Reversible functional connectivity disturbances during transient global amnesia

Peer, Michael; Nitzan, Mor; Goldberg, Ilan; Katz, Judith; Gomori, John M.; Ben‐Hur, Tamir; Arzy, Shahar

doi:10.1002/ana.24137

Cited by 57 publications

(48 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].…”

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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“…With regard to the neuropsychological deficit in TGA, recent experimental studies suggest that local dysfunction in hippocampal CA1 neurons may lead to a transient perturbation of hippocampal function (Cohen et al, 2013). Alternatively, lesions in TGA may lead to in a diachisis of memory function in widespread hippocampal networks (Peer et al, 2014). …”

Section: Discussionmentioning

confidence: 99%

Stress-related factors in the emergence of transient global amnesia with hippocampal lesions

Döhring

Schmuck

Bartsch

2014

Front. Behav. Neurosci.

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The transient global amnesia (TGA) is a rare amnesic syndrome that is characterized by an acute onset episode of an anterograde and retrograde amnesia. Its origin is still debated, but there is evidence for psychological factors involved in TGA. In neuroimaging, selective lesions in the CA1 field of the hippocampus can be detected, a region that is particularly involved in the processing of memory, stress and emotion. The aim of this study was to assess the role of psychological stress in TGA by studying the prevalence of stress related precipitating events and individual stress-related personality profiles as well as coping strategies in patients. The hypothesis of a functional differentiation of the hippocampus in mnemonic and stress-related compartments was also evaluated. From all 113 patients, 18% (n = 24) patients experienced emotional and psychological stress episodes directly before the TGA. In a cohort of 21 acute patients, TGA patients tend to cope with stress less efficiently and less constructively than controls. Patients who experienced a stress related precipitant event exhibited a higher level of anxiety in comparison to non-stress patients and controls. However, there was no difference between the general experience of stress and the number of stress inducing life events. The majority of patients (73%) did show typical magnetic resonance imaging (MRI) lesions in the CA1 region of the hippocampal cornu ammonis. There was no clear association between stressful events, distribution of hippocampal CA1 lesions and behavioral patterns during the TGA. Disadvantageous coping strategies and an elevated anxiety level may increase the susceptibility to psychological stress which may facilitate the pathophysiological cascade in TGA. The findings suggest a role of emotional stress factors in the manifestation of TGA in a subgroup of patients. Stress may be one trigger involved in the emergence of transient lesions in the hippocampal CA1 region, which are thought to be the structural and functional correlate of TGA.

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“…The DMN was identified from resting-state functional MRI scans of ten healthy subjects using a seed in the posterior cingulate cortex. Preprocessing and analysis were performed using SPM8 (Wellcome Department of Cognitive Neurology, London, UK) (for details, see [80]). epilepsy, in the postictal state, or following anesthesia, or could be manifested as chronic changes in orientation, as seen in patients with dementia or brain lesions or in the context of interictal personality changes in epilepsy [73,94,95].…”

Section: Discussionmentioning

confidence: 99%