Event-Related fMRI Study of Context Processing in Dorsolateral Prefrontal Cortex of Patients With Schizophrenia.

Context processing is conceptualized as an executive function involved in voluntary, complex actions such as overcoming automatic responses. The present study tested the hypothesis that context-processing deficits in patients with schizophrenia are associated with a dysfunction of left dorsolateral prefrontal cortex (DLPFC). Using event-related functional magnetic resonance imaging (fMRI), 17 controls and 17 medicated patients performed a version of the AX task in which a learned, automatic response had to be inhibited. In controls, left DLPFC activity increased when preparing to overcome an automatic response, whereas patients with schizophrenia showed no differential activation. In controls, context processing appeared to be associated with the differential representation of cues associated with the need to provide top-down support for overcoming automatic responses. This mechanism appeared to be impaired in patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information Processing Deficits in Remitted Schizophrenics.

This study investigated early stages of information processing in schizophrenia as assessed by a backward-masking paradigm. Ten remitted process schizophrenics and 10 matched normal controls were tested. Subjects were matched for both age and intelligence. All schizophrenics met the criteria of an early onset, poor premorbid adjustment, evidence of formal thought disorder (e.g., language disturbance) and had previously exhibited hallucinations or delusions. Stimuli were tachistoscopically exposed under two masking conditions, two stimulus durations, and five masking latencies (stimulus onset asynchronies) over four 200-trial sessions, for a total of 800 trials. A two-alternative forced-choice recognition of a T or A served as the dependent measure. Results indicated that whereas schizophrenics were more impaired than normals under both masking conditions, they were particularly impaired under the pattern mask condition. These results add support to the growing evidence of an early information processing disturbance in schizophrenia that is trait dependent and is not an artifact of nonspecific pathological disturbance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Somatosensory Processing and Schizophrenia Liability: Proprioception, Exteroceptive Sensitivity, and Graphesthesia Performance in the Biological Relatives of Schizophrenia Patients.

In the present study, the authors examined somatosensory processing in 30 biological relatives of persons with schizophrenia (hereafter called "schizophrenia relatives"), 30 biological relatives of persons with bipolar affective disorder (psychiatric family control subjects), and 30 healthy control subjects with no family history of psychopathology. All 3 groups completed a weight discrimination task, a 2-point discrimination task, and a complex cognitive somatosensory task (i.e., graphesthesia). The schizophrenia relatives performed significantly worse on all 3 somatosensory tasks compared with both the healthy control subjects and the bipolar relatives. The healthy control subjects and psychiatric family control subjects showed no significant differences on any of the somatosensory tasks. Within the weight discrimination and 2-point discrimination tasks, schizophrenia relatives showed group differences on the d' index, the measure of sensitivity, whereas all 3 groups did not differ on lnβ, the measure of response bias, suggesting a genuine difference in weight and touch sensitivity. The d' value of the weight discrimination task was significantly associated with both the cognitive-perceptual factor and negative symptom factor of the clinical questionnaire (e.g., Schizotypal Personality Questionnaire; SPQ), whereas the 2-point discrimination d' value and graphesthesia scores were significantly associated only with the cognitive-perceptual factor of the SPQ. Implications for the possible relation between somatosensory task performance and schizophrenia liability are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual Organization in Schizophrenia Spectrum Disorders: Empirical Research and Theoretical Implications.

The research into perceptual organization in schizophrenia spectrum disorders has found evidence for and against a perceptual organization deficit and has interpreted the data from within several different theoretical frameworks. A synthesis of this evidence, however, reveals that this body of work has produced reliable evidence for deficits in schizophrenia, as well as for the clinical, stimulus, and task parameters associated with normal and abnormal performance. Recent models of cognition have also advanced understanding of the underlying pathophysiological processes of perceptual organization dysfunction in schizophrenia spectrum disorders. These suggest that deficits in perceptual organization may be one manifestation of a wider disturbance in the integration of contextually related information across space and time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Primacy of Cognition in Schizophrenia.

Cognitive tasks and concepts are used increasingly in schizophrenia science and treatment. Recent meta-analyses show that across a spectrum of research domains only cognitive measures distinguish a majority of schizophrenia patients from healthy people. Average effect sizes derived from common clinical tests of attention, memory, language, and reasoning are twice as large as those obtained in structural magnetic resonance imaging and positron emission tomography studies. Chronic stress, genes, brain disturbances, task structure, gender, and sociocultural background may all enhance the sensitivity of cognitive performance to schizophrenia. At the same time, disease heterogeneity and the presence of endophenotypes and subtypes within the patient population may place upper limits on the strength of any specific cognitive finding. Schizophrenia is a complex biobehavioral disorder that manifests itself primarily in cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schizophrenia and the immediacy mechanism.

The author comments on the article "The primacy of cognition in schizophrenia," by R. W. Heinrichs (see record 2005-03019-003) and states that to the pursuit of schizophrenic/normal differences, there is no end. Heinrichs used meta-analyses to argue persuasively for the primacy of cognition for this role. His conclusion not only elicited agreement from both researchers and practitioners, but it is supported by his quantitative estimate of those differences through the use of meta-analysis and the associated effect sizes. An interesting question is why cognitive behavior should be so effective in differentiating schizophrenia patients from normal persons. The current author believes one answer is that cognitive behavior involves complex stimulus control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Referential Communication Disturbances in the Speech of Nonschizophrenic Siblings of Schizophrenia Patients.

Several different types of communication disturbances have been identified in the speech of schizophrenia patients. This study assessed 6 types of referential communication disturbances in the speech of 32 stable outpatients, 23 of their nonschizophrenic siblings, and 27 control subjects. The siblings made more frequent reference failures of all types than control subjects and did not differ from the patients on most types of disturbance. Only on the arguably most "schizophrenic" type of disturbance, the missing information reference, did patients show more deviance than siblings. On the vague reference, siblings showed more deviance than patients. These results, which are very similar to those previously reported on parents of patients, support the idea that referential disturbances reflect vulnerability to schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic Organization and Verbal Memory Efficiency in Patients With Schizophrenia.

The role of semantic organization in verbal memory efficiency in schizophrenia was investigated. Patients and healthy controls were administered a free-recall task involving 1 nonsemantically organizable list, 1 list organizable in semantic categories with typical instances, and 1 list organizable in semantic categories with atypical instances. Reduced semantic organization was observed in patients. Regression analyses showed that the semantic clustering score in the atypical organizable list made a significant contribution to recall performance in patients. When semantic clustering was controlled, the effect of diagnosis on free recall was significant. These results suggest that depth of semantic organization is a crucial factor of verbal memory performance in schizophrenia. However, semantic organizational deficit does not account for the whole recall impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commentary on two articles concerning generalized and specific cognitive deficits.

This is a commentary on essays in this journal issue by M. E. Strauss (see record 2001-17627-002) and R. A. Knight and S. A Silverstein (see record 2001-17627-003) on research methodology for studying cognitive deficits. Concentrating mostly on Knight and Silverstein's article, the authors review the psychometric issues in the matched-task design, analyze Knight and Silverstein's process-oriented objections to that design, and scrutinize their methods for studying cognitive deficits, examining 2 of their empirical studies as examples of those methods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Habit Learning and the Genetics of the Dopamine D? Receptor: Evidence From Patients With Schizophrenia and Healthy Controls.

In this study, the authors investigated the relationship between the Ser9Gly (SG) polymorphism of the dopamine D? receptor (DRD3) and striatal habit learning in healthy controls and patients with schizophrenia. Participants were given the weather prediction task, during which probabilistic cue-response associations were learned for tarot cards and weather outcomes (rain or sunshine). In both healthy controls and patients with schizophrenia, participants with Ser9Ser (SS) genotype did not learn during the early phase of the task (1-50 trials), whereas participants with SG genotype did so. During the late phase of the task (51-100 trials), both participants with SS and SG genotype exhibited significant learning. Learning rate was normal in patients with schizophrenia. These results suggest that the DRD3 variant containing glycine is associated with more efficient striatal habit learning in healthy controls and patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding Responses to Political Conflict: Interactive Effects of the Need for Closure and Salient Conflict Schemas.

Two studies examined the relationship between the need for cognitive closure and preferences for conflict-resolution strategies in 2 different samples of elite political actors. Although research has suggested that high need for closure should be associated with competitiveness, the authors argue that this relationship should be strongest among political actors with a hostile conflict schema, or representation of what a conflict is and how it should be dealt with. The authors provide evidence for this hypothesis using archival survey data on American foreign-policy officials' attitudes toward international conflict at the height of the Cold War (Study 1) and their own data on the relationship between the need for closure and conflict-strategy preferences among samples of activists from 2 political parties in Poland: a centrist party with a reputation for cooperativeness and an extremist party with a reputation for confrontation (Study 2). The broader implications of these findings are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Vernier Threshold in Patients With Schizophrenia and in Their Unaffected Siblings.

The aim of this study was to investigate magnocellular (M) and parvocellular (P) visual functions in nonmedicated patients with schizophrenia and in their unaffected siblings. Possible abnormalities in cortical integration of retinal receptive fields also were addressed. Twenty-two nonmedicated patients with schizophrenia, their unaffected siblings, and 20 age- and IQ-matched healthy control subjects received 4 vernier acuity tasks (blue-on-yellow, frequency-doubling, achromatic low and high contrast conditions) in which they were asked to detect the spatial alignment of dots and gratings. Results revealed that the patients with schizophrenia and their unaffected siblings showed selective dysfunctions in the frequency-doubling and achromatic low contrast conditions, which were devoted to investigate M pathways. In the isoluminant blue-on-yellow and high contrast achromatic conditions, there were no significant differences between the experimental groups. These results suggest that the deficit of M pathway is an endophenotype of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working Memory Consolidation Is Abnormally Slow in Schizophrenia.

This study reports evidence that patients with schizophrenia demonstrate a slowing of working memory (WM) consolidation, which is the process of transforming transient perceptual representations into durable WM representations. Sixteen schizophrenia patients and 16 healthy control participants performed a task measuring the visual WM consolidation rate in a change-detection paradigm. A target display containing 3 colored squares was followed by a variable delay of 17-483 ms, a pattern mask, and then a test stimulus. This pattern mask does not interfere with perception but disrupts WM consolidation. Control participants reached no-mask performance by 250 ms, indicating completed WM consolidation, whereas patients failed to reach no-mask performance by 483 ms. Slowed consolidation may play an important and largely unrecognized role in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conflict monitoring and cognitive control.

A neglected question regarding cognitive control is how control processes might detect situations calling for their involvement. The authors propose here that the demand for control may be evaluated in part by monitoring for conflicts in information processing. This hypothesis is supported by data concerning the anterior cingulate cortex, a brain area involved in cognitive control, which also appears to respond to the occurrence of conflict. The present article reports two computational modeling studies, serving to articulate the conflict monitoring hypothesis and examine its implications. The first study tests the sufficiency of the hypothesis to account for brain activation data, applying a measure of conflict to existing models of tasks shown to engage the anterior cingulate. The second study implements a feedback loop connecting conflict monitoring to cognitive control, using this to simulate a number of important behavioral phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conflict adaptation by means of associative learning.

Cognitive control is responsible for adapting information processing in order to carry out tasks more efficiently. Contrasting global versus local control accounts, it has recently been proposed that control operates in an associative fashion, that is, by binding stimulus–response associations after detection of conflict (Verguts & Notebaert, 2009). Here, this prediction is explicitly tested for the first time. In a task-switching study where both tasks use the same relevant information, we previously reported conflict adaptation over tasks (Notebaert & Verguts, 2008). In the current experiment, we demonstrate that this is restricted to conditions where both tasks use the same effectors, thereby supporting the associative control account. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

"Direct Measurement of Differential Cognitive Deficit in Acute Schizophrenia": Erratum.

Reports an error in the original article by J. N. Deluca (Journal of Abnormal Psychology, 1967[April], Vol 72[2], 143-146). The author's affiliation on page 143 should read as follows: "290 Madison Avenue, Morristown, New Jersey. (The following abstract of this article originally appeared in record 2005-09867-003). This is a longitudinal study in which 11 standardized test of cognitive function were administered to 20,000 normal Ss and at a later point in time readministered to those Ss of the original group (N=15) who became schizophrenic and were hospitalized. The tests were also readministered to part of the original group (N=40) who, at the same point in time, were still normal. The results, which revealed significant differential deficit on 5 of the measures, suggest that lack of motivation to reach out and actively manipulate stimuli or experience new learning produced the differences observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Convergent-Divergent Approach to Context Processing, General Intellectual Functioning, and the Genetic Liability to Schizophrenia.

Convergent and divergent validity are critically important in developing psychological measures that reveal interpretable deficits in disordered populations. This article reports on 2 studies that evaluated the validity of context processing measures. In Experiment 1, a confirmatory factor analysis of data from 481 healthy adults established the convergent validity of 2 context processing measures and showed that context processing accounted for significant amounts of variance in standard IQ and working memory measures. In Experiment 2, 20 schizophrenia patients, 16 of their healthy siblings, and 28 controls were evaluated using a novel, short context processing measure, the dot pattern expectancy (DPX) task. The DPX was sensitive to specific deficits in schizophrenia patients and their healthy siblings. These findings support the construct validity of context processing measures, suggest context processing is a component of intellectual functioning, and demonstrate that brief context processing measures remain sensitive to psychopathological deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neurophysiological markers of vulnerability to schizophrenia: Sensitivity and specificity of specific quantitative eye movement measures.

Eye-tracking deficits in schizophrenic patients and relatives have generated interest in using eye movements to mark schizophrenia liability. Efforts to develop specific quantitative measures have provided insight into the nature of the deficit and suggested what underlying neurophysiological mechanisms are involved. This study used receiver operating characteristic curve analyses to evaluate and compare the sensitivity, specificity, and overall accuracy of predicting disease liability using single and combined specific and global quantitative measures. Results indicate that measures of predictive pursuit and leading saccades significantly increased predictive accuracy compared with traditional global measures. Combining specific measures provided greater predictive accuracy compared with single measures. Implications for the use of specific eye movement measures to define schizophrenia-related phenotypes in genetic studies are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-Term Memory Deficits in Schizophrenia: Primary or Secondary Dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conflict adaptation depends on task structure.

The dependence of the Simon effect on the correspondence of the previous trial can be explained by the conflict-monitoring theory, which holds that a control system adjusts automatic activation from irrelevant stimulus information (conflict adaptation) on the basis of the congruency of the previous trial. The authors report on 4 experiments showing that conflict adaptation is mediated by task structure as well as previous congruency. Experiment 1 showed that for 2 completely segregated sets of stimulus-response pairs there was no conflict adaptation across sets. However, if the stimulus sets overlapped for 2 separate response sets, conflict adaptation could be observed across the response sets. Experiment 2 showed that this effect was not due to the use of stimulus-response sets lateralized to 1 hemisphere each. Experiment 3 showed that if response sets are common for 2 separate stimulus sets, then conflict adaptation can again be observed across sets. Finally, Experiment 4 showed local control effects in the absence of confounding feature-overlap effects. These results indicate that deployment of control as evidenced by conflict adaptation reflects task structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)