We employed a novel variant of the symptom capture paradigm and 3 T fMRI to examine 30 right-handed adult patients with a DSM-5 diagnosis of schizophrenia or schizoaffective disorder (see “ Methods” for diagnostic and exclusion criteria). Others, however, have not found auditory cortex activation 13, or found activation only in a very small cluster (11 voxels) 14 or activation which appeared to be localized to temporal lobe white matter 15. Several studies of this type 9, 10, 11, 12 have found evidence of AVH-related activations in the superior temporal cortex, the posterior part of which contains the primary auditory cortex (Heschl’s gyrus). Beyond such clinical observations, the neurological/perceptual model of AVH is testable using functional imaging, specifically the symptom capture paradigm, which compares brain activations at times when hallucinating patients hear a voice (which they typically signal by a button press) to periods when the voices are silent. A current version of this approach proposes that, in addition to there being such a ‘bottom-up’ abnormal perceptual process, ‘top-down’ influences on perception act to confer additional features on AVH, leading them to be interpreted as the voices of family, friends or people involved in a conspiracy against the patient, etc 7.Ĭomplex perceptual experiences are known to occur in neurological disorders such as epilepsy and migraine, and electrical stimulation of the temporal lobe cortex in patients undergoing brain surgery can also result in auditory experiences up to and including speech 8. In its simplest form this approach dates back to the beginning of the twentieth century as the idea that they are due to pathological (‘irritative’) neuronal activity in the auditory cortex 6. The other main approach, the ‘neurological’ or ‘perceptual’ model, proposes that AVH are in some sense genuinely perceptual in nature. Theoretical approaches to AVH include so-called ‘cognitive’ models, which argue that they are a manifestation of non-perceptual processes, for example inner speech that fails to be labeled as internally generated 3, or memories whose vividness and/or intrusiveness leads them to be misinterpreted as perceptions 4, 5. While the clinical features of the phenomenon are well established-AVH may be single or multiple, are often but not always derogatory, and may be experienced inside or outside the head (or both) 2−the mechanism or mechanisms underlying them remain obscure. Auditory verbal hallucinations (AVH) are a major symptom of schizophrenia, estimated to occur in around 70% of patients 1.
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