scholarly journals Diagnosis of brain death

2010 ◽  
Vol 2 (1) ◽  
pp. 2 ◽  
Author(s):  
Calixto Machado
Keyword(s):  
Brain Death ◽  
Perfusion Pressure ◽  
Cellular Level ◽  
Irreversible Loss ◽  
Clinical Expression ◽  
Neuronal Tissue ◽  
Brain Functions ◽  
The Mean ◽  
The Brain ◽  
Signs Of Death

Brain death (BD) should be understood as the ultimate clinical expression of a brain catastrophe characterized by a complete and irreversible neurological stoppage, recognized by irreversible coma, absent brainstem reflexes, and apnea. The most common pattern is manifested by an elevation of intracranial pressure to a point beyond the mean arterial pressure, and hence cerebral perfusion pressure falls and, as a result, no net cerebral blood flow is present, in due course leading to permanent cytotoxic injury of the intracranial neuronal tissue. A second mechanism is an intrinsic injury affecting the nervous tissue at a cellular level which, if extensive and unremitting, can also lead to BD. We review here the methodology of diagnosing death, based on finding any of the signs of death. The irreversible loss of cardio-circulatory and respiratory functions can cause death only when ischemia and anoxia are prolonged enough to produce an irreversible destruction of the brain. The sign of such loss of brain functions, that is to say BD diagnosis, is fully reviewed.

scholarly journals Refinements in the Organism as a Whole Rationale for Brain Death

2019 ◽  
Vol 86 (4) ◽  
pp. 347-358 ◽  
Author(s):  
James L. Bernat
Keyword(s):  
Brain Death ◽  
Theoretical Biology ◽  
Conscious Awareness ◽  
Control Of Respiration ◽  
Biological Models ◽  
Whole Brain ◽  
Brain Functions ◽  
And Control ◽  
The Brain

Death can be defined as the permanent cessation of the organism as a whole. Although the organism as a whole is a century-old concept, it remains better intuited than analyzed. Recent concepts in theoretical biology including hierarchies of organization, emergent functions, and mereology have informed the idea that the organism as a whole is the organism’s critical emergent functions. Because the brain conducts the critical emergent functions including conscious awareness and control of respiration and circulation, the cessation of brain functions is death of the organism. A newer concept, the brain as a whole, may offer a superior criterion of death to the whole-brain criterion, because it more closely matches accepted clinical brain death tests and confirms the cessation of the organism’s emergent functions. Although the concepts of organism as a whole and brain as a whole remain vague and in need of rigorous biophilosophical analysis, their future precision will be restricted by the categorical limitations intrinsic to theoretical biological models.

Controversies about irreversible loss of brain functions and cerebral perfusion in brain death

2016 ◽  
Vol 23 (2) ◽  
pp. e8-e8 ◽  
Author(s):  
C. Roth ◽  
W. Deinsberger ◽  
J. Kleffmann ◽  
A. Ferbert
Keyword(s):  
Brain Death ◽  
Cerebral Perfusion ◽  
Irreversible Loss ◽  
Brain Functions

Catecholamine response to a gradual increase of intracranial pressure

1993 ◽  
Vol 79 (5) ◽  
pp. 705-709 ◽  
Author(s):  
Johan van Loon ◽  
Bharati Shivalkar ◽  
Chris Plets ◽  
Jan Goffin ◽  
T. Budya Tjandra-Maga ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Intracranial Hypertension ◽  
Perfusion Pressure ◽  
Gradual Increase ◽  
Hemodynamic Changes ◽  
Content Type ◽  
Catecholamine Response ◽  
Cushing Response ◽  
The Mean ◽  
The Brain

✓ To determine the catecholamine response to progressive intracranial hypertension, intracranial pressure (ICP) was raised gradually by continuous expansion of an epidural balloon in seven dogs. Hemodynamic parameters, ICP, and cerebral perfusion pressure (CPP) were monitored continuously and serum catecholamine levels began to rise when CPP was in the low-positive range (20 to 30 mm Hg), reaching a peak just after brain death (CPP ≤ 0 mm Hg). There was no correlation between ICP and the catecholamine peak. Compared to control values, the mean increase was 286-fold for epinephrine and 78-fold for norepinephrine. Temporally, the catecholamine peak corresponded well with the observed hemodynamic changes. These results suggest that ischemia in certain parts of the brain stem is responsible for the hemodynamic changes observed in intracranial hypertension (such as the Cushing response), and they show that catecholamines play an important role in these hemodynamic changes.

scholarly journals A robust image registration interface for large volume brain atlas

2018 ◽  
Author(s):  
Hong Ni ◽  
Chaozhen Tan ◽  
Zhao Feng ◽  
Shangbin Chen ◽  
Zoutao Zhang ◽  
...  
Keyword(s):  
Large Volume ◽  
Three Dimensional ◽  
Brain Structures ◽  
Cellular Level ◽  
Brain Atlas ◽  
Biological Images ◽  
Brain Functions ◽  
Streak Image ◽  
Dataset Size ◽  
The Brain

AbstractMapping the brain structures in three-dimensional accurately is critical for an in-depth understanding of the brain functions. By using the brain atlas as a hub, mapping detected datasets into a standard brain space enables efficiently use of various datasets. However, because of the heterogeneous and non-uniform characteristics of the brain structures at cellular level brought with the recently developed high-resolution whole-brain microscopes, traditional registration methods are difficult to apply to the robust mapping of various large volume datasets. Here, we proposed a robust Brain Spatial Mapping Interface (BrainsMapi) to address the registration of large volume datasets at cellular level by introducing the extract regional features of the anatomically invariant method and a strategy of parameter acquisition and large volume transformation. By performing validation on model data and biological images, BrainsMapi can not only achieve robust registration on sample tearing and streak image datasets, different individual and modality datasets accurately, but also are able to complete the registration of large volume dataset at cellular level which dataset size reaches 20 TB. Besides, it can also complete the registration of historical vectorized dataset. BrainsMapi would facilitate the comparison, reuse and integration of a variety of brain datasets.

Information Processing in the Mammalian Olfactory System

2005 ◽  
Vol 85 (1) ◽  
pp. 281-317 ◽  
Author(s):  
Pierre-Marie Lledo ◽  
Gilles Gheusi ◽  
Jean-Didier Vincent
Keyword(s):  
Olfactory System ◽  
Cellular Level ◽  
Adult Brain ◽  
Organizational Strategies ◽  
Cellular Mechanisms ◽  
Brain Functions ◽  
Olfactory Systems ◽  
And Behavior ◽  
High Degree ◽  
The Brain

Recently, modern neuroscience has made considerable progress in understanding how the brain perceives, discriminates, and recognizes odorant molecules. This growing knowledge took over when the sense of smell was no longer considered only as a matter for poetry or the perfume industry. Over the last decades, chemical senses captured the attention of scientists who started to investigate the different stages of olfactory pathways. Distinct fields such as genetic, biochemistry, cellular biology, neurophysiology, and behavior have contributed to provide a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. So far, the combination of these approaches has been most effective at the cellular level, but there are already signs, and even greater hope, that the same is gradually happening at the systems level. This review summarizes the current ideas concerning the cellular mechanisms and organizational strategies used by the olfactory system to process olfactory information. We present findings that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the olfactory system. Recent observations supporting the necessity of such plasticity for adult brain functions are also discussed. Due to space constraints, this review focuses mainly on the olfactory systems of vertebrates, and primarily those of mammals.

scholarly journals Brain death as irreversible loss of a human’s moral status

2018 ◽  
Vol 8 (3-4) ◽  
pp. 167-178
Author(s):  
Piotr Grzegorz Nowak
Keyword(s):  
Brain Death ◽  
Organ Donation ◽  
Moral Status ◽  
Ordinary Language ◽  
Irreversible Loss ◽  
Life And Death ◽  
Dead Donor Rule ◽  
Biological Meaning ◽  
Brain Dead ◽  
The Brain

Abstract Singer claims that there are two ways of challenging the fact that brain-dead patients, from whom organs are usually retrieved, are in fact biologically alive. By means of the first, the so called dead donor rule may be abandoned, opening the way to lethal organ donation. In the second, it might be posited that terms such as “life” and “death” do not have any primary biological meaning and are applicable to persons instead of organisms. This second possibility permits one to acknowledge that brain-dead patients are deceased because they are irreversibly unconscious. In the commentary which follows, I will argue that Singer’s second option is preferable since it (a) provides a higher amount of organs available for transplant, and (b) is better suited to the meaning of “death” which occurs in ordinary language. I will also defend such a concept of death against the objections raised by Michael Nair-Collins in the article Can the brain-dead be harmed or wronged? On the moral status of brain death and its implications for organ transplantation.

Brain death

2018 ◽  
Author(s):  
Matt Wise ◽  
Paul Frost
Keyword(s):  
Brain Death ◽  
Brain Activity ◽  
Irreversible Loss ◽  
Cardiorespiratory Function ◽  
The United Kingdom ◽  
Brainstem Death ◽  
Brainstem Function ◽  
Definition Of ◽  
The Uk ◽  
The Brain

Mechanical ventilation has made it possible for the heart to continue to beat and perfuse other organs even when the brain is dead. This means that death can be diagnosed in two distinct ways: first, in the traditional manner, as permanent cessation of cardiorespiratory function; and, second, while the patient is ventilated, as brain death (BD). In 1976 the Conference of Medical Royal Colleges and their Faculties in the United Kingdom, in a statement on the diagnosis of BD, recognized the brainstem as the centre of brain activity, without which life was not possible. Brainstem death (BSD) occurs when there is complete, irreversible loss of brainstem function, that is, irreversible loss of the capacity for consciousness, coupled with irreversible loss of the capacity to breathe. In the UK, the terms BD and BSD are used interchangeably and are legally synonymous with somatic death. This chapter covers examination for BSD, complications, diagnosis, investigation, and actions arising after BSD, as well as a definition of BD.

scholarly journals Putting Cells in Motion: Advantages of Endogenous Boosting of BDNF Production

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 183
Author(s):  
Elvira Brattico ◽  
Leonardo Bonetti ◽  
Gabriella Ferretti ◽  
Peter Vuust ◽  
Carmela Matrone
Keyword(s):  
Animal Models ◽  
Musical Training ◽  
Well Being ◽  
Cellular Level ◽  
Brain Functions ◽  
The Central Nervous System ◽  
Subcortical Regions ◽  
Higher Cognitive Functions ◽  
Human Brains ◽  
The Brain

Motor exercise, such as sport or musical activities, helps with a plethora of diseases by modulating brain functions in neocortical and subcortical regions, resulting in behavioural changes related to mood regulation, well-being, memory, and even cognitive preservation in aging and neurodegenerative diseases. Although evidence is accumulating on the systemic neural mechanisms mediating these brain effects, the specific mechanisms by which exercise acts upon the cellular level are still under investigation. This is particularly the case for music training, a much less studied instance of motor exercise than sport. With regards to sport, consistent neurobiological research has focused on the brain-derived neurotrophic factor (BDNF), an essential player in the central nervous system. BDNF stimulates the growth and differentiation of neurons and synapses. It thrives in the hippocampus, the cortex, and the basal forebrain, which are the areas vital for memory, learning, and higher cognitive functions. Animal models and neurocognitive experiments on human athletes converge in demonstrating that physical exercise reliably boosts BDNF levels. In this review, we highlight comparable early findings obtained with animal models and elderly humans exposed to musical stimulation, showing how perceptual exposure to music might affect BDNF release, similar to what has been observed for sport. We subsequently propose a novel hypothesis that relates the neuroplastic changes in the human brains after musical training to genetically- and exercise-driven BDNF levels.

scholarly journals Homomeric and Heteromeric α7 Nicotinic Acetylcholine Receptors in Health and Some Central Nervous System Diseases

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 664
Author(s):  
Virginia Borroni ◽  
Francisco J. Barrantes
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Cellular Level ◽  
Nicotinic Acetylcholine ◽  
Brain Functions ◽  
Α7 Nachr ◽  
Α7 Nicotinic Acetylcholine Receptors ◽  
Form Part ◽  
Time Frames ◽  
The Brain

Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels involved in the modulation of essential brain functions such as memory, learning, and attention. Homomeric α7 nAChR, formed exclusively by five identical α7 subunits, is involved in rapid synaptic transmission, whereas the heteromeric oligomers composed of α7 in combination with β subunits display metabotropic properties and operate in slower time frames. At the cellular level, the activation of nAChRs allows the entry of Na+ and Ca2+; the two cations depolarize the membrane and trigger diverse cellular signals, depending on the type of nAChR pentamer and neurons involved, the location of the intervening cells, and the networks of which these neuronal cells form part. These features make the α7 nAChR a central player in neurotransmission, metabolically associated Ca2+-mediated signaling, and modulation of diverse fundamental processes operated by other neurotransmitters in the brain. Due to its ubiquitous distribution and the multiple functions it displays in the brain, the α7 nAChR is associated with a variety of neurological and neuropsychiatric disorders whose exact etiopathogenic mechanisms are still elusive.

scholarly journals The intractable problems with brain death and possible solutions

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Ari R. Joffe ◽  
Gurpreet Khaira ◽  
Allan R. de Caen
Keyword(s):  
Brain Death ◽  
The State ◽  
Human Organism ◽  
Irreversible Loss ◽  
Acceptable Solution ◽  
Definition Of Death ◽  
Brain Functions ◽  
Metaphysical Problem ◽  
Dead Donor Rule ◽  
Intractable Problems

AbstractBrain death has been accepted worldwide medically and legally as the biological state of death of the organism. Nevertheless, the literature has described persistent problems with this acceptance ever since brain death was described. Many of these problems are not widely known or properly understood by much of the medical community. Here we aim to clarify these issues, based on the two intractable problems in the brain death debates. First, the metaphysical problem: there is no reason that withstands critical scrutiny to believe that BD is the state of biological death of the human organism. Second, the epistemic problem: there is no way currently to diagnose the state of BD, the irreversible loss of all brain functions, using clinical tests and ancillary tests, given potential confounders to testing. We discuss these problems and their main objections and conclude that these problems are intractable in that there has been no acceptable solution offered other than bare assertions of an ‘operational definition’ of death. We present possible ways to move forward that accept both the metaphysical problem - that BD is not biological death of the human organism - and the epistemic problem - that as currently diagnosed, BD is a devastating neurological state where recovery of sentience is very unlikely, but not a confirmed state of irreversible loss of all [critical] brain functions. We argue that the best solution is to abandon the dead donor rule, thus allowing vital organ donation from patients currently diagnosed as BD, assuming appropriate changes are made to the consent process and to laws about killing.

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