S.S. Shergill, M.J. Brammer, E. Amaro, S.C. Williams, R.M. Murray, and P.K. McGuire, British Journal of Psychiatry, December 2004, 185, 516–7.
Abstract: We used functional magnetic resonance imaging to examine how brain activity associated with auditory verbal hallucinations in schizophrenia changed during hallucinatory events. Activation in the left inferior frontal and right middle temporal gyri was evident 6-9 s before the person signalled the onset of the hallucination, whereas activation in the bilateral temporal gyri and the left insula coincided with the perception of the hallucination. This supports the hypothesis that during hallucinations activation in cortical regions mediating the generation of inner speech may precede the engagement of areas implicated in the perception of auditory verbal material.