroanatomic explanation of the abnormalities in subjective spatial reasoning and extend the e xisting literature on functional brain abnormalities in affective illn ess both at rest and during specific tasks.