Regional, Directional, and Age-Dependent Properties of the Brain Undergoing Large Deformation

2002 ◽  
Vol 124 (2) ◽  
pp. 244-252 ◽  
Author(s):  
Michael T. Prange ◽  
Susan S. Margulies
Keyword(s):  
White Matter ◽  
Brain Tissue ◽  
Large Strain ◽  
Human Brain Tissue ◽  
Tissue Properties ◽  
Age Dependent ◽  
Autopsy Data ◽  
Degree Of Anisotropy ◽  
The Brain ◽  
Human Autopsy

The large strain mechanical properties of adult porcine gray and white matter brain tissues were measured in shear and confirmed in compression. Consistent with local neuroarchitecture, gray matter showed the least amount of anisotropy, and corpus callosum exhibited the greatest degree of anisotropy. Mean regional properties were significantly distinct, demonstrating that brain tissue is inhomogeneous. Fresh adult human brain tissue properties were slightly stiffer than adult porcine properties but considerably less stiff than the human autopsy data in the literature. Mixed porcine gray/white matter samples were obtained from animals at “infant” and “toddler” stages of neurological development, and shear properties compared to those in the adult. Only the infant properties were significantly different (stiffer) from the adult.

scholarly journals Spontaneous glioma-induced seizures recorded in a living human brain tissue preparation

2019 ◽  
Vol 21 (Supplement_4) ◽  
pp. iv16-iv16
Author(s):  
Alastair Kirby ◽  
Jose Pedro Lavrador ◽  
Christian Brogna ◽  
Francesco Vergani ◽  
Bassel Zebian ◽  
...  
Keyword(s):  
Human Brain ◽  
Brain Tissue ◽  
Aminolevulinic Acid ◽  
Brain Slices ◽  
Low Grade ◽  
Tissue Preparation ◽  
Spontaneous Seizure ◽  
Human Brain Tissue ◽  
Who Grade ◽  
The Brain

Abstract Gliomas often present clinically with seizures. Tumour-associated seizures can be difficult to control with medication. A deeper understanding of the cellular mechanisms underlying tumour-associated seizures would provide a basis for developing new treatments. Here, we investigate epileptic discharges in peritumoral cortex using living human brain tissue donated by people having a craniotomy for glioma resection (REC approval, 18/SW/002). The brain tissue was cut into thin slices, which preserved the architecture of the glioma and the adjacent healthy brain. The brain slices were incubated in 5-aminolevulinic acid to make the glioma cells fluorescent. This enabled us to make electrophysiological recordings of brain activity across the boundary between glioma and brain. We recorded from brain slices of 5 participants with glioblastoma and 4 participants with oligodendroglioma (WHO grade II – III). Spontaneous “seizure-like” discharges were recorded in brain slices from 5/8 participants (3 GBM, 2 oligodendroglioma) who reported seizures and from one participant (GBM) who had not had any clinical seizures. Further analysis of the seizure-like discharges revealed that they could be subdivided into two distinct types based on the major frequencies in the discharge. We concluded that human brain slices from people with either a low-grade or a high-grade glioma can generate spontaneous seizure-like discharges. The living human brain tissue preparation gives us a platform to study the mechanisms of tumour-associated seizures and how abnormal neural activity affects glioma growth.

scholarly journals P11.49 An electrophysiological signature of glioma infiltration in the ex vivo human brain

2019 ◽  
Vol 21 (Supplement_3) ◽  
pp. iii54-iii54
Author(s):  
A J Kirby ◽  
J P Lavrador ◽  
C Brogna ◽  
F Vergani ◽  
C Chandler ◽  
...  
Keyword(s):  
Human Brain ◽  
Brain Tissue ◽  
Brain Slices ◽  
Glioma Cells ◽  
Low Grade ◽  
Tissue Preparation ◽  
High Grade ◽  
Spontaneous Seizure ◽  
Human Brain Tissue ◽  
The Brain

Abstract BACKGROUND Invading glioma cells affect the physiological function of the peritumoural cortex. This may manifest clinically as seizures. Here, we investigate the effect the invading glioma cells on the electrophysiological signalling of the peritumoral cortex using living human brain tissue donated by people having a craniotomy for glioma resection (REC approval, 18/SW/002). MATERIAL AND METHODS The brain tissue was cut into thin slices, which preserved the architecture of the glioma and the adjacent healthy brain. The brain slices were incubated in 5-aminolevulinic acid to make the glioma cells fluorescent. We observed 5-ALA induced fluorescence in both low-grade and high-grade gliomas. This enabled us to make electrophysiological recordings of brain activity across the boundary between glioma and brain. RESULTS We recorded from brain slices of 5 participants with glioblastoma and 4 participants with oligodendroglioma (WHO grade II - III). Spontaneous “seizure-like” discharges were recorded in brain slices from 5/8 participants (3 GBM, 2 oligodendroglioma) who reported seizures and from one participant (GBM) who had not had any clinical seizures. Further analysis of the electrical discharges revealed that they could be subdivided into two distinct types based on the major frequencies in the discharge. CONCLUSION We concluded that human brain slices from people with either a low-grade or a high-grade glioma can generate spontaneous seizure-like discharges. This electrophysiological signature will be compared to infiltration and grade of the glioma cells in the donated sample. The living human brain tissue preparation gives us a platform to study the mechanisms of tumour-associated seizures and how abnormal neural activity affects glioma growth.

GFAP-positive astrocytes are rare or absent in primary adult human brain tissue cultures

Biologia ◽  
2009 ◽  
Vol 64 (4) ◽  
Author(s):  
Ivana Macikova ◽  
Anna Perzelova ◽  
Peter Mraz ◽  
Ivan Bizik ◽  
Juraj Steno
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Brain Tissue ◽  
Cell Phenotype ◽  
Human Brain Tissue ◽  
Adult Human Brain ◽  
Neuronal Markers ◽  
Adult Human

AbstractTraditionally, astrocytes are divided into fibrous and protoplasmic types based on their morphologic appearance. Here the cultures were prepared separately from the adult human cortical gray and white matter of brain biopsies. Both cultures differed only in the number of glial fibrillary acidic protein (GFAP)-positive cells. In the gray matter these were absent or rare, whereas in confluent cultures from the white matter they reached 0.1% of all cells. Three main morphologic types of GFAP-positive cells were found in this study: stellate, bipolar and large flat cells. GFAP-positive cells with two or three long processes mimic a neuron-like morphology. We did not find process-bearing cells expressing neuronal markers (MAP-2, NF, and N-CAM). The conflicting reports concerning GFAP immunostaining and the study dealing with the presence of putative neurons in adult human brain cultures are discussed with respect to these findings. The latter classification of astrocytes into type 1 and type 2 is based on immunostaining to A2B5 antigen: type 1 (GFAP+/A2B5−) and type 2 (GFAP+/A2B5+) astrocytes are proposed to be analogous to protoplasmic and fibrous astrocytes, respectively. In adult human brain cultures we found only small amount of A2B5-positive cells. Double immunofluorescence revealed that astroglial cells of similar fibrous or bipolar shape grown on one coverslip were either GFAP+/A2B5+ or GFAP+/A2B5−. On the other hand, the A2B5+/GFAP− immunophenotype was not observed. These results indicate that in general the cell phenotype from adult human brain tissue is not well established when they are in culture.

scholarly journals Simulating Local Deformations in the Human Cortex Due to Blood Flow-Induced Changes in Mechanical Tissue Properties: Impact on Functional Magnetic Resonance Imaging

2021 ◽  
Vol 15 ◽  
Author(s):  
Mahsa Zoraghi ◽  
Nico Scherf ◽  
Carsten Jaeger ◽  
Ingolf Sack ◽  
Sebastian Hirsch ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Brain Tissue ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Tissue Properties ◽  
The Relationship ◽  
The Brain

Investigating human brain tissue is challenging due to the complexity and the manifold interactions between structures across different scales. Increasing evidence suggests that brain function and microstructural features including biomechanical features are related. More importantly, the relationship between tissue mechanics and its influence on brain imaging results remains poorly understood. As an important example, the study of the brain tissue response to blood flow could have important theoretical and experimental consequences for functional magnetic resonance imaging (fMRI) at high spatial resolutions. Computational simulations, using realistic mechanical models can predict and characterize the brain tissue behavior and give us insights into the consequent potential biases or limitations of in vivo, high-resolution fMRI. In this manuscript, we used a two dimensional biomechanical simulation of an exemplary human gyrus to investigate the relationship between mechanical tissue properties and the respective changes induced by focal blood flow changes. The model is based on the changes in the brain’s stiffness and volume due to the vasodilation evoked by neural activity. Modeling an exemplary gyrus from a brain atlas we assessed the influence of different potential mechanisms: (i) a local increase in tissue stiffness (at the level of a single anatomical layer), (ii) an increase in local volume, and (iii) a combination of both effects. Our simulation results showed considerable tissue displacement because of these temporary changes in mechanical properties. We found that the local volume increase causes more deformation and consequently higher displacement of the gyrus. These displacements introduced considerable artifacts in our simulated fMRI measurements. Our results underline the necessity to consider and characterize the tissue displacement which could be responsible for fMRI artifacts.

scholarly journals Poro-Viscoelastic Effects During Biomechanical Testing of Human Brain Tissue

2021 ◽  
Vol 7 ◽  
Author(s):  
Alexander Greiner ◽  
Nina Reiter ◽  
Friedrich Paulsen ◽  
Gerhard A. Holzapfel ◽  
Paul Steinmann ◽  
...  
Keyword(s):  
Data Analysis ◽  
Human Brain ◽  
Brain Tissue ◽  
Mechanical Response ◽  
Large Strain ◽  
Biomechanical Testing ◽  
Tissue Response ◽  
Human Brain Tissue ◽  
Close Coupling ◽  
Shear Moduli

Brain tissue is one of the softest tissues in the human body and the quantification of its mechanical properties has challenged scientists over the past decades. Associated experimental results in the literature have been contradictory as characterizing the mechanical response of brain tissue not only requires well-designed experimental setups that can record the ultrasoft response, but also appropriate approaches to analyze the corresponding data. Due to the extreme complexity of brain tissue behavior, nonlinear continuum mechanics has proven an expedient tool to analyze testing data and predict the mechanical response using a combination of hyper-, visco-, or poro-elastic models. Such models can not only allow for personalized predictions through finite element simulations, but also help to comprehensively understand the physical mechanisms underlying the tissue response. Here, we use a nonlinear poro-viscoelastic computational model to evaluate the effect of different intrinsic material properties (permeability, shear moduli, nonlinearity, viscosity) on the tissue response during different quasi-static biomechanical measurements, i.e., large-strain compression and tension as well as indentation experiments. We show that not only the permeability but also the properties of the viscoelastic solid largely control the fluid flow within and out of the sample. This reveals the close coupling between viscous and porous effects in brain tissue behavior. Strikingly, our simulations can explain why indentation experiments yield that white matter tissue in the human brain is stiffer than gray matter, while large-strain compression experiments show the opposite trend. These observations can be attributed to different experimental loading and boundary conditions as well as assumptions made during data analysis. The present study provides an important step to better understand experimental data previously published in the literature and can help to improve experimental setups and data analysis for biomechanical testing of brain tissue in the future.

scholarly journals Fusion of quantitative susceptibility maps and T1-weighted images improve brain tissue contrast in primates

2021 ◽  
Author(s):  
Rakshit Dadarwal ◽  
Michael Ortiz-Rios ◽  
Susann Boretius
Keyword(s):  
White Matter ◽  
Brain Tissue ◽  
Brain Structures ◽  
Macaque Monkey ◽  
List Type ◽  
Subcortical Structures ◽  
Tissue Segmentation ◽  
Tissue Contrast ◽  
T1 Contrast ◽  
The Brain

AbstractRecent progress in quantitative susceptibility mapping (QSM) has enabled the accurate delineation of submillimeter scale subcortical brain structures in humans. QSM reflects the magnetic susceptibility arising from the spatial distribution of iron, myelin, and calcium in the brain. The simultaneous visualization of cortical, subcortical, and white matter structure remains, however, challenging, utilizing QSM data solely. Here we present TQ-SILiCON, a fusion method that enhances the contrast of cortical and subcortical structures and provides an excellent white matter delineation by combining QSM and conventional T1-weighted (T1w) images. In this study, we first established QSM in the macaque monkey to map iron-rich subcortical structures. Implementing the same QSM acquisition and analyses methods allowed a similar accurate delineation of subcortical structures in humans. Moreover, applying automatic brain tissue segmentation to TQ-SILiCON images of the macaque improved the classification of the brain tissue types as compared to the single T1 contrast. Furthermore, we validate our dual-contrast fusion approach in humans and similarly demonstrate improvements in automated segmentation of cortical and subcortical structures. We believe the proposed contrast will facilitate translational studies in non-human primates to investigate the pathophysiology of neurodegenerative diseases that affect the subcortical structures of the basal ganglia in humans.HighlightsThe subcortical gray matter areas of macaque monkeys are reliably mapped by QSM, much as they are in humans.Combining T1w and QSM images improves the visualization and segmentation of white matter, cortical and subcortical structures in the macaque monkey.The proposed dual contrast TQ-SILiCON provides a similar image quality also in humans.TQ-SILiCON facilitates comparative and translational neuroscience studies investigating subcortical structures.

scholarly journals Aluminium in Brain Tissue in Multiple Sclerosis

2018 ◽  
Vol 15 (8) ◽  
pp. 1777 ◽  
Author(s):  
Matthew Mold ◽  
Agata Chmielecka ◽  
Maria Rodriguez ◽  
Femia Thom ◽  
Caroline Linhart ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Brain Tissue ◽  
Graphite Furnace ◽  
Absorption Spectrometry ◽  
Aluminium Content ◽  
Human Brain Tissue ◽  
Specific Fluorescence ◽  
Significant Relationships ◽  
Genetic And Environmental Factors ◽  
The Brain

Multiple sclerosis (MS) is a devastating and debilitating neurodegenerative disease of unknown cause. A consensus suggests the involvement of both genetic and environmental factors of which the latter may involve human exposure to aluminium. There are no data on the content and distribution of aluminium in human brain tissue in MS. The aluminium content of brain tissue from 14 donors with a diagnosis of MS was determined by transversely heated graphite furnace atomic absorption spectrometry. The location of aluminium in the brain tissue of two donors was investigated by aluminium-specific fluorescence microscopy. The aluminium content of brain tissue in MS was universally high with many tissues bearing concentrations in excess of 10 μg/g dry wt. (10 ppm) and some exceeding 50 ppm. There were no statistically significant relationships between brain lobes, donor age or donor gender. Aluminium-specific fluorescence successfully identified aluminium in brain tissue in both intracellular and extracellular locations. The association of aluminium with corpora amylacea suggests a role for aluminium in neurodegeneration in MS.

scholarly journals In situ impedance measurements on postmortem porcine brain

2020 ◽  
Author(s):  
Lucas Poßner ◽  
Matthias Laukner ◽  
Florian Wilhelmy ◽  
Dirk Lindner ◽  
Uwe Pliquett ◽  
...  
Keyword(s):  
Experimental Study ◽  
White Matter ◽  
Human Brain ◽  
Brain Tissue ◽  
Human Brain Tissue ◽  
Experimental Conditions ◽  
Impedance Measurements ◽  
Porcine Brain

AbstractThe paper presents an experimental study where the distinctness of grey and white matter of an in situ postmortem porcine brain by impedance measurements is investigated. Experimental conditions that would allow to conduct the same experiment on in vivo human brain tissue are replicated.https://doi.org/10.1515/cdbme-2019-XXXX

Shear Wave Propagation of the Ferret Brain at Multiple Frequencies In Vivo

2012 ◽  
Author(s):  
Yuan Feng ◽  
Yulin Chang ◽  
Erik H. Clayton ◽  
Ruth J. Okamoto ◽  
Philip V. Bayly
Keyword(s):  
Mathematical Modeling ◽  
Mechanical Properties ◽  
White Matter ◽  
Loss Modulus ◽  
Tissue Properties ◽  
In Vivo Measurement ◽  
Dissipative Effects ◽  
Multiple Frequencies ◽  
The Brain

Mathematical modeling and computer simulations are widely used for understanding traumatic brain injury (TBI). However, accurate tissue parameters are needed, especially for the brain in vivo. In this study, we used the ferret as the animal model because it is the smallest mammal with a folded brain and significant white matter tracts. Magnetic resonance elastography (MRE) has proven useful for in vivo measurement of biological tissue properties. Mechanical properties of the ferret brain over a range of frequencies from 400–800 Hz were studied using MRE. Experiment results show both that storage and loss modulus increases with frequency and that dissipative effects in the white matter (characterized by the loss modulus G″) were significant larger than in gray matter.

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