September 2021
Volume 21, Issue 9
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2021
Contrast surround suppression in people with psychosis: A behavioral and 7 tesla fMRI study
Author Affiliations & Notes
  • Hannah R. Moser
    University of Minnesota
  • Li Shen Chong
    University of Minnesota
  • Rohit S. Kamath
    University of Minnesota
  • Scott R. Sponheim
    Minneapolis VA Medical Center
    University of Minnesota
  • Michael-Paul Schallmo
    University of Minnesota
  • Footnotes
    Acknowledgements  U01 MH108150, K01 MH120278, P41 EB015894, P30 NS076408, UL1 TR002494
Journal of Vision September 2021, Vol.21, 2047. doi:https://doi.org/10.1167/jov.21.9.2047
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      Hannah R. Moser, Li Shen Chong, Rohit S. Kamath, Scott R. Sponheim, Michael-Paul Schallmo; Contrast surround suppression in people with psychosis: A behavioral and 7 tesla fMRI study. Journal of Vision 2021;21(9):2047. doi: https://doi.org/10.1167/jov.21.9.2047.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

People with psychosis experience abnormal visual percepts (e.g., hallucinations). It is unknown if these differences are unique to specific diagnoses, or are influenced by genetic liability for psychosis (as in close biological relatives). The underlying neural processes also remain largely uncharacterized. Based on previous studies, we hypothesized people with psychosis would show reduced surround suppression during visual contrast perception, versus controls. The current study, part of the ongoing Psychosis Human Connectome Project, examined contrast surround suppression using behavioral and 7 tesla fMRI data from 43 people with psychosis (schizophrenia, schizoaffective, or bipolar diagnoses), 34 unaffected first-degree biological relatives, and 26 healthy controls. In our behavioral experiments, contrast discrimination thresholds were determined using circular gratings at seven contrast levels (0-20%). We previously showed higher contrast discrimination thresholds (without surrounds) for people with psychosis in this task. Here, we quantified threshold elevation for 10% contrast targets with a surrounding annulus (100% contrast) versus without. We expected to see less threshold elevation with surrounding stimuli in people with psychosis, compared to controls or relatives. However, no such difference was observed. 7T fMRI responses were measured in the lateral geniculate nucleus, primary visual cortex (V1), and lateral occipital complex (LOC) during a similar task at four contrast levels (10-80%). Contrast-dependent responses in V1 and LOC were suppressed by the presence of the surrounding stimulus. While there were no group differences in V1 fMRI responses, LOC responses showed greater surround suppression in controls than in relatives or people with psychosis, consistent with previous behavioral findings. While our behavioral results do not suggest weaker surround suppression in people with psychosis, there was mixed evidence for such a difference from fMRI responses in visual cortex.

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