Effect of Trabecular Architecture on Transferring Load/Impact to the Brain: A Local Model of Single Trabecula

2011 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
External Load ◽  
Animal Studies ◽  
Trabecular Architecture ◽  
Local Models ◽  
Pia Mater ◽  
The Impact ◽  
External Loads ◽  
The Brain ◽  
Load Impact

In this paper the mechanotransduction of the external load through the trabeculae in the subarachnoid space (SAS) was investigated. This has been accomplished by employing the results of our animal studies, i.e. the histology and architecture of trabeculae, and by creating local models consist of a trabecula. It is concluded that the trabeculae are mainly configured as an upright tree-like shaped, where the branches are attached to the pia mater and the stems are attached to the arachnoid. The result of the analysis reveal that said configuration of the trabeculae creates less strain in the brain when the head in subjected to external loads, and thereby damps the impact.

On the Trabecular Morphologies and Load Transfer to the Brain

2013 ◽  
Author(s):  
Siavash Hashemi ◽  
Parisa Saboori ◽  
Shahab Mansoor-Baghaei ◽  
Ali M. Sadegh
Keyword(s):  
Human Brain ◽  
Dura Mater ◽  
Subarachnoid Space ◽  
Load Transfer ◽  
Trabecular Architecture ◽  
Pia Mater ◽  
Tree Shape ◽  
External Loads ◽  
The Brain ◽  
Arachnoid Mater

The human brain trabeculae contain strands of collagen tissues connecting the arachnoid to the pia mater. In this paper the mechanotransductions of the external loads to the head passing through different trabecular architectures of the subarachnoid space were investigated. This has been accomplished by creating several local 2-D models consist of skull, dura mater, arachnoid, trabecular architecture and the brain. Different orientations of several architectures of the trabeculae were also analyzed. All models were subjected to the same loading and constraints. The strains in the brain for each model of the architecture and morphology were determined and compared to other corresponding models. It is concluded that the strain in the brain is less where the tree-shape trabeculae are upright, where the branches are attached to the arachnoid mater and the stems are attached to the pia mater. In addition, in the case of other morphologies the strain in the brain is less when the ratio of the trabecular area to the CSF space is less.

Histology and Trabecular Architecture of the Brain for Modeling of Subarachnoid Space

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
Impact Load ◽  
Angular Acceleration ◽  
Trabecular Architecture ◽  
Solid Materials ◽  
Complex Architecture ◽  
The Impact ◽  
The Brain

Subarachnoid space (SAS) plays an important role in transferring and or damping the impact load or angular acceleration to the brain (Zoghi Sadegh 2009). Previous investigations have over simplified the complex architecture of the trabeculae of SAS and employed soft solid materials. The goal of this study is to investigate the histology, architecture and mechanotransduction of subarachnoid space and in particular the trabeculae. The results of this study facilitate future modeling of the brain and thereby better understanding of the TBI.

Effects of CSF Properties on Brain Response Under Impact Loading

2009 ◽  
Author(s):  
M. S. Chafi ◽  
V. Dirisala ◽  
G. Karami ◽  
M. Ziejewski
Keyword(s):  
Human Head ◽  
Brain Response ◽  
Pia Mater ◽  
Mechanical Shocks ◽  
The Central Nervous System ◽  
Simultaneous Loading ◽  
The Impact ◽  
Impact Experiments ◽  
The Brain

In the central nervous system, the subarachnoid space is the interval between the arachnoid membrane and the pia mater. It is filled with a clear, watery liquid called cerebrospinal fluid (CSF). The CSF buffers the brain against mechanical shocks and creates buoyancy to protect it from the forces of gravity. The relative motion of the brain due to a simultaneous loading is caused because the skull and brain have different densities and the CSF surrounds the brain. The impact experiments are usually carried out on cadavers with no CSF included because of the autolysis. Even in the cadaveric head impact experiments by Hardy et al. [1], where the specimens are repressurized using artificial CSF, this is not known how far this can replicate the real functionality of CSF. With such motivation, a special interest lies on how to model this feature in a finite element (FE) modeling of the human head because it is questionable if one uses in vivo CSF properties (i.e. bulk modulus of 2.19 GPa) to validate a FE human head against cadaveric experimental data.

External and internal Load and their Effects on Professional Volleyball Training

2020 ◽  
Vol 41 (07) ◽  
pp. 468-474
Author(s):  
Ricardo Franco Lima ◽  
Ana Silva ◽  
José Afonso ◽  
Henrique Castro ◽  
Filipe Manuel Clemente
Keyword(s):  
External Load ◽  
Inertial Measurement Unit ◽  
Perceived Exertion ◽  
Measurement Unit ◽  
Internal Load ◽  
Monitoring Process ◽  
Accurate Perception ◽  
Positive Correlations ◽  
The Impact ◽  
External Loads

AbstractThe purpose of this study was twofold: (i) characterize the external and internal training load of professional volleyball players with a focus on intra-week changes and (ii) test the relationships between internal and external load measures. Eight male professional players (age: 23.0±5.22 yo; body mass: 84.5 ± 7.58 kg; height: 193.0±9.71 cm; BMI: 22.0±0.02 kg/m2) were monitored daily over 15 weeks. The monitoring process included both internal (rate of perceived exertion [RPE] and session-RPE [s-RPE]) and external load variables, which were measured by an inertial measurement unit. Results revealed that, within-week variations revealed that RPE was significantly higher during MD-2 (d=0.59) and MD-3 (d=0.56) than MD-1. A significantly higher number of jumps was observed on MD-2 than MD-1 (d=0.69). Considering the relationships between internal and external load measures, small positive correlations were found between RPE and the number of jumps (r=0.17) and between s-RPE and the number of jumps (r=0.49). In conclusion, a tapering strategy was observed on the day before a match, as internal and external loads decreased. Both internal and external load measures are necessary to provide an accurate perception of the impact of training stimuli on players.

scholarly journals Understanding Drug Delivery to the Brain Using Liposome-Based Strategies: Studies that Provide Mechanistic Insights Are Essential

2021 ◽  
Vol 23 (6) ◽  
Author(s):  
Firda Juhairiyah ◽  
Elizabeth C. M. de Lange
Keyword(s):  
Drug Delivery ◽  
Drug Transport ◽  
Animal Studies ◽  
Time Course ◽  
Liposomal Formulation ◽  
Liposomal Drug ◽  
Brain Drug Delivery ◽  
Liposomal Formulations ◽  
The Impact ◽  
The Brain

AbstractBrain drug delivery may be restricted by the blood-brain barrier (BBB), and enhancement by liposome-based drug delivery strategies has been investigated. As access to the human brain is limited, many studies have been performed in experimental animals. Whereas providing interesting data, such studies have room for improvement to provide mechanistic insight into the rate and extent of specifically BBB transport and intrabrain distribution processes that all together govern CNS target delivery of the free drug. This review shortly summarizes BBB transport and current liposome-based strategies to overcome BBB transport restrictions, with the emphasis on how to determine the individual mechanisms that all together determine the time course of free drug brain concentrations, following their administration as such, and in liposomes. Animal studies using microdialysis providing time course information on unbound drug in plasma and brain are highlighted, as these provide the mechanistic information needed to understand BBB drug transport of the drug, and the impact of a liposomal formulations of that drug on BBB transport. Overall, these studies show that brain distribution of a drug administered as liposomal formulation depends on both drug properties and liposomal formulation characteristics. In general, evidence suggests that active transporters at the BBB, either being influx or efflux transporters, are circumvented by liposomes. It is concluded that liposomal formulations may provide interesting changes in BBB transport. More mechanistic studies are needed to understand relevant mechanisms in liposomal drug delivery to the brain, providing an improved basis for its prediction in human using animal data.

Does Subarachnoid Space Protect the Brain From Blast Waves and/or Blunt Impacts?

2015 ◽  
Author(s):  
Siavash Hashemi ◽  
Ali M. Sadegh
Keyword(s):  
Blast Wave ◽  
Cross Sections ◽  
Subarachnoid Space ◽  
3D Model ◽  
Blast Waves ◽  
Local Models ◽  
Different Types ◽  
Compressive Pressure ◽  
The Brain ◽  
Head Neck

The objectives of this study is to investigate the transduction of blast wave through the SAS region and the influence of SAS including different types of trabeculae in reducing the strain in the brain, when the head is subjected to a blast wave, and finally, comparing that to a none blast load such as blunt impacts or angular accelerations of the head during contact sports or accidents. This is accomplished through a series of Global/Local models of the head, neck and the brain. Specifically, a validated FE 3D model of the head and neck is subjected to a blast wave and the time dependent local compressive pressure gradient on the dura matter is calculated. Then through several detailed local FE models of the head, consisting Dura mater, Gray matter, Subarachnoid space having trabeculae and the CSF, the strains in the brain are calculated. In the local models different architecture and morphology of the trabeculae (rod shaped and the tree-shaped) are considered. The Global/Local models were analyzed using ABAQUS 6.12. In addition, the same procedure has been carried out for a velocity impact profile corresponding to 1.1 mph. The results revealed that the shape of the trabeculae would not affect the severity of loads transferring to the brain from shock waves in blast scenarios. Moreover, the interaction between the CSF and Tree-shaped trabeculae and rods with smaller cross sections, protect the brain better in impacts.

scholarly journals Histology and Morphology of the Brain Subarachnoid Trabeculae

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Animal Studies ◽  
Fibrous Tissue ◽  
Head Movements ◽  
Type I ◽  
Pia Mater ◽  
Transmission Electron ◽  
Bright Field Microscopy ◽  
The Brain

The interface between the brain and the skull consists of three fibrous tissue layers, dura mater, arachnoid, and pia mater, known as the meninges, and strands of collagen tissues connecting the arachnoid to the pia mater, known as trabeculae. The space between the arachnoid and the pia mater is filled with cerebrospinal fluid which stabilizes the shape and position of the brain during head movements or impacts. The histology and architecture of the subarachnoid space trabeculae in the brain are not well established in the literature. The only recognized fact about the trabeculae is that they are made of collagen fibers surrounded by fibroblast cells and they have pillar- and veil-like structures. In this work the histology and the architecture of the brain trabeculae were studied, via a series of in vivo and in vitro experiments using cadaveric and animal tissue. In the cadaveric study fluorescence and bright field microscopy were employed while scanning and transmission electron microscopy were used for the animal studies. The results of this study reveal that the trabeculae are collagen based type I, and their architecture is in the form of tree-shaped rods, pillars, and plates and, in some regions, they have a complex network morphology.

Anatomical relationships of the pia mater to cerebral blood vessels in man

1986 ◽  
Vol 65 (3) ◽  
pp. 316-325 ◽  
Author(s):  
Margaret Hutchings ◽  
Roy O. Weller
Keyword(s):  
Electron Microscopy ◽  
Cerebral Cortex ◽  
Blood Vessels ◽  
Subarachnoid Space ◽  
Blood Cells ◽  
Inflammatory Cells ◽  
Perivascular Spaces ◽  
Pia Mater ◽  
Transmission Electron ◽  
The Brain

✓ Using scanning and transmission electron microscopy and light microscopy, the authors studied the human pia mater and its relationship to the entry of blood vessels into the normal cerebral cortex. The purpose of this investigation was to examine the long-established concept that the subarachnoid space communicates directly with the perivascular spaces of the cerebral cortex. Brains obtained post mortem from subjects with recent subarachnoid hemorrhage (SAH) and purulent leptomeningitis were studied by light microscopy to determine the permeability of the pia mater to red blood cells and inflammatory cells. Scanning electron microscopy showed that the normal pia mater is a flat sheet of cells that is reflected from the surface of the brain to form the outer coating of the meningeal vessels in the subarachnoid space. Transmission electron microscopy confirmed that the cells of the pia mater are joined by junctional complexes and form a continuous sheet that separates the subarachnoid space on one side from the subpial and perivascular spaces on the other. Thus, neither the pia mater nor the subarachnoid space extends into the brain beside blood vessels as they enter the cerebral cortex. The perivascular spaces were, in fact, found to be confluent with the subpial space and not with the subarachnoid space. In cases of recent SAH, red blood cells did not enter the perivascular spaces from the subarachnoid space; neither did India ink injected post mortem into the subarachnoid space pass into the perivascular spaces. The results of these crude tracer studies suggest that the pia mater is an effective barrier to the passage of particulate matter. Histological examination of brains of patients who had died with purulent leptomeningitis showed that inflammatory cells were present in the cortical perivascular spaces and in the contiguous subpial spaces. The presence of a large number of inflammatory cells in the subarachnoid space suggests that inflammatory cells readily penetrate the pia mater that separates the perivascular spaces from the subarachnoid space. The permeability of the pia mater to small molecular weight substances is briefly discussed.

scholarly journals The impact of socioeconomic and stimulus inequality on human brain physiology

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dhanya Parameshwaran ◽  
S. Sathishkumar ◽  
Tara C. Thiagarajan
Keyword(s):  
Animal Studies ◽  
Human Society ◽  
Spectral Parameters ◽  
Brain Physiology ◽  
Brain Signals ◽  
Key Aspects ◽  
The Impact ◽  
The Brain ◽  
Motorized Transport ◽  
Stimulus Environment

AbstractThe brain undergoes profound structural and dynamical alteration in response to its stimulus environment. In animal studies, enriched stimulus environments result in numerous structural and dynamical changes along with cognitive enhancements. In human society factors such as education, travel, cell phones and motorized transport dramatically expand the rate and complexity of stimulus experience but diverge in access based on income. Correspondingly, poverty is associated with significant structural and dynamical differences in the brain, but it is unknown how this relates to disparity in stimulus access. Here we studied consumption of major stimulus factors along with measurement of brain signals using EEG in 402 people in India across an income range of $0.82 to $410/day. We show that the complexity of the EEG signal scaled logarithmically with overall stimulus consumption and income and linearly with education and travel. In contrast phone use jumped up at a threshold of $30/day corresponding to a similar jump in key spectral parameters that reflect the signal energy. Our results suggest that key aspects of brain physiology increase in lockstep with stimulus consumption and that we have not fully appreciated the profound way that stimulus expanding aspects of modern life are changing our brain physiology.

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