PET regional cerebral blood flow during working and declarative memory: Relationship with task performance.

Ragland, J. Daniel; Glahn, David C.; Gur, Ruben C.; Censits, David M.; Smith, Robin; Mozley, P. David; Alavi, Abass; Gur, Raquel E.

doi:10.1037/0894-4105.11.2.222

Cited by 34 publications

(39 citation statements)

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“…Performance differences complicate interpretation of between-group differences in functional activation patterns. Early reports suggested that better task performance on working memory or executive measures resulted in relatively more brain activity in key brain regions [Haier et al, 1992;Ragland et al, 1997]. In contrast, Jansma et al [2001] reported that for some brain areas, better performance was related to less activity, potentially due to increased "automation" of for the specific cognitive process.…”

Section: Figurementioning

confidence: 99%

“…Indeed, reduced DLPFC activity in schizophrenia may be coupled with a relative increase in activity in other brain regions [Callicott et al, 2000]. Changes in the relative level of activation within brain regions of the working memory network have been reported in better-and worse-performing healthy subjects [Callicott et al, 1999;Jansma et al, 2001;Ragland et al, 1997] and across genders [Gur et al, , 2000. In patients with schizophrenia, shifts in the relative amount of activation within specific brain regions comprising the working memory network could be related to altered performance levels [Manoach, 2003] or be secondary to reductions in interregional connectivity that disrupt normal activation levels throughout the network [Selemon and Goldman-Rakic, 1999].…”

Section: Introductionmentioning

confidence: 99%

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Beyond hypofrontality: A quantitative meta‐analysis of functional neuroimaging studies of working memory in schizophrenia

Glahn

Ragland

Abramoff

et al. 2005

Human Brain Mapping

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Abstract:Although there is considerable evidence that patients with schizophrenia fail to activate the dorsolateral prefrontal cortex (DLPFC) to the degree seen in normal comparison subjects when performing working memory or executive tasks, hypofrontality may be coupled with relatively increased activity in other brain regions. However, most imaging studies of working memory in schizophrenia have focused on DLPFC activity. The goal of this work is to review functional neuroimaging studies that contrasted patients with schizophrenia and healthy comparison subjects during a prototypical working memory task, the n-back paradigm, to highlight areas of hyper-and hypoactivation in schizophrenia. We utilize a quantitative metaanalysis method to review 12 imaging studies where patients with schizophrenia were contrasted with healthy comparison subjects while performing the n-back paradigm. Although we find clear support for hypofrontality, we also document consistently increased activation in anterior cingulate and left frontal pole regions in patients with schizophrenia compared to that in controls. These data suggest that whereas reduced DLPFC activation is reported consistently in patients with schizophrenia relative to healthy subjects, abnormal activation patterns are not restricted to this region, raising questions as to whether the pathophysiological dysfunction in schizophrenia is specific to the DLPFC and about the relationship between impaired performance and aberrant activation patterns. The complex pattern of hyper-and hypoactivation consistently found across studies implies that rather than focusing on DLPFC dysregulation, researchers should consider the entire network of regions involved in a given task when making inferences about the biological mechanisms of schizophrenia. Hum Brain Mapp 25:60 -69, 2005.

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Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Beyond hypofrontality: A quantitative meta‐analysis of functional neuroimaging studies of working memory in schizophrenia

Glahn

Ragland

Abramoff

et al. 2005

Human Brain Mapping

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558

393

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“…Thus, these studies used the Wisconsin Card Sorting Test (WCST, Berman et al, 1995;Nahagama et al, 1996;Ragland et al, 1997), the Tower of London (Backer et al, 1996;Dhager et al, 1999;Morris et al, 1993), random generation tasks (Jahanshashi et al, 2000) and verbal fluency tasks (Frith et al, 1991;Paulesu et al, 1997;Phelps et al, 1997). The WCST was associated with bilateral increases in cerebral activity in the dorsolateral, inferior parietal and occipital regions and, to a lesser extent, in the frontopolar, orbital and medial regions, as well as in the temporal areas.…”

Section: The Exploration Of the Neural Substrates Of Executive Functimentioning

confidence: 99%

Exploration of the neural substrates of executive functioning by functional neuroimaging

et al. 2006

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This review presents neuroimaging studies that have explored the cerebral substrates of executive functioning. These studies have demonstrated that different executive functions not only recruit various frontal areas but also depend upon posterior (mainly parietal) regions. These results are in accordance with the hypothesis that executive functioning relies on a distributed cerebral network that is not restricted to anterior cerebral areas. However, there exists an important heterogeneity in the cerebral areas associated with these different processes, and also between different tasks assessing the same process. Since these discrepant results could be due to the paradigms used (subtraction designs), recent results obtained with conjunction and interaction analyses are presented, which confirm the role of parietal areas in executive functioning and also demonstrate the existence of some specificity in the neural substrates of the executive processes of updating, shifting and inhibition. Finally, fMRI studies show that the activity in cerebral areas involved in executive tasks can be transient or sustained. Consequently, to better characterise the functional role of areas associated with executive functioning, it is important to take into account not only the localisation of cerebral activity but also the temporal pattern of this activity.

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“…A problem with this approach is that patients and controls often require different amounts of practice, and ceiling effects can be created for controls. An alternative approach utilized in the current study is to contrast patients with controls who perform poorly but who are, otherwise, healthy.Before examining schizophrenia, we administered the PART and WCST positron emission tomography (PET) paradigm to 30 healthy volunteers to understand normal patterns of activation and the role of task performance (Ragland et al, 1997). Results showed a bilateral rCBF increase over resting baseline in inferior frontal and occipitotemporal regions for both tasks, with more consistent dorsolateral prefrontal activation for WCST than PART.…”

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confidence: 99%

“…All controls and all but 1 lefthanded patient were classified as right-handed based on a standard behavioral and selfreport inventory (Raczkowski, Kalat, & Nebes, 1974). Demographically matched controls were drawn from a larger sample of 30 participants (Ragland et al, 1997) and were selected to match patients on age, gender, and parental education (see Table 1). Estimated intellectual ability (based on Wechsler Adult Intelligence Scale-Revised [WAIS-R] Vocabulary subtest performance; Wechsler, 1987) was in the upper end of the average range for controls (scaled score = 12.8 ± 2.0) and in the lower end of the average range for patients (scaled score = 8.9 ± 3.3).…”

mentioning

confidence: 99%

Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia: A positron emission tomography study.

Ragland¹,

Gur²,

Glahn³

et al. 1998

Neuropsychology

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Schizophrenia affects prefrontal and temporal-limbic networks. These regions were examined by contrasting regional cerebral blood flow (rCBF) during executive (Wisconsin Card Sorting Test [WCST]), and declarative memory tasks (Paired Associate Recognition Test [PART]). The tasks, and a resting baseline, were administered to 15 patients with schizophrenia and 15 healthy controls during 10 min positron emission tomography 15 O-water measures of rCBF. Patients were worse on both tasks. Controls activated inferior frontal, occipitotemporal, and temporal pole regions for both tasks. Similar results were obtained for controls matched to level of patient performance. Patients showed no activation of hypothesized regions during the WCST and activated the dorsolateral prefrontal cortex during the PART. On the PART, occipitotemporal activation correlated with better performance for controls only. Better WCST performance correlated with CBF increase in prefrontal regions for controls and in the parahippocampal gyrus for patients. Results suggest that schizophrenia may involve a breakdown in the integration of a frontotemporal network that is responsive to executive and declarative memory demands in healthy individuals.Schizophrenia was previously thought of primarily as a frontal lobe disorder. Central to this model were neuropsychological results of impaired Wisconsin Card Sorting Test (WCST; Berg, 1948;Grant & Berg, 1948) performance (Goldberg, Weinberger, Berman, Pliskin, & Podd, 1987) and cerebral blood flow (CBF) findings of "hypofrontality" at rest (Ingvar & Franzen, 1974) and in response to WCST task demands (Weinberger, Berman, & Zee, 1986). An alternative model proposed that schizophrenia primarily affects temporal lobe function. Support for this theory included neuropsychological results of differentially impaired learning and memory (Saykin et al., 1991), functional imaging evidence of resting left temporal lobe hypermetabolism , and atypical midtemporal CBF asymmetries in response to memory task demands (Gur, Jaggi, Shtasel, Ragland, & Gur, 1994).Copyright 1998 by the American Psychological Association, Inc.Correspondence concerning this article should be addressed to: J. Daniel Ragland, 10th Floor Gates Building/HUP, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania 19104. ragland@bblmail.psycha.upenn.edu. J. Daniel Ragland, Ruben C. Gur, David C. Glahn, David M. Censits, Mark G. Lazarev, and Raquel E. Gur, Department of Psychiatry, University of Pennsylvania Health Systems; Robin J. Smith and Abass Alavi, Department of Radiology, University of Pennsylvania Health Systems. HHS Public Access Author manuscriptNeuropsychology. Author manuscript; available in PMC 2015 May 21. Published in final edited form as:Neuropsychology. 1998 July ; 12(3): 399-413. Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptMore recently, researchers have begun to acknowledge the reciprocal interconnectivity of the prefrontal cortex with the hippocampus (Goldman-Rakic, Selem...

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PET regional cerebral blood flow during working and declarative memory: Relationship with task performance.

Cited by 34 publications

References 50 publications

Beyond hypofrontality: A quantitative meta‐analysis of functional neuroimaging studies of working memory in schizophrenia

Beyond hypofrontality: A quantitative meta‐analysis of functional neuroimaging studies of working memory in schizophrenia

Exploration of the neural substrates of executive functioning by functional neuroimaging

Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia: A positron emission tomography study.

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