Dorsal component of the superior longitudinal fasciculus revisited: novel insights from a focused fiber dissection study

OBJECTIVEThe aim of this study was to investigate the anatomical consistency, morphology, axonal connectivity, and correlative topography of the dorsal component of the superior longitudinal fasciculus (SLF-I) since the current literature is limited and ambiguous.METHODSFifteen normal, adult, formalin-fixed cerebral hemispheres were studied through a medial to lateral fiber microdissection technique. In 5 specimens, the authors performed stepwise focused dissections of the lateral cerebral aspect to delineate the correlative anatomy between the SLF-I and the other two SLF subcomponents, namely the SLF-II and SLF-III.RESULTSThe SLF-I was readily identified as a distinct fiber tract running within the cingulate or paracingulate gyrus and connecting the anterior cingulate cortex, the medial aspect of the superior frontal gyrus, the pre–supplementary motor area (pre-SMA), the SMA proper, the paracentral lobule, and the precuneus. With regard to the morphology of the SLF-I, two discrete segments were consistently recorded: an anterior and a posterior segment. A clear cleavage plane could be developed between the SLF-I and the cingulum, thus proving their structural integrity. Interestingly, no anatomical connection was revealed between the SLF-I and the SLF-II/SLF-III complex.CONCLUSIONSStudy results provide novel and robust anatomical evidence on the topography, morphology, and subcortical architecture of the SLF-I. This fiber tract was consistently recorded as a distinct anatomical entity of the medial cerebral aspect, participating in the axonal connectivity of high-order paralimbic areas.

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Central Nervous System Processing of Emotions in Children with Fecal Incontinence and Constipation

Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie ◽

10.1024/1422-4917/a000638 ◽

2019 ◽

Vol 47 (1) ◽

pp. 67-71

Author(s):

Monika Equit ◽

Justine Niemczyk ◽

Anna Kluth ◽

Carla Thomas ◽

Mathias Rubly ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Fecal Incontinence ◽

Event Related Potentials ◽

Anterior Cingulate ◽

Afferent Pathways ◽

Study Results ◽

Related Potentials ◽

The Central Nervous System ◽

Cortical Regions

Abstract. Objective: Fecal incontinence and constipation are common disorders in childhood. The enteric nervous system and the central nervous system are highly interactive along the brain-gut axis. The interaction is mainly afferent. These afferent pathways include centers that are involved in the central nervous processing of emotions as the mid/posterior insula and the anterior cingulate cortex. A previous study revealed altered processing of emotions in children with fecal incontinence. The present study replicates these results. Methods: In order to analyze the processing of emotions, we compared the event-related potentials of 25 children with fecal incontinence and constipation to those of 15 control children during the presentation of positive, negative, and neutral pictures. Results: Children with fecal incontinence and constipation showed altered processing of emotions, especially in the parietal and central cortical regions. Conclusions: The main study results of the previous study were replicated, increasing the certainty and validity of the findings.

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Investigation on Effect of Analysis Variables on Structural Integrity of the Nuclear Piping Under Beyond Design Basis Earthquake

Volume 3B: Design and Analysis ◽

10.1115/pvp2017-66214 ◽

2017 ◽

Author(s):

Jong-Sung Kim ◽

Suk-Hyun Lee ◽

Hyeong Do Kweon

Keyword(s):

Finite Element ◽

Structural Integrity ◽

Seismic Analysis ◽

Time History ◽

Time History Analysis ◽

Design Basis ◽

History Analysis ◽

Study Results ◽

Transition Length ◽

Dynamic Time

In this study, effect of analysis variables on structural integrity of nuclear piping under beyond design basis earthquake was investigated via performing dynamic time history seismic analysis. A finite element model of the piping system such as shut-down cooling line was developed combining solid and beam elements. Dynamic time history analysis was performed via finite element elastic plastic stress analysis. Validity of the dynamic time history analysis procedure was verified via comparing with the previous study results. Finally, the effect of analysis variables such as finite element characteristics, transition length between elbow and straight line, fluid effect, etc. was investigated via performing parametric dynamic time history seismic analysis. As a result, it was found that use of the 1st incompatible element is recommended, the transition length is the same as curvature of the elbow, and fluid has to be considered.

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Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

Operative Neurosurgery ◽

10.1227/neu.0000000000000704 ◽

2015 ◽

Vol 11 (2) ◽

pp. 274-305 ◽

Cited By ~ 25

Author(s):

Kaan Yagmurlu ◽

Alexander L Vlasak ◽

Albert L Rhoton

Keyword(s):

Three Dimensional ◽

Central Core ◽

3 Dimensional ◽

Fiber Tracts ◽

Nuclear Masses ◽

Fiber Dissection ◽

Dissection Technique ◽

Human Brains ◽

The Brain ◽

Formalin Fixed

Abstract BACKGROUND The fiber tracts of the cerebrum may be a more important determinant of resection limits than the cortex. Better knowledge of the 3-dimensional (3-D) anatomic organization of the fiber pathways is important in planning safe and accurate surgery for lesions within the cerebrum. OBJECTIVE To examine the topographic anatomy of fiber tracts and subcortical gray matter of the human cerebrum and their relationships with consistent cortical, ventricular, and nuclear landmarks. METHODS Twenty-five formalin-fixed human brains and 4 whole cadaveric heads were examined by fiber dissection technique and ×6 to ×40 magnification. The fiber tracts and central core structures, including the insula and basal ganglia, were examined and their relationships captured in 3-D photography. The depth between the surface of the cortical gyri and selected fiber tracts was measured. RESULTS The topographic relationships of the important association, projection, and commissural fasciculi within the cerebrum and superficial cortical landmarks were identified. Important landmarks with consistent relationships to the fiber tracts were the cortical gyri and sulci, limiting sulci of the insula, nuclear masses in the central core, and lateral ventricles. The fiber tracts were also organized in a consistent pattern in relation to each other. The anatomic findings are briefly compared with functional data from clinicoradiological analysis and intraoperative stimulation of fiber tracts. CONCLUSION An understanding of the 3-D anatomic organization of the fiber tracts of the brain is essential in planning safe and accurate cerebral surgery.

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The Superior Frontal Longitudinal Tract: Connection between the Dorsal Premotor and the Dorsolateral Prefrontal Cortices

10.1101/2020.02.01.930552 ◽

2020 ◽

Author(s):

Mudathir Bakhit ◽

Masazumi Fujii ◽

Ryo Hiruta ◽

Masayuki Yamada ◽

Kenichiro Iwami ◽

...

Keyword(s):

Spatial Relationship ◽

Spatial Location ◽

Superior Longitudinal Fasciculus ◽

Point Patterns ◽

Dorsolateral Prefrontal ◽

Fiber Dissection ◽

Structural Connection ◽

Termination Point ◽

White Fiber ◽

Prefrontal Cortices

AbstractThe structural connection between the dorsal premotor (PMd) and the lateral prefrontal cortices (DLPFC) has been revealed, in a few studies, as the frontal longitudinal system (FLS). This study conducted a tractography analysis and a limited, postmortem, white-fiber dissection to investigate the superior FLS tract (SFLT) and analyze both its symmetry and termination point patterns. An analysis of spatial location, termination points, laterality, and correlation with the subjects’ gender or handedness was performed. SFLT was constructed in 100% of right and 88% of left hemispheres. The tracts exhibited variable patterns in different subjects in their posterior terminations. Additionally, the SFLT was found to possess a complex spatial relationship with the adjacent bundles. The SFLT was revealed successfully in two right hemispheres, where the posterior terminations were found to originate in the PMd, and its posterior terminations being totally separate from the superior longitudinal fasciculus.

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Diffusion property and functional connectivity of superior longitudinal fasciculus underpin human metacognition

10.1101/2020.03.17.994574 ◽

2020 ◽

Author(s):

Yunxuan Zheng ◽

Danni Wang ◽

Qun Ye ◽

Futing Zou ◽

Yao Li ◽

...

Keyword(s):

Functional Connectivity ◽

Structural Integrity ◽

Diffusion Tensor ◽

Memory Task ◽

Resting State Fmri ◽

Precentral Gyrus ◽

Superior Longitudinal Fasciculus ◽

Anterior Portion ◽

Inferior Parietal Cortex ◽

Cortical Regions

AbstractMetacognition as the capacity of monitoring one’s own cognition operates across domains. Here, we addressed whether metacognition in different cognitive domains rely on common or distinct neural substrates with combined diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) techniques. After acquiring DTI and resting-state fMRI data, we asked participants to perform a temporal-order memory task and a perceptual discrimination task, followed by trial-specific confidence judgments. DTI analysis revealed that the structural integrity (indexed by fractional anisotropy) in the anterior portion of right superior longitudinal fasciculus (SLF) was associated with both perceptual and mnemonic metacognitive abilities. Using perturbed mnemonic metacognitive scores produced by inhibiting the precuneus using TMS, the mnemonic metacognition scores did not correlate with individuals’ SLF structural integrity anymore, revealing the relevance of this tract in memory metacognition. In order to further verify the involvement of several cortical regions connected by SLF, we took the TMS-targeted precuneus region as a seed in a functional connectivity analysis and found the functional connectivity between precuneus and two SLF-connected regions (inferior parietal cortex and precentral gyrus) differentially mediated mnemonic but not perceptual metacognition performance. These results illustrate the importance of SLF and a putative white-matter grey-matter circuitry that supports human metacognition.

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Structural Forces: Perception and Vulnerability Factors for Tornado Sheltering within Mobile and Manufactured Housing in Alabama and Mississippi

Weather Climate and Society ◽

10.1175/wcas-d-19-0088.1 ◽

2020 ◽

Vol 12 (3) ◽

pp. 453-472 ◽

Cited By ~ 2

Author(s):

Kevin D. Ash ◽

Michael J. Egnoto ◽

Stephen M. Strader ◽

Walker S. Ashley ◽

David B. Roueche ◽

...

Keyword(s):

Structural Integrity ◽

Protective Action ◽

Public Outreach ◽

Vulnerability Factors ◽

Safety Study ◽

Manufactured Housing ◽

Structural Forces ◽

Emergency Managers ◽

Study Results ◽

Do So

AbstractSoutheastern U.S. mobile and manufactured housing (MH) residents are the most tornado-vulnerable subset of the population because of both physical and socioeconomic factors. This study builds upon prior MH resident tornado vulnerability research by statistically and geographically analyzing responses from a survey administered to these residents in the Southeast. Specifically, 257 Alabama and Mississippi MH residents were administered a survey with questions pertaining to their perceived tornado risk and vulnerability, protective action and decision-making, and beliefs about the structural integrity of their homes. Results indicate that, despite the weather and emergency management enterprises consistently suggesting that MH residents evacuate their homes for sturdier shelter during tornado events, more than 50% of MH residents believe their homes are safe sheltering locations. The prevalence of larger MHs in northern Alabama partially influences willingness to shelter within one’s MH, while higher levels of negative affectivity stemming from recent impactful tornadoes in northern Alabama influences people to evacuate their MHs for safety. Study findings also uncovered a perception and vulnerability paradox for these residents: Those who have the means to evacuate their MH often feel they have no need to do so, whereas those who recognize the potential peril of sheltering in their home and want to evacuate often lack the resources and/or self-efficacy to carry out more desirable sheltering plans. Overall, study results provide valuable information for National Weather Service forecasters, emergency managers, and media partners so that they may use it for public outreach and MH resident education.

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The Application of Concurrent Installation of the RCS Cross Over Leg and the Reactor Vessel Internals

ASME 2010 Pressure Vessels and Piping Conference: Volume 9 ◽

10.1115/pvp2010-25376 ◽

2010 ◽

Author(s):

K.-W. Park ◽

J.-H. Bae ◽

S.-H. Park

Keyword(s):

Feasibility Study ◽

Nuclear Power ◽

Power Plants ◽

Structural Integrity ◽

Reactor Vessel ◽

Pressurized Water ◽

Coolant Pump ◽

Reactor Coolant ◽

Study Results ◽

Under Construction

The reactor vessel internals (RVI) of a pressurized water reactor (PWR) must be installed precisely in the reactor vessel (RV) according to the requirements for levelness, orientation and vertical alignments for its proper functions and structural integrity. For the precise installation, deformation of the RV should be controlled during the RVI installation. Traditionally, the RVI has been installed in the RV after the completion of welding work for large bore pipings in the reactor coolant system (RCS). To reduce installation time, the concurrent installation of the RVI and RCS pipings is investigated. This paper describes the feasibility study on the concurrent installation including the Finite Element Method (FEM) analyses of the RV deformation due to the welding and heat treatment of the pipings. Based on the feasibility study results, the optimum schedule of the RVI installation in parallel with the installation of the cross-over leg pipings (reactor coolant pump inlet pipings) and confirmation measurement locations are developed. Thereby the concurrent installation will be applied to the nuclear power plants under construction in Korea, and it is expected to reduce installation period of 2 months compared to the traditional sequential installation method.

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Approaching the Atrium Through the Intraparietal Sulcus: Mapping the Sulcal Morphology and Correlating the Surgical Corridor to Underlying Fiber Tracts

Operative Neurosurgery ◽

10.1093/ons/opw037 ◽

2017 ◽

Vol 13 (4) ◽

pp. 503-516 ◽

Cited By ~ 8

Author(s):

Christos Koutsarnakis ◽

Faidon Liakos ◽

Aristotelis V. Kalyvas ◽

Evangelia Liouta ◽

John Emelifeonwu ◽

...

Keyword(s):

Longitudinal Axis ◽

Intraparietal Sulcus ◽

Superior Longitudinal Fasciculus ◽

Surface Anatomy ◽

Fiber Tracts ◽

Sulcal Morphology ◽

Surgical Corridor ◽

Risk Potential ◽

Optic Radiations ◽

Formalin Fixed

Abstract BACKROUND: Although the operative corridor used during the intraparietal transsulcal approach to the atrium has been previously investigated, most anatomical studies focus on its relationship to the optic radiations. OBJECTIVE: To study the intraparietal sulcus (IPS) morphology and to explore the subcortical anatomy with regard to the surgical trajectory used during the intraparietal transsulcal tranventricular approach. METHODS: Twenty-five adult, formalin fixed, cerebral hemispheres were investigated. Fifteen underwent the Klingler procedure and were dissected in a lateromedial direction using the fiber microdissection technique. The trajectory of the dissection resembled that of real operative settings. The remaining 10 hemispheres were cut along the longitudinal axis of the sulcus in order to correlate its surface anatomy to corresponding parts of the ventricular system. RESULTS: IPS demonstrated an interrupted course in 36% of the specimens while its branching pattern was variable. The sulcus anterior half was found to overly the atrium in all occasions. Four discrete, consecutive white matter layers were identified en route to the atrium, ie, the arcuate fibers, the arcuate segment of the superior longitudinal fasciculus, the corona radiata and tapetum, with the arcuate segment being near to the dissection trajectory. CONCLUSION: Given the angle of brain transgression during the intraparietal approach, we found the optimal dissection area to be the very middle of the sulcus. The IPS–postcentral sulcus meeting point, in contrast to previous thought, proved to risk potential injury to the arcuate segment of the superior longitudinal fasciculus, thus affecting surgical outcome.

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Multimorbidity and Regional Volumes of the Default Mode Network in Brain Aging

Gerontology ◽

10.1159/000517285 ◽

2021 ◽

pp. 1-10

Author(s):

Jen-Hung Wang ◽

Joshua Oon Soo Goh ◽

Yu-Ling Chang ◽

Shu-Cin Chen ◽

Yu-Ying Li ◽

...

Keyword(s):

Default Mode Network ◽

Structural Integrity ◽

Rating Scale ◽

Brain Aging ◽

Fasting Blood Glucose ◽

Cingulate Cortex ◽

Anterior Cingulate ◽

Cross Sectional ◽

Default Mode ◽

Posterior Cingulate

Introduction: The default mode network (DMN) is selectively vulnerable in brain aging. Little is known about the effect of multimorbidity as a whole onto the brain structural integrity. Objective: We aimed to investigate the association between multimorbidity and the structural integrity of DMN. Methods: We enrolled senior volunteers aged between 60 and 80 years in Hualien County during 2014–2018 and conducted in-person interview to collect information on chronic diseases. Fasting blood glucose and glycated hemoglobin (HbA1c) were tested. We assessed multimorbidity burden by the cumulative illness rating scale-geriatric (CIRS-G). MRI brain scans were standardized to measure the regional volume within the DMN. In a cross-sectional design, we employed stepwise regression models to evaluate the effects of age, sex, hyperglycemia, and multimorbidity on the DMN. Results: A total of 170 volunteers were enrolled with a mean age of 66.9 years, female preponderance (71%), an average mini-mental state examination score of 27.6, a mean HbA1c of 6.0, and a mean CIRS-G total score (TS) of 7.2. We found that older age was associated with reduced volumes in the hippocampus, left rostral anterior cingulate cortex, right posterior cingulate, right isthmus, precuneus, and right supramarginal. Higher levels of HbA1c and fasting glucose were associated with a reduced volume in the hippocampus only. A higher CIRS-G-TS was associated with reduced volumes in the left posterior cingulate cortex and right supramarginal gyrus; while a higher CIRS-G severity index was associated with a smaller right precuneus and right supramarginal. Conclusions: In the DMN, hippocampal volume shows vulnerability to aging and hyperglycemia, whereas the posterior cingulate, supramarginal, and precuneus cortices may be the key sites to reflect the total effects of multimorbidity.

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The cerebral isthmus: fiber tract anatomy, functional significance, and surgical considerations

Journal of Neurosurgery ◽

10.3171/2015.3.jns142680 ◽

2016 ◽

Vol 124 (2) ◽

pp. 450-462 ◽

Cited By ~ 8

Author(s):

Christos Koutsarnakis ◽

Faidon Liakos ◽

Evangelia Liouta ◽

Konstantinos Themistoklis ◽

Damianos Sakas ◽

...

Keyword(s):

White Matter ◽

Functional Significance ◽

Lateral Ventricle ◽

Anterior Part ◽

Proximal Part ◽

Microsurgical Anatomy ◽

Fiber Tract ◽

Frontal Horn ◽

Fiber Dissection ◽

Dissection Technique

OBJECT The cerebral isthmus is the white matter area located between the periinsular sulcus and the lateral ventricle. Studies demonstrating the fiber tract and topographic anatomy of this entity are lacking in current neurosurgical literature. Hence, the authors’ primary aim was to describe the microsurgical white matter anatomy of the cerebral isthmus by using the fiber dissection technique, and they discuss its functional significance. In addition, they sought to investigate its possible surgical utility in approaching lesions located in or adjacent to the lateral ventricle. METHODS This study was divided into 2 parts and included 30 formalin-fixed cerebral hemispheres, 5 of which were injected with colored silicone. In the first part, 15 uncolored specimens underwent the Klinger’s procedure and were dissected in a lateromedial direction at the level of the superior, inferior, and anterior isthmuses, and 10 were used for coronal and axial cuts. In the second part, the injected specimens were used to investigate the surgical significance of the superior isthmus in accessing the frontal horn of the lateral ventricle. RESULTS The microsurgical anatomy of the anterior, superior, and inferior cerebral isthmuses was carefully studied and recorded both in terms of topographic and fiber tract anatomy. In addition, the potential role of the proximal part of the superior isthmus as an alternative safe surgical corridor to the anterior part of the lateral ventricle was investigated. CONCLUSIONS Using the fiber dissection technique along with coronal and axial cuts in cadaveric brain specimens remains a cornerstone in the acquisition of thorough anatomical knowledge of narrow white matter areas such as the cerebral isthmus. The surgical significance of the superior isthmus in approaching the frontal horn of the lateral ventricle is stressed, but further studies must be carried out to elucidate its role in ventricular surgery.

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