scholarly journals Variability in the macro- and microstructure of the human brain and its importance to the investigation of neurological disorders

2019 ◽  
Author(s):  
András Király

The exact shape of every human brain - including its micro- and macroscopic features - is as unique as a human fingerprint, resulting in inter-individual anatomical variability. In the past two decades, the understanding of this variability advanced dramatically not only at the level of sulcal/gyral patterns, anatomical features (e.g. cortical thickness, volume and shape) and extent of cytoarchitectonic areas defined at the microscopic level, but also in the anatomical and functional connectivity of the brain. The core concept within the field of brain mapping is the use of a standardized 3D coordinate frame for data analysis and reporting of findings from neuroimaging experiments. This simple construct allows brain researchers to combine (even structural or functional) data from many subjects to create group-averaged signals. Also, where the signal is robust enough to be detected in individuals, it allows for the exploration of inter-individual variance in the location of that signal. Spatial standardization requires two basic components: (i) the specification of the 3D standard coordinate space, and (ii) a mapping function that transforms a 3D brain image from “native” space to that standard space. The first component is usually expressed by the choice of a representative 3D MR image that serves as target (template or atlas). The native image is re-sampled to standard space under the mapping function that may have few or many degrees of freedom, depending upon the experimental design. The optimal choice of atlas template and mapping function depends upon considerations of age, gender, hemispheric asymmetry, anatomical correspondence, spatial normalization methodology and disease-specificity (1). In our studies we investigated some of these aspects, e.g. 1) how gender and normal aging influences brain morphology, 2) how normal hemispheric asymmetry plays a role in lateralized neurological diseases, such as cluster headache, 3) how progressive neurodegenerative disorders, such as Huntington’s disease affect the brain structure, or 4) how we can deal with inter-individual variability in case of neurosurgical interventions, such as thalamotomy in the therapy of medication resistant tremor.


2017 ◽  
Vol 23 (9-10) ◽  
pp. 710-718 ◽  
Author(s):  
Michael C. Corballis ◽  
Isabelle S. Häberling

AbstractHemispheric asymmetry is commonly viewed as a dual system, unique to humans, with the two sides of the human brain in complementary roles. To the contrary, modern research shows that cerebral and behavioral asymmetries are widespread in the animal kingdom, and that the concept of duality is an oversimplification. The brain has many networks serving different functions; these are differentially lateralized, and involve many genes. Unlike the asymmetries of the internal organs, brain asymmetry is variable, with a significant minority of the population showing reversed asymmetries or the absence of asymmetry. This variability may underlie the divisions of labor and the specializations that sustain social life. (JINS, 2017, 23, 710–718)



2020 ◽  
Vol 19 (4) ◽  
pp. 15-19
Author(s):  
O. Slobodian ◽  
V. Kryvetskyi ◽  
T. Khmara

The introduction into medical practice of new methods of neuroimaging - computed and magnetic resonance imaging, has changed the principles of diagnosing morphological changes in the brain and opened up new horizons in the study of its structure. The literature sources provide conflicting and fragmentary data on the anatomical features and morphometric parameters of the parts of the brain, and especially its ventricular system, at different age periods of a person's life. The human brain is characterized by significant age-sex anatomical variability. It differs in men and women in different races, ethnic groups. Signs of difference persist from generation to generation and can be an important characteristic of the variability of the human brain as a species. However, the sex and age features of the structure of the cerebral ventricles, taking into account their individual anatomical variability, have not been sufficiently studied. During morphometric study of magnetic resonance tomograms a comprehensive in vivo characteristic of the cerebral ventricular system in elderly persons is presented. Gender peculiarities and inter-hemispheric asymmetry of relevant indicators are studied. The examinations were conducted in standard anatomical planes (sagittal, frontal and axial) in people with no visual signs of organic lesions of the brain and skull. 38 tomograms of elderly patients were analyzed 38 (14 men and 24 women). 13 indicators of the liquor system of the brain were studied and a significant increase of the following parameters were found in males: the length of the anterior horn of the right lateral ventricle, the length and width of the central part of the lateral ventricle both on the right and left, the length of the lower horn of the lateral ventricle on the left and right, and anterior-posterior size of the lateral ventricle on the right and left. Some of the parameters studied possessed reliable inter-hemispheric asymmetry, namely, in men on the left: the body width of the lateral ventricle, the length and width of the posterior horn of the lateral ventricle, anterior-posterior size of the lateral ventricle; in women – the length of the lower horn of the lateral ventricle on the right.



Author(s):  
Parisa Saboori ◽  
Ali Sadegh

The human head, being a vulnerable body region, is most frequently involved in traumatic brain injuries (TBI) and life threatening injuries. Accurate modeling of the variability of the brain morphology is a fundamental problem in investigating TBI. Improved computational/mathematical structural models of the brain are needed to help investigators to have a better understanding of the phenomena of different traumatic brain injuries such as concussion. The human brain is the most complex region of the body. There is a very thin membrane known as a pia mater that covers all the surface of the brain. The pia mater follows all the fissure of the brain and covers all the surface of the sulci and gyri. Sulcus is referred to any furrow in the brain. Statistically there are about 72 main sulci in the human brain. Previous FE studies of TBI have ignored sulcus morphology in their modeling and thus, their results could be unreliable. In this paper, the effect of the brain sulcus structure on mechanotransduction of impacts to the brain has been investigated. This was accomplished by using series of parametric studies and comparing the results with the model without sulci. The results of this study reveal that the brain’s strain is reduced in the present of sulcus and gyrus structures. We have hypothesized that the presence of sulcus increases the surface area of the brain thereby decreases the normal and shear strain in the brain. That is, the presence of sulcus and gyrus reduce the transduction of the external load and impacts to the white and gray matters of the brain and thereby reduces the risk of TBI. Ignoring sulci in any FE modeling and analysis of the brain may lead to unreliable results.



2020 ◽  
Vol 34 (04) ◽  
pp. 5281-5288 ◽  
Author(s):  
Satoshi Nishida ◽  
Yusuke Nakano ◽  
Antoine Blanc ◽  
Naoya Maeda ◽  
Masataka Kado ◽  
...  

The human brain can effectively learn a new task from a small number of samples, which indicates that the brain can transfer its prior knowledge to solve tasks in different domains. This function is analogous to transfer learning (TL) in the field of machine learning. TL uses a well-trained feature space in a specific task domain to improve performance in new tasks with insufficient training data. TL with rich feature representations, such as features of convolutional neural networks (CNNs), shows high generalization ability across different task domains. However, such TL is still insufficient in making machine learning attain generalization ability comparable to that of the human brain. To examine if the internal representation of the brain could be used to achieve more efficient TL, we introduce a method for TL mediated by human brains. Our method transforms feature representations of audiovisual inputs in CNNs into those in activation patterns of individual brains via their association learned ahead using measured brain responses. Then, to estimate labels reflecting human cognition and behavior induced by the audiovisual inputs, the transformed representations are used for TL. We demonstrate that our brain-mediated TL (BTL) shows higher performance in the label estimation than the standard TL. In addition, we illustrate that the estimations mediated by different brains vary from brain to brain, and the variability reflects the individual variability in perception. Thus, our BTL provides a framework to improve the generalization ability of machine-learning feature representations and enable machine learning to estimate human-like cognition and behavior, including individual variability.



Author(s):  
Preecha Yupapin ◽  
Amiri I. S. ◽  
Ali J. ◽  
Ponsuwancharoen N. ◽  
Youplao P.

The sequence of the human brain can be configured by the originated strongly coupling fields to a pair of the ionic substances(bio-cells) within the microtubules. From which the dipole oscillation begins and transports by the strong trapped force, which is known as a tweezer. The tweezers are the trapped polaritons, which are the electrical charges with information. They will be collected on the brain surface and transport via the liquid core guide wave, which is the mixture of blood content and water. The oscillation frequency is called the Rabi frequency, is formed by the two-level atom system. Our aim will manipulate the Rabi oscillation by an on-chip device, where the quantum outputs may help to form the realistic human brain function for humanoid robotic applications.



Author(s):  
Sally M. Essawy ◽  
Basil Kamel ◽  
Mohamed S. Elsawy

Some buildings hold certain qualities of space design similar to those originated from nature in harmony with its surroundings. These buildings, mostly associated with religious beliefs and practices, allow for human comfort and a unique state of mind. This paper aims to verify such effect on the human brain. It concentrates on measuring brain waves when the user is located in several spots (coordinates) in some of these buildings. Several experiments are conducted on selected case studies to identify whether certain buildings affect the brain wave frequencies of their users or not. These are measured in terms of Brain Wave Frequency Charts through EEG Device. The changes identified on the brain were then translated into a brain diagram that reflects the spiritual experience all through the trip inside the selected buildings. This could then be used in architecture to enhance such unique quality.



Author(s):  
Henrik Hogh-Olesen

Chapter 7 takes the investigation of the aesthetic impulse into the human brain to understand, first, why only we—and not our closest relatives among the primates—express ourselves aesthetically; and second, how the brain reacts when presented with aesthetic material. Brain scans are less useful when you are interested in the Why of aesthetic behavior rather than the How. Nevertheless, some brain studies have been ground-breaking, and neuroaesthetics offers a pivotal argument for the key function of the aesthetic impulse in human lives; it shows us that the brain’s reward circuit is activated when we are presented with aesthetic objects and stimuli. For why reward a perception or an activity that is evolutionarily useless and worthless in relation to human existence?



2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ross M. Lawrence ◽  
Eric W. Bridgeford ◽  
Patrick E. Myers ◽  
Ganesh C. Arvapalli ◽  
Sandhya C. Ramachandran ◽  
...  

AbstractUsing brain atlases to localize regions of interest is a requirement for making neuroscientifically valid statistical inferences. These atlases, represented in volumetric or surface coordinate spaces, can describe brain topology from a variety of perspectives. Although many human brain atlases have circulated the field over the past fifty years, limited effort has been devoted to their standardization. Standardization can facilitate consistency and transparency with respect to orientation, resolution, labeling scheme, file storage format, and coordinate space designation. Our group has worked to consolidate an extensive selection of popular human brain atlases into a single, curated, open-source library, where they are stored following a standardized protocol with accompanying metadata, which can serve as the basis for future atlases. The repository containing the atlases, the specification, as well as relevant transformation functions is available in the neuroparc OSF registered repository or https://github.com/neurodata/neuroparc.



2021 ◽  
Vol 16 ◽  
pp. 263310552110187
Author(s):  
Christopher D Link

Numerous studies have identified microbial sequences or epitopes in pathological and non-pathological human brain samples. It has not been resolved if these observations are artifactual, or truly represent population of the brain by microbes. Given the tempting speculation that resident microbes could play a role in the many neuropsychiatric and neurodegenerative diseases that currently lack clear etiologies, there is a strong motivation to determine the “ground truth” of microbial existence in living brains. Here I argue that the evidence for the presence of microbes in diseased brains is quite strong, but a compelling demonstration of resident microbes in the healthy human brain remains to be done. Dedicated animal models studies may be required to determine if there is indeed a “brain microbiome.”



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