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Clinical Effects of Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
A possible explanation for the decreased gray matter density in these disorders might be atrophy secondary to excitotoxicity and/or exposure to inflammation-related agents, such as cytokines.111 The cytokines have been shown to be triggered by such entities as pesticides, natural gas, organic and inorganic chemicals, molds, mycotoxin, and EMF. It is noteworthy that in fibromyalgia patients, gray matter loss occurred mainly in regions related to stress (parahippocampal gyrus)208 and pain processing (cingulate, insular, and prefrontal cortices),209 which might reflect their long-term experience of these symptoms. As cingulate and prefrontal cortices are particularly implicated in pain modulation209 (i.e., inhibition and facilitation of pain), structural changes in these systems could contribute to the maintenance of pain and symptom chronification in fibromyalgia. Furthermore, gray matter atrophy in areas such as parahippocampal and frontal cortices also appears consistent with cognitive deficits characteristic of fibromyalgia.210 It is clearly seen in chemically sensitive patients. Of course, total body pollutant load will be extremely influenced in the cortices. Longitudinal studies are indicated to determine whether the observed structural changes are the cause or the consequence of the disorder. If confirmed, these findings may provide a rationale for exploring neuroprotective approaches in fibromyalgia aimed at symptom treatment or indeed at their reversal.
The Skull and Brain
Published in Melanie Franklyn, Peter Vee Sin Lee, Military Injury Biomechanics, 2017
Tom Gibson, Nicholas Shewchenko, Tom Whyte
These parts of the brain are composed of grey and white matter. Grey matter is composed primarily of nerve-cell bodies concentrated in locations on the surface of the brain and deep within the brain. White matter is composed of myelinated axons that largely form tracts to connect parts of the brain to each other. In the cerebrum and cerebellum, the grey matter is the most superficial tissue, beneath which is the white matter. The brainstem, like the spinal cord, is composed of deep grey matter surrounded by white matter fibre tracts (Marieb 1998) (Figure 8.5).
Brain–Computer Interface
Published in Shampa Sen, Leonid Datta, Sayak Mitra, Machine Learning and IoT, 2018
Abhishek Mukherjee, Madhurima Gupta, Shampa Sen
As mentioned before, the largest part of the brain is the cerebrum. It is divided into two symmetrical hemispheres—right and left hemispheres—connected together by the calossum, as observed in Figure 16.1. The cortex is composed of grey and white matter, and these are nothing but bundles of neurons having special and distinctive orientations. The white matter is just the axons with myelin sheaths, while the grey matter is composed of everything else pertaining to the neurons. The cerebral cortex is the region of cortex associated with the cerebrum. It is composed of a greater number of layers compared to the cortex associated to the cerebellum. The cerebral cortex is a highly convoluted structure, composed of ridges known as gyri and fissures called sulci. Functional demarcation results in dividing each hemisphere into parietal, temporal, occipital, and frontal lobes. They all have distinct functions and yet are integrated which each other. The schematic structure and position of the lobes can be observed in Figure 16.2. As we can see, the frontal lobe is the largest of the four; it is our emotional control center and home to our personality. Thus, as expected, it is involved in a multitude of activities such as cognition (memory, problem solving, information processing, etc.), behavioral responses, and motor functioning and control. The occipital lobe is involved in visual processing while the temporal lobe takes care of sound and language. This lobe also harbors the amygdala and hippocampus, regions involved in emotions and memory, respectively. Parietal lobes function as an integration center for sensory inputs from different senses, and are also involved in spatial orientation, awareness, and sensation of self, as well as navigation. Between the cerebrum and brainstem lie the thalamus and hypothalamus. The hypothalamus acts as a relay center between the nervous system and the endocrine system. The thalamus communicates motor and sensory data to the cortex; also, it comprehends wakefulness and sleeping patterns.
Simulated brain strains resulting from falls differ between concussive events of young children and adults
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
David Koncan, Michael Gilchrist, Michael Vassilyadi, Thomas B. Hoshizaki
The mechanical properties of brain tissue change with age (Prange and Margulies 2002; Gefen et al. 2003), and the brain continually remodels as we learn and develop new skills. Myelination and significant remodelling of grey and white matter in the brain have been shown to continue into the 3rd decade of life (Lenroot and Giedd 2006). With concussion reported to be a strain-based injury (Ommaya and Gennarelli 1974; Kleiven 2007), the variations in mechanical characteristics and patterns of grey and white matter in the brain will elicit a unique mechanical response for different age groups. Grey and white matter are mechanically different as a result of their underlying microstructure; grey matter is highly isotropic while white matter is anisotropic (Prange et al. 2000; Hrapko et al. 2008). As connections are reinforced and white matter tracts develop, the mechanical response of the brain tissue under load from events such as falls will be affected.
Biofidelic human brain tissue surrogates
Published in Mechanics of Advanced Materials and Structures, 2018
Arnab Chanda, Christian Callaway, Cassie Clifton, Vinu Unnikrishnan
Even after decades of studies, the brain remains one of the most mysterious parts of the human anatomy. The central operator of the nervous system, the brain, controls every thought and action performed by the body. The principal controlling part of the brain, the cerebrum, is composed of two unique tissues called white matter and grey matter [1] (see Figure 1).Figure 2 In addition to dendrites and axons for data collection, synapses for inter-neuron communication, glial cells for support and maintenance, and capillaries for microcirculation of blood, grey matter houses the majority of neuronal cell bodies in the brain. White matter, on the other hand, is composed primarily of long-range axon tracks for information transport. The color difference between the two arises from the white myelin coating present on the axons in white matter. Generally, the grey matter is responsible for processing stimuli leading to human cognition, while white matter allows for communication throughout the brain to generate a response to the stimuli. Typically, grey matter accounts for 40% of the cerebrum by mass, while white matter composes the remaining 60% [1].
Identifying stage of Alzheimer disease using multiclass particle swarm optimisation technique
Published in Journal of Experimental & Theoretical Artificial Intelligence, 2018
In early AD, intra-neuronal filamentous deposits, or neuro fibrillary tangles (NFTs), accumulate within neurons. These deposits are composed of hyper phosphorylated tau-protein (Shiino et al., 2006). This cellular pathology disrupts axonal transport and induces widespread metabolic decline. The resulting neuronal loss is observable as gross atrophy with MRI. Temporoparietal association cortices and the medial temporal lobe are severely atrophied in AD (DeCarli, 2000), with the entorhinal cortex and hippocampus the earliest and most severely affected (Janke et al., 2001; Thompson et al., 2001). Profound atrophy is also observed in the posterior cingulate gyrus and adjacent precuneus. Specific atrophic patterns differentiate AD from frontotemporal, semantic, and Lewy body dementias (Paling et al., 2001; Studholme et al., 2001). Patients with AD show minimal primary visual, sensorimotor, and frontal atrophy until late in the disease. Before symptom onset in AD, and also in those at genetic risk, grey matter loss is detectable in the anterior hippocampal/amygdala region (Lehtovirta, Laakso, Frisoni, & Soininen, 2000; Reiman et al., 2001). Atrophying grey matter (Lˇders., Steinmetz1, & Jncke, 2002) is a sign of the progression of Alzheimer’s disease and other forms of dementia. Atrophy in the grey matter is shown as the amount of grey matter shrinks in the imaging tests (Douaud et al., 2013).