scholarly journals The Neurofunctional Model of Consciousness: The Physiological Interconnectivity of Brain Networks

2020 ◽  
Author(s):  
Umberto León-Domínguez

The present chapter integrates neural networks’ connectivity into a model that explores consciousness and volitional behavior from a neurofunctional perspective. The model poses a theoretical evidenced-based framework that organizes the brain journey of neural information flow from the ascending reticular activating system and non-specific thalamic nuclei, to cortical networks, such as the default mode network and the fronto-parietal network. These inter-connected brain networks can be divided within three hierarchical and inter-connected “functional neural loops”: (1) the “brainstem-thalamic neural loop” for arousal, (2) the “thalamo-cortical neural loop” for neural information distribution throughout the brain, and (3) the “cortico-cortical neural loop” for transforming neural information into the contents of consciousness that the individual can perceive and manipulate voluntarily. These three neural loops act as a global functional neural system, and its disruption due to brain damage can cause a person to experience catastrophic outcomes, such as a coma, a vegetative state, a minimal conscious state, or other cognitive and behavioral impairments.

2019 ◽  
Vol 19 (3&4) ◽  
pp. 102
Author(s):  
Hossein Shamsi Gooshki ◽  
Seyyed Hassan Abedian Kalkhoran ◽  
Seyyed Mohammad Mahdi Ahmadi ◽  
Abolfazl Khoshi ◽  
Hassan Goodarzi

<p>The death of the cerebral cortex is a particular type of brain death that occurs after the destruction of the cerebral cortex (the hemispheres of the brain). It is said that the individual has gone through a vegetative state. This cortex is responsible for controlling voluntary activities of the body. This condition is caused by a coma (anesthesia), and sometimes the individual remains in this state for several years. Although the person looks awake, his/her eyes are open and has some involuntary movements, there is no signs of mental and cognitive function. Moreover, the individual is physically in a state of dementia. Coma is a state in which a person cannot be awakened and does not respond to any stimulation including pain. Generally it lasts few days to a few weeks, after which some patients gradually recover, but some permanently lose all brain function (brain death), while others evolve to a vegetative state (VS). Patients in VS are unconscious and unaware of their surroundings, but they continue to have a sleep-wake cycle and can have periods of consciousness. They are able to breathe spontaneously, retain their gag, cough, sucking, and swallowing reflexes. They often look fairly “normal” to families and friends who hope and pray for their full recovery. Laws and regulations in Islamic countries originate from popular jurisprudence. Therefore, by arguing that the well-known principles of Islam are necessarily legitimate, the phenomenon of vegetative state has been recognized. Jurisprudents have conflicting opinions on brain deaths and these perspectives cannot be considered as a widespread legal basis at the level of macro policy for administrative, medical and judicial affairs. In criminal law, maniac has no criminal responsibility because the punishment is not in line with the purpose of punishment. Consequently, restrictions will be imposed on the patients. Therefore, it can be concluded that a person with vegetative state is compatible with the insanity.</p>


Author(s):  
Weihao Zheng ◽  
Xufei Tan ◽  
Tingting Liu ◽  
Xiaoxia Li ◽  
Jian Gao ◽  
...  

Abstract The thalamus plays crucial roles in consciousness generation and information processing. Previous evidence suggests that disorder of consciousness (DOC) caused by severe brain injury, is potentially related to thalamic abnormalities. However, how the morphology and microstructure change in thalamic subfields and thalamocortical fiber pathways in patients with DOC, and the relationships between these changes and the consciousness status remain unclear. Here, we generated the individual-specific thalamic parcellation in 10 DOC patients and 10 healthy controls (HC) via a novel thalamic segmentation framework based on the fiber orientation distribution (FOD) derived from 7-Tesla diffusion MRI, and investigated the shape deformation of thalamic nuclei as well as the microstructural changes associated with thalamic nuclei and thalamocortical pathways in patients with DOC. Enlargement of dorsal posterior nucleus and atrophy of anterior nucleus in the right thalamus were observed in DOC cohort relative to the HCs, and the former was closely linked to the consciousness level of the patients. We also found significant reductions of fiber density, but not fiber bundle cross-section, within several thalamic nuclei and most of the thalamocortical fiber pathways, suggesting that loss of axons might take primary responsibility for the impaired thalamocortical connections in patients with DOC rather than the change in fiber-bundle morphology. Furthermore, the individual-specific thalamic parcellation achieved 80% accuracy in classifying patients at the minimally conscious state from the vegetative state, compared to around 60% accuracy based on group-level parcellations. Our findings provide the first evidence for the shape deformation of thalamic nuclei in DOC patients and the microstructural basis of the disrupted thalamocortical connections.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Richard Huxtable

Abstract Background In the ruling in Y [2018], the UK Supreme Court has confirmed that there is no general requirement for the courts in England and Wales to authorise the withdrawal of clinically assisted nutrition and hydration from patients with prolonged disorders of consciousness. The perceived requirement, which originated in a court ruling in 1993, encompassed those in the vegetative state and those in the minimally conscious state. The ruling in Y confirms that the court may still be approached to decide difficult or contested cases, but there is otherwise no routine requirement that the judges be approached. Main body There is much to welcome in this ruling, particularly as it means that these decisions for these patients are no longer (unusually) singled out for a judicial decision, with all the financial and emotional costs that court proceedings can entail. However, there is also a risk that the ruling might have unwelcome consequences. First, there is the possibility that patients might die too soon, particularly if doctors should now adopt the courts’ previous reasoning, which has suggested that patients in the vegetative state lack interests, so treatment may – perhaps must – be withdrawn. Secondly, there is the converse possibility that patients might live too long, since empirical research suggests that – whether intentionally or not – patients’ families, clinicians, and the health system appear to promote treatment-by-default. Conclusion Rather than adopt general positions, which may be contestable and potentially risky, this article argues, on a pluralistic basis, that the individual patient should be the focus of any decision made in his or her ‘best interests’. The existing legal framework in England and Wales, which is provided by the Mental Capacity Act 2005, already points in this direction, although more efforts may be needed to ensure that those involved in making these decisions are suitably educated and supported. Fortunately, new guidance from the British Medical Association could help clinicians and families to make decisions in the future, which are appropriate for the incapacitated individual patient in question.


2019 ◽  
Vol 3 (6) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew Peterson ◽  
Adrian M. Owen

In recent years, rapid technological developments in the field of neuroimaging have provided several new methods for revealing thoughts, actions and intentions based solely on the pattern of activity that is observed in the brain. In specialized centres, these methods are now being employed routinely to assess residual cognition, detect consciousness and even communicate with some behaviorally non-responsive patients who clinically appear to be comatose or in a vegetative state. In this article, we consider some of the ethical issues raised by these developments and the profound implications they have for clinical care, diagnosis, prognosis and medical-legal decision-making after severe brain injury.


2011 ◽  
Vol 21 (1) ◽  
pp. 5-14
Author(s):  
Christy L. Ludlow

The premise of this article is that increased understanding of the brain bases for normal speech and voice behavior will provide a sound foundation for developing therapeutic approaches to establish or re-establish these functions. The neural substrates involved in speech/voice behaviors, the types of muscle patterning for speech and voice, the brain networks involved and their regulation, and how they can be externally modulated for improving function will be addressed.


2002 ◽  
Vol 7 (3) ◽  
pp. 4-5

Abstract Different jurisdictions use the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides) for different purposes, and this article reviews a specific jurisdictional definition in the Province of Ontario of catastrophic impairment that incorporates the AMA Guides. In Ontario, a whole person impairment (WPI) exceeding 54% or a mental or behavioral impairment of Class 4 or 5 qualifies the individual for catastrophic benefits, and individuals who do not meet the test receive a lesser benefit. By inference, this establishes a parity threshold among dissimilar injuries and dissimilar outcome assessment scales for benefits. In Ontario, the Glasgow Coma Scale (GCS) identifies patients who have a high probability of death or of severely disabled survival. The GCS recognizes gradations of vegetative state and disability, but translating the gradations for rating individual impairment on ordinal scales into a method of assessing percentage impairments cannot be done reliably, as explained in the AMA Guides, Fifth Edition. The AMA Guides also notes that mental and behavioral impairment in Class 4 (marked impairment) or 5 (extreme impairment) indicates “catastrophic impairment” by significantly impeding useful functioning (Class 4) or significantly impeding useful functioning and implying complete dependency on another person for care (Class 5). Translating the AMA Guides guidelines into ordinal scales cannot be done reliably.


2014 ◽  
Vol 19 (5) ◽  
pp. 3-12
Author(s):  
Lorne Direnfeld ◽  
David B. Torrey ◽  
Jim Black ◽  
LuAnn Haley ◽  
Christopher R. Brigham

Abstract When an individual falls due to a nonwork-related episode of dizziness, hits their head and sustains injury, do workers’ compensation laws consider such injuries to be compensable? Bearing in mind that each state makes its own laws, the answer depends on what caused the loss of consciousness, and the second asks specifically what happened in the fall that caused the injury? The first question speaks to medical causation, which applies scientific analysis to determine the cause of the problem. The second question addresses legal causation: Under what factual circumstances are injuries of this type potentially covered under the law? Much nuance attends this analysis. The authors discuss idiopathic falls, which in this context means “unique to the individual” as opposed to “of unknown cause,” which is the familiar medical terminology. The article presents three detailed case studies that describe falls that had their genesis in episodes of loss of consciousness, followed by analyses by lawyer or judge authors who address the issue of compensability, including three scenarios from Arizona, California, and Pennsylvania. A medical (scientific) analysis must be thorough and must determine the facts regarding the fall and what occurred: Was the fall due to a fit (eg, a seizure with loss of consciousness attributable to anormal brain electrical activity) or a faint (eg, loss of consciousness attributable to a decrease in blood flow to the brain? The evaluator should be able to fully explain the basis for the conclusions, including references to current science.


2020 ◽  
Vol 15 (4) ◽  
pp. 287-299
Author(s):  
Jie Zhang ◽  
Junhong Feng ◽  
Fang-Xiang Wu

Background: : The brain networks can provide us an effective way to analyze brain function and brain disease detection. In brain networks, there exist some import neural unit modules, which contain meaningful biological insights. Objective:: Therefore, we need to find the optimal neural unit modules effectively and efficiently. Method:: In this study, we propose a novel algorithm to find community modules of brain networks by combining Neighbor Index and Discrete Particle Swarm Optimization (DPSO) with dynamic crossover, abbreviated as NIDPSO. The differences between this study and the existing ones lie in that NIDPSO is proposed first to find community modules of brain networks, and dose not need to predefine and preestimate the number of communities in advance. Results: : We generate a neighbor index table to alleviate and eliminate ineffective searches and design a novel coding by which we can determine the community without computing the distances amongst vertices in brain networks. Furthermore, dynamic crossover and mutation operators are designed to modify NIDPSO so as to alleviate the drawback of premature convergence in DPSO. Conclusion: The numerical results performing on several resting-state functional MRI brain networks demonstrate that NIDPSO outperforms or is comparable with other competing methods in terms of modularity, coverage and conductance metrics.


Brain Injury ◽  
2020 ◽  
pp. 1-7
Author(s):  
Sarah Elizabeth Patricia Munce ◽  
Fiona Webster ◽  
Jennifer Christian ◽  
Laura E. Gonzalez-Lara ◽  
Adrian M. Owen ◽  
...  

2021 ◽  
Author(s):  
Qiushi Wang ◽  
Yuehua Xu ◽  
Tengda Zhao ◽  
Zhilei Xu ◽  
Yong He ◽  
...  

Abstract The functional connectome is highly distinctive in adults and adolescents, underlying individual differences in cognition and behavior. However, it remains unknown whether the individual uniqueness of the functional connectome is present in neonates, who are far from mature. Here, we utilized the multiband resting-state functional magnetic resonance imaging data of 40 healthy neonates from the Developing Human Connectome Project and a split-half analysis approach to characterize the uniqueness of the functional connectome in the neonatal brain. Through functional connectome-based individual identification analysis, we found that all the neonates were correctly identified, with the most discriminative regions predominantly confined to the higher-order cortices (e.g., prefrontal and parietal regions). The connectivities with the highest contributions to individual uniqueness were primarily located between different functional systems, and the short- (0–30 mm) and middle-range (30–60 mm) connectivities were more distinctive than the long-range (&gt;60 mm) connectivities. Interestingly, we found that functional data with a scanning length longer than 3.5 min were able to capture the individual uniqueness in the functional connectome. Our results highlight that individual uniqueness is present in the functional connectome of neonates and provide insights into the brain mechanisms underlying individual differences in cognition and behavior later in life.


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