Distinct Functional and Metabolic Alterations of DMN Subsystems in Alzheimer’s Disease: A Simultaneous FDG-PET/fMRI Study

Guan, Ziyun; Zhang, Miao; Zhang, Yaoyu; Li, Biao; Yao, Li

doi:10.1109/embc46164.2021.9629472

Cited by 7 publications

(10 citation statements)

References 15 publications

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“…In this study, using eLORETA-ICA, we extracted decreased activities of the memory network and occipital visual network for the rst time from the reduced alpha activity in the occipito-parieto-temporal areas in AD. In support of our result, fMRI, PET and SPECT studies with functional connectivity analysis have consistently reported hypoactivity of posterior DMN or PCC and the precuneus in AD [19][20][21] . In addition, longitudinal MRI studies with voxelbased morphometry found that in typical AD, cortical atrophy begins in the medial temporal cortex, and then spreads to connected regions through the cingulum bundle, resulting in disturbance of the memory network activity [12][13][14] .…”

Section: Discussionsupporting

confidence: 91%

“…Taking this into account, we checked the basic rhythm of each AD and ADMCI patient and found that the majority of the AD patients and all of the ADMCI patients had a basic rhythm within the alpha frequency band (AD 9.0 ± 1.1 Hz; ADMCI 9.7 ± 0.9 Hz; average frequency ± standard deviation). Moreover, in support of our assumption, a previous PET/fMRI study reported that spatial con guration of the DMN was preserved in AD 20 . A second limitation is that our correlation analysis results were uncorrected for multiple comparisons.…”

Section: Discussionsupporting

confidence: 87%

“…A recent meta-analysis of task-based fMRI studies revealed that, compared to healthy subjects, AD deteriorated speci c network activities, namely the occipital visual network, default mode network (DMN) and ventral attention network (VAN) 18 . Among these networks, decreased connectivity within the DMN in the PCC and the precuneus showed correlation with cognitive dysfunction in AD [19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

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EEG resting-state networks in Alzheimer’s disease associated with clinical symptoms

Aoki

Takahashi

Suzuki

et al. 2022

Preprint

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Alzheimer’s disease (AD) is a progressive neuropsychiatric disease affecting many elderly people and is characterized by progressive cognitive impairment of memory, visuospatial, and executive functions. As the elderly population is growing, the number of AD patients is increasing considerably. There is currently growing interest in determining AD’s cognitive dysfunction markers. We used exact low-resolution-brain-electromagnetic-tomography independent-component-analysis (eLORETA-ICA) to assess activities of five electroencephalography resting-state-networks (EEG-RSNs) in 90 drug-free AD patients and 11 drug-free patients with mild-cognitive-impairment due to AD (ADMCI). Compared to 147 healthy subjects, the AD/ADMCI patients showed significantly decreased activities in the memory network and occipital visual network, where the age difference between the AD/ADMCI and healthy groups was corrected by linear regression analysis. Furthermore, the age-corrected EEG-RSN activities showed correlations with cognitive function test scores in AD/ADMCI. In particular, decreased memory network activity showed correlations with worse total cognitive scores for both Mini-Mental-State-Examination (MMSE) and Alzheimer’s Disease-Assessment-Scale-cognitive-component-Japanese version (ADAS-J cog) including worse sub-scores for orientation, registration, repetition, word recognition and ideational praxis. Our results indicate that AD affects specific EEG-RSNs and deteriorated network activity causes symptoms. Overall, eLORETA-ICA is a useful, non-invasive tool for assessing EEG-functional-network activities and provides better understanding of the neurophysiological mechanisms underlying the disease.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

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EEG resting-state networks in Alzheimer’s disease associated with clinical symptoms

Aoki

Takahashi

Suzuki

et al. 2022

Preprint

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“…DMN plays an important role in cognitive function and internally directed thoughts. Moreover, it is closely connected with AD due to its association with AD atrophy modes and tau sedimentation [ 101 – 103 ]. CEN is a significant network obsessed with cognitive control and episodic memory [ 104 , 105 ].…”

Section: Discussionmentioning

confidence: 99%

Neuroimaging studies of acupuncture on Alzheimer’s disease: a systematic review

Yin

Wang

et al. 2023

BMC Complement Med Ther

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Background Acupuncture effectively improves cognitive function in Alzheimer’s disease (AD). Many neuroimaging studies have found significant brain alterations after acupuncture treatment of AD, but the underlying central modulation mechanism is unclear. Objective This review aims to provide neuroimaging evidence to understand the central mechanisms of acupuncture in patients with AD. Methods Relevant neuroimaging studies about acupuncture for AD were retrieved from eight English and Chinese medicine databases (PubMed, Embase, Cochrane Library, Web of Science, SinoMed, CNKI, WF, VIP) and other resources from inception of databases until June 1, 2022, and their methodological quality was assessed using RoB 2.0 and ROBINS - I. Brain neuroimaging information was extracted to investigate the potential neural mechanism of acupuncture for AD. Descriptive statistics were used for data analysis. Results Thirteen neuroimaging studies involving 275 participants were included in this review, and the overall methodological quality of included studies was moderate. The approaches applied included task-state functional magnetic resonance imaging (ts-fMRI; n = 9 studies) and rest-state functional magnetic resonance imaging (rs-fMRI; n = 4 studies). All studies focused on the instant effect of acupuncture on the brains of AD participants, including the cingulate gyrus, middle frontal gyrus, and cerebellum, indicating that acupuncture may regulate the default mode, central executive, and frontoparietal networks. Conclusion This study provides evidence of the neural mechanisms underlying the effect of acupuncture on AD involving cognitive- and motor-associated networks. However, this evidence is still in the preliminary investigation stage. Large-scale, well-designed, multimodal neuroimaging trials are still required to provide comprehensive insight into the central mechanism underlying the effect of acupuncture on AD. (Systematic review registration at PROSPERO, No. CRD42022331527).

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“…Such mechanism might have played a role in described studies in AD (Castellano et al, 2017 ; Shimizu et al, 2018 ) where increase in glucose metabolism (Castellano et al, 2017 ) and activation measured with BOLD signal (Shimizu et al, 2018 ) were not associated with any changes in cognitive functioning. AD is typically associated with glucose hypometabolism (Guan et al, 2021 ; Librizzi et al, 2021 ). Thus, reversal of glucose metabolism decline should be seen as a positive outcome.…”

Section: Discussionmentioning

confidence: 99%

A Systematic Review of the Impact of Physical Exercise-Induced Increased Resting Cerebral Blood Flow on Cognitive Functions

Renke

Marcinkowska

Kujach

et al. 2022

Front. Aging Neurosci.

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Brain perfusion declines with aging. Physical exercise represents a low-cost accessible form of intervention to increase cerebral blood flow; however, it remains unclear if exercise-induced amelioration of brain perfusion has any impact on cognition. We aimed to provide a state-of-the art review on this subject. A comprehensive search of the PubMed (MEDLINE) database was performed. On the basis of the inclusion and exclusion criteria, 14 studies were included in the analysis. Eleven of the studies conducted well-controlled exercise programs that lasted 12–19 weeks for 10–40 participants and two studies were conducted in much larger groups of subjects for more than 5 years, but the exercise loads were indirectly measured, and three of them were focused on acute exercise. Literature review does not show a direct link between exercise-induced augmentation of brain perfusion and better cognitive functioning. However, in none of the reviewed studies was such an association the primary study endpoint. Carefully designed clinical studies with focus on cognitive and perfusion variables are needed to provide a response to the question whether exercise-induced cerebral perfusion augmentation is of clinical importance.

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Distinct Functional and Metabolic Alterations of DMN Subsystems in Alzheimer’s Disease: A Simultaneous FDG-PET/fMRI Study

Cited by 7 publications

References 15 publications

EEG resting-state networks in Alzheimer’s disease associated with clinical symptoms

EEG resting-state networks in Alzheimer’s disease associated with clinical symptoms

Neuroimaging studies of acupuncture on Alzheimer’s disease: a systematic review

A Systematic Review of the Impact of Physical Exercise-Induced Increased Resting Cerebral Blood Flow on Cognitive Functions

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