BRAIN ACTIVATION-INDUCED BY THE PERCEPTUAL MAZE TEST - A PET STUDY OFCOGNITIVE PERFORMANCE

We investigated with PET the cerebral activation pattern elicited by t he perceptual maze test (PMT), a neuropsychological test used to evalu ate organic brain injury. The PMT examines visuospatial skill, general intelligence, visually guided motor planning, and the ability to obey rules. Eight right-handed volunteers were examined with PET using the tracer [O-15]butanol. Three paradigms containing the PMT, a motor con trol (SHAM), and a rest condition were examined twice in a randomized order. Solving the PMT caused extensive bilateral activations in the o ccipital lobe extending rostrally into the parietal lobe and caudally to the posterior part of the temporal lobe. Bilateral activations were also seen in the prefrontal, medial premotor, and the anterior cingul ate cortex (ACC). The premotor and primary sensory motor cortices cont ralateral to the performing hand were also activated. Marked activatio ns were noted in the visual system, including areas pertaining to visu ospatial decoding. The previously defined functional network (ACC, pre frontal and posterior parietal cortex) for the maintenance of visuospa tial attention was activated during the PMT. Extensive bilateral deact ivations were seen in frontomedial, temporal, parietal, and posterior cingulate regions. This pattern may represent relatively decreased blo od how in cortical areas pertaining to sensory modalities that were no t activated in the PMT. The decreased activity in these regions could also express diminished cognitive processing in neuronal systems that might interfere with the task-related performance. (C) 1995 Academic P ress, Inc.