Functional magnetic resonance imaging during sentence verification: A potential tool for assessment of neuro-correlates of delusional disorders

Schizophrenia is a heterogeneous disorder characterized by delusions, hallucinations, disorganized thinking, and cognitive deficits. Delusions are false beliefs that are firmly held in spite of evidence to the contrary. Functional magnetic resonance imaging is a noninvasive technique that allows investigators to assess brain function during specific thinking processes. To our knowledge, no studies have directly assessed brain function during the evaluation of delusional beliefs. In the present study, we compared the brain activity of normal healthy subjects that is associated with the evaluation of true versus false statements. fMRI images were acquired in nine subjects while they performed a task in which they were presented with, and required to validate or reject, a Ž series of true and false statements 30 of each, in total, in blocks . of five ; 50 of the sentences were autobiographical in content, and were derived from individual subject interviews held prior to scanning, while 10 sentences were A general knowledge B statements about the world. Results indicate that the right dorsal lateral Ž. prefrontal cortex RDLPFC is more active during the validation of true statements, as compared to during the negation of false statements. The RDLPFC is believed to be important to the integration of current perceptions and ideas with an individual’s existing knowledge and memories. In principle, such a procedure may be useful in the assessment of the neural correlates associated with delusional thinking. By directly assessing the evaluation of delusional beliefs, we hope to gain increased insight into the formation and maintenance of delusional thinking in schizophrenia