scholarly journals Microsurgical anatomy of the inferior limiting insular sulcus and the temporal stem

2015 ◽  
Vol 122 (6) ◽  
pp. 1263-1273 ◽  
Author(s):  
Eduardo Carvalhal Ribas ◽  
Kaan Yagmurlu ◽  
Hung Tzu Wen ◽  
Albert L. Rhoton
Keyword(s):  
White Matter ◽  
Medial Temporal Lobe ◽  
Anterior Commissure ◽  
Internal Capsule ◽  
Microsurgical Anatomy ◽  
Uncinate Fasciculus ◽  
Fiber Tracts ◽  
Transsylvian Approach ◽  
Temporal Stem ◽  
Optic Radiations

OBJECT The purpose of this study was to describe the location of each white matter pathway in the area between the inferior limiting insular sulcus (ILS) and temporal horn that may be crossed in approaches through the temporal stem to the medial temporal lobe. METHODS The fiber tracts in 14 adult cadaveric cerebral hemispheres were examined using the Klingler technique. The fiber dissections were completed in a stepwise manner, identifying each white matter pathway in different planes and describing its position in relation to the anterior end of the ILS. RESULTS The short-association fibers from the extreme capsule, which continue toward the operculae, are the most superficial subcortical layer deep to the ILS. The external capsule fibers are found deeper at an intermediate layer and are formed by the uncinate fasciculus, inferior frontooccipital fasciculus, and claustrocortical fibers in a sequential anteroposterior disposition. The anterior commissure forms the next deeper layer, and the optic radiations in the sublenticular part of the internal capsule represent the deepest layer. The uncinate fasciculus is found deep to the anterior third of the ILS, whereas the inferior frontooccipital fasciculus and optic radiations are found superficial and deep, respectively, at the posterior two-thirds of this length. CONCLUSIONS The authors' findings suggest that in the transsylvian approach, a 6-mm incision beginning just posterior to the limen insula through the ILS will cross the uncinate fasciculus but not the inferior frontooccipital fasciculus or optic radiations, but that longer incisions carry a risk to language and visual functions.

Diffusion tensor tractography of the temporal stem on the inferior limiting sulcus

2008 ◽  
Vol 108 (4) ◽  
pp. 775-781 ◽  
Author(s):  
Feng Wang ◽  
Tao Sun ◽  
Xing-Gang Li ◽  
Na-Jia Liu
Keyword(s):  
White Matter ◽  
Diffusion Tensor ◽  
Anterior Commissure ◽  
Region Of Interest ◽  
Diffusion Tensor Tractography ◽  
Optic Radiation ◽  
Uncinate Fasciculus ◽  
White Matter Tracts ◽  
Temporal Horn ◽  
Temporal Stem

Object The aim of this study was to use diffusion tensor tractography (DTT) to define the 3D relationships of the uncinate fasciculus, anterior commissure, inferior occipitofrontal fasciculus, inferior thalamic peduncle, and optic radiation and to determine the positioning landmarks of these white matter tracts. Methods The anatomy was studied in 10 adult human brain specimens. Brain DTT was performed in 10 healthy volunteers. Diffusion tensor tractography images of the white matter tracts in the temporal stem were obtained using the simple single region of interest (ROI) and multi-ROIs based on the anatomical knowledge. Results The posteroinferior insular point is the anterior extremity of intersection of the Heschl gyrus and the inferior limiting sulcus. On the inferior limiting sulcus, this point is the posterior limit of the optic radiation, and the temporal stem begins at the limen insulae and ends at the posteroinferior insular point. The distance from the limen insulae to the tip of the temporal horn is just one third the length of the temporal stem. The uncinate fasciculus comprises the core of the anterior temporal stem, behind which the anterior commissure and the inferior thalamic peduncle are located, and they occupy the anterior third of the temporal stem. The inferior occipitofrontal fasciculus passes through the entire temporal stem. The most anterior extent of the Meyer loop is located between the anterior tip of the temporal horn and the limen insulae. Most of the optic radiation crosses the postmedian two thirds of the temporal stem. Conclusions On the inferior limiting sulcus, the posteroinferior insular point is a reliable landmark of the posterior limit of the optic radiations. The limen insulae, anterior tip of the temporal horn, and posteroinferior insular point may be used to localize the white matter fibers of the temporal stem in analyzing magnetic resonance imaging or during surgery.

Microsurgical Anatomy of the White Matter Tracts in Hemispherotomy

2014 ◽  
Vol 10 (2) ◽  
pp. 305-324 ◽  
Author(s):  
Baris Kucukyuruk ◽  
Kaan Yagmurlu ◽  
Necmettin Tanriover ◽  
Mustafa Uzan ◽  
Albert L. Rhoton
Keyword(s):  
White Matter ◽  
Anterior Commissure ◽  
Posterior Part ◽  
Internal Capsule ◽  
Epileptic Seizures ◽  
Microsurgical Anatomy ◽  
Subcortical Structures ◽  
Posterior Edge ◽  
White Matter Tracts ◽  
Posterior Limb

Abstract BACKGROUND: Hemispherotomy is a surgical procedure performed for refractory epileptic seizures due to wide hemispheric damage. OBJECTIVE: To describe the microanatomy of the white matter tracts transected in a hemispherotomy and the relationship of the surgical landmarks used during the intraventricular callosotomy. METHODS: The cortical and subcortical structures were examined in 32 hemispheres. RESULTS: Incision of the temporal stem along the inferior limiting sulcus crosses the insulo-opercular fibers, uncinate, inferior occipitofrontal and middle longitudinal fasciculi, anterior commissure, and optic and auditory radiations. The incision along the superior limiting sulcus transects insulo-opercular fibers and the genu and posterior limb of internal capsule. The incision along the anterior limiting sulcus crosses the insulo-opercular fibers, anterior limb of the internal capsule, anterior commissure, and the anterior thalamic bundle. The disconnection of the posterior part of the corpus callosum may be incomplete if the point at which the last cortical branch of the anterior cerebral artery (ACA) turns upward and disappears from the view through the intraventricular exposure is used as the landmark for estimating the posterior extent of the callosotomy. This ACA branch turns upward before reaching the posterior edge of the splenium in 85% of hemispheres. The falx, followed to the posterior edge of the splenium, is a more reliable landmark for completing the posterior part of an intraventricular callosotomy. CONCLUSION: The fiber tracts disconnected in hemispherotomy were reviewed. The falx is a more reliable guide than the ACA in completing the posterior part of the intraventricular callosotomy.

scholarly journals Microsurgical anatomy of the central core of the brain

2018 ◽  
Vol 129 (3) ◽  
pp. 752-769 ◽  
Author(s):  
Eduardo Carvalhal Ribas ◽  
Kaan Yağmurlu ◽  
Evandro de Oliveira ◽  
Guilherme Carvalhal Ribas ◽  
Albert Rhoton
Keyword(s):  
White Matter ◽  
Caudate Nucleus ◽  
Internal Capsule ◽  
Central Core ◽  
Surgical Approaches ◽  
Microsurgical Anatomy ◽  
Functional Importance ◽  
Posterior Portion ◽  
External Capsule ◽  
The Brain

OBJECTIVEThe purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels.METHODSThe authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci.RESULTSThe insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the “anterior perforated substance region.” The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core.CONCLUSIONSAs a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.

scholarly journals Aberrant White Matter Microstructure as a Potential Diagnostic Marker in Alzheimer’s Disease by Automated Fiber Quantification

2020 ◽  
Author(s):  
Haifeng Chen ◽  
Ruomeng Qin ◽  
Caimei Luo ◽  
Mengchun Li ◽  
Renyuan Liu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
Neurodegenerative Disorder ◽  
Local Level ◽  
Uncinate Fasciculus ◽  
Fiber Tracts ◽  
White Matter Microstructure ◽  
Potential Biomarker ◽  
Anterior Thalamic Radiation

Abstract Background: Alzheimer’s disease (AD) has been primarily considered a progressive neurodegenerative disorder of gray matter. Neuroimaging evidence has suggested white matter microstructure are also heavily affected in AD. However, whether white matter dysfunction are localized at the specific regions of fiber tracts and whether they would be a potential biomarker for AD remain unclear.Methods：By automated fiber quantification (AFQ), we applied diffusion tensor images from 25 healthy controls (HC), 24 amnestic mild cognitive impairment (aMCI) patients and 18 AD patients to create tract profiles along 16 major white matter fibers. We compared diffusion metrics [Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (DA) and radial diffusivity (DR)] at the global and local level of fiber tracts between groups. Partial correlation analyses were used to explore the associations between white matter changes and cognitive performance. To assess the diagnostic value, we enrolled the significantly altered diffusion metrics into a random forest (RF) classifier, a type of machine learning method.Results: In the global tract level, we found that aMCI and AD patients showed higher MD, DA and DR values in some fiber tracts mostly in the left hemisphere compared to HC. In the point-wise level, widespread disruption were distributed on specific locations of different tracts. The point-wise MD measurements presented the best classification performance with respect to differentiating AD from HC. The two most important variables were localized in the prefrontal potion of left uncinate fasciculus and anterior thalamic radiation. In addition, the point-wise DA in the posterior component of the left cingulum cingulate displayed the most robust discriminative ability to identify AD from aMCI. Conclusion：Our findings provide evidence that the left-sided microstructural integrity was vulnerable in white matter fiber tracts in AD. Furthermore, the frontal lobe portion of left uncinate fasciculus and anterior thalamic radiation and the posterior component of the left cingulum cingulate played the important role in the diagnosis and surveillance of AD. These results demonstrated the potential of white matter abnormalities as a diagnostic biomarker in AD.

scholarly journals Anterior peri-insular quadrantotomy: a cadaveric white matter dissection study

2020 ◽  
Vol 25 (4) ◽  
pp. 331-339
Author(s):  
Pablo Gonzalez-Lopez ◽  
Giulia Cossu ◽  
Etienne Pralong ◽  
Matias Baldoncini ◽  
Mahmoud Messerer ◽  
...  
Keyword(s):  
White Matter ◽  
Motor Cortex ◽  
Frontal Lobe ◽  
Anterior Commissure ◽  
Internal Capsule ◽  
The Body ◽  
White Matter Tracts ◽  
Precise Understanding ◽  
Fiber Dissection ◽  
Dissection Techniques

OBJECTIVEAnterior quadrant disconnection represents a safe surgical option in well-selected pediatric patients with a large frontal lobe lesion anterior to the motor cortex. The understanding of the anatomy of the white matter tracts connecting the frontal lobe with the rest of the cerebrum forms the basis of a safe and successful disconnective surgery. The authors explored and illustrated the relevant white matter tracts sectioned during each surgical step using fiber dissection techniques.METHODSFive human cadaveric hemispheres were dissected to illustrate the frontal connections in the 3 planes. The dissections were performed from lateral to medial, medial to lateral, and ventral to dorsal to describe the various tracts sectioned during the 4 steps of this surgery, namely the anterior suprainsular window, intrafrontal disconnection, anterior callosotomy, and frontobasal disconnection.RESULTSAt the beginning of each surgical step, the U fibers were cut. During the anterior suprainsular window, the superior longitudinal fasciculus (SLF), the uncinate fasciculus, and the inferior fronto-occipital fasciculus (IFOF) were visualized and sectioned, followed by sectioning of the anterior limb of the internal capsule. During the intrafrontal disconnection, the SLF was cut, along with the corona radiata. At the medial surface the cingulum was sectioned. The anterior callosotomy disconnected the anterior third of the body of the callosum, the genu, and the rostrum. The frontobasal disconnection addressed the last remaining fibers connecting the frontal lobe with the rest of the hemisphere, namely the anterior limb of the anterior commissure.CONCLUSIONSThe anterior peri-insular quadrantotomy aims at effectively treating children with large lesions of the frontal lobe anterior to the motor cortex. A precise understanding of the gyral anatomy of this lobe along with the several white matter connections is crucial to avoid motor complications and to ensure complete disconnection.

scholarly journals Mechanism of White Matter Injury and Promising Therapeutic Strategies of MSCs After Intracerebral Hemorrhage

2021 ◽  
Vol 13 ◽  
Author(s):  
Jing Li ◽  
Linglong Xiao ◽  
Dian He ◽  
Yunhao Luo ◽  
Haitao Sun
Keyword(s):  
White Matter ◽  
Intracerebral Hemorrhage ◽  
Corticospinal Tract ◽  
Biological Effects ◽  
Internal Capsule ◽  
Therapeutic Strategies ◽  
White Matter Injury ◽  
Fiber Tracts ◽  
Predilection Site ◽  
Regenerative Repair

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke with high disability and high mortality rates, and there is no effective treatment. The predilection site of ICH is in the area of the basal ganglia and internal capsule (IC), where exist abundant white matter (WM) fiber tracts, such as the corticospinal tract (CST) in the IC. Proximal or distal white matter injury (WMI) caused by intracerebral parenchymal hemorrhage is closely associated with poor prognosis after ICH, especially motor and sensory dysfunction. The pathophysiological mechanisms involved in WMI are quite complex and still far from clear. In recent years, the neuroprotection and repairment capacity of mesenchymal stem cells (MSCs) has been widely investigated after ICH. MSCs exert many unique biological effects, including self-recovery by producing growth factors and cytokines, regenerative repair, immunomodulation, and neuroprotection against oxidative stress, providing a promising cellular therapeutic approach for the treatment of WMI. Taken together, our goal is to discuss the characteristics of WMI following ICH, including the mechanism and potential promising therapeutic targets of MSCs, aiming at providing new clues for future therapeutic strategies.

scholarly journals The white matter tracts of the cerebrum in ventricular surgery and hydrocephalus

2017 ◽  
Vol 126 (3) ◽  
pp. 945-971 ◽  
Author(s):  
Abuzer Güngör ◽  
Serhat Baydin ◽  
Erik H. Middlebrooks ◽  
Necmettin Tanriover ◽  
Cihan Isler ◽  
...  
Keyword(s):  
White Matter ◽  
Anterior Commissure ◽  
Internal Capsule ◽  
Surgical Approaches ◽  
White Matter Tracts ◽  
Lateral Ventricles ◽  
Fiber Dissection ◽  
Dissection Technique ◽  
Relationship Of ◽  
The Relationship

OBJECTIVE The relationship of the white matter tracts to the lateral ventricles is important when planning surgical approaches to the ventricles and in understanding the symptoms of hydrocephalus. The authors' aim was to explore the relationship of the white matter tracts of the cerebrum to the lateral ventricles using fiber dissection technique and MR tractography and to discuss these findings in relation to approaches to ventricular lesions. METHODS Forty adult human formalin-fixed cadaveric hemispheres (20 brains) and 3 whole heads were examined using fiber dissection technique. The dissections were performed from lateral to medial, medial to lateral, superior to inferior, and inferior to superior. MR tractography showing the lateral ventricles aided in the understanding of the 3D relationships of the white matter tracts with the lateral ventricles. RESULTS The relationship between the lateral ventricles and the superior longitudinal I, II, and III, arcuate, vertical occipital, middle longitudinal, inferior longitudinal, inferior frontooccipital, uncinate, sledge runner, and lingular amygdaloidal fasciculi; and the anterior commissure fibers, optic radiations, internal capsule, corona radiata, thalamic radiations, cingulum, corpus callosum, fornix, caudate nucleus, thalamus, stria terminalis, and stria medullaris thalami were defined anatomically and radiologically. These fibers and structures have a consistent relationship to the lateral ventricles. CONCLUSIONS Knowledge of the relationship of the white matter tracts of the cerebrum to the lateral ventricles should aid in planning more accurate surgery for lesions within the lateral ventricles.

Surgical Approaches to the Temporal Horn: An Anatomic Analysis of White Matter Tract Interruption

2016 ◽  
Vol 13 (2) ◽  
pp. 258-270 ◽  
Author(s):  
Paulo A. S. Kadri ◽  
Jean G. de Oliveira ◽  
Niklaus Krayenbühl ◽  
Uğur Türe ◽  
Evandro P. L. de Oliveira ◽  
...  
Keyword(s):  
White Matter ◽  
Anterior Commissure ◽  
Anterior Segment ◽  
Clinical Manifestations ◽  
Fiber Bundles ◽  
Surgical Approaches ◽  
Middle Temporal Gyrus ◽  
Uncinate Fasciculus ◽  
Middle Temporal ◽  
Temporal Horn

Abstract BACKGROUND: Surgical access to the temporal horn is necessary to treat tumors and vascular lesions, but is used mainly in patients with mediobasal temporal epilepsy. The surgical approaches to this cavity fall into 3 primary categories: lateral, inferior, and transsylvian. The current neurosurgical literature has underestimated the interruption of involved fiber bundles and the correlated clinical manifestations. OBJECTIVE: To delineate the interruption of fiber bundles during the different approaches to the temporal horn. METHODS: We simulated the lateral (trans-middle temporal gyrus), inferior (transparahippocampal gyrus), and transsylvian approaches in 20 previously frozen, formalin-fixed human brains (40 hemispheres). Fiber dissection was then done along the lateral and inferior aspects under the operating microscope. Each stage of dissection and its respective fiber tract interruption were defined. RESULTS: The lateral (trans-middle temporal gyrus) approach interrupted “U” fibers, the superior longitudinal fasciculus (inferior arm), occipitofrontal fasciculus (ventral segment), uncinate fasciculus (dorsolateral segment), anterior commissure (posterior segment), temporopontine, inferior thalamic peduncle (posterior fibers), posterior thalamic peduncle (anterior portion), and tapetum fibers. The inferior (transparahippocampal gyrus) approach interrupted “U” fibers, the cingulum (inferior arm), and fimbria, and transected the hippocampal formation. The transsylvian approach interrupted “U” fibers (anterobasal region of the extreme capsule), the uncinate fasciculus (ventromedial segment), and anterior commissure (anterior segment), and transected the anterosuperior aspect of the amygdala. CONCLUSION: White matter dissection improves our knowledge of the complex anatomy surrounding the temporal horn. Identifying the fiber bundles at risk during each surgical approach adds important information for choosing the appropriate surgical strategy.

scholarly journals Ethnicity-Dependent Effects of Schizophrenia Risk Variants of the OLIG2 Gene on OLIG2 Transcription and White Matter Integrity

2020 ◽  
Vol 46 (6) ◽  
pp. 1619-1628
Author(s):  
Hiroshi Komatsu ◽  
Hikaru Takeuchi ◽  
Yoshie Kikuchi ◽  
Chiaki Ono ◽  
Zhiqian Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
White Matter ◽  
Diffusion Tensor ◽  
Internal Capsule ◽  
Postmortem Brain ◽  
Nucleotide Polymorphisms ◽  
Posterior Limb ◽  
Fiber Tracts ◽  
Dorsolateral Prefrontal ◽  
The Right

Abstract Previous studies have indicated associations between several OLIG2 gene single-nucleotide polymorphisms (SNPs) and susceptibility to schizophrenia among Caucasians. Consistent with these findings, postmortem brain and diffusion tensor imaging studies have indicated that the schizophrenia-risk-associated allele (A) in the OLIG2 SNP rs1059004 predicts lower OLIG2 gene expression in the dorsolateral prefrontal cortex (DLPFC) of schizophrenia patients and reduced white matter (WM) integrity of the corona radiata in normal brains among Caucasians. In an effort to replicate the association between this variant and WM integrity among healthy Japanese, we found that the number of A alleles was positively correlated with WM integrity in some fiber tracts, including the right posterior limb of the internal capsule, and with mean blood flow in a widespread area, including the inferior frontal operculum, orbital area, and triangular gyrus. Because the A allele affected WM integrity in opposite directions in Japanese and Caucasians, we investigated a possible association between the OLIG2 gene SNPs and the expression level of OLIG2 transcripts in postmortem DLPFCs. We evaluated rs1059004 and additional SNPs in the 5′ upstream and 3′ downstream regions of rs1059004 to cover the broader region of the OLIG2 gene. The 2 SNPs (rs1059004 and rs9653711) had opposite effects on OLIG2 gene expression in the DLPFC in Japanese and Caucasians. These findings suggest ethnicity-dependent opposite effects of OLIG2 gene SNPs on WM integrity and OLIG2 gene expression in the brain, which may partially explain the failures in replicating associations between genetic variants and psychiatric phenotypes among ethnicities.

scholarly journals The Three-Dimensional Architecture of the Internal Capsule of the Human Brain Demonstrated by Fiber Dissection Technique

2015 ◽  
Vol 20 (3) ◽  
pp. 115-122 ◽  
Author(s):  
Goga Cristina ◽  
Brinzaniuc Klara ◽  
Florian I.S. ◽  
Rodriguez Mena R.
Keyword(s):  
White Matter ◽  
Three Dimensional ◽  
Internal Capsule ◽  
Brain Anatomy ◽  
Neurosurgical Procedures ◽  
Fiber Tracts ◽  
Fiber Dissection ◽  
White Matter Fiber Tracts ◽  
Three Dimensional Configuration ◽  
Dissection Technique

Abstract The fiber dissection technique involves peeling away white matter fiber tracts of the brain to display its three-dimensional anatomic arrangement. The intricate three-dimensional configuration and structure of the internal capsule (IC) is not well defined. By using the fiber dissection technique, our aim was to expose and study the IC to achieve a clearer conception of its configuration and relationships with neighboring white matter fibers and central nuclei. The lateral and medial aspects of the temporal lobes of twenty, previously frozen, formalin-fixed human brains were dissected under the operating microscope using the fiber dissection technique. The details of the three-dimensional arrangement of the fibers within the IC were studied and a comprehensive understanding of their relations was achieved. The white matter fiber dissection provides an enhanced perspective of the intricate architecture of the internal structure of brain. This enhanced understanding of intrinsic brain anatomy, particularly of functional highly relevant fiber systems such as the internal capsule, is essential for performing modern neurosurgical procedures.

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