Faculty Bibliography

Adoption of middle meningeal artery embolization in the management of chronic subdural hematomas has led to a renewed interest in dural vascular anatomy. The readily identifiable major dural arteries and potential hazards associated with their embolization are well described. Less emphasized are several levels of intrinsic dural angioarchitecture, despite their more direct relationship to dural based diseases, such as subdural hematoma and dural fistula. Fortunately, microvascular aspects of dural anatomy, previously limited to ex vivo investigations, are becoming increasingly accessible to in vivo visualization, setting the stage for synthesis of the old and the new, and providing a rationale for the endovascular approach to subdural collections in particular. In contrast with traditional anatomical didactics, where descriptions advance from larger trunks to smaller pedicles, we present a strategic approach that proceeds from a fundamental understanding of the dural microvasculature and its relationship to larger vessels.

How do people form their political beliefs? In an effort to address this question, we adopt a neuropsychological approach. In a natural experiment, we explored links between neuroanatomy and ideological preferences in two samples of brain lesion patients in New York City. Specifically, we compared the political orientations of patients with frontal lobe lesions, patients with amygdala lesions and healthy control subjects. Lesion type classification analyses revealed that people with frontal lesions held more conservative (or less liberal) beliefs than those with anterior temporal lobe lesions or no lesions. Additional analyses predicting ideology by extent of damage provided convergent evidence that greater damage in the dorsolateral prefrontal cortex-but not the amygdala-was associated with greater conservatism. These findings were robust to model specifications that adjusted for demographic, mood, and affect-related variables. Although measures of executive function failed to mediate the relationship between frontal lesions and ideology, our findings suggest that the prefrontal cortex may play a role in promoting the development of liberal ideology. Our approach suggests useful directions for future work to address the issue of whether biological developments precede political attitudes or vice versa-or both. This article is part of the theme issue 'The political brain: neurocognitive and computational mechanisms'.

Importance/UNASSIGNED:Clinical evidence of the potential treatment benefit of mechanical thrombectomy for posterior circulation distal, medium vessel occlusion (DMVO) is sparse. Objective/UNASSIGNED:To investigate the frequency as well as the clinical and safety outcomes of mechanical thrombectomy for isolated posterior circulation DMVO stroke and to compare them with the outcomes of standard medical treatment with or without intravenous thrombolysis (IVT) in daily clinical practice. Design, Setting, and Participants/UNASSIGNED:This multicenter case-control study analyzed patients who were treated for primary distal occlusion of the posterior cerebral artery (PCA) of the P2 or P3 segment. These patients received mechanical thrombectomy or standard medical treatment (with or without IVT) at 1 of 23 comprehensive stroke centers in Europe, the United States, and Asia between January 1, 2010, and June 30, 2020. All patients who met the inclusion criteria were matched using 1:1 propensity score matching. Interventions/UNASSIGNED:Mechanical thrombectomy or standard medical treatment with or without IVT. Main Outcomes and Measures/UNASSIGNED:Clinical end point was the improvement of National Institutes of Health Stroke Scale (NIHSS) scores at discharge from baseline. Safety end point was the occurrence of symptomatic intracranial hemorrhage and hemorrhagic complications were classified based on the Second European-Australasian Acute Stroke Study (ECASSII). Functional outcome was evaluated with the modified Rankin Scale (mRS) score at 90-day follow-up. Results/UNASSIGNED:Of 243 patients from all participating centers who met the inclusion criteria, 184 patients were matched. Among these patients, the median (interquartile range [IQR]) age was 74 (62-81) years and 95 (51.6%) were female individuals. Posterior circulation DMVOs were located in the P2 segment of the PCA in 149 patients (81.0%) and in the P3 segment in 35 patients (19.0%). At discharge, the mean NIHSS score decrease was -2.4 points (95% CI, -3.2 to -1.6) in the standard medical treatment cohort and -3.9 points (95% CI, -5.4 to -2.5) in the mechanical thrombectomy cohort, with a mean difference of -1.5 points (95% CI, 3.2 to -0.8; P = .06). Significant treatment effects of mechanical thrombectomy were observed in the subgroup of patients who had higher NIHSS scores on admission of 10 points or higher (mean difference, -5.6; 95% CI, -10.9 to -0.2; P = .04) and in the subgroup of patients without IVT (mean difference, -3.0; 95% CI, -5.0 to -0.9; P = .005). Symptomatic intracranial hemorrhage occurred in 4 of 92 patients (4.3%) in each treatment cohort. Conclusions and Relevance/UNASSIGNED:This study suggested that, although rarely performed at comprehensive stroke centers, mechanical thrombectomy for posterior circulation DMVO is a safe, and technically feasible treatment option for occlusions of the P2 or P3 segment of the PCA compared with standard medical treatment with or without IVT.

Microgliosis is a prominent pathological feature in many neurological diseases including multiple sclerosis (MS), a progressive auto-immune demyelinating disorder. The precise role of microglia, parenchymal central nervous system (CNS) macrophages, during demyelination, and the relative contributions of peripheral macrophages are incompletely understood. Classical markers used to identify microglia do not reliably discriminate between microglia and peripheral macrophages, confounding analyses. Here, we use a genetic fate mapping strategy to identify microglia as predominant responders and key effectors of demyelination in the cuprizone (CUP) model. Colony-stimulating factor 1 (CSF1), also known as macrophage colony-stimulating factor (M-CSF) - a secreted cytokine that regulates microglia development and survival-is upregulated in demyelinated white matter lesions. Depletion of microglia with the CSF1R inhibitor PLX3397 greatly abrogates the demyelination, loss of oligodendrocytes, and reactive astrocytosis that results from CUP treatment. Electron microscopy (EM) and serial block face imaging show myelin sheaths remain intact in CUP treated mice depleted of microglia. However, these CUP-damaged myelin sheaths are lost and robustly phagocytosed upon-repopulation of microglia. Direct injection of CSF1 into CNS white matter induces focal microgliosis and demyelination indicating active CSF1 signaling can promote demyelination. Finally, mice defective in adopting a toxic astrocyte phenotype that is driven by microglia nevertheless demyelinate normally upon CUP treatment implicating microglia rather than astrocytes as the primary drivers of CUP-mediated demyelination. Together, these studies indicate activated microglia are required for and can drive demyelination directly and implicate CSF1 signaling in these events.

Sensory input arrives in continuous sequences that humans experience as segmented units, e.g., words and events. The brain's ability to discover regularities is called statistical learning. Structure can be represented at multiple levels, including transitional probabilities, ordinal position, and identity of units. To investigate sequence encoding in cortex and hippocampus, we recorded from intracranial electrodes in human subjects as they were exposed to auditory and visual sequences containing temporal regularities. We find neural tracking of regularities within minutes, with characteristic profiles across brain areas. Early processing tracked lower-level features (e.g., syllables) and learned units (e.g., words), while later processing tracked only learned units. Learning rapidly shaped neural representations, with a gradient of complexity from early brain areas encoding transitional probability, to associative regions and hippocampus encoding ordinal position and identity of units. These findings indicate the existence of multiple, parallel computational systems for sequence learning across hierarchically organized cortico-hippocampal circuits.

Several COVID-19 vaccines have recently been approved for emergency use according to governmental immunization programs. The arrival of these vaccines has created hope for people with Parkinson's disease (PD), as this can help to mitigate their risk of becoming infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which can lead to serious, life-threatening disease, at least among those with more advanced PD. However, both persons with PD and physicians looking after these individuals have expressed concerns about the vaccine's efficacy and safety in the specific context of PD and its symptomatic treatment. Here, we discuss our perspective on these concerns, based on our interpretation of the literature plus the unfolding experience with widespread vaccination in the population at large. Because the benefits and risks of COVID-19 vaccines do not appear to be different than in the general population, we recommend COVID-19 vaccination with approved vaccines to persons with PD, unless there is a specific contraindication. Some caution seems warranted in very frail and terminally ill elderly persons with PD living in long-term care facilities.

BACKGROUND:The coronavirus disease 2019 (COVID-19) pandemic has severely affected ICUs and critical care health-care providers (HCPs) worldwide. RESEARCH QUESTION:How do regional differences and perceived lack of ICU resources affect critical care resource use and the well-being of HCPs? STUDY DESIGN AND METHODS:Between April 23 and May 7, 2020, we electronically administered a 41-question survey to interdisciplinary HCPs caring for patients critically ill with COVID-19. The survey was distributed via critical care societies, research networks, personal contacts, and social media portals. Responses were tabulated according to World Bank region. We performed multivariate log-binomial regression to assess factors associated with three main outcomes: limiting mechanical ventilation (MV), changes in CPR practices, and emotional distress and burnout. RESULTS:We included 2,700 respondents from 77 countries, including physicians (41%), nurses (40%), respiratory therapists (11%), and advanced practice providers (8%). The reported lack of ICU nurses was higher than that of intensivists (32% vs 15%). Limiting MV for patients with COVID-19 was reported by 16% of respondents, was lowest in North America (10%), and was associated with reduced ventilator availability (absolute risk reduction [ARR], 2.10; 95% CI, 1.61-2.74). Overall, 66% of respondents reported changes in CPR practices. Emotional distress or burnout was high across regions (52%, highest in North America) and associated with being female (mechanical ventilation, 1.16; 95% CI, 1.01-1.33), being a nurse (ARR, 1.31; 95% CI, 1.13-1.53), reporting a shortage of ICU nurses (ARR, 1.18; 95% CI, 1.05-1.33), reporting a shortage of powered air-purifying respirators (ARR, 1.30; 95% CI, 1.09-1.55), and experiencing poor communication from supervisors (ARR, 1.30; 95% CI, 1.16-1.46). INTERPRETATION:Our findings demonstrate variability in ICU resource availability and use worldwide. The high prevalence of provider burnout and its association with reported insufficient resources and poor communication from supervisors suggest a need for targeted interventions to support HCPs on the front lines.

PURPOSE/OBJECTIVE:Resting state functional magnetic resonance imaging (rsfMRI) is an emerging tool to explore the functional connectivity of different brain regions. We aimed to assess the disruption of functional connectivity of the Default Mode Network (DMN), Dorsal Attention Network(DAN) and Fronto-Parietal Network (FPN) in patients with glial tumors. METHODS:rsfMRI data acquired on 3T-MR of treatment-naive glioma patients prospectively recruited (2015-2019) and matched controls from the 1000 functional-connectomes-project were analyzed using the CONN functional toolbox. Seed-Based Connectivity Analysis (SBCA) and Independent Component Analysis (ICA, with 10 to 100 components) were performed to study reliably the three networks of interest. RESULTS:). For the FPN, increased connectivity was noted in the precuneus, posterior cingulate gyrus, and frontal cortex. No difference in the connectivity of the networks of interest was demonstrated between low- and high-grade gliomas, as well as when stratified by their IDH1-R132H (isocitrate dehydrogenase) mutation status. CONCLUSION/CONCLUSIONS:Altered functional connectivity is reliably found with SBCA and ICA in the DMN, DAN, and FPN in glioma patients, possibly explained by decreased connectivity between the cerebral hemispheres across the corpus callosum due to disruption of the connections.