Faculty Bibliography

The visual field region where a stimulus evokes a neural response is called the receptive field (RF). Analytical tools combined with functional MRI can estimate the receptive field of the population of neurons within a voxel. Circular population RF (pRF) methods accurately specify the central position of the pRF and provide some information about the spatial extent (diameter) of the receptive field. A number of investigators developed methods to further estimate the shape of the pRF, for example whether the shape is more circular or elliptical. There is a report that there are many pRFs with highly elliptical pRFs in early visual cortex (V1-V3; Silson et al., 2018). Large aspect ratios (>2) are difficult to reconcile with the spatial scale of orientation columns or visual field map properties in early visual cortex. We started to replicate the experiments and found that the software used in the publication does not accurately estimate RF shape: it produces elliptical fits to circular ground-truth data. We analyzed an independent data set with a different software package that was validated over a specific range of measurement conditions, to show that in early visual cortex the aspect ratios are less than 2. Furthermore, current empirical and theoretical methods do not have enough precision to discriminate ellipses with aspect ratios of 1.5 from circles. Through simulation we identify methods for improving sensitivity that may estimate ellipses with smaller aspect ratios. The results we present are quantitatively consistent with prior assessments using other methodologies.SIGNIFICANCE STATEMENT:We evaluated whether the shape of many population receptive fields in early visual cortex is elliptical and differs substantially from circular. We evaluated two tools for estimating elliptical models of the pRF; one tool was valid over the measured compliance range. Using the validated tool, we found no evidence that confidently rejects circular fits to the pRF in visual field maps V1, V2 and V3. The new measurements and analyses are consistent with prior theoretical and experimental assessments in the literature.

Low levels of engagement in implementation science (IS) among health researchers is a multifaceted issue. With the aim of guiding efforts to increase engagement in IS research, we sought to identify barriers to engagement in IS within the health research community. We performed an online survey of health researchers in the United States in 2018. Basic science researchers were excluded from the sample. IS engagement was measured by self-reported conduct of or collaboration on an IS study in the past 5 years. Potential barriers tested were (a) knowledge and awareness of IS, (b) attitudes about IS research, (c) career benefits of IS, (d) research community support, and (e) research leadership support. We performed simple logistic regressions and tested multivariable logistic regression models of researcher characteristics and potential barriers as predictors of IS engagement. Of the 1,767 health researchers, 49.7% indicated they engaged in an implementation study. Being able to define IS (aOR 3.42, 95%CI 2.68-4.36, p < .001) and having attended IS training (aOR 3.77, 95%CI 2.96-4.81, p < .001) were associated with engaging in IS research. Among other potential barriers tested, perceptions that engaging in IS would not be good for their career (aOR 0.29, 95%CI 0.2-0.41, p < .001) was strongly associated with decreased engagement in IS research. Efforts to increase researcher familiarity with IS methods and foster support for IS within research communities, along with decreasing barriers to funding and publishing, are likely to be most effective for increasing engagement in IS research.

OBJECTIVE:The SARS-Cov2 virus is protean in its manifestations, affecting nearly every organ system. However, nervous system involvement and its impact on disease outcome are poorly characterized. The objective of the study is to determine if neurological syndromes are associated with increased risk of inpatient mortality. METHODS:581 hospitalized patients with confirmed SARS-Cov2 infection, neurological involvement and brain-imaging were compared to hospitalized non-neurological COVID-19 patients. Four patterns of neurological manifestations were identified -acute stroke, new or recrudescent seizures, altered mentation with normal imaging, and neuro-COVID-19 complex. Factors present on admission were analyzed as potential predictors of in-hospital mortality, including sociodemographic variables, pre-existing comorbidities, vital-signs, laboratory values, and pattern of neurological manifestations. Significant predictors were incorporated into a disease-severity score. Patients with neurological manifestations were matched with patients of the same age and disease severity to assess the risk of death. RESULTS:4711 patients with confirmed SARS-Cov2 infection were admitted to one medical system in New York City during a 6-week period. Of these, 581 (12%) had neurological issues of sufficient concern to warrant neuro-imaging. These patients were compared to 1743 non-neurological COVID-19 patients matched for age and disease-severity admitted during the same period. Patients with altered mentation (n=258, p =0.04, OR 1.39, CI 1.04 - 1.86) or radiologically confirmed stroke (n=55, p = 0.001, OR 3.1, CI 1.65-5.92) had a higher risk of mortality than age and severity-matched controls. CONCLUSIONS:The incidence of altered mentation or stroke on admission predicts a modest but significantly higher risk of in-hospital mortality independent of disease severity. While other biomarker factors also predict mortality, measures to identify and treat such patients may be important in reducing overall mortality of COVID-19.

Initially developed for large and giant wide-necked aneurysms of the internal carotid artery, flow diverter devices are now used in almost every location safely and with effectiveness.1-5 This video demonstrates a unique case of a giant aneurysm of the right petrous internal carotid artery in a 20-yr-old patient. This is an extremely rare location, and most of patients are asymptomatic.3-6 Signs of compression of the seventh and eight cranial nerves can be present and even Horner syndrome and lower cranial nerves neuropathies. Nevertheless, rupture can lead to epistaxis and otorrhagia, and ultimately to hemorrhagic shock. The patient in the current report was otherwise healthy but presented with lightheadedness and dizziness for 10 d. The patient consented to the procedure. There was no history of major trauma or head and neck infection. A transradial endovascular flow diversion embolization of a giant aneurysm of the petrous internal carotid artery is herein demonstrated in a stepwise manner. A triaxial system was used to deploy 3 overlapping devices. Concepts of J-wire technique, multiple coverage,1 and the so-called weld technique are emphasized. The role of adjunctive coiling and main reasons for failure are also discussed.7,8 Brief cases of flow diversion embolization of aneurysms of different morphologies at different locations are used to highlight the importance of assessing vessel wall apposition and follow-up imaging.

The Eating Disorder Examination Interview Bariatric Surgery Version (EDE-BSV) assesses eating pathology after bariatric surgery but requires significant training and time to administer. Consequently, we developed a questionnaire format called the Eating Disorders After Bariatric Surgery Questionnaire (EDABS-Q). This study evaluates the consistency of responsiveness between the two formats. After surgery, 30 patients completed the EDE-BSV and EDABS-Q in a restricted randomized design. Patient reported behavior for each item which was converted to a score following the Eating Disorder Examination-Questionnaire (EDE-Q) scoring scheme. Responses fell into three distributions: (1) dichotomous, (2) ordinal, or (3) unimodal. Distributions of items were not different between the two formats and order did not influence response. Tests of agreement (normal approximation of the binomial test) and association (χ² analyses on binary data and spearman rank order correlations on ordinal items) were performed. Percent concordance was high across items (63-100%). Agreement was significant in 31 of 41 items (Bonferroni-P < 0.001). Association was significant in 10 of 21 in χ²-appropriate items (Bonferroni-P < 0.002), and the ordinal items had highly significant correlations between formats (Bonferroni-P < 0.0125). The EDABS-Q is an adequate substitute for the EDE-BSV and may be useful for research and clinical evaluation of eating pathology after bariatric surgery.

PURPOSE/OBJECTIVE:Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke that causes severe visual loss and is a harbinger of further cerebrovascular and cardiovascular events. There is a paucity of scientific information on the appropriate management of CRAO, with most strategies based on observational literature and expert opinion. In this scientific statement, we critically appraise the literature on CRAO and provide a framework within which to consider acute treatment and secondary prevention. METHODS:We performed a literature review of randomized controlled clinical trials, prospective and retrospective cohort studies, case-control studies, case reports, clinical guidelines, review articles, basic science articles, and editorials concerning the management of CRAO. We assembled a panel comprising experts in the fields of vascular neurology, neuro-ophthalmology, vitreo-retinal surgery, immunology, endovascular neurosurgery, and cardiology, and document sections were divided among the writing group members. Each member received an assignment to perform a literature review, synthesize the data, and offer considerations for practice. Multiple drafts were circulated among the group until consensus was achieved. RESULTS:Acute CRAO is a medical emergency. Systems of care should evolve to prioritize early recognition and triage of CRAO to emergency medical attention. There is considerable variability in management patterns among practitioners, institutions, and subspecialty groups. The current literature suggests that treatment with intravenous tissue plasminogen activator may be effective. Patients should undergo urgent screening and treatment of vascular risk factors. There is a need for high-quality, randomized clinical trials in this field.