Increased fMRI responses during encoding in mild cognitive impairment

Hämäläinen, Anne; Pihlajamäki, Maija; Tanila, Heikki; Hänninen, Tuomo; Niskanen, Eini; Tervo, Susanna; Karjalainen, Pasi A.; Vanninen, Ritva; Soininen, Hilkka

doi:10.1016/j.neurobiolaging.2006.08.008

Cited by 281 publications

(250 citation statements)

References 68 publications

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“…Explanations of such functional alteration include a compensatory mechanism for regional neuronal loss and disruption of the intrinsic connectivity of memory networks. 44, 45 Filbey et al 46 also found compensatory neural activation in the medial frontal and parahippocampal gyrus in young and elderly APOE4 carriers during a 9-square-grid visual WM task, similar to our findings in low-WM load.…”

Section: Discussionsupporting

confidence: 89%

Effects of theApolipoprotein Eε4 Allele on Functional MRI duringn-Back Working Memory Tasks in Healthy Middle-Aged Adults

Chen¹,

Chen

et al. 2012

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE:APOE4 is the best-documented genetic risk factor for sporadic AD. Previous research showed that APOE4 is associated with increased risk of occurrence and earlier onset of AD in a gene dose-dependent manner. However, the specific role of APOE4 in processing of brain functions requires further investigation. Investigators have used fMRI to measure brain activity on the basis of the blood oxygen level-dependent contrast. This study investigates the effects of APOE4 on fMRI during n-back WM tasks in healthy middle-aged adults.

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Section: Discussionsupporting

confidence: 89%

Effects of theApolipoprotein Eε4 Allele on Functional MRI duringn-Back Working Memory Tasks in Healthy Middle-Aged Adults

Chen¹,

Chen

et al. 2012

AJNR Am J Neuroradiol

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“…This information suggests that increased activation of the caudal hippocampus is compensatory, due to the initial atrophy in the anterior hippocampus [81] . Combining cortical volume and thickness measures with cognitive tests to predict the conversion of aMCI to AD, Liu and colleagues found decreased hippocampal volumes in progressive aMCI patients compared with controls and stable aMCI patients.…”

Section: Mri and Functional Mri Approaches In The Hippocampus Of Amcmentioning

confidence: 93%

“…Taken together, the evidence suggests that the variability in fMRI data from aMCI patients probably relates to the complex relationships between the severity of clinical impairment and their performance in the memory task used as the fMRI paradigm [73,74] . One explanation is that these studies do not require participants to perform below a particular cutoff on neuropsychological memory tests, and therefore, some patients perform relatively well on neuropsychological testing, despite clinical manifestations of impaired memory in daily life.…”

Section: Task-based Functional Mrimentioning

confidence: 95%

Can multi-modal neuroimaging evidence from hippocampus provide biomarkers for the progression of amnestic mild cognitive impairment?

Chen

Zhang

2015

Neurosci. Bull.

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Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD). As a part of the medial temporal lobe memory system, the hippocampus is one of the brain regions affected earliest by AD neuropathology, and shows progressive degeneration as aMCI progresses to AD. Currently, no validated biomarkers can precisely predict the conversion from aMCI to AD. Therefore, there is a great need of sensitive tools for the early detection of AD progression. In this review, we summarize the specifi c structural and functional changes in the hippocampus from recent aMCI studies using neurophysiological and neuroimaging data. We suggest that a combination of advanced multi-modal neuroimaging measures in discovering biomarkers will provide more precise and sensitive measures of hippocampal changes than using only one of them. These will potentially affect early diagnosis and disease-modifying treatments. We propose a new sequential and progressive framework in which the impairment spreads from the integrity of fibers to volume and then to function in hippocampal subregions. Meanwhile, this is likely to be accompanied by progressive impairment of behavioral and neuropsychological performance in the progression of aMCI to AD.

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“…Disease severity can also be quantified by measurement of the hippocampal volume, for example there was increased recruitment of the posterior hippocampus and fusiform gyrus in the MCI compared to the HC during an associate encoding task, with the increased recruitment linearly correlated to the atrophy of the hippocampus in the MCI group [20]. In an encoding task with visual stimuli, the aMCI subjects had higher activation in right parahippocampal gyrus compared to HC and those that showed the greatest activation in this region within the aMCI group, had the greater cognitive decline within the following 2.5 years [21].…”

Section: Introductionmentioning

confidence: 99%

Altered Brain Activation During a Verbal Working Memory Task in Subjects with Amnestic Mild Cognitive Impairment

Bokde

Karmann

Born

et al. 2010

JAD

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In subjects with Mild Cognitive Impairment (MCI) memory disorders indicate a high risk for conversion to Alzheimer's disease (AD). The objective of this study was to delineate the differences in brain activation between amnestic MCI and age-matched healthy controls (HC) during a verbal working memory task. The verbal working memory task was a delay match to sample design. Brain activation was measured using functional magnetic resonance imaging. There were 8 subjects in each group and were matched for performance. The task was analyzed as an event-related design. Group differences were calculated using Analysis of Covariance (ANCOVA) with statistical significance at p < 0.05 corrected. Both groups activated a wide network in the posterior and frontal areas of the brain. There was higher activation in the parietal and frontal lobes in the MCI compared to the HC during the maintenance phase. There were no areas in the HC that activated higher than the MCI subjects. Response time in the task in the HC group was correlated to the left hippocampus during encoding phase and to the parietal and frontal areas during the recall phase. In the MCI group there was strong correlation to the inferior and middle temporal gyrii during encoding, the middle frontal gyrus during the maintenance phase, and hippocampus during recall phase. The activation differences between groups may be compensatory mechanisms within the MCI group for the effects of the putative AD neuropathology. This has been the first study that has examined verbal working memory in MCI.

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Increased fMRI responses during encoding in mild cognitive impairment

Cited by 281 publications

References 68 publications

Effects of theApolipoprotein Eε4 Allele on Functional MRI duringn-Back Working Memory Tasks in Healthy Middle-Aged Adults

Effects of theApolipoprotein Eε4 Allele on Functional MRI duringn-Back Working Memory Tasks in Healthy Middle-Aged Adults

Can multi-modal neuroimaging evidence from hippocampus provide biomarkers for the progression of amnestic mild cognitive impairment?

Altered Brain Activation During a Verbal Working Memory Task in Subjects with Amnestic Mild Cognitive Impairment

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