Decreased Metabolism in the Posterior Medial Network with Concomitantly Increased Metabolism in the Anterior Temporal Network During Transient Global Amnesia

Yi, SangHak; Park, Young Ho; Jang, Jae Won; Lim, Jae Sung; Chun, In Kook; Kim, SangYun

doi:10.1007/s10548-017-0602-y

Cited by 4 publications

(5 citation statements)

References 37 publications

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“…Peer et al [25] investigated a brain network in TGA patients for the first time using rs-fMRI, and they reported a significant reduction in functional connectivity of the episodic memory network during TGA, which was more pronounced in the hyperacute phase than in the postacute phase. A report using positron emission tomography demonstrated hypometabolic clusters in the left temporal and bilateral parieto-occipital regions that belong to the posterior medial network, as well as hypermetabolic clusters in the bilateral inferior frontal regions that belong to the anterior temporal network [26]. Another study with single photon emission computed tomography reported decreased cerebral perfusion at the left precuneus, one of the resigns of the DMN, with posterior medial network disruption [27].…”

Section: Discussionmentioning

confidence: 99%

Is Transient Global Amnesia a Network Disease?

2018

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Background: We evaluated a brain network using graph theoretical analysis and microstructural abnormalities of the white matter in patients with transient global amnesia (TGA). Methods: Twenty patients with TGA and healthy control subjects were recruited, and they underwent diffusion tensor imaging (DTI) scans. Graph theory was applied to obtain network measures based on DTI data. We investigated the network measures and microstructural abnormalities of white matter using tract-based spatial statistics (TBSS) analysis in the patients with TGA. Results: Measures of global topology were not different between the patients with TGA and healthy subjects. However, there were significant differences of hubs organization; the strength of the right superior and inferior orbitofrontal, the right inferior frontal operculum, the left superior parietal, and left postcentral gyrus, the cluster coefficient of the right middle orbitofrontal and left inferior parietal gyrus, the betweenness centrality of the left angular gyrus, and the pagerank centrality of the right superior and inferior orbitofrontal, right inferior frontal operculum, left superior parietal, and left postcentral gyrus in the patients with TGA were significantly lower than those in healthy subjects. Regarding the analysis of the white matter microstructure with TBSS, there were no differences in the fractional anisotropy and mean diffusivity values between the 2 groups. Conclusions: We newly identify a reorganization of network hubs of the brain network in patients with TGA, especially in the regions of the default-mode network. These alterations of the brain network may play a role in the pathophysiologic mechanism underlying TGA and suggest that TGA is a network disease.

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Section: Discussionmentioning

confidence: 99%

Is Transient Global Amnesia a Network Disease?

2018

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“…Recently, cytotoxic edema of the hippocampus has been related to the pathogenesis of a TGA [13]. Fluorodeoxyglucose-positron emission tomography (FDG-PET) studies revealed that a TGA is associated with decreased metabolism in the posterior medial network [14]. Compensatorily, metabolism within the anterior temporal network is increased [14].…”

Section: Discussionmentioning

confidence: 99%

Simultaneous transient global amnesia and Takotsubo syndrome after death of a relative: a case report

Finsterer

Stöllberger

2019

J Med Case Reports

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IntroductionSimultaneous occurrence of transient global amnesia and Takotsubo syndrome has been only rarely reported. Here we report another patient with a transient global amnesia and concomitant Takotsubo syndrome.Case presentationOur patient is a 64-year-old white man with a previous history of myocarditis from borreliosis who developed sudden-onset confusional state with perseverations and repetition of the same questions during a funeral for his brother-in-law. Upon neurological work-up and after spontaneous resolution of most of the neurological deficits, transient global amnesia was diagnosed. Blood tests revealed moderate renal insufficiency, elevated troponin-T, and elevated N-terminal prohormone of brain natriuretic peptide. Electrocardiography showed left anterior hemiblock and negative T-waves in V2–V6. Upon transthoracic echocardiography the apical type of a Takotsubo syndrome was suspected. Since coronary angiography was normal and electrocardiography and echocardiographic abnormalities resolved under candesartan, bisoprolol, acetyl-salicylic acid, and atorvastatin within a few days after onset, Takotsubo syndrome was diagnosed.ConclusionsSince Takotsubo syndrome may be associated with transient global amnesia a causal relation may exist. A possible trigger for both conditions could be severe emotional stress from the loss of a close relative. A possible common pathomechanism could be overstimulation of adrenergic receptors in the myocardium, the cerebrum, or the coronary or cerebral arteries. Whether pre-existing myocardial compromise promotes the development of Takotsubo syndrome requires further investigations.

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“… 48 The authors concluded that these results may be related to a disruption of the posterior medial network, 49 also described as involved in episodic memory. 50 Another study, 24 using FDG-PET in TGA patients, 24–72 hours after onset, also reported decreased metabolism in the posterior medial network, suggesting that this network alteration may explain the symptoms appearing earlier, during the acute phase. Park et al .…”

Section: Discussionmentioning

confidence: 96%

“…The goal of this study was to provide a better understanding of the pathophysiological mechanisms contributing to amnesia and anxiety in TGA. We aimed at explaining the absence of structural alterations and the heterogeneity in the previous PET results by testing the hypothesis that TGA is a transient network disorder 24 affecting the limbic circuit and leading to both memory deficits and anxiety. The objective was thus to examine brain metabolism using FDG-PET in a group of TGA patients in acute or recovery phases.…”

Section: Introductionmentioning

confidence: 99%

Disruption in normal correlational patterns of metabolic networks in the limbic circuit during transient global amnesia

Segobin

Renault

Viader

et al. 2023

Brain Communications

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Transient global amnesia is characterized by the sudden apparition of a severe episodic amnesia, mainly anterograde, associated with emotional changes. Even though the symptoms are stereotyped, cerebral mechanism underlying transient global amnesia remain unexplained and previous studies using positron emission tomography do not show any clear results or consensus on cerebral regions impacted during transient global amnesia. This study included a group of 10 transient global amnesic patients who underwent 18F-fluorodeoxyglucose positron emission tomography during the acute or the recovery phase of the episode and 10 paired healthy controls. Episodic memory was evaluated with the Encoding-Storage-Retrieval paradigm and a story recall test of the Wechsler’s Memory Scale and anxiety was assessed with the Spielberger scale. We used statistical parametric mapping to identify modifications of whole-brain metabolism. Regarding hypometabolism, there was no brain region systematically affected in all transient global amnesic patients and the comparison between amnesic patients and controls did not show any significant differences. To better understand the specific implication of the limbic circuit in the pathophysiology of transient global amnesia, we then conducted a correlational analysis that included regions of this network. Our findings showed that in healthy controls, regions of the limbic circuit seem to operate in a synchronized way with all regions being highly correlated to each other. On the opposite, in transient global amnesic patients, we observed a clear disruption of this normal correlational patterns between regions with the medial temporal lobe (the hippocampus, parahippocampal gyrus and amygdala) included in one cluster and the orbitofrontal cortex, anterior and posterior cingulate gyrus and thalamus gathered in the other one. Given the individual variability in the time course of transient global amnesia, the direct comparison between a group of patients and controls does not seem to favor the identification of subtle and transient alterations in regional metabolism. The involvement of an extended network, such as the limbic circuit, seem more likely to explain the symptoms of patients. Indeed, the synchronization of regions within the limbic circuit seems to be altered during transient global amnesia, which could explain the amnesia and anxiety observed in transient global amnesic patients. The present study thus deepens our understanding of the mechanisms underlying not only amnesia but also the emotional component of transient global amnesia by considering it as a disruption in the normal correlational patterns within the limbic circuit.

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Decreased Metabolism in the Posterior Medial Network with Concomitantly Increased Metabolism in the Anterior Temporal Network During Transient Global Amnesia

Cited by 4 publications

References 37 publications

Is Transient Global Amnesia a Network Disease?

Is Transient Global Amnesia a Network Disease?

Simultaneous transient global amnesia and Takotsubo syndrome after death of a relative: a case report

Disruption in normal correlational patterns of metabolic networks in the limbic circuit during transient global amnesia

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