Icon formation in chronic schizophrenics

Schwartz, Barry; Winstead, Daniel K.

doi:10.1016/0006-3223(85)90200-8

Cited by 20 publications

(14 citation statements)

References 20 publications

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“…[17][18][19] The hypothesis of transient channel dysfunction was confirmed by other investigators using different methods. [17][18][19] The hypothesis of transient channel dysfunction was confirmed by other investigators using different methods.…”

Section: Visual Channel Dysfunction In Schizophreniamentioning

confidence: 81%

“…[13][14][15][16] It must be noted, however, that achromatic stimuli with low contrast are especially suitable for the investigation of transient channels but allow only a limited possibility to draw conclusions regarding the functioning of sustained channels. [17][18][19][20][21][22][23][24][25][26][27] Several factors may contribute to the inhomogeneity of data, including methodological differences, patient selection, and medication effects. Some findings suggest a transient channel dysfunction, and a number of studies also report impaired sustained channel functions.…”

Section: C/d) Highermentioning

confidence: 99%

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Spatiotemporal Visual Processing in Schizophrenia

Kéri

Antal

Szekeres

et al. 2002

JNP

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Studies examining visual processing in schizophrenia have provided inconsistent results. In this study, the authors measured static and dynamic visual contrast sensitivity (CS) in patients with schizophrenia (n=20) and control subjects (n=15). Extrapyramidal symptoms were evaluated with the Simpson-Angus scale. In the static condition, the patients with schizophrenia showed reduced CS in the spatial frequency range of 2.9-14.4 cycles per degree of visual angle (c/d). In the dynamic condition, CS loss was present over the whole range tested (0.5-14.4 c/d). Higher Simpson-Angus scores and higher doses of antipsychotic medication were associated with more severe CS deficits. These results suggest that the hypodopaminergic state induced by antipsychotic medication may produce parkinsonian visual impairments in schizophrenia patients.

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Section: Visual Channel Dysfunction In Schizophreniamentioning

confidence: 81%

Section: C/d) Highermentioning

confidence: 99%

Spatiotemporal Visual Processing in Schizophrenia

Kéri

Antal

Szekeres

et al. 2002

JNP

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“…Patients with schizophrenia (SZ), their first degree relatives and individuals diagnosed with schizotypal personality disorder (SPD) have deficient visual information processing as assessed by a variety of paradigms including visual backward masking (VBM), motion perception, spatial localization, eye tracking and visual contrast sensitivity (VCS) (Braff and Saccuzzo, 1981; Schwartz and Winstead, 1985; Schwartz et al, 1987, 1988; Green et al, 1994; O'Donnell et al, 1996; Saccuzzo et al, 1996; Cadenhead et al, 1998; Slaghuis, 1998; Chen et al, 1999; Green and Nuechterlein, 1999; Slaghuis and Curran, 1999; Keri et al, 2000, 2002; Butler et al, 2001). With increasing knowledge of information processing in the visual system, it has been possible to apply newer paradigms in SZ spectrum populations in order to specify the underlying mechanisms and possible neural substrates responsible for the observed deficits.…”

Section: Introductionmentioning

confidence: 99%

“…Perhaps one of the most straightforward ways in which M vs. P pathway processing in SZ has been investigated has been to measure VCS to stimuli designed to activate one pathway more than the other (Schwartz and Winstead, 1985, 1997; Schwartz et al, 1987, 1988; Slaghuis, 1998; Chen et al, 1999; Keri et al, 2000, 2002; Butler et al, 2001, 2009; Kiss et al, 2010; Kent et al, 2011; Halasz et al, 2013). VCS is defined as the inverse of the contrast needed in a stimulus (typically, a sinusoidal grating) in order for that stimulus to be just barely detectable, referred to as “contrast threshold.” The advantage of using the VCS paradigm is that it can isolate activity in a given pathway.…”

Section: Introductionmentioning

confidence: 99%

Schizophrenia spectrum participants have reduced visual contrast sensitivity to chromatic (red/green) and luminance (light/dark) stimuli: new insights into information processing, visual channel function, and antipsychotic effects

Cadenhead¹,

Dobkins²,

McGovern³

et al. 2013

Front. Psychol.

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Background: Individuals with schizophrenia spectrum diagnoses have deficient visual information processing as assessed by a variety of paradigms including visual backward masking, motion perception and visual contrast sensitivity (VCS). In the present study, the VCS paradigm was used to investigate potential differences in magnocellular (M) vs. parvocellular (P) channel function that might account for the observed information processing deficits of schizophrenia spectrum patients. Specifically, VCS for near threshold luminance (black/white) stimuli is known to be governed primarily by the M channel, while VCS for near threshold chromatic (red/green) stimuli is governed by the P channel.Methods: VCS for luminance and chromatic stimuli (counterphase-reversing sinusoidal gratings, 1.22 c/degree, 8.3 Hz) was assessed in 53 patients with schizophrenia (including 5 off antipsychotic medication), 22 individuals diagnosed with schizotypal personality disorder and 53 healthy comparison subjects.Results: Schizophrenia spectrum groups demonstrated reduced VCS in both conditions relative to normals, and there was no significant group by condition interaction effect. Post-hoc analyses suggest that it was the patients with schizophrenia on antipsychotic medication as well as SPD participants who accounted for the deficits in the luminance condition.Conclusions: These results demonstrate visual information processing deficits in schizophrenia spectrum populations but do not support the notion of selective abnormalities in the function of subcortical channels as suggested by previous studies. Further work is needed in a longitudinal design to further assess VCS as a vulnerability marker for psychosis as well as the effect of antipsychotic agents on performance in schizophrenia spectrum populations.

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“…patients need higher contrast in order to perceive a stimulus). This trend was particularly pronounced when using low SF [29-31] but see [32, 33]. Slaghuis et al compared the contrast sensitivity at low and high SF and found that patients with deficit/negative syndrome have significantly worse CS on the low SF than controls or patients with predominantly positive symptomatology [26, 34].…”

Section: Visual Information Processing Performance Biomarkers In Smentioning

confidence: 99%

New visual information processing abnormality biomarkers for the diagnosis of schizophrenia

Koychev

El‐Deredy

Deakin

2011

Expert Opinion on Medical Diagnostics

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Introduction-Schizophrenia is currently diagnosed on the basis of patient reports and clinical observations. A diagnosis based on aetiology is inherently more reliable due to being closer to the disease process than the overt clinical manifestations. Accordingly, recent research in schizophrenia has focused on the development of biomarkers in a bit to improve the reliability and neurobiological relevance of the diagnosis. Visual information processing is one of these promising fields of recent biomarker research.Areas covered-This article provides an overview of the available literature regarding deficits in schizophrenia detectable through psychophysical (contrast and motion sensitivity, visual backward-masking), ERP (P1 and N1 visual evoked potentials) and oscillatory (signal power and phase-locking factor of evoked oscilations) measures and their validity as trait or state biomarkers of the disease. The methodology included a search on articles related to visual information processing in schizophrenia on the PubMed database.Expert opinion-Biomarker research in schizophrenia is a rapidly expanding area. Evidence exists to suggest that both psychotic and manic symptoms are associated with visual processing abnormalities. A specific impairment confined to the magnocellular component of the visual system might be a trait biomarker of schizophrenia.

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Icon formation in chronic schizophrenics

Cited by 20 publications

References 20 publications

Spatiotemporal Visual Processing in Schizophrenia

Spatiotemporal Visual Processing in Schizophrenia

Schizophrenia spectrum participants have reduced visual contrast sensitivity to chromatic (red/green) and luminance (light/dark) stimuli: new insights into information processing, visual channel function, and antipsychotic effects

New visual information processing abnormality biomarkers for the diagnosis of schizophrenia

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