Posterior Quadrant Disconnection: A Fiber Dissection Study

AbstractBACKGROUNDPosterior quadrant disconnection can be highly effective in the surgical treatment of selected cases of refractory epilepsy. The technique aims to deafferent extensive areas of epileptogenic posterior cortex from the rest of the brain by isolating the temporoparietooccipital cortex.OBJECTIVETo describe this procedure and relevant white matter tracts with a specific emphasis on the extent of callosotomy in an anatomic study.METHODSTwenty hemispheres were dissected according to Klingler's fiber dissection technique illustrating the peri-insular (temporal stem, superior longitudinal fasciculus, corona radiata) and mesial disconnection (mesiotemporal cortex, cingulum, and corpus callosum).RESULTSExtensive white matter tract disconnection is obtained after posterior quadrant disconnection. Callosal fibers connecting the anterior most part of the parietal cortex invariably ran through the isthmus of the corpus callosum and need to be disconnected, while frontal lobe connections including the corticospinal tract and the anterior two-thirds of the corpus callosum are spared during the procedure.CONCLUSIONOur findings suggest the involvement of both the splenium and the isthmus in interhemispheric propagation in posterior cortex epilepsies. Sectioning the total extent of the posterior one-third of the corpus callosum might therefore be necessary to achieve optimal outcomes in posterior quadrant epilepsy surgery.

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Surgical anatomy of supratentorial midline lesions

Neurosurgical FOCUS ◽

10.3171/foc.2005.18.6.14 ◽

2005 ◽

Vol 18 (6) ◽

pp. 1-9 ◽

Cited By ~ 43

Author(s):

M. Gazi Yaşargil ◽

Uğur Türe ◽

Dianne C. H. Yaşargil ¸

Keyword(s):

White Matter ◽

Surgical Approach ◽

Surgical Anatomy ◽

Cerebral Hemispheres ◽

Surgical Exploration ◽

Fiber Dissection ◽

Dissection Technique ◽

Surgical Aspects ◽

The Brain

Object In this paper the authors correlate the surgical aspects of deep median and paramedian supratentorial lesions with the connective fiber systems of the white matter of the brain. Methods The cerebral hemispheres of 10 cadaveric brains were dissected in a mediolateral direction by using the fiber dissection technique, corresponding to the surgical approach. Conclusions This study illuminates the delicacy of the intertwined and stratified fiber laminae of the white matter, and establishes that these structures can be preserved at surgical exploration in patients.

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Anatomic Study of the Central Core of the Cerebrum Correlating 7-T Magnetic Resonance Imaging and Fiber Dissection With the Aid of a Neuronavigation System

Operative Neurosurgery ◽

10.1227/neu.0000000000000271 ◽

2013 ◽

Vol 10 (2) ◽

pp. 294-304 ◽

Cited By ~ 8

Author(s):

Carlos Alarcon ◽

Matteo de Notaris ◽

Kenneth Palma ◽

Guadalupe Soria ◽

Alessandro Weiss ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

White Matter ◽

Magnetic Resonance ◽

Ex Vivo ◽

Central Core ◽

Resonance Imaging ◽

Anatomic Study ◽

Neuronavigation System ◽

Fiber Dissection ◽

Dissection Technique

Abstract BACKGROUND: Different strategies have been used to study the fiber tract anatomy of the human brain in vivo and ex vivo. Nevertheless, the ideal method to study white matter anatomy has yet to be determined because it should integrate information obtained from multiple sources. OBJECTIVE: We developed an anatomic method in cadaveric specimens to study the central core of the cerebrum combining traditional white matter dissection with high-resolution 7-T magnetic resonance imaging (MRI) of the same specimen coregistered using a neuronavigation system. METHODS: Ten cerebral hemispheres were prepared using the traditional Klingler technique. Before dissection, a structural ultrahigh magnetic field 7-T MRI study was performed on each hemisphere specifically prepared with surface fiducials for neuronavigation. The dissection was then performed from the medial hemispheric surface using the classic white fiber dissection technique. During each step of the dissection, the correlation between the anatomic findings and the 7-T MRI was evaluated with the neuronavigation system. RESULTS: The anatomic study was divided in 2 stages: diencephalic and limbic. The diencephalic stage included epithalamic, thalamic, hypothalamic, and subthalamic components. The limbic stage consisted of extending the dissection to complete the Papez circuit. The detailed information given by the combination of both methods allowed us to identify and validate the position of fibers that may be difficult to appreciate and dissect (ie, the medial forebrain bundle). CONCLUSION: The correlation of high-definition 7-T MRI and the white matter dissection technique with neuronavigation significantly improves the understanding of the structural connections in complex areas of the human cerebrum.

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THE METABOLISM OF NORMAL BRAIN AND HUMAN GLIOMAS IN RELATION TO CELL TYPE AND DENSITY

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o55-052 ◽

1955 ◽

Vol 33 (3) ◽

pp. 395-403 ◽

Cited By ~ 37

Author(s):

Irving H. Heller ◽

K. A. C. Elliott

Keyword(s):

Cerebral Cortex ◽

White Matter ◽

Brain Tumors ◽

Corpus Callosum ◽

Oxygen Uptake ◽

Glial Cells ◽

Cerebellar Cortex ◽

Unit Weight ◽

Uptake Rates ◽

The Brain

Per unit weight, cerebral and cerebellar cortex respire much more actively than corpus callosum. The rate per cell nucleus is highest in cerebral cortex, lower in corpus callosum, and still lower in cerebellar cortex. The oxygen uptake rates of the brain tumors studied, with the exception of an oligodendroglioma, were about the same as that of white matter on the weight basis but lower than that of cerebral cortex or white matter on the cell basis. In agreement with previous work, an oligodendroglioma respired much more actively than the other tumors. The rates of glycolysis of the brain tumors per unit weight were low but, relative to their respiration rate, glycolysis was higher than in normal gray or white matter. Consideration of the figures obtained leads to the following tentative conclusions: Glial cells of corpus callosum respire more actively than the neurons of the cerebellar cortex. Neurons of the cerebral cortex respire on the average much more actively than neurons of the cerebellar cortex or glial cells. Considerably more than 70% of the oxygen uptake by cerebral cortex is due to neurons. The oxygen uptake rates of normal oligodendroglia and astrocytes are probably about the same as the rates found per nucleus in an oligodendroglioma and in astrocytomas; oligodendroglia respire much more actively than astrocytes.

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A higher proportion of ermin-immunopositive oligodendrocytes in areas of remyelination

PLoS ONE ◽

10.1371/journal.pone.0256155 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0256155

Author(s):

Intakhar Ahmad ◽

Stig Wergeland ◽

Eystein Oveland ◽

Lars Bø

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Corpus Callosum ◽

Mouse Model ◽

Grey Matter ◽

Early Stage ◽

Relative Proportion ◽

Normal Appearing White Matter ◽

The Brain

Incomplete remyelination is frequent in multiple sclerosis (MS)-lesions, but there is no established marker for recent remyelination. We investigated the role of the oligodendrocyte/myelin protein ermin in de- and remyelination in the cuprizone (CPZ) mouse model, and in MS. The density of ermin+ oligodendrocytes in the brain was significantly decreased after one week of CPZ exposure (p < 0.02). The relative proportion of ermin+ cells compared to cells positive for the late-stage oligodendrocyte marker Nogo-A increased at the onset of remyelination in the corpus callosum (p < 0.02). The density of ermin-positive cells increased in the corpus callosum during the CPZ-phase of extensive remyelination (p < 0.0001). In MS, the density of ermin+ cells was higher in remyelinated lesion areas compared to non-remyelinated areas both in white- (p < 0.0001) and grey matter (p < 0.0001) and compared to normal-appearing white matter (p < 0.001). Ermin immunopositive cells in MS-lesions were not immunopositive for the early-stage oligodendrocyte markers O4 and O1, but a subpopulation was immunopositive for Nogo-A. The data suggest a relatively higher proportion of ermin immunopositivity in oligodendrocytes compared to Nogo-A indicates recent or ongoing remyelination.

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On the microstructural origin of brain white matter hydraulic permeability

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2105328118 ◽

2021 ◽

Vol 118 (36) ◽

pp. e2105328118

Author(s):

Marco Vidotto ◽

Andrea Bernardini ◽

Marco Trovatelli ◽

Elena De Momi ◽

Daniele Dini

Keyword(s):

White Matter ◽

Corpus Callosum ◽

Drug Transport ◽

Three Dimensional ◽

Principal Component ◽

Hydraulic Permeability ◽

Convection Enhanced Delivery ◽

Brain White Matter ◽

Significant Difference ◽

The Brain

Brain microstructure plays a key role in driving the transport of drug molecules directly administered to the brain tissue, as in Convection-Enhanced Delivery procedures. The proposed research analyzes the hydraulic permeability of two white matter (WM) areas (corpus callosum and fornix) whose three-dimensional microstructure was reconstructed starting from the acquisition of electron microscopy images. We cut the two volumes with 20 equally spaced planes distributed along two perpendicular directions, and, on each plane, we computed the corresponding permeability vector. Then, we considered that the WM structure is mainly composed of elongated and parallel axons, and, using a principal component analysis, we defined two principal directions, parallel and perpendicular, with respect to the axons’ main direction. The latter were used to define a reference frame onto which the permeability vectors were projected to finally obtain the permeability along the parallel and perpendicular directions. The results show a statistically significant difference between parallel and perpendicular permeability, with a ratio of about two in both the WM structures analyzed, thus demonstrating their anisotropic behavior. Moreover, we find a significant difference between permeability in corpus callosum and fornix, which suggests that the WM heterogeneity should also be considered when modeling drug transport in the brain. Our findings, which demonstrate and quantify the anisotropic and heterogeneous character of the WM, represent a fundamental contribution not only for drug-delivery modeling, but also for shedding light on the interstitial transport mechanisms in the extracellular space.

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Anatomy of the Anterior Temporal Lobe and the Frontotemporal Region Demonstrated by Fiber Dissection

Neurosurgery ◽

10.1227/01.neu.0000140843.62311.24 ◽

2004 ◽

Vol 55 (5) ◽

pp. 1174-1184 ◽

Cited By ~ 74

Author(s):

Diedrik Peuskens ◽

Johannes van Loon ◽

Frank Van Calenbergh ◽

Raymond van den Bergh ◽

Jan Goffin ◽

...

Keyword(s):

White Matter ◽

Temporal Lobe ◽

Anterior Commissure ◽

Three Dimensional ◽

Dimensional Structure ◽

Surgical Approaches ◽

Anterior Temporal Lobe ◽

White Matter Tracts ◽

Fiber Dissection ◽

Dissection Technique

Abstract OBJECTIVE: The white matter structure of the anterior temporal lobe and the frontotemporal region is complex and not well appreciated from the available neurosurgical literature. The fiber dissection method is an excellent means of attaining a thorough knowledge of the three-dimensional structure of the white matter tracts. This study was performed to demonstrate the usefulness of the dissection technique in understanding the white matter anatomy and the effects of current surgical approaches on the subcortical structure of the region. METHODS: Seventeen brain specimens obtained at routine autopsy were dissected by use of Klingler's fiber dissection technique after preparation by fixation and freezing. The dissections were performed with an operating microscope and followed a stepwise pattern of progressive white matter dissection. RESULTS: The dissection is described in an orderly fashion showing the white matter tracts of the anterior temporal lobe and the frontotemporal region. An insight is gained into the three-dimensional course of the anterior loop of the optic radiation, the temporal stem, the anterior commissure, and the ansa peduncularis. CONCLUSION: The anterior temporal lobe and the frontotemporal region contain several important white matter tracts that can be uniquely understood by performing a white matter dissection of the region. Surgical procedures on the anterior temporal lobe differ substantially as to their repercussions on the subcortical white matter tract anatomy, as shown by the findings in this study.

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Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

Operative Neurosurgery ◽

10.1227/neu.0000000000000704 ◽

2015 ◽

Vol 11 (2) ◽

pp. 274-305 ◽

Cited By ~ 25

Author(s):

Kaan Yagmurlu ◽

Alexander L Vlasak ◽

Albert L Rhoton

Keyword(s):

Three Dimensional ◽

Central Core ◽

3 Dimensional ◽

Fiber Tracts ◽

Nuclear Masses ◽

Fiber Dissection ◽

Dissection Technique ◽

Human Brains ◽

The Brain ◽

Formalin Fixed

Abstract BACKGROUND The fiber tracts of the cerebrum may be a more important determinant of resection limits than the cortex. Better knowledge of the 3-dimensional (3-D) anatomic organization of the fiber pathways is important in planning safe and accurate surgery for lesions within the cerebrum. OBJECTIVE To examine the topographic anatomy of fiber tracts and subcortical gray matter of the human cerebrum and their relationships with consistent cortical, ventricular, and nuclear landmarks. METHODS Twenty-five formalin-fixed human brains and 4 whole cadaveric heads were examined by fiber dissection technique and ×6 to ×40 magnification. The fiber tracts and central core structures, including the insula and basal ganglia, were examined and their relationships captured in 3-D photography. The depth between the surface of the cortical gyri and selected fiber tracts was measured. RESULTS The topographic relationships of the important association, projection, and commissural fasciculi within the cerebrum and superficial cortical landmarks were identified. Important landmarks with consistent relationships to the fiber tracts were the cortical gyri and sulci, limiting sulci of the insula, nuclear masses in the central core, and lateral ventricles. The fiber tracts were also organized in a consistent pattern in relation to each other. The anatomic findings are briefly compared with functional data from clinicoradiological analysis and intraoperative stimulation of fiber tracts. CONCLUSION An understanding of the 3-D anatomic organization of the fiber tracts of the brain is essential in planning safe and accurate cerebral surgery.

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Physical activity, aerobic fitness and brain white matter: their role for executive functions in adolescence

10.1101/674846 ◽

2019 ◽

Author(s):

Ilona Ruotsalainen ◽

Tetiana Gorbach ◽

Jaana Perkola ◽

Ville Renvall ◽

Heidi J. Syväoja ◽

...

Keyword(s):

Physical Activity ◽

Working Memory ◽

White Matter ◽

Corpus Callosum ◽

Executive Functions ◽

Fractional Anisotropy ◽

Aerobic Fitness ◽

The Body ◽

The Relationship ◽

The Brain

AbstractPhysical activity and exercise beneficially link to brain properties and cognitive functions in older adults, but it is unclear how these results generalise to other age groups. During adolescence, the brain undergoes significant changes, which are especially pronounced in white matter. Existing studies provide contradictory evidence regarding the influence of physical activity or aerobic-exercise on executive functions in youth. Little is also known about the link between both aerobic fitness and physical activity with white matter during puberty. For this reason, we investigated the connection between both aerobic fitness (20-m shuttle run) and physical activity (moderate-to-vigorous intensity physical activity) with white matter in 59 adolescents (12.7–16.2 years). We further determined whether white matter interacts with the connection of fitness or physical activity with three core executive functions (sustained attention, spatial working memory and response inhibition). Our results showed that only the level of aerobic fitness, but not of physical activity was related to white matter properties. Furthermore, the white matter of specific tracts also moderated the links of aerobic fitness and physical activity with working memory. Our results suggest that aerobic fitness and physical activity have an unequal contribution to the properties of white matter in adolescent brains. We propose that the differences in white matter properties could underlie the variations in the relationship between either physical activity or aerobic fitness with working memory.HighlightsAerobic fitness level, but not physical activity, is associated with white matter properties in several white matter tracts in the brain.The relationship between aerobic fitness and working memory was moderated by fractional anisotropy of the body of corpus callosum and in the right superior corona radiata.The relationship between physical activity and working memory was moderated by fractional anisotropy of the body and genu of corpus callosum.

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Twenty-First Birthday Drinking: Extreme Drinking Episodes and White Matter Microstructural Changes in the Fornix and Corpus Callosum

10.31234/osf.io/c8tyv ◽

2019 ◽

Author(s):

Cassandra L. Boness ◽

Ozlem Korucuoglu ◽

Jarrod M Ellingson ◽

Anne M. Merrill ◽

Yoanna E. McDowell ◽

...

Keyword(s):

White Matter ◽

Corpus Callosum ◽

Cognitive Deficits ◽

Heavy Drinking ◽

Alcohol Exposure ◽

The Body ◽

High Dose ◽

Birthday Celebration ◽

Brain Changes ◽

The Brain

Twenty-first birthday drinking is characterized by extreme alcohol consumption. Accumulating evidence suggests that high-dose bingeing is related to structural brain changes and cognitive deficits. This is particularly problematic in the transition from adolescence to adulthood when the brain is still maturing, elevating the brain’s sensitivity to the acute effects of alcohol intoxication. Heavy drinking is associated with reduced structural integrity in the hippocampus and corpus callosum and is accompanied by cognitive deficits. However, there is little research examining changes in the human brain related to discrete heavy drinking episodes. The present study investigated whether alcohol exposure during a 21st birthday celebration would result in changes to white matter microstructure by utilizing Diffusion Tensor Imaging (DTI) measures and a quasi-experimental design. By examining structural changes in the brain from pre- to post-celebration within subjects (N = 49) prospectively, we were able to more directly observe brain changes following an extreme drinking episode. Region of interest analyses demonstrated increased fractional anisotropy (FA) in the posterior fornix (p < 0.0001) and in the body of the corpus callosum (p = 0.0029) from pre- to post-birthday celebration. These results suggest acute white matter damage to the fornix and corpus callosum following an extreme drinking episode, which is especially problematic during continued neurodevelopment. Twenty-first birthday drinking may, therefore, be considered an important target event for preventing acute brain injury in young adults.

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