Perceptual Organization Impairment in Schizophrenia and Associated Brain Mechanisms: Review of Research from 2005 to 2010

Abstract

Perceptual organization (PO) refers to the processes by which visual information is structured into coherent patterns such as groups, contours, perceptual wholes, and object representations. Impairments in PO have been demonstrated in schizophrenia since the 1960s and have been linked to several illness-related factors including poor premorbid functioning, poor prognosis, and disorganized symptoms. This literature was last reviewed in 2005. Since then, electrophysiological (electroencephalographic, event-related potential, and magnetoencephalographic) and fMRI studies in both patient and nonpatient samples have clarified brain mechanisms involved in the impairment, and additional behavioral studies in patients and nonpatients have clarified the computational mechanisms. In addition, data now exist on the functional consequences of PO impairments, in terms of secondary difficulties in face processing, selective attention, working memory, and social cognition. Preliminary data on drug effects on PO and on changes in response to treatment suggest that anomalies in PO may furnish a biomarker for the integrity of its associated biological mechanisms. All of this recent evidence allows for a clearer picture of the nature of the impairment and how it relates to broader aspects of brain and behavioral functioning in schizophrenia.

Shift toward prior knowledge confers a perceptual advantage in early psychosis and psychosis-prone healthy individuals

“…This finding is not directly relevant to the main question addressed in this study but it is interesting because it contrasts with previous studies in patients with established schizophrenia who show reduced ability to spontaneously disambiguate two-tone images of faces without prior knowledge (46,47). This previous effect is most likely related to well-established schizophrenic deficits in early and midlevel vision that affect perceptual organization, context processing and integration (37,38,(48)(49)(50)(51)(52)(53) rather than to top-down influences from high-level visual cognition as in the current study. We did not directly probe early and midlevel visual function in our participants, but it seems most likely that the absence of impairments in spontaneous disambiguation of two-tone images in the clinical group might be due to the specific nature of our stimulus material, which was extensively piloted to be difficult to disambiguate without prior knowledge (for details, see SI Materials and Methods).…”

On the functions, mechanisms, and malfunctions of intracortical contextual modulation

“…A recent review of the large body of evidence on this issue (Lesh et al, 2011) noted that reduced cognitive control involves reductions in dendritic spines, reduced GABA release in PV interneurons, and reduced PFC-related gamma band activity -all of which are consistent with the evidence cited above. In addition, decreased cognitive control in schizophrenia is related to an increase in disorganized symptoms, mirroring the findings from studies of reduced perceptual organization in the disorder (Phillips & Silverstein, 2003;Silverstein & Keane, 2011). These data from patients are supported by experimental studies in animals (O'Reilly, et al, 2014), including those demonstrating methods by which schizophrenia-related cognitive control impairments may be reduced (Lee et al, 2012a).…”

“…This has now been demonstrated in over 50 studies (reviewed in Silverstein & Keane, 2011). These findings are not due to medication effects, or to generalized performance deficits: in cases where grouping of targets and distracters interferes with task accuracy, schizophrenia patients demonstrate greater accuracy than controls (e.g., Place & Gilmore, 1980;Silverstein et al, 2013;Uhlhaas et al, 2006).…”

“…Importantly, abnormalities in these domains are significantly correlated with each other (Lindenmayer, Bernstein-Hyman, & Grochowski, 1994;Walther et al, 2014), and with severity of perceptual organization impairments (reviewed in Phillips & Silverstein, 2003;Silverstein & Keane, 2011). This all suggests that in schizophrenia there is a widespread failure in dynamic, context-sensitive, grouping.…”

Bender-Gestalt Test: Normalizing the Bender Visual-Motor Test Among 5-7 Year-Old Kurdish Children

“…After a while, Pascal, Haink and Suttel developed a widely accepted scoring procedure for adults (Koppitz, 1963). Koppitz introduced a scoring procedure for children that is extensively applied to assessing the growth process and the sensory-motor coordination (Silverstein et al, 2011). The Bender Visual-Motor Test is the fifth psychological instrument recommended for clinical evaluations.…”