Psychophysical assessment of magno- and parvocellular function in 
schizophrenia

Delord, Sandrine; Ducato, Maria Giovanna; Pins, Delphine; Devinck, Frédéric; Thomas, Pierre; Boucart, Muriel; Knoblauch, Kenneth

doi:10.1017/s0952523806233017

Cited by 22 publications

(14 citation statements)

References 34 publications

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“…Thus, our results suggest that these subcortical and cortical mechanisms are relatively intact in SZ. A previous study found abnormal luminance discriminations in SZ (Delord et al, 2006). This result, however, is in contrast to normal luminance matching in the no-context control condition reported here.…”

Section: Discussionmentioning

confidence: 83%

Visual Context Processing in Schizophrenia

Yang

Tadin

Glasser

et al. 2012

Clinical Psychological Science

128

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Abnormal perceptual experiences are central to schizophrenia but the nature of these anomalies remains undetermined. We investigated contextual processing abnormalities across a comprehensive set of visual tasks. For perception of luminance, size, contrast, orientation and motion, we quantified the degree to which the surrounding visual context altered a center stimulus’ appearance. Across tasks, healthy participants showed robust contextual effects, as evidenced by pronounced misperceptions of center stimuli. Schizophrenia patients exhibited intact contextual modulations of luminance and size, but showed weakened contextual modulations of contrast, performing more accurately than controls. Strong motion and orientation context effects correlated with worse symptoms and social functioning. Importantly, the overall strength of contextual modulation across tasks did not differ between controls and schizophrenia patients. Additionally, performance measures across contextual tasks were uncorrelated, implying discrete underlying processes. These findings reveal that abnormal contextual modulation in schizophrenia is selective, arguing against the proposed unitary contextual processing dysfunction.

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Section: Discussionmentioning

confidence: 83%

Visual Context Processing in Schizophrenia

Yang

Tadin

Glasser

et al. 2012

Clinical Psychological Science

128

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“…It remains an open question whether these visual deficits are restricted to patients with negative symptoms (e.g., Slaghuis, 1998) and to certain stimuli, such as low spatial frequency gratings (Kéri et al, 2004). Delord et al (2006) found that contrast detection thresholds of schizophrenic patients were significantly poorer than those of controls for all frequencies, arguing rather for a general visual deficit. Patients show also strongly deteriorated performance for high contrast stimuli when these stimuli are fragmented, i.e., where only parts of the contour of an object are visible.…”

Section: Discussionmentioning

confidence: 97%

Schizophrenia and visual backward masking: a general deficit of target enhancement

Herzog¹,

Roinishvili²,

Chkonia³

et al. 2013

Front. Psychol.

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The obvious symptoms of schizophrenia are of cognitive and psychopathological nature. However, schizophrenia affects also visual processing which becomes particularly evident when stimuli are presented for short durations and are followed by a masking stimulus. Visual deficits are of great interest because they might be related to the genetic variations underlying the disease (endophenotype concept). Visual masking deficits are usually attributed to specific dysfunctions of the visual system such as a hypo- or hyper-active magnocellular system. Here, we propose that visual deficits are a manifestation of a general deficit related to the enhancement of weak neural signals as occurring in all other sorts of information processing. We summarize previous findings with the shine-through masking paradigm where a shortly presented vernier target is followed by a masking grating. The mask deteriorates visual processing of schizophrenic patients by almost an order of magnitude compared to healthy controls. We propose that these deficits are caused by dysfunctions of attention and the cholinergic system leading to weak neural activity corresponding to the vernier. High density electrophysiological recordings (EEG) show that indeed neural activity is strongly reduced in schizophrenic patients which we attribute to the lack of vernier enhancement. When only the masking grating is presented, EEG responses are roughly comparable between patients and control. Our hypothesis is supported by findings relating visual masking to genetic deviants of the nicotinic α7 receptor (CHRNA7).

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“…Various studies assert that visual deficits in schizophrenia patients are related to the parvocellular pathway or are related to the interaction between the magnocellular and parvocellular pathways [61, 64]. Table 2 shows some of comparative studies of magnocellular and parvocellular pathway in schizophrenia.…”

Section: Dopamine and Glutamine Rolementioning

confidence: 99%

Ophthalmology Issues in Schizophrenia

Gracitelli

Abe

Diniz-Filho

et al. 2015

Curr Psychiatry Rep

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Schizophrenia is a complex mental disorder associated with not only cognitive dysfunctions, such as memory and attention deficits, but also changes in basic sensory processing. Although most studies on schizophrenia have focused on disturbances in higher-order brain functions associated with the prefrontal cortex or frontal cortex, recent investigations have also reported abnormalities in low-level sensory processes, such as the visual system. At very early stages of the disease, schizophrenia patients frequently describe in detail symptoms of a disturbance in various aspects of visual perception that may lead to worse clinical symptoms and decrease in quality of life. Therefore, the aim of this review is to describe the various studies that have explored the visual issues in schizophrenia.

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Psychophysical assessment of magno- and parvocellular function in schizophrenia

Cited by 22 publications

References 34 publications

Visual Context Processing in Schizophrenia

Visual Context Processing in Schizophrenia

Schizophrenia and visual backward masking: a general deficit of target enhancement

Ophthalmology Issues in Schizophrenia

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