Death and Dying
Gary Seay, Susana Nuccetelli in Engaging Bioethics, 2017
Anatomical studies of the human brain typically divide it into the cerebrum, cerebellum, and brainstem. Of these regions, the most primitive is the brainstem or lower brain, which controls spontaneous functions such as swallowing, heartbeat, and respiration. Its reticular activating system regulates sleep-and-wake cycles and turns consciousness on and off. But the contents of consciousness are controlled by the cerebrum or higher brain—especially by its outer shell, the cortex, sometimes called ‘neocortex’ because it was the last to evolve. Although much remains to be discovered about brain function, consciousness is associated with cerebral cortical and subcortical activity, on which mental capacities such as awareness, reasoning, and memory depend. When the higher brain is absent or has sustained catastrophic damage, consciousness may be permanently absent, depending on the severity of the condition. Disorders of consciousness range from brain death and permanent vegetative state (PVS), both characterized by the permanent absence of all mental activity including feelings of pain and pleasure, to the minimally conscious state (MCS) and locked-in-syndrome (LIS). MCS involves some self-awareness and the ability to follow simple commands, give gestural or verbal responses, and make purposeful movements. Patients in LIS are conscious, though brain damage has left them aware of their environment, with open eyes but total paralysis, except for, typically, eye or eyelid movements used for communication.
Introduction: Epilepsy
Candace M. Kent, David M. Chan in Analysis of a Model for Epilepsy, 2022
The term semiology refers to the clinical manifestations, in terms of signs (objective features) and symptoms (subjective features), that are peculiar to seizures originating from a particular region of the brain. The terms anterior, posterior, lateral, and medial refer to the front, back, side, and middle, respectively, of the brain. The human brain is divided into two halves, the left cerebral hemisphere and the right cerebral hemisphere. Each hemisphere is, in turn, divided into four lobes: the frontal lobe, located anteriorly; the occipital lobe, located posteriorly; the parietal lobe, located between the frontal and occipital lobes; and the temporal lobe, located medially and laterally. The cortical tissue or cortex of the brain is the “gray matter” covering both cerebral hemispheres, and is gray because it contains the cell bodies of neurons. The neocortex makes up most of the cortex and consists of six layers of different types of neurons [42].
Neurological issues
Andrea Utley in Motor Control, Learning and Development, 2018
The cerebral cortex is the executive suite of the nervous system, and it enables us to communicate, perceive and produce voluntary movement. Three types of functional areas can be found in the cerebral cortex: motor areas, sensory motor areas and associated areas. The cerebral cortex is the largest part of the human brain, associated with higher brain functions such as thought and action. The cerebral cortex is divided into two hemispheres which, although they look symmetrical, have somewhat different functions. The left and right hemispheres of the cerebral cortex are connected by the corpus callosum, a large bundle of interconnecting nerve fibers. The cerebral cortex can be divided into four ‘lobes’: the frontal lobe, parietal lobe, occipital lobe and temporal lobe, with each lobe being represented in each hemisphere. Initial learning is dependent on the frontal cerebral cortex, control is ‘passed’ to cerebellum with practice and researchers are interested in how type of practice, context and feedback influence this process (Marsh et al. 2011).
Focal cortical dysplasia: an update on diagnosis and treatment
Published in Expert Review of Neurotherapeutics, 2021
Surgical management of epilepsy related to FCD should include certain requirements and a multidisciplinary team [122,142] with the expertise to recognize them or highlight them according to a growing scale of complexity, which includes a) preoperative investigations aimed at correlating electroclinical data, brain MRI and, in some centers, FDG PET scan co-registration, and in complex and MRI-negative cases, invasive monitoring, b) multidisciplinary analysis of the patient’s three-dimensional brain anatomy for precise surgical planning, and c) intraoperative identification of surface and subcortical anatomy using neuronavigation and cortical and subcortical mapping. In order to achieve the best outcome, this multi-modality approach requires the participation of neurologists and neurophysiologists for surgical planning [6,142].
3.0 Tesla MRI scanner evaluation of supratentorial major white matter tracts and central core anatomical structures of postmortem human brain hemispheres fixed by Klingler method
Published in British Journal of Neurosurgery, 2021
Murat Atar, Ceren Kizmazoglu, Ismail Kaya, Nevin Aydin, Ufuk Corumlu, Gulden Sozer, Hasan Emre Aydin, Orhan Kalemci, Nuri Karabay, Nurullah Yuceer
Studies examining the human brain have been primarily conducted using the gross dissection, macroscopic examination, and myelin staining techniques; however, these methods are somewhat inadequate. The identification of white matter tracts has gained tremendous momentum following the description and publication of a new method by Joseph Klingler nearly 80 years ago.1,2 In the mid-1980s, it became possible to observe the anatomical structure of the human brain in great detail using magnetic resonance imaging (MRI). The aim of this study was to determine the exact anatomical boundaries of the white matter tracts in post-mortem human brain hemispheres fixed by the Klinger method using 3.0 Tesla MRI scanner images. Some brain MRI morphometry studies have started to use cortical thickness as a biomarker for disease diagnosis and follow-up or in determining prognosis.3–6 These morphometry studies have started to be standardized via multi-center studies in parallel with the increase in the quality of brain MRI.7
Early loss of cerebellar Purkinje cells in human and a transgenic mouse model of Alzheimer’s disease
Published in Neurological Research, 2021
Kiran Chaudhari, Linshu Wang, Jonas Kruse, Ali Winters, Nathalie Sumien, Ritu Shetty, Jude Prah, Ran Liu, Jiong Shi, Michael Forster, Shao-Hua Yang
The human brain is characterized by the evolutionally expanded cerebrum and remarkable cognitive capacity [1], whereas the cerebellum is considered a more archaic brain structure for motor coordination. Accordingly, research of Alzheimer’s disease (AD) has been exclusively focused on the cognition, especially the hippocampus and cerebral cortex [2]. Although neuropathology and functional cerebellar changes have been observed in AD patients back to 1980s [3,4], the cerebellum’s involvement in AD has been under-appreciated. Indeed, both tau aggregation and Aβ plaques, two hallmarks of AD, are occasionally observed in the cerebellum at late stages in AD patients and transgenic AD mouse models [5–9]. Further, the cerebellar atrophy was only observed at the late stage of AD [10]. Nonetheless, brain atrophy in different regions does not always follow β-amyloid or tau deposit pattern [11]. The accumulation of Aβ plaques in the brain does not correlate with cognitive impairments. While tangles correlate strongly with cognitive decline and neuronal and synapse loss, mutations in tau cause frontotemporal dementia, not AD [12].
Related Knowledge Centers
- Brainstem
- Central Nervous System
- Cerebellum
- Nervous System
- Cerebrum
- Spinal Cord
- Brain
- Body
- Sensory Nervous System
- Neurocranium