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. 2014 May 13;9(5):e95146.
doi: 10.1371/journal.pone.0095146. eCollection 2014.

Nonlinear complexity analysis of brain FMRI signals in schizophrenia

Moses O Sokunbi  1 , Victoria B Gradin  2 , Gordon D Waiter  3 , George G Cameron  3 , Trevor S Ahearn  3 , Alison D Murray  3 , Douglas J Steele  4 , Roger T Staff  5
Affiliations

Nonlinear complexity analysis of brain FMRI signals in schizophrenia

Moses O Sokunbi et al. PLoS One. .

Erratum in

  • PLoS One. 2014;9(8):e105741

Abstract

We investigated the differences in brain fMRI signal complexity in patients with schizophrenia while performing the Cyberball social exclusion task, using measures of Sample entropy and Hurst exponent (H). 13 patients meeting diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM IV) criteria for schizophrenia and 16 healthy controls underwent fMRI scanning at 1.5 T. The fMRI data of both groups of participants were pre-processed, the entropy characterized and the Hurst exponent extracted. Whole brain entropy and H maps of the groups were generated and analysed. The results after adjusting for age and sex differences together show that patients with schizophrenia exhibited higher complexity than healthy controls, at mean whole brain and regional levels. Also, both Sample entropy and Hurst exponent agree that patients with schizophrenia have more complex fMRI signals than healthy controls. These results suggest that schizophrenia is associated with more complex signal patterns when compared to healthy controls, supporting the increase in complexity hypothesis, where system complexity increases with age or disease, and also consistent with the notion that schizophrenia is characterised by a dysregulation of the nonlinear dynamics of underlying neuronal systems.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. The Cyberball social exclusion task.
Figure 2
Figure 2. Plots of mean whole brain complexity of the individual participants with increasing age.
(A) Mean whole brain Sample entropy. (B) Mean whole brain Hurst exponent. Error bars denote the standard error of the mean.
Figure 3
Figure 3. Group mean complexity differences after correcting for age and sex differences together in the GLM.
(A) Group mean Sample entropy. (B) Group mean Hurst exponent.
Figure 4
Figure 4. Correlation between sample entropy and Hurst exponent, and ROC curves.
(A) Linear regression curve estimation between the mean whole brain sample entropy and mean whole brain Hurst exponent for the whole population. (B) ROC curve for Sample entropy. (C) ROC curve for Hurst exponent.
Figure 5
Figure 5. Scatter plots and rendered images showing differences between control and patients with schizophrenia after correcting for age and sex differences together.
Scatter plots depict the mean SampEn and H values at different brain ROI. Rendered images show the difference in SampEn and H between the control and patients with schizophrenia. Regions shown have higher complexity in patients with schizophrenia. See table 2 for a complete list of these regions (threshold p = 0.005 and corrected cluster p<0.05).
See this image and copyright information in PMC

References

    1. Robert PH, Migneco V, Chaix I, Berthet L, Kazes M, et al. (1997) Use of a sequencing task designed to stress the supervisory system in schizophrenic subjects. Psychological Medicine 27: 1287–1294. - PubMed
    1. Gradin V, Waiter G, Kumar P, Stickle C, Milders M, et al. (2012) Social Exclusion in Schizophrenia. PLoS One 7(8): e42608 doi:10.1371/journal.pone.0042608 - DOI - PMC - PubMed
    1. Picchioni MM, Murray RM (2007) Schizophrenia BMJ. 335: 91–5. - PMC - PubMed
    1. Couture SM, Penn DL, Roberts DL (2006) The functional significance of social cognition in schizophrenia: a review. Schizophrenia bulletin 32 Suppl 1 S44–63. - PMC - PubMed
    1. Williams KD, Cheung CKT, Choi W (2000) Cyberostracism: Effects of being ignored over the internet. Journal of personality and social psychology 79(5): 748–762. - PubMed

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