Decoupling of regional neural activity and inter-regional functional connectivity in Alzheimer’s Disease – a simultaneous PET/MRI study

Purpose: Alzheimer’s disease (AD) and mild cognitive impairment (MCI), a syndrome at-risk for AD, are characterized by both aberrant regional neural activity and disrupted inter-regional functional connectivity (FC). It is, however, not clear how aberrant regional neural activity and inter-regional FC interact across MCI and AD. Thus, we investigated the interplay between regional neural activity and inter-regional topological measures of FC in MCI and AD using simultaneous PET/MR measurement.Methods: We scanned 19 patients with MCI, 33 patients with AD, and 26 healthy individuals by simultaneous FDG-PET/resting-state fMRI. First, we assessed regional glucose metabolism identified through FDG-PET (as a proxy of regional neural activity), and inter-regional FC topology through clustering coefficient and degree centrality (as surrogates of local segregation and global connectivity, respectively, based on fMRI blood oxygenation). Next, we examined the potential moderating effect of disease status (MCI or AD) on the link between regional metabolism and inter-regional FC topology using hierarchical moderated multiple regression analysis.Results: Not only regional metabolism and inter-regional FC metrics were disrupted in in MCI and AD patients, but also AD significantly alters coupling between regional metabolism and inter-regional FC, particularly in the right inferior temporal, supplementary motor area and planum temporal areas, where AD moderated the effect of their regional glucose metabolism on predicting their inter-reginal FC. Conclusion: Our findings demonstrated that AD decouples the association between regional neural activity and functional segregation.

Territorios de sacrificio. Un dispositivo biopolítico de control para la apropiación y degradación de la vida en México

Through a historical and theoretical review of the urban planning of the state of Puebla in central Mexico, this text gives an account of the way in which the regional metabolism has led to the generation of sacrificial territories for the purpose of extraction and appropriation from the set of living forces or from the vital power on which capital feeds: energy, arable land, water assets and human labor. We investigate the proposal of the struggles of the South, from whom we return to the category of production of territories of sacrifice, as well as the analytical proposal of the bodies-territories as spaces of resistance of academics and feminist activists, to understand the logic of the degradation of the life of a particularly indigenous territory Santa María Zacatepec, Puebla, an indigenous people that for more than 10 years have resisted against the sacrificial projects.

Efektivitas Intervensi Motor Imagery (MI) terhadap Rehabilitasi Pasien Post stroke: A Systematic Review

Background: Motor Imagery (MI) is an intervention to improve motor skills in post stroke hemiparesis patients by focusing on weak body parts. Objective: To describe the effectiveness of providing MI in the rehabilitation of post stroke patients. Method: The database used to identify suitable articles obtained from Scopus, ProQuest and Pubmed was limited to the last 5 years of publication from 2016 to 2020, English, and fulltext articles. The literature review used the keyword "Motor Imagery" AND "Stroke Rehabilitation". In searching articles used "AND". Only 8 articles met the inclusion criteria. This review was from these 8 articles. Results: MI has effectiveness in cognitive, sensory and motor post-stroke patients by stimulating neuroplasticity in various areas of the brain so that it accelerates the increase in O2, glucose and various metabolites that lead to increased regional metabolism through dilation of cerebral arterioles and capillaries. MI which is given routinely will help the recovery of motor function of post-stroke patients and increase patient independence. Conclusion: MI has a lot of effectiveness in the rehabilitation of post stroke patients. Suggestion: MI is considered necessary to be applied in hospitals in Indonesia. Keywords: motor imagery; stroke; rehabilitation ABSTRAK Latar belakang: Motor Imagery (MI) merupakan intervensi untuk meningkatkan keterampilan motorik pada pasien hemiparesis post stroke dengan berfokus pada bagian tubuh yang lemah. Tujuan: Untuk menjabarkan efektivitas pemberian MI pada rehabilitasi pasien post stroke. Metode: Database yang digunakan dalam penelitian ini adalah Scopus, Proquest dan Pubmed terbatas untuk publikasi 5 tahun terakhir dari 2016 hingga 2020, full text article dan berbahasa Inggris. Kata kunci yang digunakan adalah “Motor Imagery” AND “Stroke Rehabilitation”. Systematic review ini menggunakan 8 artikel yang sesuai dengan kriteria inklusi. Hasil: MI memiliki efektivitas pada kognitif, sensorik dan motorik pasien post stroke dengan merangsang neuroplastisitas pada berbagai area otak sehingga memperlancar peningkatan O2, glukosa dan berbagai metabolit yang mengarah ke peningkatan metabolisme regional melalui dilatasi arteriol serebral dan kapiler. Motor Imagery (MI) yang diberikan secara rutin akan membantu pemulihan fungsi motorik pasien post stroke dan meningkatkan kemandirian pasien. Simpulan: MI memiliki banyak efektivitas pada rehabilitasi pasien post stroke Saran: MI dipandang perlu untuk diterapkan di rumah sakit yang ada di Indonesia. Kata kunci: motor imagery; stroke; rehabilitation

Low septal to lateral wall 18F-FDG ratio is highly associated with mechanical dyssynchrony in non-ischemic CRT candidates

Background In order to better understand the concept of mechanical dyssynchrony, a promising hallmark of cardiac resynchronization therapy (CRT) response, we investigated its effect on regional myocardial metabolism and myocardial blood flow (MBF) in non-ischemic CRT candidates. Results Thirty consecutive non-ischemic CRT eligible patients underwent static 18F-FDG and resting dynamic 13N-NH3 PET/CT. 18F-FDG uptake and MBF for septal and lateral wall were analysed and septal-to-lateral wall ratios (SLR) were calculated. Based on the presence of mechanical dyssynchrony (septal flash and/or apical rocking) on echocardiography, patients were divided into 2 groups, with (n = 23) and without (n = 7) mechanical dyssynchrony. Patients with mechanical dyssynchrony had significantly lower 18F-FDG SUVmean in the septum compared with the lateral wall (5.58 ± 2.65 vs 11.19 ± 4.10, p < 0.0001), while patients without mechanical dyssynchrony had a more homogeneous 18F-FDG distribution (7.33 ± 2.88 vs 8.31 ± 2.50, respectively, p = 0.30). Similarly, MBF was significantly different between the septal and lateral wall in the dyssynchrony group (0.57 ± 0.11 ml/g/min vs 0.92 ± 0.23 ml/g/min, respectively, p < 0.0001), whereas no difference was observed in the non-dyssynchrony group (0.61 ± 0.23 ml/g/min vs 0.77 ± 0.21 ml/g/min, respectively, p = 0.16). 18F-FDG SLR, but not MBF SLR, was associated with the presence of mechanical dyssynchrony and showed a significant inverse correlation with volumetric reverse remodeling after CRT (r = − 0.62, p = 0.001). Conclusions Non-ischemic heart failure patients with mechanical dyssynchrony demonstrate heterogeneous regional metabolism and MBF compared with patients without dyssynchrony. However, only 18F-FDG SLR appeared to be highly associated with the presence of mechanical dyssynchrony. Trial registration Clinicaltrials, NCT02537782. Registered 2 September 2015.

Decoupling of inter-regional functional connectivity and regional neural activity in Alzheimer Disease

Alzheimer’s disease (AD) and mild cognitive impairment (MCI) are characterized by aberrant regional neural activity and disrupted inter-regional functional connectivity (FC). It is, however, poorly understood how changes in regional neural activity and inter-regional FC interact in AD and MCI. Here, we investigated the link between regional neural activity and nodal topological measures of FC through simultaneous PET/MR measurement in 20 patients with MCI, 33 patients with AD, and 26 healthy individuals. First, we assessed regional glucose metabolism identified through FDG-PET (rFDG) (as a proxy of regional neural activity), and regional FC topology through clustering coefficient (CC) and degree centrality (DC) (as surrogates of local segregation and global connectivity, respectively). Next, we examined the potential moderating effect of disease status (AD or MCI) on the link between rFDG and FC topology using hierarchical moderated multiple regression analysis. Alterations in rFDG, CC, and DC were widespread in patients, and AD alters physiological coupling between regional metabolism and functional connectivity particularly in the inferior temporal gyus and supplementary motor areas. While rFDG correlated with CC in healthy subjects, this correlation was lost in AD patients. We suggest that AD pathology decouples the normal association between regional neural activity and functional segregation.

Regional Brain Metabolism in a Murine Systemic Lupus Erythematosus Model

Systemic lupus erythematosus (SLE) is characterized by multiorgan inflammation, neuropsychiatric disorders (NPSLE), and anti-nuclear antibodies. We previously identified a subset of anti-DNA antibodies (DNRAb) cross-reactive with the N-methyl-D-aspartate receptor, present in 30% to 40% of patients, able to enhance excitatory post-synaptic potentials and trigger neuronal apoptosis. DNRAb + mice exhibit memory impairment or altered fear response, depending on whether the antibody penetrates the hippocampus or amygdala. Here, we used 18F-fluorodeoxyglucose (FDG) microPET to plot changes in brain metabolism after regional blood-brain barrier (BBB) breach. In DNRAb + mice, metabolism declined at the site of BBB breach in the first 2 weeks and increased over the next 2 weeks. In contrast, DNRAb — mice exhibited metabolic increases in these regions over the 4 weeks after the insult. Memory impairment was present in DNRAb + animals with hippocampal BBB breach and altered fear conditioning in DNRAb + mice with amygdala BBB breach. In DNRAb + mice, we observed an inverse relationship between neuron number and regional metabolism, while a positive correlation was observed in DNRAb — mice. These findings suggest that local metabolic alterations in this model take place through different mechanisms with distinct time courses, with important implications for the interpretation of imaging data in SLE subjects.