Related Experiment Videos
Pathways that make voices: white matter changes in auditory hallucinations.
Daniela Hubl1, Thomas Koenig, Werner Strik
1Department of Psychiatric Neurophysiology, University Hospital of Clinical Psychiatry, Bern, Switzerland. hubl@puk.unibe.ch
Archives of General Psychiatry
|July 9, 2004
Summary
Schizophrenia patients experiencing auditory hallucinations show altered white matter tracts. These changes in the arcuate fasciculus and corpus callosum may explain their difficulty distinguishing inner speech from external sounds.
Area of Science:
- Neuroimaging
- Schizophrenia Research
- Cognitive Neuroscience
Background:
- Auditory hallucinations are a core symptom of schizophrenia, with debated origins.
- Altered connectivity between frontal and parietotemporal speech areas is hypothesized in hallucination pathogenesis.
- Magnetic resonance diffusion tensor imaging (DTI) investigates white matter tract directionality.
Purpose of the Study:
- To investigate if abnormal activation patterns in auditory hallucinations correlate with structural changes in frontal-parietotemporal speech networks using DTI.
- To examine white matter integrity in patients with and without auditory hallucinations compared to healthy controls.
Main Methods:
- Diffusion tensor imaging (DTI) and structural MRI were used on a 1.5 T scanner.
- Fractional anisotropy (FA) was assessed in 13 patients with hallucinations, 13 without, and 13 healthy controls.
- Analysis of variance and voxel-based t tests identified significant differences in FA values between groups.
Main Results:
- Patients with hallucinations exhibited significantly higher white matter directionality in the temporoparietal arcuate fasciculus and anterior corpus callosum.
- Differences were most pronounced in left hemispheric fiber tracts, including the cingulate bundle, when comparing hallucinating patients to those without.
- Significantly higher white matter directionality was observed in hallucinating patients compared to both control groups.
Conclusions:
- Alterations in white matter tracts during inner speech in hallucinating patients may cause abnormal coactivation of auditory processing regions.
- This abnormal activation could lead to an inability to differentiate self-generated thoughts from external stimuli.
- Findings suggest a structural basis for the sensory misattribution in auditory hallucinations.