Failure to deactivate in the prefrontal cortex in schizophrenia: dysfunction of the default mode network?
TL;DR: Patients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task, including an area in the anterior prefrontal/anterior cingulate cortex that corresponds to one of the two midline components of the ‘default mode network’ implicated in functions related to maintaining one's sense of self.
Abstract: BackgroundFunctional imaging studies using working memory tasks have documented both prefrontal cortex (PFC) hypo- and hyperactivation in schizophrenia. However, these studies have often failed to consider the potential role of task-related deactivation.MethodThirty-two patients with chronic schizophrenia and 32 age- and sex-matched normal controls underwent functional magnetic resonance imaging (fMRI) scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.ResultsThe controls showed activation in the expected frontal regions. There were also clusters of deactivation, particularly in the anterior cingulate/ventromedial PFC and the posterior cingulate cortex/precuneus. Compared to the controls, the schizophrenic patients showed reduced activation in the right dorsolateral prefrontal cortex (DLPFC) and other frontal areas. There was also an area in the anterior cingulate/ventromedial PFC where the patients showed apparently greater activation than the controls. This represented a failure of deactivation in the schizophrenic patients. Failure to activate was a function of the patients' impaired performance on the n-back task, whereas the failure to deactivate was less performance dependent.ConclusionsPatients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task. The area of failure of deactivation is in the anterior prefrontal/anterior cingulate cortex and corresponds to one of the two midline components of the ‘default mode network’ implicated in functions related to maintaining one's sense of self.
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TL;DR: This review defines the DMN concept with regard to its neuro-anatomy, its functional organisation through low frequency neuronal oscillations, its relation to other recently discovered low frequency resting state networks, and the cognitive functions it is thought to serve, and introduces methodological and analytical issues and challenges.
1,515 citations
TL;DR: Among patients, the magnitude of MPFC task suppression negatively correlated with default connectivity, suggesting an association between the hyperactivation and hyperconnectivity in schizophrenia.
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References
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TL;DR: Previous findings of impaired lateral prefrontal activation during WM performance in schizophrenic patients could not be confirmed after the exclusion of incorrectly performed or omitted trials in the functional analysis, but superior temporal cortex dysfunction in patients with schizophrenia may be regarded as schizophrenia-specific finding in terms of psychiatric diagnosis specificity.
90 citations
"Failure to deactivate in the prefro..." refers result in this paper
...studies reporting deactivations have used working memory tasks : one (Walter et al. 2007) found that schizophrenic patients failed to deactivate in the superior temporal cortex, but the other two (both of which used the n-back task) had findings comparable with ours....
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...Three studies reporting deactivations have used working memory tasks : one (Walter et al. 2007) found that schizophrenic patients failed to deactivate in the superior temporal cortex, but the other two (both of which used the n-back task) had findings comparable with ours....
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TL;DR: Functional magnetic resonance imaging data are consistent with findings reported in recent studies showing increased PFC and parietal activation in schizophrenia when the effects of reduced WM task performance in patients with schizophrenia are addressed.
86 citations
"Failure to deactivate in the prefro..." refers background in this paper
...Further studies have documented either hyperfrontality or a pattern of mixed hypo- and hyperfrontality (e.g. Callicott et al. 2003 ; Hugdahl et al. 2004; Thermenos et al. 2005 ; Tan et al. 2006; Schneider et al. 2007)....
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TL;DR: Results suggest that both sentence content and speaker voice priming effects occurred bilaterally along the length of the superior temporal sulcus (STS), suggesting that both are processed in a single underlying system without any significant asymmetries for content vs. voice processing.
Abstract: This article presents results obtained from applying various tools from FSL (FMRIB Software Library) to data from the repetition priming experiment used for the HBM'05 Functional Image Analysis Contest. We present analyses from the model-based General Linear Model (GLM) tool (FEAT) and from the model-free independent component analysis tool (MELODIC). We also discuss the application of tools for the correction of image distortions prior to the statistical analysis and the utility of recent advances in functional magnetic resonance imaging (FMRI) time series modeling and inference such as the use of optimal constrained HRF basis function modeling and mixture modeling inference. The combination of hemodynamic response function (HRF) and mixture modeling, in particular, revealed that both sentence content and speaker voice priming effects occurred bilaterally along the length of the superior temporal sulcus (STS). These results suggest that both are processed in a single underlying system without any significant asymmetries for content vs. voice processing.
63 citations
"Failure to deactivate in the prefro..." refers methods in this paper
...Group comparisons between patients and controls were performed within the FEAT module, with mixed-effects GLM models (Beckmann et al. 2006)....
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TL;DR: Failure of left STG 'deactivation' and left fronto-temporal disconnectivity are not consistent findings in schizophrenia; neither are they trait-markers for genetic risk.
35 citations
TL;DR: In this article, the rendimiento cognitivos of diestros and zurdos were evaluated in two groups: one consisting of 25 diestro and 25 zurdo.
Abstract: Objetivo. Contribuir al conocimiento de las diferencias cognitivas existentes entre diestros y zurdos, mediante la valoracion del rendimiento cognitivo en un grupo de sujetos adultos diestros y otro de zurdos de similares caracteristicas en cuanto al genero, edad y nivel cultural gracias a la escala de inteligencia de Wechsler para adultos (WAIS-III). Sujetos y metodos. Se estudiaron dos grupos: uno formado por 25 diestros (GD) y otro formado por 25 zurdos (GZ). Ninguno de los sujetos del estudio presentaba deficiencias mentales ni trastornos neurologicos. La media de edad era de 24,28 anos, con un rango entre 20 y 28 anos. Resultados. No hay diferencias en el cociente intelectual (verbal y manipulativo), entre los dos grupos. El GZ obtuvo peores resultados que los diestros en velocidad de procesamiento y en las pruebas de aritmetica y claves, mientras que el GD consiguio mejores resultados en el subtest de figuras incompletas. Conclusiones. El GZ tiene un rendimiento cognitivo similar al del GD, con ligeras deficiencias en actividades de componente visuoperceptivo. Se hace necesario seguir profundizando en las diferencias cognitivas y neuropsicologicas entre diestros y zurdos, ya que el rendimiento cognitivo de los zurdos continua siendo un tema en discusion.
10 citations
"Failure to deactivate in the prefro..." refers background in this paper
...Thus, Weinberger et al. (2001) proposed that even when schizophrenic patients are able to keep up with processing demands, they do so less efficiently than controls, and this ‘working harder to keep up’ necessitates the recruitment of greater and/or less focused cerebral metabolic activity....
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...Thus, Weinberger et al. (2001) proposed that even when schizophrenic patients are able to keep up with processing demands, they do so less efficiently than controls, and this ‘working harder to keep up’ necessitates the recruitment of greater and/or less focused cerebral metabolic activity. Callicott et al. (2003) and Manoach (2003) have further proposed that there is an inverted U-shaped function between...
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