Examining "cognitive" theories of auditory hallucinations in schizophrenia: a functional neuroimaging study
Theories of auditory-verbal hallucinations (AVH) in schizophrenia can be broadly divided into 'perceptual' and 'cognitive' types, with the former proposing abnormal activations in auditory perceptual cortex with or without additional processes, and the latter that AVH represent the misinterpretation of cognitive processes as perceptual. Our group has recently found evidence that experience of AVH is not associated with activation in the auditory cortex, while perception of real speech does so, effectively ruling out the perceptual approach. The proposed study aims to follow up this finding by examining the two main contemporary cognitive theories of AVH, Frith's mislabelled inner speech proposal, and the proposal that AVH represent intrusive memories. We will examine whole-brain activations in schizophrenic patients with nearly continuous AVH as well as demographically matched patients without current AVH and healthy controls. To test the mislabelled inner speech proposal we will use a short-term memory task that is known to activate brain regions involved in subvocal rehearsal and short-term storage of information. To test the intrusive memory proposal, we will use an autobiographical recall task developed by ourselves, modified to elicit recall of negatively emotionally valenced memories. Differences in the general function of brain systems involved in a) short-term storage and rehearsal, and b) autobiographical recall of negatively valenced memories will be examined by comparing task-related activations between patients with and without AVH and the healthy controls. We will also examine whether experience of AVH dynamically alters activation in either the short-term memory task or the autobiographical recall task. Thus, the project has potential for developing new treatments for AVH, both physical and psychological.
Instituto de Salud Carlos III, con la cofinanciación de Fondo Europeo de Desarrollo Regional "Una manera de hacer Europa"