Re-analysis of previous orientation-dependent surround suppression schizophrenia studies
ثبت نشده
چکیده
The key assumptions of the use of a ratio to adjust the numerator to control for a particular variable (denominator) are that the relationship between the denominator and numerator is linear and that it passes through the origin. To investigate these assumptions, we performed regressions of orthogonal and parallel surround thresholds against no-surround thresholds2. As shown in Fig. R1 (left column) below, the relationships do appear to be linear but the y -intercept is consistently below zero.
منابع مشابه
Diminished orientation-specific surround suppression of visual processing in schizophrenia.
Visual perception of a stimulus is a function of the visual context in which it is displayed. Surround suppression is a specific form of contextual modulation whereby the perceived contrast of a center stimulus is decreased by a high-contrast surround. Recent studies have demonstrated that individuals with schizophrenia are less prone to visual contextual effects, suggesting impairments in cort...
متن کاملReduced visual surround suppression in schizophrenia shown by measuring contrast detection thresholds
Visual perception in schizophrenia is attracting a broad interest given the deep knowledge that we have about the visual system in healthy populations. One example is the class of effects known collectively as visual surround suppression. For example, the visibility of a grating located in the visual periphery is impaired by the presence of a surrounding grating of the same spatial frequency an...
متن کاملGABA concentration is reduced in visual cortex in schizophrenia and correlates with orientation-specific surround suppression.
The neural mechanisms underlying cognitive deficits in schizophrenia remain essentially unknown. The GABA hypothesis proposes that reduced neuronal GABA concentration and neurotransmission results in cognitive impairments in schizophrenia. However, few in vivo studies have directly examined this hypothesis. We used magnetic resonance spectroscopy (MRS) at high field to measure visual cortical G...
متن کاملVisual Surround Suppression in Schizophrenia
Compared to unaffected observers patients with schizophrenia (SZ) show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgments of contrast - a manifestation of weaker surround suppression (SS). To examine the generality of this phenomenon we measured the ability of 24 individuals with SZ to judge the luminance, contrast, orien...
متن کاملCenter-surround interactions in a network model of layer 4Ca of primary visual cortex
Context integration is an ubiquitious principle in cortical processing underlying many perceptual and cognitive functions. Several neuropsychiatric disorders have been associated with an impairment of integration of context information, particularly schizophrenia [5]. One way to investigate the mechanisms underlying context processing and its impairments, is to look at context integration in th...
متن کامل