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Anatomy of the head and neck
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
Although the surface of the cerebrum is composed of grey matter, its interior consists primarily of nerve axon pathways or white matter. Association fibres interconnect areas of the cortex within each cerebral hemisphere (Figure 1.8). Shorter association or arcuate fibres pass from one gyrus to another, whereas longer association fibres are arranged in bundles, or fasciculi. Longitudinal fasciculi link the lobes of each cerebral hemisphere. Commissural fibres link the two hemispheres and allow communication between them. These fibres are formed into densely packed bands of nerve axons, such as the corpus callosum and the anterior commissure (Figure 1.8a-g).
Brain Injury and Infant Cardiac Surgery: Overview
Published in Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin, Brain Injury and Pediatric Cardiac Surgery, 2019
The neurological features of this lesion, i.e., particularly spastic diplegia, relate to the topography of the injury.18,19 Thus, in spastic diplegia, the lower extremity is involved more than the upper extremity. Because of the focal necrosis in the periventricular white matter, the motor fibers emanating from the cerebral cortex and subserving lower extremity function are preferentially affected. Fibers subserving the function of upper extremities course more laterally and thus are less likely to be injured or are injured less. However, because there is also more diffuse injury to cerebral white matter, association fibers are affected, and this involvement may account for at least some of the cognitive deficits that one sees on follow-up in affected infants.
Anatomy for neurotrauma
Published in Hemanshu Prabhakar, Charu Mahajan, Indu Kapoor, Essentials of Anesthesia for Neurotrauma, 2018
Vasudha Singhal, Sarabpreet Singh
Association fibers include the superior longitudinal fasciculus (connecting the frontal and occipital lobes); the inferior longitudinal fasciculus (that connect the temporal with the occipital lobe); the arcuate fasciculus (connecting the frontal lobe with the occipito-frontal cortex); the uncinate fasciculus (that connect the frontal and anterior temporal lobes); and the cingulum (underlying the cortex of the cingulate gyrus).
Nineteenth- and twentieth-century brain maps relating to locations and constructions of brain functions
Published in Journal of the History of the Neurosciences, 2022
Wernicke (1874) did not accept the functional equivalence of the cerebral surface as promoted by Flourens. Nor did he accept the localized, arbitrarily defined mental functions of the phrenologists, which were based on common sense distinctions. Wernicke believed that only the most elementary of mental functions, such as perceptual functions, could be associated with certain parts of the cortex. He believed that the brain was a mosaic of simple functions related to sensory information from the external world. Anything beyond these simple elements was the result of the links provided by the association fibers of the brain. He conceptualized these connections as analogous to connections among nervous elements in reflexes. His brain maps were line-drawings,9A line-drawing may appear crudely drawn, a shorthand way of depicting something, but it is designed to show only enough of known information to illustrate the point. The information it does include is crucial to orient the viewer. By its nature, it is a straightforward yet abstract illustration. with hypothetical pathways drawn on them.
The role of diffusion tensor imaging in characterizing injury patterns on athletes with concussion and subconcussive injury: a systematic review
Published in Brain Injury, 2021
Maryam Tayebi, Samantha J. Holdsworth, Allen A. Champagne, Douglas J. Cook, Poul Nielsen, Tae-Rin Lee, Alan Wang, Justin Fernandez, Vickie Shim
Several studies examined the whole regions of the brain, while others just focused on specific white matter tracts of association fibers, projection fibers, commissural fibers, or gray matter (GM). Figures 9 and 10 illustrate the number of papers which reported significant differences between the athletes with concussion and control group according to the name of white matter tracts. Based on this figure, the genu of the corpus callosum (CC) (Nstudies = 21 out of 39), superior longitudinal fasciculus (N studies = 15 out of 39), and anterior corona radiata (Nstudies = 13 out of 39) were the most remarkable fibers which showed substantial alterations. Among the studies conducted on the subconcussed players (Figure 11), splenium of CC (Nstudies = 10 out of 19), genu of CC (Nstudies = 8 out of 19), and posterior internal capsule (N studies = 7 out of 19) were found to be the most vulnerable tracts.
Cellular and extracellular white matter alterations indicate conversion to psychosis among individuals at clinical high-risk for psychosis
Published in The World Journal of Biological Psychiatry, 2021
Felix L. Nägele, Ofer Pasternak, Lisa V. Bitzan, Marius Mußmann, Jonas Rauh, Marek Kubicki, Gregor Leicht, Martha E. Shenton, Amanda E. Lyall, Christoph Mulert
Specifically, free-water imaging studies in subjects following their first psychotic episode have shown widespread elevations in FW following the onset of psychosis, accompanied with more focal FAT changes (Pasternak et al. 2012; Lyall et al. 2018). Moreover, two previous free-water imaging studies in independent CHR samples (Wang et al. 2016; Tang et al. 2019) reported reduced FAT in CHR subjects, but did not identify increased FW (Tang et al. 2019). These studies suggest that structural abnormalities observed in interhemispheric and association fibres may already be present in the CHR stage and may reflect a neurodevelopmental predisposition to display prodromal symptoms (Tang et al. 2019). However, these studies have yielded inconclusive results regarding the issue of whether these brain abnormalities are indicative of transition to psychosis, necessitating additional investigation.