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Kirsten Panton, Johanna Badcock, J. Edwin Dickinson, David Badcock; Poorer contour integration occurs in students with positive schizotypy. Journal of Vision 2017;17(10):1367. doi: https://doi.org/10.1167/17.10.1367.
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© ARVO (1962-2015); The Authors (2016-present)
Schizophrenia patients exhibit poor contour integration on the Jittered Orientation Visual Integration (JOVI) task even at the first episode of illness, but little is known about visual integration abilities prior to illness onset. Here we examined if similar difficulties occur in healthy individuals prone to psychosis. We used a modified JOVI task – the Radial Frequency Jittered Orientation Tolerance (RFJOT) task - in students with high (n = 59) and low (n = 80) positive schizotypy traits, a risk marker for schizophrenia. For this task, the observer decides whether a spatially sampled contour present in a field of Gabor patches is left-ward or right-ward pointing. As the orientation jitter of sampled patches changes (0o, 7o, 11o, 15o, 19o, 23o, 27o), the stimulus becomes more difficult to see, with thresholds representing the amount of jitter that causes performance to decline to 75% accuracy. Participants were given an infinite amount of time to respond, in order to dissociate integration ability from individual differences in processing speed. There were no significant group differences at 0o jitter, which suggests attention to the task was adequate regardless of schizotypy status. However, compared to the low schizotypy group, the high schizotypy group had a significantly lower proportion of correct responses, collapsed across non-zero jitter levels, and significantly lower thresholds, with medium effect sizes for both outcomes. The results indicate that poorer contour integration occurs in high positive schizotypes who are at increased risk for schizophrenia. These findings add to extensive evidence of visual integration dysfunction in schizophrenia, and suggest that similar difficulties may be present prior to first diagnosis, i.e. poor contour integration represents a trait marker of schizophrenia. The RFJOT task may offer a useful measure of visual integration, indexing risk for schizophrenia, in general community samples.
Meeting abstract presented at VSS 2017
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