scholarly journals Requirements for coregistration accuracy in on-scalp MEG

2017 ◽  
Author(s):  
Rasmus Zetter ◽  
Joonas Iivanainen ◽  
Matti Stenroos ◽  
Lauri Parkkonen
Keyword(s):  
Sensor Arrays ◽  
Cryogenic Cooling ◽  
Minimum Norm ◽  
Forward Modelling ◽  
Optically Pumped ◽  
Position Errors ◽  
Sensor Position ◽  
Different Types ◽  
Position And Orientation ◽  
The Brain

AbstractRecent advances in magnetic sensing has made on-scalp magnetoencephalography (MEG) possible. In particular, optically-pumped magnetometers (OPMs) have reached sensitivity levels that enable their use in MEG. In contrast to the SQUID sensors used in current MEG systems, OPMs do not require cryogenic cooling and can thus be placed within millimetres from the head, enabling the construction of sensor arrays that conform to the shape of an individual’s head. To properly estimate the location of neural sources within the brain, one must accurately know the position and orientation of sensors in relation to the head. With the adaptable on-scalp MEG sensor arrays, this coregistration becomes more challenging than in current SQUID-based MEG systems that use rigid sensor arrays.Here, we used simulations to quantify how accurately one needs to know the position and orientation of sensors in an on-scalp MEG system. The effects that different types of localisation errors have on forward modelling and source estimates obtained by minimum-norm estimation, dipole fitting, and beamforming are detailed.We found that sensor position errors generally have a larger effect than orientation errors and that these errors affect the localisation accuracy of superficial sources the most. To obtain similar or higher accuracy than with current SQUID-based MEG systems, RMS sensor position and orientation errors should be < 4 mm and < 10°, respectively.

“Where is Dementia?” A Systematic Literature Review Exploring Neuroanatomical Aspects of Dementia

2017 ◽  
Vol 2 (15) ◽  
pp. 9-23 ◽  
Author(s):  
Chorong Oh ◽  
Leonard LaPointe
Keyword(s):  
English Language ◽  
Signs And Symptoms ◽  
Behavioral Symptoms ◽  
Journal Articles ◽  
People With Dementia ◽  
Different Types ◽  
Precise Diagnosis ◽  
Physical Changes ◽  
The Brain ◽  
Language Literature

Dementia is a condition caused by and associated with separate physical changes in the brain. The signs and symptoms of dementia are very similar across the diverse types, and it is difficult to diagnose the category by behavioral symptoms alone. Diagnostic criteria have relied on a constellation of signs and symptoms, but it is critical to understand the neuroanatomical differences among the dementias for a more precise diagnosis and subsequent management. With this regard, this review aims to explore the neuroanatomical aspects of dementia to better understand the nature of distinctive subtypes, signs, and symptoms. This is a review of English language literature published from 1996 to the present day of peer-reviewed academic and medical journal articles that report on older people with dementia. This review examines typical neuroanatomical aspects of dementia and reinforces the importance of a thorough understanding of the neuroanatomical characteristics of the different types of dementia and the differential diagnosis of them.

The Acute Effect of Alcohol on Various Memory Processes

2010 ◽  
Vol 24 (4) ◽  
pp. 249-252 ◽  
Author(s):  
Márk Molnár ◽  
Roland Boha ◽  
Balázs Czigler ◽  
Zsófia Anna Gaál
Keyword(s):  
Low Dose ◽  
Short Term Memory ◽  
Acute Effect ◽  
Long Term Memory ◽  
Term Memory ◽  
Memory Processes ◽  
Different Types ◽  
The Brain ◽  
Legal Consequences

This review surveys relevant and recent data of the pertinent literature regarding the acute effect of alcohol on various kinds of memory processes with special emphasis on working memory. The characteristics of different types of long-term memory (LTM) and short-term memory (STM) processes are summarized with an attempt to relate these to various structures in the brain. LTM is typically impaired by chronic alcohol intake but according to some data a single dose of ethanol may have long lasting effects if administered at a critically important age. The most commonly seen deleterious acute effect of alcohol to STM appears following large doses of ethanol in conditions of “binge drinking” causing the “blackout” phenomenon. However, with the application of various techniques and well-structured behavioral paradigms it is possible to detect, albeit occasionally, subtle changes of cognitive processes even as a result of a low dose of alcohol. These data may be important for the consideration of legal consequences of low-dose ethanol intake in conditions such as driving, etc.

Types of refractive errors and methods for their diagnosis

2020 ◽  
pp. 30-36
Author(s):  
Olga Lemzyakova
Keyword(s):  
Optical System ◽  
Contact Lenses ◽  
Vision Impairment ◽  
Refractive Errors ◽  
Vision Correction ◽  
Light Rays ◽  
Different Types ◽  
Almost All ◽  
Degrees Of Severity ◽  
The Brain

Refraction of the eye means its ability to bend (refract) light in its own optical system. In a normal state, which is called emmetropia, light rays passing through the optical system of the eye focus on the retina, from where the impulse is transmitted to the visual cortex of the brain and is analyzed there. A person sees equally well both in the distance and near in this situation. However, very often, refractive errors develop as a result of various types of influences. Myopia, or short-sightedness, occurs when the light rays are focused in front of the retina as a result of passing through the optical system of the eye. In this case, a person will clearly distinguish close objects and have difficulties in seeing distant objects. On the opposite side is development of farsightedness (hypermetropia), in which the focusing of light rays occurs behind the retina — such a person sees distant objects clearly, but outlines of closer objects are out of focus. Near vision impairment in old age is a natural process called presbyopia, it develops due to the lens thickening. Both myopia and hypermetropia can have different degrees of severity. The variant, when different refractive errors are observed in different eyes, is called anisometropia. In the same case, if different types of refraction are observed in the same eye, it is astigmatism, and most often it is a congenital pathology. Almost all of the above mentioned refractive errors require correction with spectacles or use of contact lenses. Recently, people are increasingly resorting to the methods of surgical vision correction.

Ligand and Structure-based Modeling of Passive Diffusion through the Blood-Brain Barrier

2018 ◽  
Vol 25 (9) ◽  
pp. 1073-1089 ◽  
Author(s):  
Santiago Vilar ◽  
Eduardo Sobarzo-Sanchez ◽  
Lourdes Santana ◽  
Eugenio Uriarte
Keyword(s):  
Blood Brain Barrier ◽  
In Silico ◽  
Passive Diffusion ◽  
Brain Barrier ◽  
Barrier Permeability ◽  
Blood Brain Barrier Permeability ◽  
Blood Brain ◽  
Brain Barrier Permeability ◽  
Different Types ◽  
The Brain

Background: Blood-brain barrier transport is an important process to be considered in drug candidates. The blood-brain barrier protects the brain from toxicological agents and, therefore, also establishes a restrictive mechanism for the delivery of drugs into the brain. Although there are different and complex mechanisms implicated in drug transport, in this review we focused on the prediction of passive diffusion through the blood-brain barrier. Methods: We elaborated on ligand-based and structure-based models that have been described to predict the blood-brain barrier permeability. Results: Multiple 2D and 3D QSPR/QSAR models and integrative approaches have been published to establish quantitative and qualitative relationships with the blood-brain barrier permeability. We explained different types of descriptors that correlate with passive diffusion along with data analysis methods. Moreover, we discussed the applicability of other types of molecular structure-based simulations, such as molecular dynamics, and their implications in the prediction of passive diffusion. Challenges and limitations of experimental measurements of permeability and in silico predictive methods were also described. Conclusion: Improvements in the prediction of blood-brain barrier permeability from different types of in silico models are crucial to optimize the process of Central Nervous System drug discovery and development.

Development of a New Image-Guided Neuronavigation System: Mixed-Reality Projection Mapping Is Accurate and Feasible

2021 ◽  
Author(s):  
Tsukasa Koike ◽  
Taichi Kin ◽  
Shota Tanaka ◽  
Katsuya Sato ◽  
Tatsuya Uchida ◽  
...  
Keyword(s):  
Image Processing ◽  
Mixed Reality ◽  
Improve Patient Safety ◽  
Projection Mapping ◽  
Normalized Mutual Information ◽  
Image Guided ◽  
Brain Surface ◽  
Initial Surgery ◽  
Position And Orientation ◽  
The Brain

Abstract BACKGROUND Image-guided systems improve the safety, functional outcome, and overall survival of neurosurgery but require extensive equipment. OBJECTIVE To develop an image-guided surgery system that combines the brain surface photographic texture (BSP-T) captured during surgery with 3-dimensional computer graphics (3DCG) using projection mapping. METHODS Patients who underwent initial surgery with brain tumors were prospectively enrolled. The texture of the 3DCG (3DCG-T) was obtained from 3DCG under similar conditions as those when capturing the brain surface photographs. The position and orientation at the time of 3DCG-T acquisition were used as the reference. The correct position and orientation of the BSP-T were obtained by aligning the BSP-T with the 3DCG-T using normalized mutual information. The BSP-T was combined with and displayed on the 3DCG using projection mapping. This mixed-reality projection mapping (MRPM) was used prospectively in 15 patients (mean age 46.6 yr, 6 males). The difference between the centerlines of surface blood vessels on the BSP-T and 3DCG constituted the target registration error (TRE) and was measured in 16 fields of the craniotomy area. We also measured the time required for image processing. RESULTS The TRE was measured at 158 locations in the 15 patients, with an average of 1.19 ± 0.14 mm (mean ± standard error). The average image processing time was 16.58 min. CONCLUSION Our MRPM method does not require extensive equipment while presenting information of patients’ anatomy together with medical images in the same coordinate system. It has the potential to improve patient safety.

scholarly journals A Review on Epilepsy and its Management

2020 ◽  
Vol 10 (3) ◽  
pp. 273-279
Author(s):  
V.V. Potnis ◽  
Ketan G. Albhar ◽  
Pritamsinh Arjun Nanaware ◽  
Vishal S. Pote
Keyword(s):  
Developing Countries ◽  
Neurological Disorders ◽  
Genetic Factors ◽  
Future Trends ◽  
Brain Infection ◽  
The World ◽  
Different Types ◽  
Patients With Epilepsy ◽  
The Brain

Today, people face various types of stress in everyday fast life and most people in the world suffer from various neurological disorder. Epilepsy is one of the most common neurological disorders of the brain, affecting about 50 million people around the world, and 90% of them are coming from developing countries. Genetic factors and brain infection, stroke, tumors and epilepsy cause high fever. It imposes a great economic burden on the health systems of countries associated with stigma and discrimination against the patient and also his family in the community, in the workplace, school and home. Many patients with epilepsy suffer from severe emotional stress, behavioral disorders and extreme social isolation. There are many different types of seizure and mechanisms by which the brain generates seizures. The two features of generating seizures are hyperexcitability of neurons and a hyper synchronousneural circuits. A variety of mechanisms alters the balance between excitation and inhibition in predisposing brain local or generalized hyperexcitability region and a hypersynchronia. Purpose of the review is to discuss the history, epidemiology, etiology, pathophysiology, classification of epilepsy, symtomps, diagnosis, management of epilepsy and future trends. Keywords: Anti-epileptic drugs, pathophysiology, seizures, epidemiology, hypersynchrony

scholarly journals State of the art olfactometers. Different types

2021 ◽  
Keyword(s):  
Human Beings ◽  
Pathological Conditions ◽  
New Concepts ◽  
Different Types ◽  
Clinical Diagnoses ◽  
Human Use ◽  
The Brain ◽  
Very High ◽  
Human Olfaction

The complexity of human olfaction is very high and the importance of being able to measure it directly, objectively and qualitatively has led experts to search for mechanisms that can be applied. Human beings use this sense, which is one of the oldest, to recognize danger and distinguish between pleasant and unpleasant odors. Smells are mixtures of molecules that, at different concentrations in the inhaled air, stimulate the olfactory area and are recognized at the brain level. Therefore, there is a coding and decoding system. Human olfactometer techniques use equipment designed to be able to measure its intensity and quality of volatile substances. If we are able to measure this sense, we will be able to know its variations and be able to make clinical diagnoses in normal and pathological conditions and diagnose the losses that occur in certain infectious, degenerative diseases, traumatic processes and other variants. For many years, systems have been developed that can measure subjective olfaction in humans, as well as objective forms, but it is also true that there is no equipment available that is fast, simple handling and that can be applied in daily clinical services. Aim of the Study Present the recent achievements in olfactometer technology; Elaborate the scientific articles about olfactometry published mainly in the last 10 years; To gather the information published in the last years in relation to the usefulness, existence in the market and purposes of equipment that can measure the odors, what we will call the Smell-o-meter or olfactometer for human use. Material and Methods: In the first part of this research we will gather most of the information existing so far in international bibliography, as well as the achievements and utilities obtained to date. Following, we will analyze all the new concepts related to smell-o-meters devices that exist on the market and assess the possibility, based on what has been done so far, to seek new practical systems for application in the medical field.

scholarly journals What is Interoception and Why is it Important?

2021 ◽  
Vol 9 ◽  
Author(s):  
Melissa Barker ◽  
Rebecca Brewer ◽  
Jennifer Murphy
Keyword(s):  
Mental Health ◽  
The Body ◽  
Physical And Mental Health ◽  
Heart Beating ◽  
Different Types ◽  
The Brain

What is the word for the sense of signals that come from inside your body, such as feeling your heart beating and your breathing, or knowing when you are hungry? This is called interoception. Interoception is one of our senses, like vision, hearing, taste, smell, and touch. In this article, we talk about what interoception is and how information about these feelings is sent from the body to the brain. We will also talk a little about how interoception is measured and the different types of interoception. Finally, we will discuss why interoception might be important for things like recognising emotions in ourselves and in other people, our physical and mental health, and why understanding how interoception changes throughout our lives might help us to understand where differences in interoception across different people come from.

scholarly journals Glucose status in cerebrospinal fluid (CSF) in different meningitic children in a hospital in Chittagong, Bangladesh

2013 ◽  
Vol 6 (1-2) ◽  
pp. 41-49
Author(s):  
Sharmistha Mitra ◽  
Robiul Hasan Bhuiyan ◽  
Md Arifuzzaman ◽  
Mohammad Sayedul Islam ◽  
Mahmood A Chowdhury ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Glucose Level ◽  
Viral Meningitis ◽  
Pyogenic Meningitis ◽  
Detailed Medical History ◽  
Different Types ◽  
The Brain ◽  
Very High ◽  
Potential Tool ◽  
Glucose Status

Meningitis is referred to as an inflammatory process of the leptomeninges and cerebrospinal fluid (CSF) within the sub-arachnoid space of the brain. We have investigated glucose status in CSF in different types of meningitis together with detailed medical history in children. In addition, we have also carried out the detailed cytological and microbiological examinations. A total of 40 subjects were investigated. We observed that the glucose level was significantly decreased (<20 mg/dl) in 65%, moderately decreased (20-40 mg/dl) in 20% and mildly decreased (40-50mg/dl) in 15% of the patients in our study. Patients with Pyogenic meningitis had tremendously reduced glucose level (9.0 mg/dl) in their CSF whereas in viral meningitis the CSF glucose level is highly variable (10 to 65 mg/dl). Furthermore, 5 (12.5%) patients showed high lymphocyte counts and 34 (85%) patients showed high neutrophil counts. Interestingly, in Pyogenic meningitis, the neutrophil count was very high compared to that in viral meningitis. The present study clearly demonstrates that biochemical parameters such as glucose level in CSF might be a potential tool for detecting meningitis and as well as differentiation of the different types of meningitis. DOI: http://dx.doi.org/10.3329/cujbs.v6i1-2.17080 The Chittagong Univ. J. B. Sci.,Vol. 6(1&2):41-49, 2011

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