BACKGROUND: Neuroimaging studies of schizophrenic subjects performing working memory (WM) tasks have demonstrated a relative hypoactivity of prefrontal cortex compared with normal subjects. METHODS: Using functional magnetic resonance imaging (fMRI), we compared dorsolateral prefrontal cortex (DLPFC) activation in 12 schizophrenic and 10 normal subjects during rewarded performance of a WM task. Subjects performed a modified version of the Sternberg Item Recognition Paradigm (SIRP), a continuous performance, choice reaction time (RT) task that requires WM. We compared a high WM load condition with a nonWM choice RT condition and with a low WM load condition. RESULTS: Schizophrenic subjects performed the tasks better than chance but worse than normal subjects. They showed greater activation than normal subjects in the left DLPFC but did not differ in the right DLPFC or in the control region. In the schizophrenic group, left DLPFC activation was inversely correlated with task performance, as measured by errors. CONCLUSIONS: These findings contrast with previous studies that demonstrated task-related hypofrontality in schizophrenia. Task parameters that may contribute to this difference are discussed. We hypothesize that the performance and activation differences we observed are also manifestations of prefrontal dysfunction in schizophrenia. They reflect inefficient functioning of the neural circuitry involved in WM.
BACKGROUND: Neuroimaging studies of schizophrenic subjects performing working memory (WM) tasks have demonstrated a relative hypoactivity of prefrontal cortex compared with normal subjects. METHODS: Using functional magnetic resonance imaging (fMRI), we compared dorsolateral prefrontal cortex (DLPFC) activation in 12 schizophrenic and 10 normal subjects during rewarded performance of a WM task. Subjects performed a modified version of the Sternberg Item Recognition Paradigm (SIRP), a continuous performance, choice reaction time (RT) task that requires WM. We compared a high WM load condition with a nonWM choice RT condition and with a low WM load condition. RESULTS:Schizophrenic subjects performed the tasks better than chance but worse than normal subjects. They showed greater activation than normal subjects in the left DLPFC but did not differ in the right DLPFC or in the control region. In the schizophrenic group, left DLPFC activation was inversely correlated with task performance, as measured by errors. CONCLUSIONS: These findings contrast with previous studies that demonstrated task-related hypofrontality in schizophrenia. Task parameters that may contribute to this difference are discussed. We hypothesize that the performance and activation differences we observed are also manifestations of prefrontal dysfunction in schizophrenia. They reflect inefficient functioning of the neural circuitry involved in WM.
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Authors: Anastasia Yendiki; Douglas N Greve; Stuart Wallace; Mark Vangel; Jeremy Bockholt; Bryon A Mueller; Vince Magnotta; Nancy Andreasen; Dara S Manoach; Randy L Gollub Journal: Neuroimage Date: 2010-05-05 Impact factor: 6.556
Authors: Karolina Kauppi; Lars T Westlye; Martin Tesli; Francesco Bettella; Christine L Brandt; Morten Mattingsdal; Torill Ueland; Thomas Espeseth; Ingrid Agartz; Ingrid Melle; Srdjan Djurovic; Ole A Andreassen Journal: Schizophr Bull Date: 2014-11-11 Impact factor: 9.306
Authors: Thomas P White; Marije Jansen; Kathrin Doege; Karen J Mullinger; S Bert Park; Elizabeth B Liddle; Penny A Gowland; Susan T Francis; Richard Bowtell; Peter F Liddle Journal: Hum Brain Mapp Date: 2012-06-19 Impact factor: 5.038
Authors: Dara S Manoach; Adrian K C Lee; Matti S Hämäläinen; Kara A Dyckman; Jesse S Friedman; Mark Vangel; Donald C Goff; Jason J S Barton Journal: Biol Psychiatry Date: 2013-02-04 Impact factor: 13.382