Effects of stimulus structure and target-distracter similarity on the development of visual memory representations in schizophrenia

Abstract

The data provide further evidence for a schizophrenia-related impairment in perceptual organisation and in the ability to develop memory representations for novel stimuli.

Cortical contributions to impaired contour integration in schizophrenia

“…This hypothesis is supported by data suggesting that the level of brain activation in regions V1 and V2 no longer predicts performance on perception tasks after behavioral evidence of perceptual learning has occurred (Ghose, Yang, & Maunsell, 2002; Yotsumoto, Watanabe, & Sasaki, 2008). It is also consistent with prior data on reduced within-session perceptual learning during perceptual organization tasks in schizophrenia (Place & Gilmore, 1980; Silverstein, Bakshi, Nuernberger, Carpinello, & Wilkniss, 2005; Silverstein, 1998, 2009; Silverstein et al, 1996), especially when top-down input is required for efficient task performance [see (Silverstein, 2009) for review]. For example, a prior 4-day perceptual learning study by our group (Silverstein et al, 2006) demonstrated that while the contour integration performance of controls saturated by day two, the performance of schizophrenia patients was continuing to improve on the 4 th day of exposure, even though it began to improve on Day 2.…”

Visual perceptual remediation for individuals with schizophrenia: Rationale, method, and three case studies.

“…Given the large body of evidence indicating that schizophrenia is associated with multiple visual perceptual impairments, including low-level deficits (Butler et al, 2008; Butler et al, 2005; Javitt & Freedman, 2015), and the relation between these alterations and impairments in higher-level cognitive (Dias et al, 2011; Silverstein et al, 2005), social cognitive (Butler et al, 2009; Green et al, 2012), and role (Rassovsky et al, 2011) functioning, we sought to evaluate the efficacy of a visual perceptual training program to improve visual processing in this condition. The UE training program targets broad-based visual function, including low-level visual processes (e.g., contrast sensitivity) and higher-level visual processes (e.g., visual attention and search; Deveau, Lovcik, et al, 2014; Deveau, Ozer, et al, 2014; Deveau & Seitz, 2014).…”

“…There is also evidence for disturbances in higher-level visual perceptual processes, including alterations in the effects of prior knowledge on the processing of visual sensory information, as suggested by work using size constancy, depth inversion, and other visual illusion paradigms (Keane, Silverstein, Wang, & Papathomas, 2013; Silverstein et al, 2013). Research has indicated that among individuals with schizophrenia, specific visual-processing alterations are significantly related to poorer performance on higher-order cognitive tasks (e.g., pattern recognition, context processing; Dias et al, 2011; Silverstein et al, 2005); impaired social cognition, including facial and emotion recognition (Butler et al, 2009; Green, Hellemann, Horan, Lee, & Wynn, 2012; Soria Bauser et al, 2012); impaired reading ability (Revheim et al, 2014); poorer treatment response (Silverstein et al, 2013; Silverstein, Schenkel, Valone, & Nuernberger, 1998); and worse functional outcomes (Rassovsky, Horan, Lee, Sergi, & Green, 2011). Such findings suggest that therapeutic strategies that directly target the visual-processing impairments associated with schizophrenia could potentially drive gains in higher-level cognitive, social, and role functioning, in addition to improving visual functions.…”

Impaired Visual Cortical Plasticity in Schizophrenia

“…While this impairment may partially underlie visual processing deficits in SZ (31–40), it is unlikely to account for the entire spectrum of SZ symptomatology. Moreover, while our experiment did not address the competency of neuroplasticity in other cortical regions, impairment in visual cortex plasticity may reflect more general plasticity dysfunction affecting other cortical regions and sensory modalities, such as the auditory cortex (64).…”

“…SZ is associated with visual learning and memory deficits (31–34) as well as early visual processing impairments that contribute to deficits in higher order visual processing and overall functioning (35–40). Given the putative role of NMDA receptor hypofunction in mediating these and other SZ deficits, we used a visual HFS paradigm previously shown to potentiate VEPs (14) to test the hypotheses that 1) visual plasticity is deficient in SZ, 2) SZ patients have a normal VSSR to tetanizing HFS, indicating that their deficient potentiation is not due to reduced attention to the tetanus, and 3) the VSSR to HFS, reflecting oscillatory entrainment of visual cortical neurons, is directly related to the magnitude of visual potentiation.…”