Daniel C Javitt1, Esther Rabinowicz, Gail Silipo, Elisa C Dias. 1. Program in Cognitive Neuroscience and Schizophrenia Nathan Kline Institute for Psychiatric Research, New York University School of Medicine 140 Old Orangeburg Road Orangeburg, NY 10962, United States. javitt@nki.rfmh.org
Abstract
BACKGROUND: Deficits in working memory performance are among the most widely replicated findings in schizophrenia. Roles of encoding vs. memory retention in working memory remain unresolved. The present study evaluated working memory performance in schizophrenia using an AX-type continuous performance test (AX-CPT) paradigm. METHODS: Participants included 48 subjects with schizophrenia and 27 comparison subjects. Behavior was obtained in 3 versions of the task, which differed based upon ease of cue interoperability. In a simple cue version of the task, cue letters were replaced with red or green circles. In the complex cue version, letter/color conjunctions served as cues. RESULTS: In the base version of the task, patients showed increased rates of false alarms to invalidly cued targets, similar to prior reports. However, when the cue stimuli were replaced with green or red circles to ease interpretation, patients showed similar false alarm rates to controls. When feature conjunction cues were used, patients were also disproportionately affected relative to controls. No significant group by interstimulus interval interaction effects were observed in either the simple or complex cue conditions, suggesting normal retention of information even in the presence of overall performance decrements. CONCLUSIONS: These findings suggest first, that cue manipulation disproportionately affects AX-CPT performance in schizophrenia and, second, that substantial behavioral deficits may be observed on working memory tasks even in the absence of disturbances in mnemonic retention.
BACKGROUND: Deficits in working memory performance are among the most widely replicated findings in schizophrenia. Roles of encoding vs. memory retention in working memory remain unresolved. The present study evaluated working memory performance in schizophrenia using an AX-type continuous performance test (AX-CPT) paradigm. METHODS:Participants included 48 subjects with schizophrenia and 27 comparison subjects. Behavior was obtained in 3 versions of the task, which differed based upon ease of cue interoperability. In a simple cue version of the task, cue letters were replaced with red or green circles. In the complex cue version, letter/color conjunctions served as cues. RESULTS: In the base version of the task, patients showed increased rates of false alarms to invalidly cued targets, similar to prior reports. However, when the cue stimuli were replaced with green or red circles to ease interpretation, patients showed similar false alarm rates to controls. When feature conjunction cues were used, patients were also disproportionately affected relative to controls. No significant group by interstimulus interval interaction effects were observed in either the simple or complex cue conditions, suggesting normal retention of information even in the presence of overall performance decrements. CONCLUSIONS: These findings suggest first, that cue manipulation disproportionately affects AX-CPT performance in schizophrenia and, second, that substantial behavioral deficits may be observed on working memory tasks even in the absence of disturbances in mnemonic retention.
Authors: William M Perlstein; Neha K Dixit; Cameron S Carter; Douglas C Noll; Jonathan D Cohen Journal: Biol Psychiatry Date: 2003-01-01 Impact factor: 13.382
Authors: Michael J Coleman; Olga Krastoshevsky; Xiawei Tu; Nancy R Mendell; Deborah L Levy Journal: Schizophr Res Date: 2012-05-27 Impact factor: 4.939
Authors: Corby L Dale; Anne M Findlay; R Alison Adcock; Mary Vertinski; Melissa Fisher; Alexander Genevsky; Stephanie Aldebot; Karuna Subramaniam; Tracy L Luks; Gregory V Simpson; Srikantan S Nagarajan; Sophia Vinogradov Journal: Int J Psychophysiol Date: 2009-10-28 Impact factor: 2.997
Authors: Daniel C Javitt; Kevin M Spencer; Gunvant K Thaker; Georg Winterer; Mihály Hajós Journal: Nat Rev Drug Discov Date: 2008-01 Impact factor: 84.694