title: Aberrations in the arcuate fasciculus are associated with auditory verbal hallucinations in psychotic and in non-psychotic individuals.
abstract: The pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the arcuate fasciculus, the major tract connecting frontal and temporo-parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non-psychotic individuals with AVH as well as patients with AVH and non-hallucinating matched controls. We compared tract integrity of the arcuate fasiculus and of three other control tracts, between 35 non-psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the arcuate fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non-psychotic individuals with AVH. As increased MTR in the arcuate fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia.
authors: Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, the Netherlands. a.d.deweijer@umcutrecht.nl
authors: Antoin D
authors: AD
authors: de Weijer
authors: Sebastiaan F W
authors: SF
authors: Neggers
authors: Kelly M S
authors: KM
authors: Diederen
authors: René C W
authors: RC
authors: Mandl
authors: René S
authors: RS
authors: Kahn
authors: Hilleke E
authors: HE
authors: Hulshoff Pol
authors: Iris E
authors: IE
authors: Sommer
mesh_terms: D000704:Analysis of Variance; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006212:Hallucinations / Q000209:etiology / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D009415:Nerve Net / Q000473:pathology; D011618:Psychotic Disorders / Q000150:complications; D013702:Temporal Lobe / Q000473:pathology*