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Brian Keane, Sabine Kastner, Danielle Paterno, Genna Erlikhman, Steven Silverstein; Lateral interactions in schizophrenia: What is the role of spatial frequency?. Journal of Vision 2014;14(10):55. doi: 10.1167/14.10.55.
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Introduction. According to recent behavioral studies, people with schizophrenia are poor at filling-in between collinear elements because of impaired long-range horizontal connections in early visual cortex. However, patients also poorly process low spatial frequencies (SFs), which is thought to arise from dysfunction along the magnocellular pathway. In this study, we aimed to replicate the finding of impaired lateral interactions in schizophrenia and also to determine whether such impairments can be improved by employing high SF elements. Method. We had 24 persons with schizophrenia and 25 well-matched controls repeatedly detect a low-contrast element flanked by collinear or orthogonal high-contrast elements. An up/down staircase governed the contrast of the central target so that subjects detected the target 79.4% of the time. The three element display (target + flankers) was scaled in size to produce a lower and higher spatial frequency condition (4 and 10 cycles/deg, respectively). Results. Contrast thresholds were lower in the collinear than the orthogonal condition (p<.000001), indicating a robust collinear facilitation effect. Somewhat surprisingly, the effect did not depend at all on subject group (p=.62). There was a marginal three way interaction (p=.07) such that collinear facilitation in the clinical group tended to strengthen (relative to controls) at the lower SF, which was opposite to what we predicted. Interestingly, increased levels of conceptual disorganization among patients correlated with weaker collinear facilitation (p<.05), which fits with findings from other perceptual organization tasks. Conclusion. These results indicate thatâ€"in schizophreniaâ€"lateral interactions are intact and do not weaken at lower SFs. At the same time, patients with disorganized thinking are worse at perceptual organization, though it remains unclear whether this effect originates in early visual areas.
Meeting abstract presented at VSS 2014
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