White Tracts Research Articles

Genetic influence on microstructure integrity and motor progression in Parkinson's disease

BackgroundUp to 10 % of Parkinson's disease (PD) populations carry a genetic risk variant, which may not only increase one's chance of developing PD but also affect disease presentation and progression. We hypothesize motor impairment in genetic carriers of PD correlate to different patterns of microstructural changes over time. Design/methodsData were accessed from the Parkinson's Progression Markers Initiative (PPMI) project. Connectometry analyses were performed for GBA1+ PD, LRRK2+ PD, and sporadic PD correlating white matter structural changes, as measured by quantitative anisotropy (QA), with motor impairment, as measured by MDS-UPDRS III. ResultsThere was a negative correlation between QA and MDS-UPDRS III in all 3 cohorts at 48 months. In GBA1+ PD (n = 12), the white matter tracts identified were cortical and subcortical, while in the LRRK2+ PD (n = 18) and sporadic PD (n = 45) cohorts white tracts identified were primarily subcortical and within the brainstem. ConclusionsOur findings highlight the association between motor symptom progrerssion and structural connectivity in individuals with GBA1+ PD, LRRK2+ PD, and sporadic PD. Due to the small sample size, larger studies are needed in the future to confirm the findings.

White matter tract crossing and bottleneck regions in the fetal brain.

There is a growing interest in using diffusion MRI to study the white matter tracts and structural connectivity of the fetal brain. Recent progress in data acquisition and processing suggests that this imaging modality has a unique role in elucidating the normal and abnormal patterns of neurodevelopment in utero. However, there have been no efforts to quantify the prevalence of crossing tracts and bottleneck regions, important issues that have been extensively researched for adult brains. In this work, we determined the brain regions with crossing tracts and bottlenecks between 23 and 36 gestational weeks. We performed probabilistic tractography on 59 fetal brain scans and extracted a set of 51 distinct white tracts, which we grouped into 10 major tract bundle groups. We analyzed the results to determine the patterns of tract crossings and bottlenecks. Our results showed that 20-25% of the white matter voxels included two or three crossing tracts. Bottlenecks were more prevalent. Between 75-80% of the voxels were characterized as bottlenecks, with more than 40% of the voxels involving four or more tracts. The results of this study highlight the challenge of fetal brain tractography and structural connectivity assessment and call for innovative image acquisition and analysis methods to mitigate these problems.

Abstract 092: Vasospasm as a Consequence of IVIg Usage for GBS.

Introduction The relationship between Intravenous Immunoglobulin (IVIg) and cerebrovascular vasospasm is poorly and incompletely understood. Some case reports have identified IVIg as potential therapy for vasospasm, while others have implicated it as a causative agent in primarily coronary artery vasospasm and the development of atypical angina. This case illustrates a situation in which a patient with Guillain‐Barre Syndrome (GBS) was started on IVIg and developed subsequent vasospasm with cerebral infarcts requiring intra‐arterial therapy. Methods Case Report Results Our patient is a 62 year old female with a history of cervicothoracic subdural hematoma status postevacuation with left leg weakness, hypertension, known right ICA aneurysm, and chronic left ICA occlusion who presented as a transfer from an outside facility where she initially presented with progressive back pain, lower extremity weakness, areflexia and dysautonomia. MRI brain initially demonstrated posterior‐predominant T2 hyperintensities affecting subcortial white tracts suggestive of PRES. Lumbar puncture demonstrated cytoalbuminologic dissociation supporting a superimposed GBS. IVIg was initiated, however the patient's mentation and examination declined. Repeat MRI demonstrates bilateral, posterior‐predominant acute multifocal ischemic infarcts. Vessel imaging demonstrated vasospasm of the basilar and bilateral anterior Circle of Willis. Oral Verapamil was initiated. Digital Subtraction Angiography confirmed these findings; intra‐arterial verapamil was utilized with significant improvement in the patient's examination. Conclusion IVIg has only a weak association with coronary artery vasospasm, however is heavily implicated in the onset of this patient's diffuse vasospastic ischemic disease. Prompt identification and aggressive initiation of treatment is essential in minimizing the burden of ischemic stroke and optimizing outcomes for these complex patients.

PM2.5 data inputs alter identification of disadvantaged communities

Communities of color and lower income are often found to experience disproportionate levels of fine particulate matter (PM2.5) air pollution in the US (Pope and Dockery 2006 J. Air Waste Manage. Assoc. 56 709–42; Brook et al 2010 Circulation 121 2331–78; Tessum et al 2021 Sci. Adv. 7 eabf4491). The federal and several state governments use relatively coarsely resolved (12 km) PM2.5 concentration estimates to identify overburdened communities. Newly available PM2.5 datasets estimate concentrations at increasingly high spatial resolutions (50 m–1 km), with different magnitudes and spatial patterns, potentially affecting assessments of racial, ethnic, and socioeconomic exposure disparities. We show that two recently available high-resolution datasets from the scientific community and the 12 km dataset are consistent for national and regional average, but not intraurban, PM2.5 concentration disparities in 2019. The datasets consistently indicate that regional average PM2.5 concentrations are higher in the least White (by 3%–65%) and most Hispanic census tracts (2%–47%), compared with in the most Non-Hispanic White tracts. However, in nine of the ten most populous cities, the three datasets differ on the order of least-to-most exposed population subgroups. We identified 1029 tracts (representing ∼4.5 million people) as disadvantaged (⩾65th percentile for poverty and ⩾90th percentile PM2.5 as defined by the Climate and Economic Justice Screening Tool) in all three datasets, 335 tracts (∼1.5 million people) as disadvantaged using both high-resolution datasets but not the 12 km dataset, and 695 tracts (∼2.7 million people) as disadvantaged in the 12 km dataset but not the high-resolution datasets. The 12 km dataset does not capture intraurban disparities and may mischaracterize disproportionately exposed neighborhoods. The high-resolution PM2.5 datasets can be further improved by ground-truthing with observations from rapidly expanding ground and mobile monitoring and by integrating across available datasets.

The Most Vulnerable Populations: Exploring the FEMA National Risk Index by Racial/Ethnic Group

Introduction:The US Federal Emergency Management Agency (FEMA) has created a publicly available National Risk Index (NRI) using natural disaster and community risk factor data to provide numeric and visual representations of communities’ disaster risk. Of particular interest is the index’s use of the social vulnerability and community resilience variables. This study’s purpose was to identify and explore differences in vulnerability and resilience based on racial demographic data at the census tract level. By identifying communities at the highest risk, we can address modifiable risk factors to improve natural disaster outcomes for vulnerable populations.Method:This project used merged data from the US Census Bureau’s 2019 American Community Survey and source data for the FEMA NRI. Using Microsoft Excel, we created scatter plots of the social vulnerability and community resilience variables by census tract and predominant racial group, and calculated the mean, standard deviation, and statistical difference between those variables by race.Results:In census tracts where Native Americans made up ≥50% of the population:1) There was a positive linear association between percent of Native Americans and increased social vulnerability.2) The average social vulnerability score (ASV) was significantly higher (ASV = 55.74) than for predominantly White tracts (ASV = 31.43) (p < 0.001).3) The average risk score (ARS) was significantly higher (ARS = 30.18) compared to predominantly White tracts (ARS = 16.98) (p < 0.001).4) The average resilience index score (ARIS) was significantly lower (ARIS = 51.83) than predominantly White tracts (ARIS = 55.08) (p < 0.001).Conclusion:Results show that census tracts with predominantly Native American populations face significantly higher natural disaster risk and social vulnerability, and have significantly lower resilience scores compared to predominantly White tracts. Using modifiable factors to improve community resilience and decrease social vulnerability, the US can better protect communities at high natural disaster risk.

Correlation Between Motor Progression and Structural Connectivity in GBA, LRRK2, and sporadic Parkinson’s Disease (S42.005)

<h3>Objective:</h3> To examine longitudinal structural connectivity changes and their correlation to motor symptom progression in people with GBA, LRRK2, or sporadic Parkinson’s disease (PD). <h3>Background:</h3> Monogenetic forms of PD account for 5–10% of PD populations. Compared to LRRK2-related and sporadic PD, GBA-related PD patients have more severe motor symptoms and are at greater risk of developing dementia. We hypothesize differences in motor progression between PD cohorts are associated with changes in structural connectivity. <h3>Design/Methods:</h3> Data were accessed from the Parkinson’s Progressive Markers Initiative (PPMI) project. Subjects were divided into three cohorts: GBA, LRRK2, and sporadic PD (control). Longitudinal connectometry analyses were carried out at baseline, 24 and 48 months, correcting for age, sex, and mean DaTscan striatal binding. We investigated the correlation between white matter tract structural changes, as measured by quantitative anisotropy (QA), and changes in motor symptoms, as measured by Movement Disorders Society-Unified Parkinson’s Rating Scale Part III (MDS-UPDRS III). <h3>Results:</h3> There was a negative correlation between QA of the corpus callosum and corticothalamic tracts and MDS-UPDRS III score in GBA cohorts at 24 (n=11, FDR = 0.0007) and 48 months (n=12, FDR=0.007). The LRRK2 cohorts showed a negative correlation between QA of the corpus callosum, corticospinal, and parietopontine tracts and the MDS-UPDRS III at 48 months only (n=18, FDR=0.025). There were no significant associations in the sporadic cohorts. <h3>Conclusions:</h3> Worsening motor impairment is associated with a decline in structural connectivity in select white matter tracts in GBA-related and LRRK2-related PD, which was not seen in the sporadic PD cohorts. These findings suggest a selective vulnerability of white tracts in monogenic forms of PD. <b>Disclosure:</b> Dr. Yu has nothing to disclose. Miss Wilson has nothing to disclose. An immediate family member of Dr. Rodriguez-Porcel has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Anmeal. Dr. Rodriguez-Porcel has received publishing royalties from a publication relating to health care. Dr. Cooper has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Acorda. Dr. Cooper has received research support from NIH. Dr. Cooper has received research support from Ralph H Johnson VA Medical Center.

THE CONTRIBUTION OF DIFFUSION TENSOR IMAGING TO CONVENTIONAL MAGNETIC RESONANCE IMAGING IN THE DIAGNOSIS OF MULTIPLE SCLEROSIS PATIENTS

Aim: The aim of this study is to investigate whether anisotropic diffusion is superior to conventional magnetic resonance imaging for understanding the pathophysiology of multiple sclerosis (MS) disease by Fractional anisotropy (FA) measurements.&#x0D; Material and Methods: In our study, FA measurements were made from the plaque, the periplaque area, the normal appeared white matter contralateral to the plaque and normal appearing white matter areas in MS patients and from the normal white matter in the control group. 3D trography maps were made in all MS patients and it was evaluated whether white pathways were affected by MS disease.&#x0D; Results: When the degree of anisotropy was compared to the control group, the degree of plaques was found lowest. Increase was observed in periplaque, the normal appeared white matter contralateral to the plaque and normal appearing white matter, respectively. The active plaque FA value was found to be lower than the chronic plaque FA value, and the chronic plaque FA was found to be lower than the normal white matter FA value. It has been shown that plaques traced along axonal pathways in MS patients cause interruption in axonal pathways. &#x0D; Conclusion: Progressive decrease in anisotropy from normal appearing white matter to periplaque white matter and plaque level indicates myelin damage. This suggests that the white matter that appears normal on T2 images on conventional MR is not actually normal. Based on these results, it was thought that diffusion tensor imaging would be useful in evaluating the burden of disease in MS patients.

Hemodialysis-Related Acute Brain Injury Demonstrated by Application of Intradialytic Magnetic Resonance Imaging and Spectroscopy.

Hemodialysis (HD) results in reduced brain blood flow, and HD-related circulatory stress and regional ischemia are associated with brain injury over time. However, studies to date have not provided definitive direct evidence of acute brain injury during a HD treatment session. Using intradialytic magnetic resonance imaging (MRI) and spectroscopy to examine HD-associated changes in brain structure and neurochemistry, the authors found that multiple white (WM) tracts had diffusion imaging changes characteristic of cytotoxic edema, a consequence of ischemic insult and a precursor to fixed structural WM injury. Spectroscopy showed decreases in prefrontal N -acetyl aspartate (NAA) and choline concentrations consistent with energy deficit and perfusion anomaly. This suggests that one HD session can cause brain injury and that studies of interventions that mitigate this treatment's effects on the brain are warranted. Hemodialysis (HD) treatment-related hemodynamic stress results in recurrent ischemic injury to organs such as the heart and brain. Short-term reduction in brain blood flow and long-term white matter changes have been reported, but the basis of HD-induced brain injury is neither well-recognized nor understood, although progressive cognitive impairment is common. We used neurocognitive assessments, intradialytic anatomical magnetic resonance imaging, diffusion tensor imaging, and proton magnetic resonance spectroscopy to examine the nature of acute HD-associated brain injury and associated changes in brain structure and neurochemistry relevant to ischemia. Data acquired before HD and during the last 60 minutes of HD (during maximal circulatory stress) were analyzed to assess the acute effects of HD on the brain. We studied 17 patients (mean age 63±13 years; 58.8% were male, 76.5% were White, 17.6% were Black, and 5.9% were of Indigenous ethnicity). We found intradialytic changes, including the development of multiple regions of white matter exhibiting increased fractional anisotropy with associated decreases in mean diffusivity and radial diffusivity-characteristic features of cytotoxic edema (with increase in global brain volumes). We also observed decreases in proton magnetic resonance spectroscopy-measured N -acetyl aspartate and choline concentrations during HD, indicative of regional ischemia. This study demonstrates for the first time that significant intradialytic changes in brain tissue volume, diffusion metrics, and brain metabolite concentrations consistent with ischemic injury occur in a single dialysis session. These findings raise the possibility that HD might have long-term neurological consequences. Further study is needed to establish an association between intradialytic magnetic resonance imaging findings of brain injury and cognitive impairment and to understand the chronic effects of HD-induced brain injury. NCT03342183 .

Violent Crime, Physical Inactivity, and Obesity: Examining Spatial Relationships by Racial/Ethnic Composition of Community Residents.

Violence is a public health issue that disproportionately affects communities of color in urban centers. There is limited understanding of how violent crime is associatedwith adult physical inactivity and obesity prevalence given the racial/ethnic composition of community residents. This research aimed to address this gap by examining census tract-level data in Chicago, IL. Ecological data gathered from a variety of sources were analyzed in 2020. Violent crime rate represented the number of police-reported incidents of homicide, aggravated assault, and armed robbery per 1,000 residents. Spatial error and ordinary least square regression models were evaluated to determine if violent crime rate was significant associated with prevalence (%) of adult physical inactivity and obesity among all Chicago census tracts (N = 798), majority non-Hispanic (NH) White tracts (n = 240), majority NH Black tracts (n = 280), majority Hispanic tracts (n = 169), and racially diverse tracts (n = 109). Majority was defined as ≥ 50% representation. After adjusting for socioeconomic and environmental measures (e.g., median income, grocery store availability, walkability index), violent crime rate was associated with % physical inactivity and % obesity at the census tract level in Chicago, IL (both p < 0.001). Associations were statistically significant among majority NH Black and Hispanic tracts, but not majority NH White and racially diverse tracts. Future studies should evaluate the structural drivers of violence and the influence these drivers have on adult physical inactivity and obesity risk, particularly in communities of color.

National trends and disparities in retail food environments in the USA between 1990 and 2014.

To describe national disparities in retail food environments by neighbourhood composition (race/ethnicity and socio-economic status) across time and space. We examined built food environments (retail outlets) between 1990 and 2014 for census tracts in the contiguous USA (n 71 547). We measured retail food environment as counts of all food stores, all unhealthy food sources (including fast food, convenience stores, bakeries and ice cream) and healthy food stores (including supermarkets, fruit and vegetable markets) from National Establishment Time Series business data. Changes in food environment were mapped to display spatial patterns. Multi-level Poisson models, clustered by tract, estimated time trends in counts of food stores with a land area offset and independent variables population density, racial composition (categorised as predominantly one race/ethnicity (>60 %) or mixed), and inflation-adjusted income tertile. The contiguous USA between 1990 and 2014. All census tracts (n 71 547). All food stores and unhealthy food sources increased, while the subcategory healthy food remained relatively stable. In models adjusting for population density, predominantly non-Hispanic Black, Hispanic, Asian and mixed tracts had significantly more destinations of all food categories than predominantly non-Hispanic White tracts. This disparity increased over time, predominantly driven by larger increases in unhealthy food sources for tracts which were not predominantly non-Hispanic White. Income and food store access were inversely related, although disparities narrowed over time. Our findings illustrate a national food landscape with both persistent and shifting spatial patterns in the availability of establishments across neighbourhoods with different racial/ethnic and socio-economic compositions.

Reassessing the Relationship Between Mortgage Loan Investment and Crime Across Race/Ethnicity, Disadvantage, and Instability

Home loans are associated with fewer crimes in neighborhoods and some research shows investment may be especially helpful in disadvantaged or minority neighborhoods. To replicate and extend this research, we estimate a series of multilevel negative binomial models on crime to (1) replicate prior research, (2) examine the robustness of extant findings to variable specification, and (3) expand on prior work by examining the conditional role of residential instability. In line with prior work, our results show that tracts receiving larger absolute and relative loan amounts experience fewer violent crimes. However, the magnitude of crime-reduction benefits of investment are attenuated when including aggravated assaults or accounting for the relative value of the loans. Though investment was associated with lower violent crime in all types of tracts, disproportionate benefits of investment—that is, more bang for the buck—occurs more consistently in White tracts than tracts of color. These findings underscore the importance of replication for ensuring sound housing and anti-crime policies.

Spatial Disadvantage and Racial Disparities in Gun Homicides.

A spatially disadvantaged census tract is one that is surrounded by disadvantaged tracts. More spatially disadvantaged neighborhoods may experience more violence, independent of their own level of disadvantage, and majority Black middle-class neighborhoods are more likely to be spatially disadvantaged than majority white neighborhoods. The purpose of this paper is to study how much of the racial difference in gun homicide rates between majority Black and majority white middle-class neighborhoods can be explained by differences in spatial disadvantage. To study this, comparable majority Black and majority white tracts were matched to understand how gun homicide rates differ in neighborhoods with similar levels of disadvantage. Further matching on spatial disadvantage reduced the disparity in gun homicides between majority Black and majority white middle-class neighborhoods, suggesting that spatial disadvantage accounts for some but not all of the disparity.

Housing Instability and Socioeconomic Disparities in Health: Evidence from the U.S. Economic Recession.

While a number of studies have observed the effects of housing instability on health outcomes, fewer have emphasized pre-existing socioeconomic disparities in health and the influence of housing instability on subsequent health outcomes in the wake of the economic recession. Using national data on six adult health indictors and foreclosure data aggregated by census tract, this study examines the association between neighborhood housing insecurity and health outcomes, particularly focusing on various income levels and racial groups in about 200 U.S. metropolitan areas after the 2008 housing crisis. Results suggest that high levels of housing instability induced by high levels of foreclosed properties in certain neighborhoods were strongly associated with more health problems among residents, but the results varied according to the income level and the dominant racial group in these neighborhoods. With regard to income levels, adverse health conditions in lower income neighborhoods remained longer and became stronger than those in higher income neighborhoods. The findings also show variation among racial groups: While multiple health problems plagued all income levels in white tracts, more severe and worsening pre-existing health problems appeared in lower income minority tracts. In addition, neighborhood housing instability generated by mortgage foreclosures was strongly associated with heart-related diseases, particularly in middle-income White neighborhoods, and mental health problems, particularly in upper-income Hispanic tracts. Finally, among multiple health indicators, mental health problems were the most common health conditions during the U.S. economic recession. In light of the socioeconomic disparities in health, policy makers should establish effective policy tools that integrate health and urban and housing planning.

Biking where Black: Connecting transportation planning and infrastructure to disproportionate policing

This study asks whether deficiencies in transportation are associated with disproportionate policing in Chicago using the case of cycling. I examine how the number of bicycle citations issued per street segment are influenced by the availability of bicycle facilities and street characteristics, controlling for crash incidence, police presence, and neighborhood characteristics. Tickets were issued 8 times more often per capita in majority Black tracts and 3 times more often in majority Latino tracts compared to majority white tracts. More tickets were issued on major streets, but up to 85% fewer were issued when those streets had bike facilities, which were less prevalent in Black and Latino neighborhoods. Tickets were not associated with bicycle injury-crashes and inversely associated with vehicle injury-crashes. Infrastructure inequities compound the effects of racially-biased policing in the context of transportation safety strategies. Remedies include the removal of traffic enforcement from safe systems strategies and equitable investment in cycling.

COVID-19 pandemic reveals persistent disparities in nitrogen dioxide pollution

The unequal spatial distribution of ambient nitrogen dioxide ([Formula: see text]), an air pollutant related to traffic, leads to higher exposure for minority and low socioeconomic status communities. We exploit the unprecedented drop in urban activity during the COVID-19 pandemic and use high-resolution, remotely sensed [Formula: see text] observations to investigate disparities in [Formula: see text] levels across different demographic subgroups in the United States. We show that, prior to the pandemic, satellite-observed [Formula: see text] levels in the least White census tracts of the United States were nearly triple the [Formula: see text] levels in the most White tracts. During the pandemic, the largest lockdown-related [Formula: see text] reductions occurred in urban neighborhoods that have 2.0 times more non-White residents and 2.1 times more Hispanic residents than neighborhoods with the smallest reductions. [Formula: see text] reductions were likely driven by the greater density of highways and interstates in these racially and ethnically diverse areas. Although the largest reductions occurred in marginalized areas, the effect of lockdowns on racial, ethnic, and socioeconomic [Formula: see text] disparities was mixed and, for many cities, nonsignificant. For example, the least White tracts still experienced ∼1.5 times higher [Formula: see text] levels during the lockdowns than the most White tracts experienced prior to the pandemic. Future policies aimed at eliminating pollution disparities will need to look beyond reducing emissions from only passenger traffic and also consider other collocated sources of emissions such as heavy-duty vehicles.

Abstract 005: Violent Crime, Physical Inactivity, And Obesity: Examining Differences In Spatial Relationships By Racial/ethnic Composition Of Community Residents

Introduction: Violent crime (e.g., homicide, aggravated assault) is a major public health issue that disproportionately affects communities of color in large urban centers. Studies have reported that residents in high crime communities are less likely to engage in physical activity. There is limited understanding of how violent crime influences physical inactivity and obesity at the community level. We aimed to address this gap by examining differences in spatial relationships between violent crime rate, physical inactivity, and obesity by racial/ethnic composition of community residents in Chicago, IL. Hypothesis: We assessed the hypothesis that violent crime rate is associated with the prevalence of physical inactivity and obesity at the census tract level in Chicago, IL. Methods: We conducted an ecological assessment of 2018 census tract data obtained from various sources. We used data from the City of Chicago to calculate per capita violent crime rate (number of incidents per 1,000 residents) for all census tracts (N = 801). Data on physical inactivity and obesity prevalence (%) were acquired from the CDC. Socio-demographic data (i.e., % Non-Hispanic (NH) White, % NH Black, % Hispanic, median household income) were obtained from the census bureau. We examined spatial lag and error models to determine if violent crime rate is associated with % physical inactivity and % obesity after controlling for socio-demographic characteristics and amenity availability (i.e., per capita outdoor parks and grocery stores). Stratified models were examined to identify differences in associations among majority NH White, NH Black, and Hispanic census tracts (defined as ≥ 50% representation). Results: NH Black census tracts (n = 278) had significantly higher rates of violent crime, physical inactivity, and obesity than Hispanic (n = 169) and NH White tracts (n = 240). Overall, violent crime rate was positivity associated with % physical inactivity (p&lt;0.001) but not % obesity (p=0.77) in Chicago after controlling for covariates. Stratified models revealed that violent crime rate was positively associated with % physical inactivity (p&lt;0.001) and % obesity (p=0.01) among NH Black tracts. Violent crime rate was not associated with % physical inactivity or % obesity among Hispanic and NH White census tracts. Conclusions: Racial/ethnic composition of residents appears to influence census-tract level associations between violent crime rate, physical inactivity, and obesity. Violent crime appears to be more relevant to physical inactivity and obesity in Chicago’s NH Black communities compared to Hispanic and NH White communities.

Anatomy and White Matter Connections of the Parahippocampal Gyrus

The parahippocampal gyrus is understood to have a role in high cognitive functions including memory encoding and retrieval and visuospatial processing. A detailed understanding of the exact location and nature of associated white tracts could significantly improve postoperative morbidity related to declining capacity. Through diffusion tensor imaging-based fiber tracking validated by gross anatomic dissection as ground truth, we have characterized these connections based on relationships to other well-known structures. Diffusion imaging from the Human Connectome Project for 10 healthy adult controls was used for tractography analysis. We evaluated the parahippocampal gyrus as a whole based on connectivity with other regions. All parahippocampal gyrus tracts were mapped in both hemispheres, and a lateralization index was calculated with resultant tract volumes. We identified 2 connections of the parahippocampal gyrus: inferior longitudinal fasciculus and cingulum. Lateralization of the cingulum was detected (P < 0.05). The parahippocampal gyrus is an important center for memory processing. Subtle differences in executive functioning following surgery for limbic tumors may be better understood in the context of the fiber-bundle anatomy highlighted by this study.

Availability of menthol cigarettes in Oakland, California after a partial flavor ban.

This study measures the availability of menthol cigarettes in Oakland, California where such products were banned from the majority of tobacco retailers, except for those who sold a significant amount of tobacco (e.g., 60% gross income). Out of a total of 385 retailers in Oakland, only forty-eight retailers were exempt from this ban at the time of data collection. In February 2019, seven months after the ban went into effect, we selected a stratified random sample of 15 census tracts, based on race/ethnicity. In pairs, data collectors walked on opposite sides of the street and collected all discarded cigarette packs (n=641) from the streets and sidewalks on weekdays. Overall, we found almost half (46.0%; 95% CI=32.6%-59.3%) of the packs collected were menthol, with Newport as the dominant brand. We found at least one pack of menthol cigarettes in 14 of the 15 sampled census tracts. In predominantly black/African American census tracts, the proportion of menthol cigarettes collected was significantly higher (70.1%; 95% CI=62.6%-77.7%) when compared to mixed race/ethnicity (55.9%; 95% CI=41.0-70.9%) and white tracts (35.1%; 95% CI=13.2%-57.1%). Finally, there was a moderate and negative correlation between distance to exempt tobacco retailer and menthol availability (r=-0.66, p<.05). The proportion of menthol cigarette packs decreased the further away census tracts were from exempt tobacco retailers. Results from this study lend support that partial bans provide disproportionate availability of menthol cigarettes in black/African American census tracts. Complete bans may help eliminate disparities associated with menthol cigarette use across communities.

Diffusion tensor imaging for assessment of normally appearing white matter of the brain and spinal cord in cases of multiple sclerosis: a multi-parametric correlation in view of patient\u2019s clinical status

BackgroundConventional MRI provides important morphologic information regarding the brain and spinal cord involvement by demyelinating plaques. However, it is of almost no value in assessing the normal-appearing white matter which has been proved by multiple pathologic studies to be directly and indirectly involved in the process of multiple sclerosis. Diffusion-weighted imaging and diffusion tensor imaging MRI have been widely used in multiple researches as a better solution for studying the normal-appearing white matter. The purpose of this study was to evaluate the role of diffusion tensor imaging examination of the normal-appearing white matter of the brain and spinal cord in patients with multiple sclerosis and to determine the relationship between diffusion tensor imaging metrics and patient’s clinical status.ResultsThe significant negative correlation found between expanded disability status scale score of secondary progressive MS patients and global (brain and spinal cord) average fractional anisotropy values in normal-appearing white matter and tracts (P = 0.000). Correlation between average apparent diffusion coefficient of corpus callosum tract and expanded disability status scale score revealed a significant positive correlation in RRMS (P = 0.001). While in secondary progressive MS, a significant negative correlation between fractional anisotropy average of the corpus callosum tract and expanded disability status scale score was noted (P = 0.015).ConclusionThere is a strong relationship between diffusion tensor imaging readings and clinical status of patients can be used to understand unexplained deterioration over disease course and also can be used when conventional MRI findings are equivocal. Corpus callosum affection in MS patients is intimately related to clinical status and its assessment should be done whenever possible.

What is the Functional Difference Between Sagittal With Metopic and Isolated Sagittal Craniosynotosis?

The purpose of this study is to understand the neurological differences between patients born with combined sagittal and metopic craniosynostosis (SMc) and isolated sagittal craniosynostosis (ISc) by studying aberrations in functional brain connectivity and white matter microstructure, before surgery, utilizing functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI). The authors collected DTI and resting-state (ie, no sedation and asleep) functional connectivity MRI data in 10 infant patients preoperatively: 5 in the SMc group (4.3 ± 1 months) and 5 in the ISc group (4.8 ± 1.1 months). Resting state fMRI imaging and DTI data were acquired using a 3-T Siemens Trio MRI system (Erlangen, Germany) while the infant patients slept. fMRI data were corrected for movement using SPM, underwent cerebrospinal fluid and white matter signal regression and further analyzed with BioImageSuite. For the DTI data, 3 diffusion runs were averaged, processed utilizing FMRIB Software Library, and analyzed statistically using BioImageSuite. Comparing the SMc versus ISc groups, SMc demonstrated that there was increased connectivity, statistically significant differences, in neural networks between children with sagittal synostosis alone versus those with sagittal with metopic synostosis, in the right BA 31 and BA 23 (corresponding to the posterior cingulate cortex (PCC) (P < 0.001). Analysis of the DTI revealed increased fractional anisotropy (normal maturation of white tracts) in the SMc group in the cingulum compared to the ISc group (P < 0.05). Differences in the functional networks include increased connectivity right frontoparietal network (RFPN) in ISc and increased connectivity in the primary visual network (V1) in SMc (P < 0.001). The SMc had increased connectivity as measured by fMR in the PCC, an area associated with attention deficit hyperactivity disorder. The DTI analysis demonstrated an increase in fractional anisotropy of the cingulum in the SMc group, a white matter tract projecting from the cingulate cortex; connections of the limbic (emotional regulation) system are instrumental. In SMc, increase of connectivity in the PCC correlates with an increase in maturation of the cingulum compared to ISc. There is increased connectivity of the RFPN network in the ISc and increased connectivity of the V1 network in the SMc patients. The SMc group has increased connectivity in the PCC, the original seed of the DMN network, and decreased connectivity to the RFPN network. The pattern of increased connectivity in the area of the DMN and decreased connectivity in the RFPN network is similar to the trend when comparing ADHD patients to normal controls. SMc has more similar functional network connectivity to ADHD as compared to ISc.