The authors examined the severity of Schneiderian first-rank symptoms in relation to regional cerebral blood flow (rCBF) with the use of PET. Eighty-seven schizophrenic patients were imaged during an eyes-closed condition during which they were instructed to relax and not perform any specific task (random episodic silent thought, or REST). Schneiderian symptoms were rated by using structured assessment instruments. The Schneiderian score of the patients was positively correlated with rCBF in right superior parietal cortex and negatively correlated with rCBF in left posterior cingulate gyrus and in left lingual gyrus. The results of this study demonstrate a cerebral pattern of activation related to Schneiderian symptoms and reinforce the hypothesis of an involvement of cortical areas that mediate space and body representation in such phenomena.