Anatomical integrity within the inferior fronto-occipital fasciculus and semantic processing deficits in schizophrenia spectrum disorders

Werner Surbeck; Jürgen Hänggi; Felix Scholtes; Petra V Viher; André Schmidt; Katharina Stegmayer; Erich Studerus; Udine E Lang; Anita Riecher-Rössler; Werner Strik; Erich Seifritz; Stefan Borgwardt; Boris B Quednow; Sebastian Walther

doi:10.1016/j.schres.2019.12.025

Anatomical integrity within the inferior fronto-occipital fasciculus and semantic processing deficits in schizophrenia spectrum disorders

Schizophr Res. 2020 Apr:218:267-275. doi: 10.1016/j.schres.2019.12.025. Epub 2020 Jan 13.

Authors

Affiliations

¹ Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, Zurich, Switzerland; Department of Neuroanatomy, Faculty of Medicine, University of Liège, Liège, Belgium; Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, Zurich, Switzerland. Electronic address: werner.surbeck@puk.zh.ch.
² Division Neuropsychology, Department of Psychology, University of Zurich, Zurich, Switzerland.
³ Department of Neuroanatomy, Faculty of Medicine, University of Liège, Liège, Belgium; Department of Neurosurgery, University Hospital of Liège, Liège, Belgium.
⁴ Translational Research Center, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
⁵ Department of Psychiatry (UPK), University of Basel, Basel, Switzerland.
⁶ Medical Faculty, University of Basel, Basel, Switzerland.
⁷ Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH, Zurich, Switzerland.
⁸ Department of Psychiatry (UPK), University of Basel, Basel, Switzerland; Department of Psychiatry and Psychotherapy, University of Lübeck, Germany.
⁹ Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich, University and ETH, Zurich, Switzerland.

PMID: 31948896
DOI: 10.1016/j.schres.2019.12.025

Abstract

The core symptoms of schizophrenia spectrum disorders (SSD) include abnormal semantic processing which may rely on the ventral language stream of the human brain. Thus, structural disruption of the ventral language stream may play an important role in semantic deficits observed in SSD patients. Therefore, we compared white matter tract integrity in SSD patients and healthy controls using diffusion tensor imaging combined with probabilistic fiber tractography. For the ventral language stream, we assessed the inferior fronto-occipital fasciculus [IFOF], inferior longitudinal fasciculus, and uncinate fasciculus. The arcuate fasciculus and corticospinal tract were used as control tracts. In SSD patients, the relationship between semantic processing impairments and tract integrity was analyzed separately. Three-dimensional tract reconstructions were performed in 45/44 SSD patients/controls ("Bern sample") and replicated in an independent sample of 24/24 SSD patients/controls ("Basel sample"). Multivariate analyses of fractional anisotropy, mean, axial, and radial diffusivity of the left IFOF showed significant differences between SSD patients and controls (p_(FDR-corr) < 0.001, η_p² = 0.23) in the Bern sample. Axial diffusivity (AD) of the left UF was inversely correlated with semantic impairments (r = -0.454, p_(FDR-corr) = 0.035). In the Basel sample, significant group differences for the left IFOF were replicated (p < .01, η_p² = 0.29), while the correlation between AD of the left IFOF and semantic processing decline (r = -0.376, p = .09) showed a statistical trend. No significant effects were found for the dorsal language stream. This is direct evidence for the importance of the integrity of the ventral language stream, in particular the left IFOF, in semantic processing deficits in SSD.

Keywords: Diffusion tensor imaging; First episode psychosis; Formal thought disorder; Inferior frontooccipital fasciculus; Schizophrenia; Semantic impairment.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anisotropy
Diffusion Tensor Imaging
Humans
Nerve Net
Neural Pathways / diagnostic imaging
Schizophrenia* / complications
Schizophrenia* / diagnostic imaging
Semantics
White Matter* / diagnostic imaging