scholarly journals Relative luminosity in the extreme red

1936 ◽  
Vol 155 (886) ◽  
pp. 664-683 ◽  
Keyword(s):  
Electromagnetic Wave ◽  
Direct Evidence ◽  
Scattered Light ◽  
Photochemical Reactions ◽  
Visual Process ◽  
Infra Red ◽  
Relative Luminosity ◽  
The Many ◽  
Double Monochromator ◽  
The Brain

When an electromagnetic wave of a suitable frequency enters the eye it is followed in a short space of time by a visual sensation in the brain. This "visual process" can be divided up into stages, such as the conversion of the electromagnetic wave into a stimulus, the production and transmission of nerve impulses actuated by this stimulus, and the conscious sensation arising thereform. Although no direct evidence is forthcoming, it is generally believed that the first stage referred to is a photochemical one similar in its behaviour to the many photochemical reactions known to be produced by light of visible frequencies. This paper describes experiments in the extreme red and discusses their application to a photochemical theory of the primary visual process. It is generally assumed that vision extends on the red side of the spectrum to a wave-lengths of about 800 mμ , but some authors claim to have seen longer wave-lengths than this (840 mμ ). Nutting states that light of 1000 mμ is visible if sufficiently intense. In most of these observations account has not been taken of the width of the spectral range of the light used, nor has care been taken to obtain very pure light. It will be shown in this paper that, when working above 820 mμ , it is necessary to use a double monochromator, together with an "infra-red" filter to ensure that the light seen is not scattered light.

scholarly journals Is There a Brain Microbiome?

2021 ◽  
Vol 16 ◽  
pp. 263310552110187
Author(s):  
Christopher D Link
Keyword(s):  
Animal Models ◽  
Human Brain ◽  
Neurodegenerative Diseases ◽  
Ground Truth ◽  
Healthy Human ◽  
Strong Motivation ◽  
The Many ◽  
The Brain

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.”

A discussion of apraxia, aphasia, and gestural language

1984 ◽  
Vol 246 (6) ◽  
pp. R884-R887
Author(s):  
N. Helm-Estabrooks
Keyword(s):  
Sign Language ◽  
Cerebral Hemisphere ◽  
Communication Disorder ◽  
Left Cerebral Hemisphere ◽  
Language Behavior ◽  
Normal Language ◽  
Symbolic Gestures ◽  
The Many ◽  
The Relationship ◽  
The Brain

It is understood that damage to the left cerebral hemisphere in adulthood may result in syndromes of language disturbances called the aphasias. The study of these syndromes sheds light on normal language processes, the relationship between language behavior and the brain, and how best to treat aphasic individuals. Aphasia, for some, is a central communication disorder affecting all symbolic behavior in all modalities (i.e., speech, writing, and gesture). Difficulty producing symbolic gestures on command is called apraxia. Others view aphasia as a manifestation of a motor-sequencing disorder affecting all gestural systems including those required for speech movements. These divergent theories of the underlying nature of aphasia can be tested through examination of deaf individuals who use sign language before onset of aphasia. Poizner et al. [Am. J. Physiol. 246 (Regulatory Integrative Comp. Physiol. 15): R868-R883, 1984] studied three such patients with different aphasia syndromes: one patient had a nonsymbolic, motor-sequencing disorder; one had a gestural apraxia; and one had neither. These findings force the conclusion that neither the symbolic nor motor-sequencing theory of aphasia can account for the many varieties of that disorder.

scholarly journals Scatterometry Measurements With Scattered Light Imaging Enable New Insights Into the Nerve Fiber Architecture of the Brain

2021 ◽  
Vol 15 ◽  
Author(s):  
Miriam Menzel ◽  
Marouan Ritzkowski ◽  
Jan A. Reuter ◽  
David Gräßel ◽  
Katrin Amunts ◽  
...  
Keyword(s):  
Human Brain ◽  
Nerve Fiber ◽  
Brain Tissue ◽  
Scattered Light ◽  
Polar Angle ◽  
Nerve Fibers ◽  
Fiber Architecture ◽  
Whole Brain ◽  
Tissue Samples ◽  
The Brain

The correct reconstruction of individual (crossing) nerve fibers is a prerequisite when constructing a detailed network model of the brain. The recently developed technique Scattered Light Imaging (SLI) allows the reconstruction of crossing nerve fiber pathways in whole brain tissue samples with micrometer resolution: the individual fiber orientations are determined by illuminating unstained histological brain sections from different directions, measuring the transmitted scattered light under normal incidence, and studying the light intensity profiles of each pixel in the resulting image series. So far, SLI measurements were performed with a fixed polar angle of illumination and a small number of illumination directions, providing only an estimate of the nerve fiber directions and limited information about the underlying tissue structure. Here, we use a display with individually controllable light-emitting diodes to measure the full distribution of scattered light behind the sample (scattering pattern) for each image pixel at once, enabling scatterometry measurements of whole brain tissue samples. We compare our results to coherent Fourier scatterometry (raster-scanning the sample with a non-focused laser beam) and previous SLI measurements with fixed polar angle of illumination, using sections from a vervet monkey brain and human optic tracts. Finally, we present SLI scatterometry measurements of a human brain section with 3 μm in-plane resolution, demonstrating that the technique is a powerful approach to gain new insights into the nerve fiber architecture of the human brain.

scholarly journals Features of diagnosis of cognitive disorders in patients with chronic brain ischemia

2016 ◽  
pp. 8-11
Author(s):  
N.P. Pavliuk
Keyword(s):  
Quality Of Life ◽  
Health Care ◽  
Cognitive Impairment ◽  
Cognitive Disorders ◽  
Chronic Ischemia ◽  
Modern Health Care ◽  
Chronic Brain Ischemia ◽  
The Many ◽  
The Brain

One of the major problems in modern health care are cerebrovascular disease, which occupy a leading place in the structure of mortality and disability in the population. Among the many clinical features of chronic ischemia of the brain is a key manifestation of cognitive impairment that often determine the severity of condition and quality of life of the patient and his relatives. Diagnosis of cognitive impairment is very important, as the timely appointment of therapy may prevent or at least delay the development of dementia.

scholarly journals CORTICAL PHASE TRANSITIONS, NONEQUILIBRIUM THERMODYNAMICS AND THE TIME-DEPENDENT GINZBURG–LANDAU EQUATION

2012 ◽  
Vol 26 (06) ◽  
pp. 1250035 ◽  
Author(s):  
WALTER J. FREEMAN ◽  
ROBERTO LIVI ◽  
MASASHI OBINATA ◽  
GIUSEPPE VITIELLO
Keyword(s):  
Phase Transitions ◽  
Landau Equation ◽  
Power Laws ◽  
Time Dependent ◽  
Many Body ◽  
Ginzburg Landau ◽  
Ginzburg Landau Equation ◽  
Characteristic Space ◽  
The Many ◽  
The Brain

The formation of amplitude modulated and phase modulated assemblies of neurons is observed in the brain functional activity. The study of the formation of such structures requires that the analysis has to be organized in hierarchical levels, microscopic, mesoscopic, macroscopic, each with its characteristic space-time scales and the various forms of energy, electric, chemical, thermal produced and used by the brain. In this paper, we discuss the microscopic dynamics underlying the mesoscopic and the macroscopic levels and focus our attention on the thermodynamics of the nonequilibrium phase transitions. We obtain the time-dependent Ginzburg–Landau equation for the nonstationary regime and consider the formation of topologically nontrivial structures such as the vortex solution. The power laws observed in functional activities of the brain is also discussed and related to coherent states characterizing the many-body dissipative model of brain.

Writing About Dance

2010 ◽  
Author(s):  
Wendy R. Oliver
Keyword(s):  
Critical Thinking ◽  
Thinking Skills ◽  
Critical Thinking Skills ◽  
Research Papers ◽  
Art Form ◽  
Writing Assignment ◽  
The Many ◽  
The Brain

Master the art of writing about dance! And learn about dance at the same time. This comprehensive guide provides students with instructions for writing about dance in many different contexts. It brings together the many different kinds of writing that can be effectively used in a variety of dance classes from technique to appreciation. In addition, it offers strategies for improving critical thinking skills, and shows how writing and critical thinking are closely linked. Part I focuses on informal writing such as freewriting, with sample exercises and prompts. Part II outlines approaches to writing three different kinds of formal papers: critiques, essays and research papers. Writing about dance teaches on two levels. First, the writer is learning dance content as s/he writes. Engaging in the writing assignment causes the writer to take a look at an aspect of dance and to become a 'momentary expert'. Secondly, writing itself is a way of learning. Writing involves the brain in three kinds of interaction, that is, the intellectual act of critically thinking, the physical act of writing or typing, and the visual aspect of seeing the writing on the page. The critical thinking and contemplation involved in writing can deepen students understanding of dance technique, dance creativity, and dance as an art form. Students will use this book on their own, or teachers may make assignments from it. It teaches about dance writing, but also about the very basics of dance appreciation.

scholarly journals Targeting α-Synuclein for PD Therapeutics: A Pursuit on All Fronts

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 391 ◽  
Author(s):  
Margaux Teil ◽  
Marie-Laure Arotcarena ◽  
Emilie Faggiani ◽  
Florent Laferriere ◽  
Erwan Bezard ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Clinical Trials ◽  
Substantia Nigra ◽  
Dopaminergic Neurons ◽  
Lewy Bodies ◽  
Curative Treatment ◽  
Preclinical Studies ◽  
Cytoplasmic Inclusions ◽  
The Many ◽  
The Brain

Parkinson’s Disease (PD) is characterized both by the loss of dopaminergic neurons in the substantia nigra and the presence of cytoplasmic inclusions called Lewy Bodies. These Lewy Bodies contain the aggregated α-synuclein (α-syn) protein, which has been shown to be able to propagate from cell to cell and throughout different regions in the brain. Due to its central role in the pathology and the lack of a curative treatment for PD, an increasing number of studies have aimed at targeting this protein for therapeutics. Here, we reviewed and discussed the many different approaches that have been studied to inhibit α-syn accumulation via direct and indirect targeting. These analyses have led to the generation of multiple clinical trials that are either completed or currently active. These clinical trials and the current preclinical studies must still face obstacles ahead, but give hope of finding a therapy for PD with time.

scholarly journals Live View of Gonadotropin-Releasing Hormone Containing Neuron Migration

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 463-468 ◽  
Author(s):  
Elizabeth P. Bless ◽  
Heather J. Walker ◽  
Kwok W. Yu ◽  
J. Gabriel Knoll ◽  
Suzanne M. Moenter ◽  
...  
Keyword(s):  
Real Time ◽  
Direct Evidence ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Migratory Route ◽  
The Brain

Neurons that synthesize GnRH control the reproductive axis and migrate over long distances and through different environments during development. Prior studies provided strong clues for the types of molecules encountered and movements expected along the migratory route. However, our studies provide the first real-time views of the behavior of GnRH neurons in the context of an in vitro preparation that maintains conditions comparable to those in vivo. The live views provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more changes in direction after they enter the brain. Perturbations of guiding fibers distal to moving GnRH neurons in the nasal compartment influenced movement without detectable changes in the fibers in the immediate vicinity of moving GnRH neurons. This suggests that the use of fibers by GnRH neurons for guidance may entail selective signaling in addition to mechanical guidance. These studies establish a model to evaluate the influences of specific molecules that are important for their migration.

The many faces of insulin-like peptide signalling in the brain

2012 ◽  
Vol 13 (4) ◽  
pp. 225-239 ◽  
Author(s):  
Ana M. Fernandez ◽  
Ignacio Torres-Alemán
Keyword(s):  
The Many ◽  
The Brain

scholarly journals The infra-red secondary spectrum of hydrogen

1926 ◽  
Vol 112 (760) ◽  
pp. 196-212 ◽  
Keyword(s):  
Diffraction Grating ◽  
Capillary Tube ◽  
Internal Diameter ◽  
Large Glass ◽  
Glass Bulb ◽  
Infra Red ◽  
The Many ◽  
Disc Electrodes ◽  
Accurate Record ◽  
Aluminium Disc

The first observations of the "many lined" spectrum of hydrogen in the infra-red made by Croze, who measured the wave-lengths of 72 lines between 6838 Å. U. to the nearest on the Rowland system. Porlezza measured the wave-lengths of 43 lines between H a , though his plates were treated to record up to 8000 Å. U. Croze corrected some of his earlier lines and added some 27 more, but did not extend the further limit beyond 8027 Å. U., and his later results were still only given to the nearest integer. As Merton and Barratt had investigated the secondary spectrum only for wave-lengths less than H a , it was thought desirable to re-investigate the infra-red region, to obtain a more accurate record of the wave-lengths of the lines, and to push the limit, if possible, to longer wave-lengths. A plain diffraction grating spectroscope fitted with quartz lenses was used. The grating had 14,500 lines to the inch and gave a dispersion of 25 Å. per mm. An H-shaped vacumm-tube, fitted with aluminium disc electrodes at the heads of the upright stems, contained hydrogen, and to one stem of the tube a large glass bulb was sealed, so that a considerable volume of gas was available at about 2 mm. pressur. The capillary tube connecting the stems was 2 mm. internal diameter, and light emerging from the end of this tube parallel to the tube was directed on to the slit of the spectroscope with a quartz lens. In this "end-on" position the intensity of the secondary spectrum was at a maximum.

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