Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

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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Internal structure of the cerebral hemispheres: an introduction of fiber dissection technique

Arquivos de Neuro-Psiquiatria ◽

10.1590/s0004-282x2005000200011 ◽

2005 ◽

Vol 63 (2a) ◽

pp. 252-258 ◽

Cited By ~ 12

Author(s):

Igor de Castro ◽

Daniel de Holanda Christoph ◽

Daniel Paes dos Santos ◽

José Alberto Landeiro

Keyword(s):

Three Dimensional ◽

Medial Aspect ◽

Lateral Aspect ◽

Critical Pathways ◽

Brain Hemispheres ◽

The Central Nervous System ◽

Fiber Dissection ◽

Dissection Technique ◽

The Brain ◽

Neuroimaging Techniques

The aim of this study is to introduce the fiber dissection technique and its importance in the comprehension of the three-dimensional intrinsic anatomy of the brain. A total of twenty brain hemispheres were dissected. Using Kingler's technique we demonstrated the intrinsic structures of the brain. The supra lateral aspect of the brain as well as the medial aspect were presented. The most important fiber systems were demonstrated. The use and comprehension of new neuroimaging techniques demand a better understanding of this fascinating anatomy. The knowledge acquired with this technique will improve our understanding of critical pathways of the central nervous system.

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Deciphering the frontostriatal circuitry through the fiber dissection technique: direct structural evidence on the morphology and axonal connectivity of the fronto-caudate tract

Journal of Neurosurgery ◽

10.3171/2020.7.jns201287 ◽

2021 ◽

pp. 1-13

Author(s):

Spyridon Komaitis ◽

Christos Koutsarnakis ◽

Evgenia Lani ◽

Theodosis Kalamatianos ◽

Evangelos Drosos ◽

...

Keyword(s):

Diffusion Tensor ◽

Anterior Part ◽

Relevant Literature ◽

The Body ◽

Fiber Tracts ◽

Brodmann Areas ◽

Fiber Dissection ◽

Dissection Technique ◽

Subcortical Pathway ◽

Formalin Fixed

OBJECTIVEThe authors sought to investigate the very existence and map the topography, morphology, and axonal connectivity of a thus far ill-defined subcortical pathway known as the fronto-caudate tract (FCT) since there is a paucity of direct structural evidence regarding this pathway in the relevant literature.METHODSTwenty normal adult cadaveric formalin-fixed cerebral hemispheres (10 left and 10 right) were explored through the fiber microdissection technique. Lateral to medial and medial to lateral dissections were carried out in a tandem manner in all hemispheres. Attention was focused on the prefrontal area and central core since previous diffusion tensor imaging studies have recorded the tract to reside in this territory.RESULTSIn all cases, the authors readily identified the FCT as a fan-shaped pathway lying in the most medial layer of the corona radiata and traveling across the subependymal plane before terminating on the superolateral margin of the head and anterior part of the body of the caudate nucleus. The FCT could be adequately differentiated from adjacent fiber tracts and was consistently recorded to terminate in Brodmann areas 8, 9, 10, and 11 (anterior pre–supplementary motor area and the dorsolateral, frontopolar, and fronto-orbital prefrontal cortices). The authors were also able to divide the tract into a ventral and a dorsal segment according to the respective topography and connectivity observed. Hemispheric asymmetries were not observed, but instead the authors disclosed asymmetry within the FCT, with the ventral segment always being thicker and bulkier than the dorsal one.CONCLUSIONSBy using the fiber microdissection technique, the authors provide sound structural evidence on the topography, morphology, and connectional anatomy of the FCT as a distinct part of a wider frontostriatal circuitry. The findings are in line with the tract’s putative functional implications in high-order motor and behavioral processes and can potentially inform current surgical practice in the fields of neuro-oncology and functional neurosurgery.

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

ARS Medica Tomitana ◽

10.2478/arsm-2014-0021 ◽

2015 ◽

Vol 20 (3) ◽

pp. 115-122 ◽

Cited By ~ 1

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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The anatomy of Meyer's loop revisited: changing the anatomical paradigm of the temporal loop based on evidence from fiber microdissection

Journal of Neurosurgery ◽

10.3171/2014.12.jns14281 ◽

2015 ◽

Vol 122 (6) ◽

pp. 1253-1262 ◽

Cited By ~ 24

Author(s):

Cristina Goga ◽

Uğur Türe

Keyword(s):

Internal Capsule ◽

Temporal Region ◽

Optic Radiation ◽

Anterior Portion ◽

Anterior Extension ◽

Fiber Dissection ◽

Dissection Technique ◽

Meyer’S Loop ◽

Human Brains ◽

Formalin Fixed

OBJECT The goal in this study was to explore and further refine comprehension of the anatomical features of the temporal loop, known as Meyer's loop. METHODS The lateral and inferior aspects of 20 previously frozen, formalin-fixed human brains were dissected under the operating microscope by using fiber microdissection. RESULTS A loop of the fibers in the anterior temporal region was clearly demonstrated in all dissections. This temporal loop, or Meyer's loop, is commonly known as the anterior portion of the optic radiation. Fiber microdissection in this study, however, revealed that various projection fibers that emerge from the sublentiform portion of the internal capsule (IC-SL), which are the temporopontine fibers, occipitopontine fibers, and the posterior thalamic peduncle (which includes the optic radiation), participate in this temporal loop and become a part of the sagittal stratum. No individual optic radiation fibers could be differentiated in the temporal loop. The dissections also disclosed that the anterior extension and angulation of the temporal loop vary significantly. CONCLUSIONS The fiber microdissection technique provides clear evidence that a loop in the anterior temporal region exists, but that this temporal loop is not formed exclusively by the optic radiation. Various projection fibers of the IC-SL, of which the optic radiation is only one of the several components, display this common course. The inherent limitations of the fiber dissection technique preclude accurate differentiation among individual fibers of the temporal loop, such as the optic radiation fibers.

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Three-Dimensional Microsurgical Anatomy and the Safe Entry Zones of the Brainstem

Operative Neurosurgery ◽

10.1227/neu.0000000000000466 ◽

2014 ◽

Vol 10 (4) ◽

pp. 602-620 ◽

Cited By ~ 45

Author(s):

Kaan Yagmurlu ◽

Albert L. Rhoton ◽

Necmettin Tanriover ◽

Jeffrey A. Bennett

Keyword(s):

Cranial Nerves ◽

Three Dimensional ◽

Surface Structures ◽

Microsurgical Anatomy ◽

Entry Zone ◽

3 Dimensional ◽

Cerebellar Peduncles ◽

Fiber Dissection ◽

Dissection Techniques ◽

Dissection Technique

Abstract BACKGROUND: There have been no studies of the structure and safe surgical entry zones of the brainstem based on fiber dissection studies combined with 3-dimensional (3-D) photography. OBJECTIVE: To examine the 3-D internal architecture and relationships of the proposed safe entry zones into the midbrain, pons, and medulla. METHODS: Fifteen formalin and alcohol-fixed human brainstems were dissected by using fiber dissection techniques, ×6 to ×40 magnification, and 3-D photography to define the anatomy and the safe entry zones. The entry zones evaluated were the perioculomotor, lateral mesencephalic sulcus, and supra- and infracollicular areas in the midbrain; the peritrigeminal zone, supra- and infrafacial approaches, acoustic area, and median sulcus above the facial colliculus in the pons; and the anterolateral, postolivary, and dorsal medullary sulci in the medulla. RESULTS: The safest approach for lesions located below the surface is usually the shortest and most direct route. Previous studies have often focused on surface structures. In this study, the deeper structures that may be at risk in each of the proposed safe entry zones plus the borders of each entry zone were defined. This study includes an examination of the relationships of the cerebellar peduncles, long tracts, intra-axial segments of the cranial nerves, and important nuclei of the brainstem to the proposed safe entry zones. CONCLUSION: Fiber dissection technique in combination with the 3-D photography is a useful addition to the goal of making entry into the brainstem more accurate and safe.

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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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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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Human brain organoids in Alzheimer’s disease

Organoid ◽

10.51335/organoid.2021.1.e5 ◽

2021 ◽

Vol 1 ◽

pp. e5

Author(s):

You Jung Kang ◽

Hansang Cho

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neuronal Damage ◽

Three Dimensional ◽

Neuronal Loss ◽

Model Systems ◽

Key Characteristics ◽

Brain Organoid ◽

Human Brains ◽

The Brain

Alzheimer’s disease (AD) is a progressive neurological disorder that typically involves neuronal damage leading to the deterioration of cognitive and essential body functions in aging brains. Major signatures of AD pathology include the deposition of amyloid plaques and neurofibrillary tangles, disruption of the blood-brain barrier, and induction of hyper-activated proinflammation in the brain, leading to synaptic impairment and neuronal loss. However, conventional pharmacotherapeutic modalities merely alleviate symptoms, but do not cure AD, partly because drug screening has used model systems with limited accuracy in terms of reflecting AD pathology in human brains. In this regard, several AD organoids have received substantial attention as alternatives to AD animal models. In this review, we summarize the key characteristics required for the generation of a pathologically relevant AD brain organoid. We also overview major experimental organoid models of AD brains, such as spheroids, three-dimensional (3D) bioprinted constructs, and 3D brain-on-chips, and discuss their strengths and weaknesses for AD research. This review will provide valuable information that will inspire future efforts to engineer authentic AD organoids for the study of AD pathology and for the discovery of novel AD therapeutic strategies.

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