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. 2017 Sep 1;20(9):740-746.
doi: 10.1093/ijnp/pyx045.

Disrupted Olfactory Integration in Schizophrenia: Functional Connectivity Study

Sara Kiparizoska  1 , Toshikazu Ikuta  1
Affiliations

Disrupted Olfactory Integration in Schizophrenia: Functional Connectivity Study

Sara Kiparizoska et al. Int J Neuropsychopharmacol. .

Abstract

Background: Evidence for olfactory dysfunction in schizophrenia has been firmly established. However, in the typical understanding of schizophrenia, olfaction is not recognized to contribute to or interact with the illness. Despite the solid presence of olfactory dysfunction in schizophrenia, its relation to the rest of the illness remains largely unclear. Here, we aimed to examine functional connectivity of the olfactory bulb, olfactory tract, and piriform cortices and isolate the network that would account for the altered olfaction in schizophrenia.

Methods: We examined the functional connectivity of these specific olfactory regions in order to isolate other brain regions associated with olfactory processing in schizophrenia. Using the resting state functional MRI data from the Center for Biomedical Research Excellence in Brain Function and Mental Illness, we compared 84 patients of schizophrenia and 90 individuals without schizophrenia.

Results: The schizophrenia group showed disconnectivity between the anterior piriform cortex and the nucleus accumbens, between the posterior piriform cortex and the middle frontal gyrus, and between the olfactory tract and the visual cortices.

Conclusions: The current results suggest functional disconnectivity of olfactory regions in schizophrenia, which may account for olfactory dysfunction and disrupted integration with other sensory modalities in schizophrenia.

Keywords: functional connectivity; olfaction; resting state fMRI; schizophrenia; sensory integration.

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Figures

Figure 1.
Figure 1.
Four regions of interest (ROIs) specified in the MNI 152 2-mm brain space. Axial images shown included regions anterior to the brain stem (y ≧ -12).
Figure 2.
Figure 2.
Olfactory tract connectivity. Regions that showed significantly lesser connectivity in the schizophrenia (SZ) group than the control group.
Figure 3.
Figure 3.
Anterior piriform connectivity. Regions that showed significantly lesser connectivity in the schizophrenia (SZ) group than the control group.
Figure 4.
Figure 4.
Posterior piriform connectivity. Regions that showed significantly lesser connectivity in the schizophrenia (SZ) group than the control group.
See this image and copyright information in PMC

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