The neural substrates of memory systems impairment in Alzheimer's disease. A PET study of resting brain glucose utilization

Desgranges, Béatrice; Baron, Jean‐Claude; Sayette, Vincent de La; Petit-Taboué, M.C.; Bénali, Karim; Landeau, Brigitte; Lechevalier, B; Eustache, Francis

doi:10.1093/brain/121.4.611

Cited by 300 publications

(212 citation statements)

References 113 publications

(168 reference statements)

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“…Interaction analyses revealed that a network including the left temporoparietal and inferior frontal regions was significantly less recruited in AD patients than in the control group, when comparing word to WL2 nonword conditions. This result is in keeping with previous neuroimaging findings showing a correlation between semantic deficits in AD patients and impairment of left temporoparietal areas, as measured by structural MRI or resting brain metabolism [Desgranges et al, 1998;Grossman et al, 1997Grossman et al, , 1998]. As suggested by Grossmann et al [2003], impaired activity in the left temporoparietal and frontal regions in AD patients could reflect impaired integration of lexicosemantic information, regardless of the domain of knowledge or the nature of the task.…”

Section: Cortical Activation For Lexicosemantic Representations In Adsupporting

confidence: 91%

“…By contrast, brain regions underlying (sublexical) phonological levels of language processing are primarily located in the left (or bilateral) superior temporal area, and more specifically in the superior temporal sulcus and the posterior superior temporal gyrus; these regions are activated when participants listen to both meaningful and meaningless speech (e.g., nonwords), but not when listening to acoustically matched nonverbal sounds [Binder, 2000;Binder and Price, 2001;Binder et al, 2000;Burton et al, 2000Burton et al, , 2005Demonet et al, 1992Demonet et al, , 1994Hickok and Poeppel, 2000;Jacquemot et al, 2003;Jancke et al, 2002;Majerus et al, 2002;Mazoyer et al, 1993;Mummery et al, 1999;Perani et al, 1996;Poldrack et al, 2001;Specht and Reul, 2003]. In our study, on the basis of available neuroimaging studies that have studied language processing in AD, we expected decreased activation in left temporoparietal areas, as well as in the left lateral frontal cortex when AD patients had to repeat words and activate lexicosemantic levels of language representation [Desgranges et al, 1998;Grossman et al, 2003Grossman et al, , 2004Zahn et al, 2004]. With respect to phonological processing, we expected decreased activity (compared to elderly controls) in the posterior superior temporal gyrus and Broca's area when AD patients had to repeat nonwords, in line with previous structural neuroanatomical findings [Harasty et al, 2001].…”

Section: Introductionmentioning

confidence: 77%

“…With respect to lexicosemantic deficits in AD, neuroimaging studies using positron emission tomography (PET) or structural magnetic resonance imaging (MRI) techniques have investigated correlations between behavioral performance on semantic tasks and brain metabolism or structure in AD patients. These studies have shown that the extent of the semantic impairment correlates with reduced resting state brain metabolism or cortical atrophy located in the left lateral temporal, inferior parietal, or medial occipital areas [Desgranges et al, 1998;Grossman et al, 2003;Hirono et al, 2001;Zahn et al, 2004]. Furthermore, an fMRI study investigated semantic processing in AD patients by measuring hemodynamic brain responses during a pleasantness judgment task for printed words [Grossman et al, 2003].…”

Section: Introductionmentioning

confidence: 99%

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Neural substrates of phonological and lexicosemantic representations in Alzheimer's disease

Peters

Majerus

Collette

et al. 2007

Human Brain Mapping

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Abstract:The language profile of patients suffering from Alzheimer's disease (AD) is characterized not only by lexicosemantic impairments but also by phonological deficits, as shown by an increasing number of neuropsychological studies. This study explored the functional neural correlates underlying phonological and lexicosemantic processing in AD. Using H 215 O PET functional brain imaging, a group of mild to moderate AD patients and a group of age-matched controls were asked to repeat four types of verbal stimuli: words, wordlike nonwords (WL1), non-wordlike nonwords (WL2) and simple vowels. The comparison between the different conditions allowed us to determine brain activation preferentially associated with lexicosemantic or phonological levels of language representations. When repeating words, AD patients showed decreased activity in the left temporo-parietal and inferior frontal regions relative to controls, consistent with distorted lexicosemantic representations. Brain activity was abnormally increased in the right superior temporal area during word repetition, a region more commonly associated with perceptual-phonological processing. During repetition of WL1 and WL2 nonwords, AD patients showed decreased activity in the middle part of the superior temporal gyrus, presumably associated with sublexical phonological information; at the same time, AD patients showed larger activation than controls in the inferior temporal gyrus, typically associated with lexicosemantic levels of representation. Overall, the results suggest that AD patients use altered pathways to process phonological and lexicosemantic information, possibly related to a progressive loss of specialization of phonological and lexicosemantic neural networks. Hum Brain Mapp 30: [185][186][187][188][189][190][191][192][193][194][195][196][197][198][199] 2009. V V C 2007 Wiley-Liss, Inc.

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Section: Cortical Activation For Lexicosemantic Representations In Adsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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Neural substrates of phonological and lexicosemantic representations in Alzheimer's disease

Peters

Majerus

Collette

et al. 2007

Human Brain Mapping

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“…In fact, it is one of the brain regions most affected by AD, even at the very early clinical manifestations of the disease (Salmon et al, 2008; for reviews, see Buckner, 2004 andSperling et al, 2010). PET studies showed that episodic memory retrieval is correlated with brain metabolism in the PCC in AD patients (Desgranges et al, 1998(Desgranges et al, , 2002, as well as in patients with MCI and questionable AD (Chételat et al, 2003;Salmon et al, 2008). More recently, Bastin et al (2010) showed that CER performance, as assessed by the PDP, was related to metabolism in the PCC in pre-dementia stage AD patients.…”

Section: Familiarity and Parietal Cortexmentioning

confidence: 99%

Item familiarity and controlled associative retrieval in Alzheimer's disease: An fMRI study

Genon

Collette

Feyers

et al. 2013

Cortex

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Typical Alzheimer's disease (AD) is characterized by an impaired form of associative memory, recollection, that includes the controlled retrieval of associations. In contrast, familiarity-based memory for individual items may sometimes be preserved in the early stages of the disease. This is the first study that directly examines whole brain regional activity during one core aspect of the recollection function: associative controlled episodic retrieval (CER), contrasted to item familiarity in AD patients. Cerebral activity related to associative CER and item familiarity in AD patients and healthy controls (HC) was measured with functional magnetic resonance imaging during a word-pair recognition task to which the process dissociation procedure was applied. Some patients had null CER estimates (AD-), whereas others did show some CER abilities (AD+), although significantly less than HC. In contrast, familiarity estimates were equivalent in the three groups. In AD+, as in controls, associative CER activated the inferior precuneus/posterior cingulate cortex (PCC). When performing group comparisons, no region was found to be significantly more activated during CER in HC than AD+ and vice versa. However, during associative CER, functional connectivity between this region and the hippocampus, the inferior parietal and dorsolateral prefrontal cortex (DLPFC) was significantly higher in HC than in AD+. In all three groups, item familiarity was related to activation along the intraparietal sulcus (IPS). In conclusion, whereas the preserved automatic detection of an old item (without retrieval of accurate word association) is related to parietal activation centred on the IPS, the inferior precuneus/PCC supports associative CER ability in AD patients, as in HC. However, AD patients have deficient functional connectivity during associative CER, suggesting that the residual recollection function in these patients might be impoverished by the lack of some recollection-related aspects such as autonoetic quality, episodic details and verification.

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“…Resultant images were then smoothed using a classical Gaussian kernel of 14 mm, to blur individual variations and to increase the signal-to-noise ratio. In order to remove the confounding effect of intersubject variability in global CMRglc, the CMRGlc images were divided pixel by pixel by the individual value for the cerebellar vermis (this value being not statistically different from controls), as classically performed in previous studies [14,15,16,19]. .…”

Section: Image Handling and Transformationsmentioning

confidence: 99%

Anatomical and functional alterations in semantic dementia: A voxel-based MRI and PET study

Desgranges

Matuszewski

Piolino

et al. 2007

Neurobiology of Aging

138

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Rare studies have used MRI and voxel based morphometry (VBM) to assess atrophy, and only two PET studies used SPM to examine functional changes in semantic dementia (SD). Our aim was to highlight both morphological and functional abnormalities in a same group of 10 SD patients, in the entire brain, using a "state of the art" methodology (optimized VBM procedure, PET data corrected for partial volume effects and voxel based analyses). We also used an extensive neuropsychological battery. We showed that main alterations concerned the left temporal lobe, in accordance with the striking impairment of semantic memory in SD patients, as well as the hippocampal region, which may partly explain their moderate episodic memory deficits. Hypometabolism was more extensive than grey matter loss in both temporal lobes, and specifically concerned the orbitofrontal areas, consistent with the moderate impairment of executive functions and behavioural changes. While PET is more sensitive than MRI, there is striking concordance between morphological and functional abnormalities, which contrast with the discordance observed in Alzheimer"s disease and might be a typical feature of SD.3

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The neural substrates of memory systems impairment in Alzheimer's disease. A PET study of resting brain glucose utilization

Abstract: Summary The aim of this study was to determine the neuronal basis for memory impairment in Alzheimer's disease by taking advantage of the clinical and metabolic heterogeneity of this pathology. To this end, 19 patients satisfying the NINCDS-

Cited by 300 publications

References 113 publications

Neural substrates of phonological and lexicosemantic representations in Alzheimer's disease

Neural substrates of phonological and lexicosemantic representations in Alzheimer's disease

Item familiarity and controlled associative retrieval in Alzheimer's disease: An fMRI study

Anatomical and functional alterations in semantic dementia: A voxel-based MRI and PET study

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