scholarly journals Muscle Tone Physiology and Abnormalities

Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 282
Author(s):  
Jacky Ganguly ◽  
Dinkar Kulshreshtha ◽  
Mohammed Almotiri ◽  
Mandar Jog
Keyword(s):  
Neural Circuits ◽  
Muscle Tone ◽  
Control Mechanisms ◽  
Cortical Connections ◽  
Definition Of ◽  
Passive Stretch ◽  
Hand Dystonia ◽  
The Brain ◽  
Homeostatic Mechanisms ◽  
Simple Definition

The simple definition of tone as the resistance to passive stretch is physiologically a complex interlaced network encompassing neural circuits in the brain, spinal cord, and muscle spindle. Disorders of muscle tone can arise from dysfunction in these pathways and manifest as hypertonia or hypotonia. The loss of supraspinal control mechanisms gives rise to hypertonia, resulting in spasticity or rigidity. On the other hand, dystonia and paratonia also manifest as abnormalities of muscle tone, but arise more due to the network dysfunction between the basal ganglia and the thalamo-cerebello-cortical connections. In this review, we have discussed the normal homeostatic mechanisms maintaining tone and the pathophysiology of spasticity and rigidity with its anatomical correlates. Thereafter, we have also highlighted the phenomenon of network dysfunction, cortical disinhibition, and neuroplastic alterations giving rise to dystonia and paratonia.

Application of Scanning Electron Microscopy to Medical Research

1969 ◽  
Vol 27 ◽  
pp. 12-13
Author(s):  
J. D. Hutchison
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Medical Research ◽  
Prosthetic Heart Valve ◽  
School Of Medicine ◽  
Transmission Electron ◽  
Definition Of ◽  
Mechanism Of Failure ◽  
The Brain ◽  
Scanning Electron

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.

Comparison of Fluorine(18)-fluorodeoxyglucose and Gallium(68)-citrate PET/CT in patients with tuberculosis

2019 ◽  
Vol 58 (05) ◽  
pp. 371-378
Author(s):  
Alfred O. Ankrah ◽  
Ismaheel O. Lawal ◽  
Tebatso M.G. Boshomane ◽  
Hans C. Klein ◽  
Thomas Ebenhan ◽  
...  
Keyword(s):  
Tracer Uptake ◽  
Pet Ct ◽  
The Mean ◽  
18F Fdg ◽  
Definition Of ◽  
Gallium 68 ◽  
Attending Physician ◽  
Pet Scans ◽  
The Brain

Abstract 18F-FDG and 68Ga-citrate PET/CT have both been shown to be useful in the management of tuberculosis (TB). We compared the abnormal PET findings of 18F-FDG- and 68Ga-citrate-PET/CT in patients with TB. Methods Patients with TB on anti-TB therapy were included. Patients had a set of PET scans consisting of both 18F-FDG and 68Ga-citrate. Abnormal lesions were identified, and the two sets of scans were compared. The scan findings were correlated to the clinical data as provided by the attending physician. Results 46 PET/CT scans were performed in 18 patients, 11 (61 %) were female, and the mean age was 35.7 ± 13.5 years. Five patients also had both studies for follow-up reasons during the use of anti-TB therapy. Thirteen patients were co-infected with HIV. 18F-FDG detected more lesions than 68Ga-citrate (261 vs. 166, p < 0.0001). 68Ga-citrate showed a better definition of intracerebral lesions due to the absence of tracer uptake in the brain. The mean SUVmax was higher for 18F-FDG compared to 68Ga-citrate (5.73 vs. 3.01, p < 0.0001). We found a significant correlation between the SUVmax of lesions that were determined by both tracers (r = 0.4968, p < 0.0001). Conclusion Preliminary data shows 18F-FDG-PET detects more abnormal lesions in TB compared to 68Ga-citrate. However, 68Ga-citrate has better lesion definition in the brain and is therefore especially useful when intracranial TB is suspected.

DIRECTIONS OF ASSOCIATIVE IDENTIFICATION OF PERSONAL NAMES

2019 ◽  
Vol 18 (28) ◽  
pp. 118-128
Author(s):  
Olena Karpenko ◽  
Tetiana Stoianova
Keyword(s):  
Proper Names ◽  
Mental Lexicon ◽  
Point Of View ◽  
Sound Symbolism ◽  
Personal Names ◽  
Communicative Process ◽  
Proper Name ◽  
Definition Of ◽  
Scientific Value ◽  
The Brain

The article is devoted to the study of personal names from a cognitive point of view. The study is based on the cognitive concept that speech actually exists not in the speech, not in linguistic writings and dictionaries, but in consciousness, in the mental lexicon, in the language of the brain. The conditions for identifying personal names can encompass not only the context, encyclopedias, and reference books, but also the sound form of the word. In the communicative process, during a free associative experiment, which included a name and a recipient’s mental lexicon. The recipient was assigned a task to quickly give some association to the name. The aggregate of a certain number of reactions of different recipients forms the associative field of a proper name. The associative experiment creates the best conditions for identifying the lexeme. The definition of a monosemantic personal name primarily includes the search of what it denotes, while during the process of identifying a polysemantic personal name recipients tend have different reactions. Scientific value is posed by the effect of the choice of letters for the name, sound symbolism, etc. The following belong to the generalized forms of identification: usage of a hyperonym; synonyms and periphrases or simple descriptions; associations denoting the whole (name stimulus) by reference to its part (associatives); cognitive structures such as “stimulus — association” and “whole (stimulus) — part (associative)”; lack of adjacency; mysterious associations. The topicality of the study is determined by its perspective to identify the directions of associative identification of proper names, which is one of the branches of cognitive onomastics. The purpose of the study is to identify, review, and highlight the directions of associative identification of proper names; the object of the research is the names in their entirety and variety; its subject is the existence of names in the mental lexicon, which determines the need for singling out the directions for the associative identification of the personal names.

Neuroethics

2017 ◽  
Keyword(s):  
Brain Function ◽  
Ethical Issues ◽  
Wearable Technologies ◽  
Definition Of Death ◽  
Populations At Risk ◽  
The Future ◽  
Aging Adults ◽  
Definition Of ◽  
The Brain ◽  
New Criteria

We have new answers to how the brain works and tools which can now monitor and manipulate brain function. Rapid advances in neuroscience raise critical questions with which society must grapple. What new balances must be struck between diagnosis and prediction, and invasive and noninvasive interventions? Are new criteria needed for the clinical definition of death in cases where individuals are eligible for organ donation? How will new mobile and wearable technologies affect the future of growing children and aging adults? To what extent is society responsible for protecting populations at risk from environmental neurotoxins? As data from emerging technologies converge and are made available on public databases, what frameworks and policies will maximize benefits while ensuring privacy of health information? And how can people and communities with different values and perspectives be maximally engaged in these important questions? Neuroethics: Anticipating the Future is written by scholars from diverse disciplines—neurology and neuroscience, ethics and law, public health, sociology, and philosophy. With its forward-looking insights and considerations for the future, the book examines the most pressing current ethical issues.

scholarly journals An architectonic type principle in the development of laminar patterns of cortico-cortical connections

2021 ◽  
Author(s):  
Sarah F. Beul ◽  
Alexandros Goulas ◽  
Claus C. Hilgetag
Keyword(s):  
Structural Connectivity ◽  
Macaque Monkey ◽  
Brain Regions ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Cortical Connections ◽  
Cortical Projections ◽  
Structural Connections ◽  
High Degree ◽  
The Brain

AbstractStructural connections between cortical areas form an intricate network with a high degree of specificity. Many aspects of this complex network organization in the adult mammalian cortex are captured by an architectonic type principle, which relates structural connections to the architectonic differentiation of brain regions. In particular, the laminar patterns of projection origins are a prominent feature of structural connections that varies in a graded manner with the relative architectonic differentiation of connected areas in the adult brain. Here we show that the architectonic type principle is already apparent for the laminar origins of cortico-cortical projections in the immature cortex of the macaque monkey. We find that prenatal and neonatal laminar patterns correlate with cortical architectonic differentiation, and that the relation of laminar patterns to architectonic differences between connected areas is not substantially altered by the complete loss of visual input. Moreover, we find that the degree of change in laminar patterns that projections undergo during development varies in proportion to the relative architectonic differentiation of the connected areas. Hence, it appears that initial biases in laminar projection patterns become progressively strengthened by later developmental processes. These findings suggest that early neurogenetic processes during the formation of the brain are sufficient to establish the characteristic laminar projection patterns. This conclusion is in line with previously suggested mechanistic explanations underlying the emergence of the architectonic type principle and provides further constraints for exploring the fundamental factors that shape structural connectivity in the mammalian brain.

A simple definition of ‘intentionally’

Cognition ◽  
2021 ◽  
Vol 214 ◽  
pp. 104806
Author(s):  
Tadeg Quillien ◽  
Tamsin C. German
Keyword(s):  
Definition Of ◽  
Simple Definition

scholarly journals Conceptual and Practical Issues in the Pharmacological Treatment of Brain Injury

1993 ◽  
Vol 4 (3) ◽  
pp. 227-237 ◽  
Author(s):  
Donald G. Stein ◽  
Marylou M. Glasier ◽  
Stuart W. Hoffman
Keyword(s):  
Central Nervous System ◽  
Brain Injury ◽  
Time Course ◽  
Chemical Activity ◽  
Behavioral Testing ◽  
Naturally Occurring ◽  
New Information ◽  
Definition Of ◽  
Injury And Repair ◽  
The Brain

It is only within the last ten years that research on treatment for central nervous system (CNS) recovery after injury has become more focused on the complexities involved in promoting recovery from brain injury when the CNS is viewed as an integrated and dynamic system. There have been major advances in research in recovery over the last decade, including new information on the mechanics and genetics of metabolism and chemical activity, the definition of excitotoxic effects and the discovery that the brain itself secretes complex proteins, peptides and hormones which are capable of directly stimulating the repair of damaged neurons or blocking some of the degenerative processes caused by the injury cascade. Many of these agents, plus other nontoxic naturally occurring substances, are being tested as treatment for brain injury. Further work is needed to determine appropriate combinations of treatments and optimum times of administration with respect to the time course of the CNS disorder. In order to understand the mechanisms that mediate traumatic brain injury and repair, there must be a merging of findings from neurochemical studies with data from intensive behavioral testing.

scholarly journals The emulation theory of representation: Motor control, imagery, and perception

2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Neural Circuits ◽  
Sensory Information ◽  
The Body ◽  
Feedback Delay ◽  
Run Off ◽  
Effects Of Feedback ◽  
The Brain

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

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