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Makris N, Rushmore R, Kaiser J, Albaugh M, Kubicki M, Rathi Y, Zhang F, O’Donnell LJ, Yeterian E, Caviness VS, Kennedy DN. A Proposed Human Structural Brain Connectivity Matrix in the Center for Morphometric Analysis Harvard-Oxford Atlas Framework: A Historical Perspective and Future Direction for Enhancing the Precision of Human Structural Connectivity with a Novel Neuroanatomical Typology. Dev Neurosci 2023; 45:161-180. [PMID: 36977393 PMCID: PMC10526721 DOI: 10.1159/000530358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
A complete structural definition of the human nervous system must include delineation of its wiring diagram (e.g., Swanson LW. Brain architecture: understanding the basic plan, 2012). The complete formulation of the human brain circuit diagram (BCD [Front Neuroanat. 2020;14:18]) has been hampered by an inability to determine connections in their entirety (i.e., not only pathway stems but also origins and terminations). From a structural point of view, a neuroanatomic formulation of the BCD should include the origins and terminations of each fiber tract as well as the topographic course of the fiber tract in three dimensions. Classic neuroanatomical studies have provided trajectory information for pathway stems and their speculative origins and terminations [Dejerine J and Dejerine-Klumpke A. Anatomie des Centres Nerveux, 1901; Dejerine J and Dejerine-Klumpke A. Anatomie des Centres Nerveux: Méthodes générales d'étude-embryologie-histogénèse et histologie. Anatomie du cerveau, 1895; Ludwig E and Klingler J. Atlas cerebri humani, 1956; Makris N. Delineation of human association fiber pathways using histologic and magnetic resonance methodologies; 1999; Neuroimage. 1999 Jan;9(1):18-45]. We have summarized these studies previously [Neuroimage. 1999 Jan;9(1):18-45] and present them here in a macroscale-level human cerebral structural connectivity matrix. A matrix in the present context is an organizational construct that embodies anatomical knowledge about cortical areas and their connections. This is represented in relation to parcellation units according to the Harvard-Oxford Atlas neuroanatomical framework established by the Center for Morphometric Analysis at Massachusetts General Hospital in the early 2000s, which is based on the MRI volumetrics paradigm of Dr. Verne Caviness and colleagues [Brain Dev. 1999 Jul;21(5):289-95]. This is a classic connectional matrix based mainly on data predating the advent of DTI tractography, which we refer to as the "pre-DTI era" human structural connectivity matrix. In addition, we present representative examples that incorporate validated structural connectivity information from nonhuman primates and more recent information on human structural connectivity emerging from DTI tractography studies. We refer to this as the "DTI era" human structural connectivity matrix. This newer matrix represents a work in progress and is necessarily incomplete due to the lack of validated human connectivity findings on origins and terminations as well as pathway stems. Importantly, we use a neuroanatomical typology to characterize different types of connections in the human brain, which is critical for organizing the matrices and the prospective database. Although substantial in detail, the present matrices may be assumed to be only partially complete because the sources of data relating to human fiber system organization are limited largely to inferences from gross dissections of anatomic specimens or extrapolations of pathway tracing information from nonhuman primate experiments [Front Neuroanat. 2020;14:18, Front Neuroanat. 2022;16:1035420, and Brain Imaging Behav. 2021;15(3):1589-1621]. These matrices, which embody a systematic description of cerebral connectivity, can be used in cognitive and clinical studies in neuroscience and, importantly, to guide research efforts for further elucidating, validating, and completing the human BCD [Front Neuroanat. 2020;14:18].
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Affiliation(s)
- Nikos Makris
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Richard Rushmore
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA
| | - Jonathan Kaiser
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - Matthew Albaugh
- Department of Psychiatry, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Marek Kubicki
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, USA
| | - Yogesh Rathi
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Psychiatry Neuroimaging Laboratory, Harvard Medical School, Brigham and Women’s Hospital, Boston, MA, USA
| | - Fan Zhang
- Department of Radiology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Lauren J. O’Donnell
- Department of Radiology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Edward Yeterian
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
- Department of Psychology, Colby College, Waterville, ME, USA
| | - Verne S. Caviness
- Center for Morphometric Analysis, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
| | - David N. Kennedy
- Department of Psychiatry, University of Massachusetts Chan Medical School, Worcester, MA, USA
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Charvet CJ. Mapping Human Brain Pathways: Challenges and Opportunities in the Integration of Scales. BRAIN, BEHAVIOR AND EVOLUTION 2023; 98:194-209. [PMID: 36972574 PMCID: PMC11310840 DOI: 10.1159/000530317] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/16/2023] [Indexed: 03/29/2023]
Abstract
The human brain is composed of a complex web of pathways. Diffusion magnetic resonance (MR) tractography is a neuroimaging technique that relies on the principle of diffusion to reconstruct brain pathways. Its tractography is broadly applicable to a range of problems as it is amenable for study in individuals of any age and from any species. However, it is well known that this technique can generate biologically implausible pathways, especially in regions of the brain where multiple fibers cross. This review highlights potential misconnections in two cortico-cortical association pathways with a focus on the aslant tract and inferior frontal occipital fasciculus. The lack of alternative methods to validate observations from diffusion MR tractography means there is a need to develop new integrative approaches to trace human brain pathways. This review discusses integrative approaches in neuroimaging, anatomical, and transcriptional variation as having much potential to trace the evolution of human brain pathways.
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Affiliation(s)
- Christine J Charvet
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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Guberinic A, van den Elshout R, Kozicz T, Laan MT, Henssen D. Overview of the microanatomy of the human brainstem in relation to the safe entry zones. J Neurosurg 2022; 137:1524-1534. [PMID: 35395628 DOI: 10.3171/2022.2.jns211997] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 02/07/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The primary objective of this anatomical study was to apply innovative imaging techniques to increase understanding of the microanatomical structures of the brainstem related to safe entry zones. The authors hypothesized that such a high-detail overview would enhance neurosurgeons' abilities to approach and define anatomical safe entry zones for use with microsurgical resection techniques for intrinsic brainstem lesions. METHODS The brainstems of 13 cadavers were studied with polarized light imaging (PLI) and 11.7-T MRI. The brainstem was divided into 3 compartments-mesencephalon, pons, and medulla-for evaluation with MRI. Tissue was further sectioned to 100 μm with a microtome. MATLAB was used for further data processing. Segmentation of the internal structures of the brainstem was performed with the BigBrain database. RESULTS Thirteen entry zones were reported and assessed for their safety, including the anterior mesencephalic zone, lateral mesencephalic sulcus, interpeduncular zone, intercollicular region, supratrigeminal zone, peritrigeminal zone, lateral pontine zone, median sulcus, infracollicular zone, supracollicular zone, olivary zone, lateral medullary zone, and anterolateral sulcus. The microanatomy, safety, and approaches are discussed. CONCLUSIONS PLI and 11.7-T MRI data show that a neurosurgeon possibly does not need to consider the microanatomical structures that would not be visible on conventional MRI and tractography when entering the mentioned safe entry zones. However, the detailed anatomical images may help neurosurgeons increase their understanding of the internal architecture of the human brainstem, which in turn could lead to safer neurosurgical intervention.
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Affiliation(s)
- Alis Guberinic
- 1Department of Neurosurgery, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Rik van den Elshout
- 2Department of Radiology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Tamas Kozicz
- 3Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota; and
- 4Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Mark Ter Laan
- 1Department of Neurosurgery, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
| | - Dylan Henssen
- 2Department of Radiology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
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Sitek KR, Calabrese E, Johnson GA, Ghosh SS, Chandrasekaran B. Structural Connectivity of Human Inferior Colliculus Subdivisions Using in vivo and post mortem Diffusion MRI Tractography. Front Neurosci 2022; 16:751595. [PMID: 35392412 PMCID: PMC8981148 DOI: 10.3389/fnins.2022.751595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 01/27/2022] [Indexed: 12/05/2022] Open
Abstract
Inferior colliculus (IC) is an obligatory station along the ascending auditory pathway that also has a high degree of top-down convergence via efferent pathways, making it a major computational hub. Animal models have attributed critical roles for the IC in in mediating auditory plasticity, egocentric selection, and noise exclusion. IC contains multiple functionally distinct subdivisions. These include a central nucleus that predominantly receives ascending inputs and external and dorsal nuclei that receive more heterogeneous inputs, including descending and multisensory connections. Subdivisions of human IC have been challenging to identify and quantify using standard brain imaging techniques such as MRI, and the connectivity of each of these subnuclei has not been identified in the human brain. In this study, we estimated the connectivity of human IC subdivisions with diffusion MRI (dMRI) tractography, using both anatomical-based seed analysis as well as unsupervised k-means clustering. We demonstrate sensitivity of tractography to overall IC connections in both high resolution post mortem and in vivo datasets. k-Means clustering of the IC streamlines in both the post mortem and in vivo datasets generally segregated streamlines based on their terminus beyond IC, such as brainstem, thalamus, or contralateral IC. Using fine-grained anatomical segmentations of the major IC subdivisions, the post mortem dataset exhibited unique connectivity patterns from each subdivision, including commissural connections through dorsal IC and lateral lemniscal connections to central and external IC. The subdivisions were less distinct in the context of in vivo connectivity, although lateral lemniscal connections were again highest to central and external IC. Overall, the unsupervised and anatomically driven methods provide converging evidence for distinct connectivity profiles for each of the IC subdivisions in both post mortem and in vivo datasets, suggesting that dMRI tractography with high quality data is sensitive to neural pathways involved in auditory processing as well as top-down control of incoming auditory information.
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Affiliation(s)
- Kevin R. Sitek
- SoundBrain Lab, Brain and Auditory Sciences Research Initiative, Department of Communication and Science Disorders, University of Pittsburgh, Pittsburgh, PA, United States
- *Correspondence: Kevin R. Sitek,
| | - Evan Calabrese
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - G. Allan Johnson
- Center for In Vivo Microscopy, Duke University, Durham, NC, United States
| | - Satrajit S. Ghosh
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
| | - Bharath Chandrasekaran
- SoundBrain Lab, Brain and Auditory Sciences Research Initiative, Department of Communication and Science Disorders, University of Pittsburgh, Pittsburgh, PA, United States
- Bharath Chandrasekaran,
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Jones R, Maffei C, Augustinack J, Fischl B, Wang H, Bilgic B, Yendiki A. High-fidelity approximation of grid- and shell-based sampling schemes from undersampled DSI using compressed sensing: Post mortem validation. Neuroimage 2021; 244:118621. [PMID: 34587516 PMCID: PMC8631240 DOI: 10.1016/j.neuroimage.2021.118621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/02/2021] [Accepted: 09/24/2021] [Indexed: 12/31/2022] Open
Abstract
While many useful microstructural indices, as well as orientation distribution functions, can be obtained from multi-shell dMRI data, there is growing interest in exploring the richer set of microstructural features that can be extracted from the full ensemble average propagator (EAP). The EAP can be readily computed from diffusion spectrum imaging (DSI) data, at the cost of a very lengthy acquisition. Compressed sensing (CS) has been used to make DSI more practical by reducing its acquisition time. CS applied to DSI (CS-DSI) attempts to reconstruct the EAP from significantly undersampled q-space data. We present a post mortem validation study where we evaluate the ability of CS-DSI to approximate not only fully sampled DSI but also multi-shell acquisitions with high fidelity. Human brain samples are imaged with high-resolution DSI at 9.4T and with polarization-sensitive optical coherence tomography (PSOCT). The latter provides direct measurements of axonal orientations at microscopic resolutions, allowing us to evaluate the mesoscopic orientation estimates obtained from diffusion MRI, in terms of their angular error and the presence of spurious peaks. We test two fast, dictionary-based, L2-regularized algorithms for CS-DSI reconstruction. We find that, for a CS acceleration factor of R=3, i.e., an acquisition with 171 gradient directions, one of these methods is able to achieve both low angular error and low number of spurious peaks. With a scan length similar to that of high angular resolution multi-shell acquisition schemes, this CS-DSI approach is able to approximate both fully sampled DSI and multi-shell data with high accuracy. Thus it is suitable for orientation reconstruction and microstructural modeling techniques that require either grid- or shell-based acquisitions. We find that the signal-to-noise ratio (SNR) of the training data used to construct the dictionary can have an impact on the accuracy of CS-DSI, but that there is substantial robustness to loss of SNR in the test data. Finally, we show that, as the CS acceleration factor increases beyond R=3, the accuracy of these reconstruction methods degrade, either in terms of the angular error, or in terms of the number of spurious peaks. Our results provide useful benchmarks for the future development of even more efficient q-space acceleration techniques.
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Affiliation(s)
- Robert Jones
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA.
| | - Chiara Maffei
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Jean Augustinack
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Bruce Fischl
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA; Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hui Wang
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Berkin Bilgic
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Anastasia Yendiki
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
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Adil SM, Calabrese E, Charalambous LT, Cook JJ, Rahimpour S, Atik AF, Cofer GP, Parente BA, Johnson GA, Lad SP, White LE. A high-resolution interactive atlas of the human brainstem using magnetic resonance imaging. Neuroimage 2021; 237:118135. [PMID: 33951517 PMCID: PMC8480283 DOI: 10.1016/j.neuroimage.2021.118135] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/15/2021] [Accepted: 04/28/2021] [Indexed: 12/30/2022] Open
Abstract
Conventional atlases of the human brainstem are limited by the inflexible, sparsely-sampled, two-dimensional nature of histology, or the low spatial resolution of conventional magnetic resonance imaging (MRI). Postmortem high-resolution MRI circumvents the challenges associated with both modalities. A single human brainstem specimen extending from the rostral diencephalon through the caudal medulla was prepared for imaging after the brain was removed from a 65-year-old male within 24 h of death. The specimen was formalin-fixed for two weeks, then rehydrated and placed in a custom-made MRI compatible tube and immersed in liquid fluorocarbon. MRI was performed in a 7-Tesla scanner with 120 unique diffusion directions. Acquisition time for anatomic and diffusion images were 14 h and 208 h, respectively. Segmentation was performed manually. Deterministic fiber tractography was done using strategically chosen regions of interest and avoidance, with manual editing using expert knowledge of human neuroanatomy. Anatomic and diffusion images were rendered with isotropic resolutions of 50 μm and 200 μm, respectively. Ninety different structures were segmented and labeled, and 11 different fiber bundles were rendered with tractography. The complete atlas is available online for interactive use at https://www.civmvoxport.vm.duke.edu/voxbase/login.php?return_url=%2Fvoxbase%2F. This atlas presents multiple contrasting datasets and selected tract reconstruction with unprecedented resolution for MR imaging of the human brainstem. There are immediate applications in neuroanatomical education, with the potential to serve future applications for neuroanatomical research and enhanced neurosurgical planning through "safe" zones of entry into the human brainstem.
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Affiliation(s)
- Syed M Adil
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States; Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States.
| | - Evan Calabrese
- University of California San Francisco, Department of Radiology & Biomedical Imaging, San Francisco, CA, United States.
| | - Lefko T Charalambous
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States; Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States.
| | - James J Cook
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States.
| | - Shervin Rahimpour
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States.
| | - Ahmet F Atik
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, United States.
| | - Gary P Cofer
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States.
| | - Beth A Parente
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States.
| | - G Allan Johnson
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States.
| | - Shivanand P Lad
- Department of Neurosurgery, Duke University Medical Center, Durham, NC, United States.
| | - Leonard E White
- Department of Neurology, Duke University Medical Center, Durham, NC, United States; Duke Institute for Brain Sciences, Duke University, Durham NC, United States.
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Lohkamp KJ, Kiliaan AJ, Shenk J, Verweij V, Wiesmann M. The Impact of Voluntary Exercise on Stroke Recovery. Front Neurosci 2021; 15:695138. [PMID: 34321996 PMCID: PMC8311567 DOI: 10.3389/fnins.2021.695138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/15/2021] [Indexed: 12/29/2022] Open
Abstract
Stroke treatment is limited to time-critical thrombectomy and rehabilitation by physiotherapy. Studies report beneficial effects of exercise; however, a knowledge gap exists regarding underlying mechanisms that benefit recovery of brain networks and cognition. This study aims to unravel therapeutic effects of voluntary exercise in stroke-induced mice to develop better personalized treatments. Male C57Bl6/JOlaHsd mice were subjected to transient middle cerebral artery occlusion. After surgery, the animals were divided in a voluntary exercise group with access to running wheels (RW), and a control group without running wheels (NRW). During 6 days post-stroke, activity/walking patterns were measured 24/7 in digital ventilated cages. Day 7 post-surgery, animals underwent MRI scanning (11.7T) to investigate functional connectivity (rsfMRI) and white matter (WM) integrity (DTI). Additionally, postmortem polarized light imaging (PLI) was performed to quantify WM fiber density and orientation. After MRI the animals were sacrificed and neuroinflammation and cerebral vascularisation studied. Voluntary exercise promoted myelin density recovery corresponding to higher fractional anisotropy. The deteriorating impact of stroke on WM dispersion was detected only in NRW mice. Moreover, rsfMRI revealed increased functional connectivity, cerebral blood flow and vascular quality leading to improved motor skills in the RW group. Furthermore, voluntary exercise showed immunomodulatory properties post-stroke. This study not only helped determining the therapeutic value of voluntary exercise, but also provided understanding of pathological mechanisms involved in stroke.
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Affiliation(s)
- Klara J Lohkamp
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Preclinical Imaging Center - PRIME, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - Amanda J Kiliaan
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Preclinical Imaging Center - PRIME, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - Justin Shenk
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Preclinical Imaging Center - PRIME, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - Vivienne Verweij
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Preclinical Imaging Center - PRIME, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - Maximilian Wiesmann
- Department of Medical Imaging, Anatomy, Radboud University Medical Center, Preclinical Imaging Center - PRIME, Radboud Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
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Chavoshnejad P, Li X, Zhang S, Dai W, Vasung L, Liu T, Zhang T, Wang X, Razavi MJ. Role of axonal fibers in the cortical folding patterns: A tale of variability and regularity. BRAIN MULTIPHYSICS 2021. [DOI: 10.1016/j.brain.2021.100029] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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9
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Howells H, Simone L, Borra E, Fornia L, Cerri G, Luppino G. Reproducing macaque lateral grasping and oculomotor networks using resting state functional connectivity and diffusion tractography. Brain Struct Funct 2020; 225:2533-2551. [PMID: 32936342 PMCID: PMC7544728 DOI: 10.1007/s00429-020-02142-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 09/02/2020] [Indexed: 12/31/2022]
Abstract
Cortico-cortical networks involved in motor control have been well defined in the macaque using a range of invasive techniques. The advent of neuroimaging has enabled non-invasive study of these large-scale functionally specialized networks in the human brain; however, assessing its accuracy in reproducing genuine anatomy is more challenging. We set out to assess the similarities and differences between connections of macaque motor control networks defined using axonal tracing and those reproduced using structural and functional connectivity techniques. We processed a cohort of macaques scanned in vivo that were made available by the open access PRIME-DE resource, to evaluate connectivity using diffusion imaging tractography and resting state functional connectivity (rs-FC). Sectors of the lateral grasping and exploratory oculomotor networks were defined anatomically on structural images, and connections were reproduced using different structural and functional approaches (probabilistic and deterministic whole-brain and seed-based tractography; group template and native space functional connectivity analysis). The results showed that parieto-frontal connections were best reproduced using both structural and functional connectivity techniques. Tractography showed lower sensitivity but better specificity in reproducing connections identified by tracer data. Functional connectivity analysis performed in native space had higher sensitivity but lower specificity and was better at identifying connections between intrasulcal ROIs than group-level analysis. Connections of AIP were most consistently reproduced, although those connected with prefrontal sectors were not identified. We finally compared diffusion MR modelling with histology based on an injection in AIP and speculate on anatomical bases for the observed false negatives. Our results highlight the utility of precise ex vivo techniques to support the accuracy of neuroimaging in reproducing connections, which is relevant also for human studies.
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Affiliation(s)
- Henrietta Howells
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.
| | - Luciano Simone
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy.
| | - Elena Borra
- Department of Medicine and Surgery, Neuroscience Unit, University of Parma, Parma, Italy
| | - Luca Fornia
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Gabriella Cerri
- MoCA Laboratory, Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Giuseppe Luppino
- Department of Medicine and Surgery, Neuroscience Unit, University of Parma, Parma, Italy
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Guo SM, Yeh LH, Folkesson J, Ivanov IE, Krishnan AP, Keefe MG, Hashemi E, Shin D, Chhun BB, Cho NH, Leonetti MD, Han MH, Nowakowski TJ, Mehta SB. Revealing architectural order with quantitative label-free imaging and deep learning. eLife 2020; 9:e55502. [PMID: 32716843 PMCID: PMC7431134 DOI: 10.7554/elife.55502] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 07/24/2020] [Indexed: 01/21/2023] Open
Abstract
We report quantitative label-free imaging with phase and polarization (QLIPP) for simultaneous measurement of density, anisotropy, and orientation of structures in unlabeled live cells and tissue slices. We combine QLIPP with deep neural networks to predict fluorescence images of diverse cell and tissue structures. QLIPP images reveal anatomical regions and axon tract orientation in prenatal human brain tissue sections that are not visible using brightfield imaging. We report a variant of U-Net architecture, multi-channel 2.5D U-Net, for computationally efficient prediction of fluorescence images in three dimensions and over large fields of view. Further, we develop data normalization methods for accurate prediction of myelin distribution over large brain regions. We show that experimental defects in labeling the human tissue can be rescued with quantitative label-free imaging and neural network model. We anticipate that the proposed method will enable new studies of architectural order at spatial scales ranging from organelles to tissue.
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Affiliation(s)
| | - Li-Hao Yeh
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | | | | | | | - Matthew G Keefe
- Department of Anatomy, University of California, San FranciscoSan FranciscoUnited States
| | - Ezzat Hashemi
- Department of Neurology, Stanford UniversityStanfordUnited States
| | - David Shin
- Department of Anatomy, University of California, San FranciscoSan FranciscoUnited States
| | | | - Nathan H Cho
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | | | - May H Han
- Department of Neurology, Stanford UniversityStanfordUnited States
| | - Tomasz J Nowakowski
- Department of Anatomy, University of California, San FranciscoSan FranciscoUnited States
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11
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Jain A, Maurya AK, Ulrich L, Jaeger M, Rossi RM, Neels A, Schucht P, Dommann A, Frenz M, Akarçay HG. Polarimetric imaging in backscattering for the structural characterization of strongly scattering birefringent fibrous media. OPTICS EXPRESS 2020; 28:16673-16695. [PMID: 32549485 DOI: 10.1364/oe.390303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Interpreting the polarimetric data from fiber-like macromolecules constitutive of tissue can be difficult due to strong scattering. In this study, we probed the superficial layers of fibrous tissue models (membranes consisting of nanofibers) displaying varying degrees of alignment. To better understand the manifestation of membranes' degree of alignment in polarimetry, we analyzed the spatial variations of the backscattered light's Stokes vectors as a function of the orientation of the probing beam's linear polarization. The degree of linear polarization reflects the uniaxially birefringent behavior of the membranes. The rotational (a-)symmetry of the backscattered light's degree of linear polarization provides a measure of the membranes' degree of alignment.
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12
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Rushmore RJ, Bouix S, Kubicki M, Rathi Y, Yeterian EH, Makris N. How Human Is Human Connectional Neuroanatomy? Front Neuroanat 2020; 14:18. [PMID: 32351367 PMCID: PMC7176274 DOI: 10.3389/fnana.2020.00018] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/23/2020] [Indexed: 01/16/2023] Open
Abstract
The structure of the human brain has been studied extensively. Despite all the knowledge accrued, direct information about connections, from origin to termination, in the human brain is extremely limited. Yet there is a widespread misperception that human connectional neuroanatomy is well-established and validated. In this article, we consider what is known directly about human structural and connectional neuroanatomy. Information on neuroanatomical connections in the human brain is derived largely from studies in non-human experimental models in which the entire connectional pathway, including origins, course, and terminations, is directly visualized. Techniques to examine structural connectivity in the human brain are progressing rapidly; nevertheless, our present understanding of such connectivity is limited largely to data derived from homological comparisons, particularly with non-human primates. We take the position that an in-depth and more precise understanding of human connectional neuroanatomy will be obtained by a systematic application of this homological approach.
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Affiliation(s)
- R Jarrett Rushmore
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States.,Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Center for Morphometric Analysis, Department of Psychiatry and Neurology, A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sylvain Bouix
- Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States
| | - Marek Kubicki
- Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Center for Morphometric Analysis, Department of Psychiatry and Neurology, A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Yogesh Rathi
- Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Center for Morphometric Analysis, Department of Psychiatry and Neurology, A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Edward H Yeterian
- Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Center for Morphometric Analysis, Department of Psychiatry and Neurology, A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Department of Psychology, Colby College, Waterville, ME, United States
| | - Nikos Makris
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, United States.,Psychiatric Neuroimaging Laboratory, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, United States.,Center for Morphometric Analysis, Department of Psychiatry and Neurology, A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
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13
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Birefringence Changes of Dendrites in Mouse Hippocampal Slices Revealed with Polarizing Microscopy. Biophys J 2020; 118:2366-2384. [PMID: 32294480 DOI: 10.1016/j.bpj.2020.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/20/2020] [Accepted: 03/06/2020] [Indexed: 11/23/2022] Open
Abstract
Intrinsic optical signal (IOS) imaging has been widely used to map the patterns of brain activity in vivo in a label-free manner. Traditional IOS refers to changes in light transmission, absorption, reflectance, and scattering of the brain tissue. Here, we use polarized light for IOS imaging to monitor structural changes of cellular and subcellular architectures due to their neuronal activity in isolated brain slices. To reveal fast spatiotemporal changes of subcellular structures associated with neuronal activity, we developed the instantaneous polarized light microscope (PolScope), which allows us to observe birefringence changes in neuronal cells and tissues while stimulating neuronal activity. The instantaneous PolScope records changes in transmission, birefringence, and slow axis orientation in tissue at a high spatial and temporal resolution using a single camera exposure. These capabilities enabled us to correlate polarization-sensitive IOS with traditional IOS on the same preparations. We detected reproducible spatiotemporal changes in both IOSs at the stratum radiatum in mouse hippocampal slices evoked by electrical stimulation at Schaffer collaterals. Upon stimulation, changes in traditional IOS signals were broadly uniform across the area, whereas birefringence imaging revealed local variations not seen in traditional IOS. Locations with high resting birefringence produced larger stimulation-evoked birefringence changes than those produced at low resting birefringence. Local application of glutamate to the synaptic region in CA1 induced an increase in both transmittance and birefringence signals. Blocking synaptic transmission with inhibitors CNQX (for AMPA-type glutamate receptor) and D-APV (for NMDA-type glutamate receptor) reduced the peak amplitude of the optical signals. Changes in both IOSs were enhanced by an inhibitor of the membranous glutamate transporter, DL-TBOA. Our results indicate that the detection of activity-induced structural changes of the subcellular architecture in dendrites is possible in a label-free manner.
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14
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Henssen DJHA, Weber RC, de Boef J, Mollink J, Kozicz T, Kurt E, van Cappellen van Walsum AM. Post-mortem 11.7 Tesla Magnetic Resonance Imaging vs. Polarized Light Imaging Microscopy to Measure the Angle and Orientation of Dorsal Root Afferents in the Human Cervical Dorsal Root Entry Zone. Front Neuroanat 2019; 13:66. [PMID: 31312124 PMCID: PMC6614433 DOI: 10.3389/fnana.2019.00066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/18/2019] [Indexed: 11/18/2022] Open
Abstract
Background: Destruction of the afferents by dorsal root entry zone (DREZ) surgery may be an effective treatment of intractable neuropathic pain, though it remains a high-risk surgical intervention. Potential complications due to the lesioning of structures within the cervical spinal cord other than the DREZ can be minimized by accurate knowledge of the optimal insertion angle [i.e., the angle between the DREZ and the posterior median sulcus (PMS)]. The employed insertion angle was based on measurements between the DREZ and the PMS on post-mortem transverse slices. However, new, more sophisticated imaging techniques are currently available and are thought to yield higher spatial resolution and more accurate images. Obejctive: This article measures the angle between the DREZ and the PMS on 11.7T post-mortem magnetic resonance images and compares these findings with polarized light imaging (PLI) microscopy images of the same specimens in order to quantify fiber orientation within the DREZ. Methods: To visualize the anatomy of the cervical DREZ, magnetic resonance imaging (MRI), diffusion-weighted MRI (dMRI), probabilistic tractography, and PLI were performed on three post-mortem human cervical spinal cords at level C5–C6. The MR data was used to measure the angle between the DREZ and the PMS. MR images were complemented by probabilistic tractography results. Then, the orientation of fibers within the DREZ was quantified by use of PLI microscopy. Results: Median angle between the DREZ and the PMS, as measured on MR-images, was found to be 40.1° (ranging from 34.2° to 49.1°) and 39.8° (ranging from 31.1° to 47.8°) in the left and right hemicord, respectively. Median fiber orientation within the DREZ, as quantified by PLI, was 28.5° (ranging from 12.0° to 44.3°) and 27.7° (ranging from 8.5° to 38.1°) in the left and right hemicord, respectively. Conclusion: Our study, which provides an improved understanding of the anatomy of the DREZ, the angle between the DREZ and the PMS and the median fiber orientation within the DREZ, could contribute to safer DREZ-lesioning surgery to treat chronic neuropathic pain in the future.
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Affiliation(s)
- Dylan Jozef Hendrik Augustinus Henssen
- Department of Anatomy, Donders Institute for Brain, Cognition & Behavior, Radboud University Medical Center, Nijmegen, Netherlands.,Unit of Functional Neurosurgery, Department of Neurosurgery, Radboud University Medical Center, Nijmegen, Netherlands
| | - Rosanna Christina Weber
- Department of Anatomy, Donders Institute for Brain, Cognition & Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jesse de Boef
- Department of Anatomy, Donders Institute for Brain, Cognition & Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jeroen Mollink
- Department of Anatomy, Donders Institute for Brain, Cognition & Behavior, Radboud University Medical Center, Nijmegen, Netherlands.,Nuffield Department of Clinical Neurosciences, Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom
| | - Tamas Kozicz
- Department of Clinical Genomics, Mayo Clinic Minnesota, Rochester, MN, United States
| | - Erkan Kurt
- Unit of Functional Neurosurgery, Department of Neurosurgery, Radboud University Medical Center, Nijmegen, Netherlands
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15
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Mollink J, Hiemstra M, Miller KL, Huszar IN, Jenkinson M, Raaphorst J, Wiesmann M, Ansorge O, Pallebage-Gamarallage M, van Cappellen van Walsum AM. White matter changes in the perforant path area in patients with amyotrophic lateral sclerosis. Neuropathol Appl Neurobiol 2019; 45:570-585. [PMID: 31002412 PMCID: PMC6852107 DOI: 10.1111/nan.12555] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 04/15/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that white matter degeneration of the perforant path - as part of the Papez circuit - is a key feature of amyotrophic lateral sclerosis (ALS), even in the absence of frontotemporal dementia (FTD) or deposition of pTDP-43 inclusions in hippocampal granule cells. METHODS We used diffusion Magnetic Resonance Imaging (dMRI), polarized light imaging (PLI) and immunohistochemical analysis of post mortem hippocampus specimens from controls (n = 5) and ALS patients (n = 14) to study white matter degeneration in the perforant path. RESULTS diffusion Magnetic Resonance Imaging demonstrated a decrease in fractional anisotropy (P = 0.01) and an increase in mean diffusivity (P = 0.01) in the perforant path in ALS compared to controls. PLI-myelin density was lower in ALS (P = 0.05) and correlated with fractional anisotropy (r = 0.52, P = 0.03). These results were confirmed by immunohistochemistry; both myelin (proteolipid protein, P = 0.03) and neurofilaments (SMI-312, P = 0.02) were lower in ALS. Two out of the fourteen ALS cases showed pTDP-43 pathology in the dentate gyrus, but with comparable myelination levels in the perforant path to other ALS cases. CONCLUSION We conclude that degeneration of the perforant path occurs in ALS patients and that this may occur before, or independent of, pTDP-43 aggregation in the dentate gyrus of the hippocampus. Future research should focus on correlating the degree of cognitive decline to the amount of white matter atrophy in the perforant path.
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Affiliation(s)
- J Mollink
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.,Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - M Hiemstra
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - K L Miller
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - I N Huszar
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - M Jenkinson
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - J Raaphorst
- Department of Neurology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - M Wiesmann
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - O Ansorge
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - A M van Cappellen van Walsum
- Department of Anatomy, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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16
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Caspers S, Axer M. Decoding the microstructural correlate of diffusion MRI. NMR IN BIOMEDICINE 2019; 32:e3779. [PMID: 28858413 DOI: 10.1002/nbm.3779] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
Diffusion imaging has evolved considerably over the past decade. While it provides valuable information about the structural connectivity at the macro- and mesoscopic scale, bridging the gap to the microstructure at the level of single nerve fibers poses an enormous challenge. This is particularly true for the human brain with its large size, its large white-matter volume and availability of histological techniques for studying human whole-brain sections and subsequent 3D reconstruction. Classic post-mortem techniques for studying the fiber architecture of the brain, such as myeloarchitectonic staining or dye tracing, are complemented by novel histological approaches, such as 3D polarized light imaging or optical coherence tomography, enabling unique insight into the fiber architecture from large fiber bundles within deep white matter to single nerve fibers in the cortex. The present review discusses the benefits and challenges of these latest developments in comparison with the classic techniques, with particular focus on the mutual exchange between in vivo and post-mortem diffusion imaging and post-mortem microstructural approaches for understanding the wiring of the brain across different scales.
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Affiliation(s)
- Svenja Caspers
- C. and O. Vogt Institute for Brain Research, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
- JARA-BRAIN, Jülich-Aachen Research Alliance, Jülich, Germany
| | - Markus Axer
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
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17
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Jeurissen B, Descoteaux M, Mori S, Leemans A. Diffusion MRI fiber tractography of the brain. NMR IN BIOMEDICINE 2019; 32:e3785. [PMID: 28945294 DOI: 10.1002/nbm.3785] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
The ability of fiber tractography to delineate non-invasively the white matter fiber pathways of the brain raises possibilities for clinical applications and offers enormous potential for neuroscience. In the last decade, fiber tracking has become the method of choice to investigate quantitative MRI parameters in specific bundles of white matter. For neurosurgeons, it is quickly becoming an invaluable tool for the planning of surgery, allowing for visualization and localization of important white matter pathways before and even during surgery. Fiber tracking has also claimed a central role in the field of "connectomics," a technique that builds and studies comprehensive maps of the complex network of connections within the brain, and to which significant resources have been allocated worldwide. Despite its unique abilities and exciting applications, fiber tracking is not without controversy, in particular when it comes to its interpretation. As neuroscientists are eager to study the brain's connectivity, the quantification of tractography-derived "connection strengths" between distant brain regions is becoming increasingly popular. However, this practice is often frowned upon by fiber-tracking experts. In light of this controversy, this paper provides an overview of the key concepts of tractography, the technical considerations at play, and the different types of tractography algorithm, as well as the common misconceptions and mistakes that surround them. We also highlight the ongoing challenges related to fiber tracking. While recent methodological developments have vastly increased the biological accuracy of fiber tractograms, one should be aware that, even with state-of-the-art techniques, many issues that severely bias the resulting structural "connectomes" remain unresolved.
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Affiliation(s)
- Ben Jeurissen
- imec-Vision Lab, Dept. of Physics, University of Antwerp, Belgium
| | - Maxime Descoteaux
- Centre de Recherche CHUS, University of Sherbrooke, Sherbrooke, Canada
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Faculty of Science, University of Sherbrooke, Canada
| | - Susumu Mori
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Alexander Leemans
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
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18
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David S, Heemskerk AM, Corrivetti F, Thiebaut de Schotten M, Sarubbo S, Corsini F, De Benedictis A, Petit L, Viergever MA, Jones DK, Mandonnet E, Axer H, Evans J, Paus T, Leemans A. The Superoanterior Fasciculus (SAF): A Novel White Matter Pathway in the Human Brain? Front Neuroanat 2019; 13:24. [PMID: 30890921 PMCID: PMC6412356 DOI: 10.3389/fnana.2019.00024] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/07/2019] [Indexed: 01/01/2023] Open
Abstract
Fiber tractography (FT) using diffusion magnetic resonance imaging (dMRI) is widely used for investigating microstructural properties of white matter (WM) fiber-bundles and for mapping structural connections of the human brain. While studying the architectural configuration of the brain's circuitry with FT is not without controversy, recent progress in acquisition, processing, modeling, analysis, and visualization of dMRI data pushes forward the reliability in reconstructing WM pathways. Despite being aware of the well-known pitfalls in analyzing dMRI data and several other limitations of FT discussed in recent literature, we present the superoanterior fasciculus (SAF), a novel bilateral fiber tract in the frontal region of the human brain that-to the best of our knowledge-has not been documented. The SAF has a similar shape to the anterior part of the cingulum bundle, but it is located more frontally. To minimize the possibility that these FT findings are based on acquisition or processing artifacts, different dMRI data sets and processing pipelines have been used to describe the SAF. Furthermore, we evaluated the configuration of the SAF with complementary methods, such as polarized light imaging (PLI) and human brain dissections. The FT results of the SAF demonstrate a long pathway, consistent across individuals, while the human dissections indicate fiber pathways connecting the postero-dorsal with the antero-dorsal cortices of the frontal lobe.
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Affiliation(s)
- Szabolcs David
- Image Sciences Institute, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Anneriet M. Heemskerk
- Image Sciences Institute, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | | | | | - Silvio Sarubbo
- Structural and Functional Connectivity Lab Project, Department of Emergency, Division of Neurosurgery, “S. Chiara” Hospital, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Francesco Corsini
- Structural and Functional Connectivity Lab Project, Department of Emergency, Division of Neurosurgery, “S. Chiara” Hospital, Azienda Provinciale per i Servizi Sanitari (APSS), Trento, Italy
| | - Alessandro De Benedictis
- Department of Neurosciences, Division of Neurosurgery, “Bambino Gesù” Children Hospital, IRCCS, Rome, Italy
| | - Laurent Petit
- Groupe d’Imagerie Neurofonctionnelle (GIN), Institut des Maladies Neurodégératives (IMN)-UMR5293-CNRS, CEA, Université de Bordeaux, Bordeaux, France
| | - Max A. Viergever
- Image Sciences Institute, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Derek K. Jones
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff, United Kingdom
| | | | - Hubertus Axer
- Hans Berger Department of Neurology, Jena University Hospital, Friedrich-Schiller University Jena, Jena, Germany
| | - John Evans
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff, United Kingdom
| | - Tomáš Paus
- Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada
- Departments of Psychology and Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Alexander Leemans
- Image Sciences Institute, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
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Zhang T, Kong J, Jing K, Chen H, Jiang X, Li L, Guo L, Lu J, Hu X, Liu T. Optimization of macaque brain DMRI connectome by neuron tracing and myelin stain data. Comput Med Imaging Graph 2018; 69:9-20. [PMID: 30170273 PMCID: PMC6176488 DOI: 10.1016/j.compmedimag.2018.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 04/26/2018] [Accepted: 06/18/2018] [Indexed: 12/11/2022]
Abstract
Accurate assessment of connectional anatomy of primate brains can be an important avenue to better understand the structural and functional organization of brains. To this end, numerous connectome projects have been initiated to create a comprehensive map of the connectional anatomy over a large spatial expanse. Tractography based on diffusion MRI (dMRI) data has been used as a tool by many connectome projects in that it is widely used to visualize axonal pathways and reveal microstructural features on living brains. However, the measures obtained from dMRI are indirect inference of microstructures. This intrinsic limitation reduces the reliability of dMRI in constructing connectomes for brains. In this work, we proposed a framework to increase the accuracy of constructing a dMRI-based connectome on macaque brains by integrating meso-scale connective information from tract-tracing data and micro-scale axonal orientation information from myelin stain data. Our results suggest that this integrative framework could advance the mapping accuracy of dMRI based connections and axonal pathways, and demonstrate the prospect of the proposed framework in constructing a large-scale connectome on living primate brains.
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Affiliation(s)
- Tuo Zhang
- School of Automation and Brain Decoding Research Center, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Jun Kong
- Emory University, Atlanta, GA, United States
| | - Ke Jing
- Nanjing University of Science and Technology, Nanjing, Jiangsu, China
| | - Hanbo Chen
- Cortical Architecture Imaging and Discovery Lab, The University of Georgia, Athens, GA, United States
| | - Xi Jiang
- Cortical Architecture Imaging and Discovery Lab, The University of Georgia, Athens, GA, United States
| | - Longchuan Li
- Marcus Autism Center, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA, United States
| | - Lei Guo
- School of Automation and Brain Decoding Research Center, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Jianfeng Lu
- Nanjing University of Science and Technology, Nanjing, Jiangsu, China
| | - Xiaoping Hu
- University of California, Riverside, CA, United States
| | - Tianming Liu
- Cortical Architecture Imaging and Discovery Lab, The University of Georgia, Athens, GA, United States.
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20
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Ex vivo visualization of the trigeminal pathways in the human brainstem using 11.7T diffusion MRI combined with microscopy polarized light imaging. Brain Struct Funct 2018; 224:159-170. [PMID: 30293214 PMCID: PMC6373363 DOI: 10.1007/s00429-018-1767-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 10/02/2018] [Indexed: 01/12/2023]
Abstract
Classic anatomical atlases depict a contralateral hemispheral representation of each side of the face. Recently, however, a bilateral projection of each hemiface was hypothesized, based on animal studies that showed the coexistence of an additional trigeminothalamic tract sprouting from the trigeminal principal sensory nucleus that ascends ipsilaterally. This study aims to provide an anatomical substrate for the hypothesized bilateral projection. Three post-mortem human brainstems were scanned for anatomical and diffusion magnetic resonance imaging at 11.7T. The trigeminal tracts were delineated in each brainstem using track density imaging (TDI) and tractography. To evaluate the reconstructed tracts, the same brainstems were sectioned for polarized light imaging (PLI). Anatomical 11.7T MRI shows a dispersion of the trigeminal tract (tt) into a ventral and dorsal portion. This bifurcation was also seen on the TDI maps, tractography results and PLI images of all three specimens. Referring to a similar anatomic feature in primate brains, the dorsal and ventral tracts were named the dorsal and ventral trigeminothalamic tract (dtt and vtt), respectively. This study shows that both the dtt and vtt are present in humans, indicating that each hemiface has a bilateral projection, although the functional relevance of these tracts cannot be determined by the present anatomical study. If both tracts convey noxious stimuli, this could open up new insights into and treatments for orofacial pain in patients.
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21
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Stereoscopic visual area connectivity: a diffusion tensor imaging study. Surg Radiol Anat 2018; 40:1197-1208. [PMID: 30088052 DOI: 10.1007/s00276-018-2076-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE To study the white matter tracts connecting the different stereoscopic visual areas of the brain by diffusion tensor imaging. METHODS In a previous study, we identified the cortical activations to a visual 3D stimulation in 12 subjects using functional MRI (fMRI). These areas of cortical activations [V5, V6, lateral occipital complex (LOC) and intra parietal sulcus areas (IPS)] in addition to the lateral geniculate nucleus (LGN) and the primary visual area V1 were chosen as regions of interest (ROIs). We studied by deterministic tractography the connections existing between these ROIs. RESULTS Found connections were divided into three groups. The first group entails the geniculo-extrastriate connections. LGN was connected to V5, V6, IPS and LOC. These fibers course in the inferior longitudinal fascicule. The second group comprises the associative fibers. V1 was connected to V5 and LOC through the transverse occipital fascicule on one hand, and, to V6 and IPS through the stratum proprium cuni on the other hand. Connections between V5 and LOC, and V6 and IPS course within the vertical occipital fascicule. The third group contains commissural fibers. Forceps major entailed the connections between both V1, both V6, both IPS and IPS and contralateral V6. LGN was connected to contralateral LGN, V1, V6, IPS and LOC. CONCLUSIONS We have elucidated numerous connections between the visual areas and the LGN. Generalization of these results to the remainder of the population must remain prudent due to the limited number of subjects in this study.
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22
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Tittgemeyer M, Rigoux L, Knösche TR. Cortical parcellation based on structural connectivity: A case for generative models. Neuroimage 2018; 173:592-603. [PMID: 29407457 DOI: 10.1016/j.neuroimage.2018.01.077] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 12/14/2022] Open
Abstract
One of the major challenges in systems neuroscience is to identify brain networks and unravel their significance for brain function -this has led to the concept of the 'connectome'. Connectomes are currently extensively studied in large-scale international efforts at multiple scales, and follow different definitions with respect to their connections as well as their elements. Perhaps the most promising avenue for defining the elements of connectomes originates from the notion that individual brain areas maintain distinct (long-range) connection profiles. These connectivity patterns determine the areas' functional properties and also allow for their anatomical delineation and mapping. This rationale has motivated the concept of connectivity-based cortex parcellation. In the past ten years, non-invasive mapping of human brain connectivity has led to immense advances in the development of parcellation techniques and their applications. Unfortunately, many of these approaches primarily aim for confirmation of well-known, existing architectonic maps and, to that end, unsuitably incorporate prior knowledge and frequently build on circular argumentation. Often, current approaches also tend to disregard the specific apertures of connectivity measurements, as well as the anatomical specificities of cortical areas, such as spatial compactness, regional heterogeneity, inter-subject variability, the multi-scaling nature of connectivity information, and potential hierarchical organisation. From a methodological perspective, however, a useful framework that regards all of these aspects in an unbiased way is technically demanding. In this commentary, we first outline the concept of connectivity-based cortex parcellation and discuss its prospects and limitations in particular with respect to structural connectivity. To improve reliability and efficiency, we then strongly advocate for connectivity-based cortex parcellation as a modelling approach; that is, an approximation of the data based on (model) parameter inference. As such, a parcellation algorithm can be formally tested for robustness -the precision of its predictions can be quantified and statistics about potential generalization of the results can be derived. Such a framework also allows the question of model constraints to be reformulated in terms of hypothesis testing through model selection and offers a formative way to integrate anatomical knowledge in terms of prior distributions.
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Affiliation(s)
| | - Lionel Rigoux
- Max-Planck-Institute for Metabolism Research, Cologne, Germany
| | - Thomas R Knösche
- Max-Planck-Institute for Cognitive and Brain Sciences, Leipzig, Germany
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Jelescu IO, Budde MD. Design and validation of diffusion MRI models of white matter. FRONTIERS IN PHYSICS 2017; 28:61. [PMID: 29755979 PMCID: PMC5947881 DOI: 10.3389/fphy.2017.00061] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Diffusion MRI is arguably the method of choice for characterizing white matter microstructure in vivo. Over the typical duration of diffusion encoding, the displacement of water molecules is conveniently on a length scale similar to that of the underlying cellular structures. Moreover, water molecules in white matter are largely compartmentalized which enables biologically-inspired compartmental diffusion models to characterize and quantify the true biological microstructure. A plethora of white matter models have been proposed. However, overparameterization and mathematical fitting complications encourage the introduction of simplifying assumptions that vary between different approaches. These choices impact the quantitative estimation of model parameters with potential detriments to their biological accuracy and promised specificity. First, we review biophysical white matter models in use and recapitulate their underlying assumptions and realms of applicability. Second, we present up-to-date efforts to validate parameters estimated from biophysical models. Simulations and dedicated phantoms are useful in assessing the performance of models when the ground truth is known. However, the biggest challenge remains the validation of the "biological accuracy" of estimated parameters. Complementary techniques such as microscopy of fixed tissue specimens have facilitated direct comparisons of estimates of white matter fiber orientation and densities. However, validation of compartmental diffusivities remains challenging, and complementary MRI-based techniques such as alternative diffusion encodings, compartment-specific contrast agents and metabolites have been used to validate diffusion models. Finally, white matter injury and disease pose additional challenges to modeling, which are also discussed. This review aims to provide an overview of the current state of models and their validation and to stimulate further research in the field to solve the remaining open questions and converge towards consensus.
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Affiliation(s)
- Ileana O Jelescu
- Centre d'Imagerie Biomédicale, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matthew D Budde
- Zablocki VA Medical Center, Dept. of Neurosurgery, Medical College Wisconsin, Milwaukee, WI, USA
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Menzel M, Reckfort J, Weigand D, Köse H, Amunts K, Axer M. Diattenuation of brain tissue and its impact on 3D polarized light imaging. BIOMEDICAL OPTICS EXPRESS 2017; 8:3163-3197. [PMID: 28717561 PMCID: PMC5508822 DOI: 10.1364/boe.8.003163] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/05/2017] [Accepted: 05/18/2017] [Indexed: 05/03/2023]
Abstract
3D-polarized light imaging (3D-PLI) reconstructs nerve fibers in histological brain sections by measuring their birefringence. This study investigates another effect caused by the optical anisotropy of brain tissue - diattenuation. Based on numerical and experimental studies and a complete analytical description of the optical system, the diattenuation was determined to be below 4 % in rat brain tissue. It was demonstrated that the diattenuation effect has negligible impact on the fiber orientations derived by 3D-PLI. The diattenuation signal, however, was found to highlight different anatomical structures that cannot be distinguished with current imaging techniques, which makes Diattenuation Imaging a promising extension to 3D-PLI.
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Affiliation(s)
- Miriam Menzel
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich 52425,
Germany
| | - Julia Reckfort
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich 52425,
Germany
| | - Daniel Weigand
- JARA-Institute for Quantum Information, RWTH Aachen University, Aachen 52056,
Germany
| | - Hasan Köse
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich 52425,
Germany
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich 52425,
Germany
- Cécile and Oskar Vogt Institute of Brain Research, University of Düsseldorf, Düsseldorf 40204,
Germany
| | - Markus Axer
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich 52425,
Germany
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25
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Kamiya K, Hori M, Irie R, Miyajima M, Nakajima M, Kamagata K, Tsuruta K, Saito A, Nakazawa M, Suzuki Y, Mori H, Kunimatsu A, Arai H, Aoki S, Abe O. Diffusion imaging of reversible and irreversible microstructural changes within the corticospinal tract in idiopathic normal pressure hydrocephalus. NEUROIMAGE-CLINICAL 2017; 14:663-671. [PMID: 28348958 PMCID: PMC5358533 DOI: 10.1016/j.nicl.2017.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 03/05/2017] [Accepted: 03/10/2017] [Indexed: 11/05/2022]
Abstract
The symptoms of idiopathic normal pressure hydrocephalus (iNPH) can be improved by shunt surgery, but prediction of treatment outcome is not established. We investigated changes of the corticospinal tract (CST) in iNPH before and after shunt surgery by using diffusion microstructural imaging, which infers more specific tissue properties than conventional diffusion tensor imaging. Two biophysical models were used: neurite orientation dispersion and density imaging (NODDI) and white matter tract integrity (WMTI). In both methods, the orientational coherence within the CSTs was higher in patients than in controls, and some normalization occurred after the surgery in patients, indicating axon stretching and recovery. The estimated axon density was lower in patients than in controls but remained unchanged after the surgery, suggesting its potential as a marker for irreversible neuronal damage. In a Monte-Carlo simulation that represented model axons as undulating cylinders, both NODDI and WMTI separated the effects of axon density and undulation. Thus, diffusion MRI may distinguish between reversible and irreversible microstructural changes in iNPH. Our findings constitute a step towards a quantitative image biomarker that reflects pathological process and treatment outcomes of iNPH. NODDI and WMTI provide markers of reversible and irreversible changes in iNPH. Measures of axon orientation indicated recovery from stretching after surgery. Axon density remained low after surgery, suggesting chronic neuronal damage. Axon stretching in simulations differentially affected diffusion metrics.
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Key Words
- AD, axial diffusivity
- AWF, axonal water fraction
- Axon density
- Axon undulation
- CSF, cerebrospinal fluid
- CST, corticospinal tract
- DTI, diffusion tensor imaging
- Diffusion MRI
- FA, fractional anisotropy
- Idiopathic normal pressure hydrocephalus
- MD, mean diffusivity
- NODDI, neurite orientation dispersion and density imaging
- ODI, orientation dispersion index
- RD, radial diffusivity
- ROI, region of interest
- VF, volume fraction
- VOI, volume of interest
- WMTI, white matter tract integrity
- iNPH, idiopathic normal pressure hydrocephalus
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Affiliation(s)
- Kouhei Kamiya
- Department of Radiology, The University of Tokyo, Bunkyo, Tokyo, Japan; Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Masaaki Hori
- Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Ryusuke Irie
- Department of Radiology, The University of Tokyo, Bunkyo, Tokyo, Japan; Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Masakazu Miyajima
- Department of Neurosurgery, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Madoka Nakajima
- Department of Neurosurgery, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Koji Kamagata
- Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Kouhei Tsuruta
- Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Asami Saito
- Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Misaki Nakazawa
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa, Tokyo, Japan
| | - Yuichi Suzuki
- Department of Radiology, The University of Tokyo Hospital, Bunkyo, Tokyo, Japan
| | - Harushi Mori
- Department of Radiology, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Akira Kunimatsu
- Department of Radiology, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Hajime Arai
- Department of Neurosurgery, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Shigeki Aoki
- Department of Radiology, Juntendo University School of Medicine, Bunkyo, Tokyo, Japan
| | - Osamu Abe
- Department of Radiology, The University of Tokyo, Bunkyo, Tokyo, Japan
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26
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Bastiani M, Oros-Peusquens AM, Seehaus A, Brenner D, Möllenhoff K, Celik A, Felder J, Bratzke H, Shah NJ, Galuske R, Goebel R, Roebroeck A. Automatic Segmentation of Human Cortical Layer-Complexes and Architectural Areas Using Ex vivo Diffusion MRI and Its Validation. Front Neurosci 2016; 10:487. [PMID: 27891069 PMCID: PMC5102896 DOI: 10.3389/fnins.2016.00487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/11/2016] [Indexed: 11/14/2022] Open
Abstract
Recently, several magnetic resonance imaging contrast mechanisms have been shown to distinguish cortical substructure corresponding to selected cortical layers. Here, we investigate cortical layer and area differentiation by automatized unsupervised clustering of high-resolution diffusion MRI data. Several groups of adjacent layers could be distinguished in human primary motor and premotor cortex. We then used the signature of diffusion MRI signals along cortical depth as a criterion to detect area boundaries and find borders at which the signature changes abruptly. We validate our clustering results by histological analysis of the same tissue. These results confirm earlier studies which show that diffusion MRI can probe layer-specific intracortical fiber organization and, moreover, suggests that it contains enough information to automatically classify architecturally distinct cortical areas. We discuss the strengths and weaknesses of the automatic clustering approach and its appeal for MR-based cortical histology.
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Affiliation(s)
- Matteo Bastiani
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht UniversityMaastricht, Netherlands; Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4)Jülich, Germany
| | | | - Arne Seehaus
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht UniversityMaastricht, Netherlands; Department of Biology, TU DarmstadtDarmstadt, Germany
| | - Daniel Brenner
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4) Jülich, Germany
| | - Klaus Möllenhoff
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4) Jülich, Germany
| | - Avdo Celik
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4) Jülich, Germany
| | - Jörg Felder
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4) Jülich, Germany
| | - Hansjürgen Bratzke
- Department of Forensic Medicine, Faculty of Medicine, Goethe University Frankfurt Frankfurt, Germany
| | - Nadim J Shah
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-4)Jülich, Germany; Department of Neurology, Faculty of Medicine, Jülich Aachen Research Alliance, RWTH Aachen UniversityAachen, Germany
| | - Ralf Galuske
- Department of Biology, TU Darmstadt Darmstadt, Germany
| | - Rainer Goebel
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht UniversityMaastricht, Netherlands; Department of Neuroimaging and Neuromodeling, Netherlands Institute for Neuroscience - KNAWAmsterdam, Netherlands
| | - Alard Roebroeck
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
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27
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Wu Y, Sun D, Wang Y, Wang Y, Ou S. Segmentation of the Cingulum Bundle in the Human Brain: A New Perspective Based on DSI Tractography and Fiber Dissection Study. Front Neuroanat 2016; 10:84. [PMID: 27656132 PMCID: PMC5013069 DOI: 10.3389/fnana.2016.00084] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/17/2016] [Indexed: 11/24/2022] Open
Abstract
The cingulum bundle (CB) is a critical white matter fiber tract in the brain, which forms connections between the frontal lobe, parietal lobe and temporal lobe. In non-human primates, the CB is actually divided into distinct subcomponents on the basis of corticocortical connections. However, at present, no study has verified similar distinct subdivisions in the human brain. In this study, we reconstructed these distinct subdivisions in the human brain, and determined their exact cortical connections using high definition fiber tracking (HDFT) technique on 10 healthy adults and a 488-subject template from the Human Connectome Project (HCP-488). Fiber dissections were performed to verify tractography results. Five CB segments were identified. CB-I ran from the subrostral areas to the precuneus and splenium, encircling the corpus callosum (CC). CB-II arched around the splenium and extended anteriorly above the CC to the medial aspect of the superior frontal gyrus (SFG). CB-III connected the superior parietal lobule (SPL) and precuneus with the medial aspect of the SFG. CB-IV was a relatively minor subcomponent from the SPL and precuneus to the frontal region. CB-V, the para-hippocampal cingulum, stemmed from the medial temporal lobe and fanned out to the occipital lobes. Our findings not only provide a more accurate and detailed description on the associated architecture of the subcomponents within the CB, but also offer new insights into the functional role of the CB in the human brain.
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Affiliation(s)
- Yupeng Wu
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University Shenyang, China
| | - Dandan Sun
- Department of Cardiovascular Ultrasound, The First Affiliated Hospital of China Medical University Shenyang, China
| | - Yong Wang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University Shenyang, China
| | - Yibao Wang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University Shenyang, China
| | - Shaowu Ou
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University Shenyang, China
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28
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Augustinack JC, van der Kouwe AJW. Postmortem imaging and neuropathologic correlations. HANDBOOK OF CLINICAL NEUROLOGY 2016; 136:1321-39. [PMID: 27430472 DOI: 10.1016/b978-0-444-53486-6.00069-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Postmortem imaging refers to scanning autopsy specimens using magnetic resonance imaging (MRI) or optical imaging. This chapter summarizes postmortem imaging and its usefulness in brain mapping. Standard in vivo MRI has limited resolution due to time constraints and does not deliver cortical boundaries (e.g., Brodmann areas). Postmortem imaging offers a means to obtain ultra-high-resolution images with appropriate contrast for delineating cortical regions. Postmortem imaging provides the ability to validate MRI properties against histologic stained sections. This approach has enabled probabilistic mapping that is based on ex vivo MRI contrast, validated to histology, and subsequently mapped on to an in vivo model. This chapter emphasizes structural imaging, which can be validated with histologic assessment. Postmortem imaging has been applied to neuropathologic studies as well. This chapter includes many ex vivo studies, but focuses on studies of the medial temporal lobe, often involved in neurologic disease. New research using optical imaging is also highlighted.
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Affiliation(s)
- Jean C Augustinack
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.
| | - André J W van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
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29
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Mitter C, Jakab A, Brugger PC, Ricken G, Gruber GM, Bettelheim D, Scharrer A, Langs G, Hainfellner JA, Prayer D, Kasprian G. Validation of In utero Tractography of Human Fetal Commissural and Internal Capsule Fibers with Histological Structure Tensor Analysis. Front Neuroanat 2015; 9:164. [PMID: 26732460 PMCID: PMC4689804 DOI: 10.3389/fnana.2015.00164] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 12/07/2015] [Indexed: 12/20/2022] Open
Abstract
Diffusion tensor imaging (DTI) and tractography offer the unique possibility to visualize the developing white matter macroanatomy of the human fetal brain in vivo and in utero and are currently under investigation for their potential use in the diagnosis of developmental pathologies of the human central nervous system. However, in order to establish in utero DTI as a clinical imaging tool, an independent comparison between macroscopic imaging and microscopic histology data in the same subject is needed. The present study aimed to cross-validate normal as well as abnormal in utero tractography results of commissural and internal capsule fibers in human fetal brains using postmortem histological structure tensor (ST) analysis. In utero tractography findings from two structurally unremarkable and five abnormal fetal brains were compared to the results of postmortem ST analysis applied to digitalized whole hemisphere sections of the same subjects. An approach to perform ST-based deterministic tractography in histological sections was implemented to overcome limitations in correlating in utero tractography to postmortem histology data. ST analysis and histology-based tractography of fetal brain sections enabled the direct assessment of the anisotropic organization and main fiber orientation of fetal telencephalic layers on a micro- and macroscopic scale, and validated in utero tractography results of corpus callosum and internal capsule fiber tracts. Cross-validation of abnormal in utero tractography results could be achieved in four subjects with agenesis of the corpus callosum (ACC) and in two cases with malformations of internal capsule fibers. In addition, potential limitations of current DTI-based in utero tractography could be demonstrated in several brain regions. Combining the three-dimensional nature of DTI-based in utero tractography with the microscopic resolution provided by histological ST analysis may ultimately facilitate a more complete morphologic characterization of axon guidance disorders at prenatal stages of human brain development.
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Affiliation(s)
- Christian Mitter
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of ViennaVienna, Austria; Institute of Neurology, Medical University of ViennaVienna, Austria
| | - András Jakab
- Computational Imaging Research Lab, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna Vienna, Austria
| | - Peter C Brugger
- Department of Systematic Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna Vienna, Austria
| | - Gerda Ricken
- Institute of Neurology, Medical University of Vienna Vienna, Austria
| | - Gerlinde M Gruber
- Department of Systematic Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna Vienna, Austria
| | - Dieter Bettelheim
- Division of Obstetrics and Feto-maternal Medicine, Department of Obstetrics and Gynecology, Medical University of Vienna Vienna, Austria
| | - Anke Scharrer
- Clinical Institute for Pathology, Medical University of Vienna Vienna, Austria
| | - Georg Langs
- Computational Imaging Research Lab, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna Vienna, Austria
| | | | - Daniela Prayer
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna Vienna, Austria
| | - Gregor Kasprian
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna Vienna, Austria
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30
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Fatima M, Tan R, Halliday GM, Kril JJ. Spread of pathology in amyotrophic lateral sclerosis: assessment of phosphorylated TDP-43 along axonal pathways. Acta Neuropathol Commun 2015. [PMID: 26216351 PMCID: PMC4517552 DOI: 10.1186/s40478-015-0226-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Introduction The progression of amyotrophic lateral sclerosis (ALS) through the brain has recently been staged using independent neuropathological and neuroimaging modalities. The two schemes tie into the concept of pathological spread through corticofugal axonal transmission that stems from observation of oligodendrocyte pTDP-43 aggregates along with neuronal inclusions. Here, we aimed to assess evidence of transmission along axonal pathways by looking for pTDP-43 oligodendrocyte pathology in involved white matter tracts, and to present a first validation of the neuropathological staging scheme. pTDP-43 immunohistochemistry was performed in select white matter tracts and grey matter regions from the staging scheme in postmortem-confirmed ALS cases (N = 34). Double-labelling immunofluorescence was performed to confirm co-localisation of pTDP-43 immunoreactivity to oligodendrocytes. Results While pTDP-43 immunoreactive oligodendrocytes were frequent in the white matter under the motor and sensory cortices, similar assessment of the white matter along the corticospinal tract and in the corpus callosum and cingulum bundle of the same cases revealed no pTDP-43 pathology, questioning the involvement of oligodendrocytes in pathological propagation. The assessment of Betz cell loss revealed that the lack of deep white matter pTDP-43 oligodendrocyte pathology was not due to an absence of motor axons. Assessment of the propagation of pathology to different grey matter regions validated that all cases could be allocated to one of four neuropathological stages, although Stage 4 cases were found to differ significantly in age of onset (~10 years older) and disease duration (shorter duration than Stage 3 and similar to Stage 2). Conclusions Four stages of ALS neuropathology can be consistently identified, although evidence of sequential clinical progression requires further assessment. As limited pTDP-43 oligodendrocyte pathology in deep corticospinal and other white matter tracts from the motor cortex was observed, the propagation of pathology between neurons may not involve oligodendrocytes and the interpretation of the changes observed on neuroimaging should be modified accordingly. Electronic supplementary material The online version of this article (doi:10.1186/s40478-015-0226-y) contains supplementary material, which is available to authorized users.
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31
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Bastiani M, Roebroeck A. Unraveling the multiscale structural organization and connectivity of the human brain: the role of diffusion MRI. Front Neuroanat 2015; 9:77. [PMID: 26106304 PMCID: PMC4460430 DOI: 10.3389/fnana.2015.00077] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 05/21/2015] [Indexed: 01/31/2023] Open
Abstract
The structural architecture and the anatomical connectivity of the human brain show different organizational principles at distinct spatial scales. Histological staining and light microscopy techniques have been widely used in classical neuroanatomical studies to unravel brain organization. Using such techniques is a laborious task performed on 2-dimensional histological sections by skilled anatomists possibly aided by semi-automated algorithms. With the recent advent of modern magnetic resonance imaging (MRI) contrast mechanisms, cortical layers and columns can now be reliably identified and their structural properties quantified post-mortem. These developments are allowing the investigation of neuroanatomical features of the brain at a spatial resolution that could be interfaced with that of histology. Diffusion MRI and tractography techniques, in particular, have been used to probe the architecture of both white and gray matter in three dimensions. Combined with mathematical network analysis, these techniques are increasingly influential in the investigation of the macro-, meso-, and microscopic organization of brain connectivity and anatomy, both in vivo and ex vivo. Diffusion MRI-based techniques in combination with histology approaches can therefore support the endeavor of creating multimodal atlases that take into account the different spatial scales or levels on which the brain is organized. The aim of this review is to illustrate and discuss the structural architecture and the anatomical connectivity of the human brain at different spatial scales and how recently developed diffusion MRI techniques can help investigate these.
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Affiliation(s)
- Matteo Bastiani
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
| | - Alard Roebroeck
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
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32
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Ardila A, Bernal B, Rosselli M. Language and visual perception associations: meta-analytic connectivity modeling of Brodmann area 37. Behav Neurol 2015; 2015:565871. [PMID: 25648869 PMCID: PMC4306224 DOI: 10.1155/2015/565871] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 12/09/2014] [Accepted: 12/17/2014] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Understanding the functions of different brain areas has represented a major endeavor of neurosciences. Historically, brain functions have been associated with specific cortical brain areas; however, modern neuroimaging developments suggest cognitive functions are associated to networks rather than to areas. OBJECTIVE The purpose of this paper was to analyze the connectivity of Brodmann area (BA) 37 (posterior, inferior, and temporal/fusiform gyrus) in relation to (1) language and (2) visual processing. METHODS Two meta-analyses were initially conducted (first level analysis). The first one was intended to assess the language network in which BA37 is involved. The second one was intended to assess the visual perception network. A third meta-analysis (second level analysis) was then performed to assess contrasts and convergence between the two cognitive domains (language and visual perception). The DataBase of Brainmap was used. RESULTS Our results support the role of BA37 in language but by means of a distinct network from the network that supports its second most important function: visual perception. CONCLUSION It was concluded that left BA37 is a common node of two distinct networks-visual recognition (perception) and semantic language functions.
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Affiliation(s)
- Alfredo Ardila
- Department of Communication Sciences and Disorders, Florida International University, Miami, FL 33199, USA
| | - Byron Bernal
- Radiology Department and Research Institute, Miami Children's Hospital, Miami, FL 33155, USA
| | - Monica Rosselli
- Department of Psychology, Florida Atlantic University, Davie, FL 33314, USA
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33
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Zemmoura I, Serres B, Andersson F, Barantin L, Tauber C, Filipiak I, Cottier JP, Venturini G, Destrieux C. FIBRASCAN: a novel method for 3D white matter tract reconstruction in MR space from cadaveric dissection. Neuroimage 2014; 103:106-118. [PMID: 25234114 DOI: 10.1016/j.neuroimage.2014.09.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 08/27/2014] [Accepted: 09/04/2014] [Indexed: 01/13/2023] Open
Abstract
INTRODUCTION Diffusion tractography relies on complex mathematical models that provide anatomical information indirectly, and it needs to be validated. In humans, up to now, tractography has mainly been validated by qualitative comparison with data obtained from dissection. No quantitative comparison was possible because Magnetic Resonance Imaging (MRI) and dissection data are obtained in different reference spaces, and because fiber tracts are progressively destroyed by dissection. Here, we propose a novel method and software (FIBRASCAN) that allow accurate reconstruction of fiber tracts from dissection in MRI reference space. METHOD Five human hemispheres, obtained from four formalin-fixed brains were prepared for Klingler's dissection, placed on a holder with fiducial markers, MR scanned, and then dissected to expose the main association tracts. During dissection, we performed iterative acquisitions of the surface and texture of the specimens using a laser scanner and two digital cameras. Each texture was projected onto the corresponding surface and the resulting set of textured surfaces was coregistered thanks to the fiducial holders. The identified association tracts were then interactively segmented on each textured surface and reconstructed from the pile of surface segments. Finally, the reconstructed tracts were coregistered onto ex vivo MRI space thanks to the fiducials. Each critical step of the process was assessed to measure the precision of the method. RESULTS We reconstructed six fiber tracts (long, anterior and posterior segments of the superior longitudinal fasciculus; Inferior fronto-occipital, Inferior longitudinal and uncinate fasciculi) from cadaveric dissection and ported them into ex vivo MRI reference space. The overall accuracy of the method was of the order of 1mm: surface-to-surface registration=0.138mm (standard deviation (SD)=0.058mm), deformation of the specimen during dissection=0.356mm (SD=0.231mm), and coregistration surface-MRI=0.6mm (SD=0.274mm). The spatial resolution of the method (distance between two consecutive surface acquisitions) was 0.345mm (SD=0.115mm). CONCLUSION This paper presents the robustness of a novel method, FIBRASCAN, for accurate reconstruction of fiber tracts from dissection in the ex vivo MR reference space. This is a major step toward quantitative comparison of MR tractography with dissection results.
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Affiliation(s)
- Ilyess Zemmoura
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Anatomie, Tours, France; CHRU de Tours, Service de Neurochirurgie, Tours, France.
| | - Barthélémy Serres
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Informatique, EA6300 Tours, France
| | - Frédéric Andersson
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France
| | - Laurent Barantin
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France
| | - Clovis Tauber
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France
| | - Isabelle Filipiak
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France
| | - Jean-Philippe Cottier
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; CHRU de Tours, Service de Neuroradiologie, Tours, France
| | - Gilles Venturini
- Université François-Rabelais de Tours, Laboratoire d'Informatique, EA6300 Tours, France
| | - Christophe Destrieux
- INSERM U930 Imagerie et Cerveau, Université François-Rabelais de Tours, Tours, France; Université François-Rabelais de Tours, Laboratoire d'Anatomie, Tours, France; CHRU de Tours, Service de Neurochirurgie, Tours, France
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Alarcon C, de Notaris M, Palma K, Soria G, Weiss A, Kassam A, Prats-Galino A. 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. Oper Neurosurg (Hagerstown) 2013; 10 Suppl 2:294-304; discussion 304. [DOI: 10.1227/neu.0000000000000271] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
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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Affiliation(s)
- Carlos Alarcon
- Laboratory of Surgical Neuroanatomy (LSNA), Universitat de Barcelona, Barcelona, Spain
- Department of Neurosurgery, Hospital Universitario de Bellvitge, Barcelona, Spain
| | - Matteo de Notaris
- Laboratory of Surgical Neuroanatomy (LSNA), Universitat de Barcelona, Barcelona, Spain
- Department of Neurosurgery, Hospital Clinic, Barcelona, Spain
| | - Kenneth Palma
- Experimental MRI 7T Unit, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Guadalupe Soria
- Laboratory of Surgical Neuroanatomy (LSNA), Universitat de Barcelona, Barcelona, Spain
- Department of Neurosurgery, University of Pisa, Pisa, Italy
| | - Alessandro Weiss
- Department of Neurosurgery, Division of Neurosurgery, University of Ottawa, Ottawa, Ontario, Canada
| | - Amin Kassam
- Laboratory of Surgical Neuroanatomy (LSNA), Universitat de Barcelona, Barcelona, Spain
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Axer H, Klingner CM, Prescher A. Fiber anatomy of dorsal and ventral language streams. BRAIN AND LANGUAGE 2013; 127:192-204. [PMID: 22632814 DOI: 10.1016/j.bandl.2012.04.015] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 04/05/2012] [Accepted: 04/23/2012] [Indexed: 06/01/2023]
Abstract
Recent advances in neuroimaging have led to new insights into the organization of language related networks. Increasing evidence supports the model of dorsal and ventral streams of information flow between language-related areas. Therefore, a review of the descriptions of language-related fiber anatomy in the human and monkey brain was performed. In addition, case studies of macroscopical fiber dissection and polarized light imaging (PLI) with special focus on the ventral stream were done. Several fiber structures can be identified to play a role in language, i.e. the arcuate fasciculus as a part of the superior longitudinal fasciculus, the middle longitudinal fasciculus, the inferior fronto-occipital fasciculus, and extreme and external capsules. Substantial differences between human and monkey fiber architecture have been identified. Despite inconsistencies based on different terminologies used, there can be no doubt that dorsal and ventral language streams have a clear correlation in the structure of white matter tracts.
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Affiliation(s)
- Hubertus Axer
- Hans Berger Department of Neurology, Jena University Hospital, Jena, Germany.
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Breuer L, Axer M, Dammers J. A new constrained ICA approach for optimal signal decomposition in polarized light imaging. J Neurosci Methods 2013; 220:30-8. [DOI: 10.1016/j.jneumeth.2013.08.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/19/2013] [Accepted: 08/22/2013] [Indexed: 11/27/2022]
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Kotz SA, Anwander A, Axer H, Knösche TR. Beyond cytoarchitectonics: the internal and external connectivity structure of the caudate nucleus. PLoS One 2013; 8:e70141. [PMID: 23922939 PMCID: PMC3724823 DOI: 10.1371/journal.pone.0070141] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 06/14/2013] [Indexed: 11/18/2022] Open
Abstract
While there is ample evidence on the functional and connectional differentiation of the caudate nucleus (CN), less is known about its potential microstructural subdivisions. However, this latter aspect is critical to the local information processing capabilities of the tissue. We applied diffusion MRI, a non-invasive in vivo method that has great potential for the exploration of the brain structure-behavior relationship, in order to characterize the local fiber structure in gray matter of the CN. We report novel evidence of a functionally meaningful structural tri-partition along the anterior-posterior axis of this region. The connectivity of the CN subregions is in line with connectivity evidence from earlier invasive studies in animal models. In addition, histological validation using polarized light imaging (PLI) confirms these results, corroborating the notion that cortico-subcortico-cortical loops involve microstructurally differentiated regions in the caudate nucleus. Methodologically speaking, the comparison with advanced analysis of diffusion MRI shows that diffusion tensor imaging (DTI) yields a simplified view of the CN fiber architecture which is refined by advanced high angular resolution imaging methods.
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Affiliation(s)
- Sonja A Kotz
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
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Ford AA, Triplett W, Sudhyadhom A, Gullett J, McGregor K, Fitzgerald DB, Mareci T, White K, Crosson B. Broca's area and its striatal and thalamic connections: a diffusion-MRI tractography study. Front Neuroanat 2013; 7:8. [PMID: 23675324 PMCID: PMC3650618 DOI: 10.3389/fnana.2013.00008] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 04/22/2013] [Indexed: 12/25/2022] Open
Abstract
In the recent decades structural connectivity between Broca's area and the basal ganglia has been postulated in the literature, though no direct evidence of this connectivity has yet been presented. The current study investigates this connectivity using a novel diffusion-weighted imaging (DWI) fiber tracking method in humans in vivo. Our findings suggest direct connections between sub-regions of Broca's area and the anterior one-third of the putamen, as well as the ventral anterior nucleus of the thalamus. Thus, we are the first to provide a detailed account of inferred circuitry involving basal ganglia, thalamus, and Broca's area, which would be a prerequisite to substantiate their support of language processing.
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Affiliation(s)
- Anastasia A Ford
- Department of Veterans Affairs Rehabilitation Research and Development Brain Rehabilitation Research Center, Malcom Randall VA Medical Center Gainesville, FL, USA ; Department of Psychology, University of Florida Gainesville, FL, USA
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Aggarwal M, Zhang J, Pletnikova O, Crain B, Troncoso J, Mori S. Feasibility of creating a high-resolution 3D diffusion tensor imaging based atlas of the human brainstem: a case study at 11.7 T. Neuroimage 2013; 74:117-27. [PMID: 23384518 DOI: 10.1016/j.neuroimage.2013.01.061] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/12/2013] [Accepted: 01/28/2013] [Indexed: 11/24/2022] Open
Abstract
A three-dimensional stereotaxic atlas of the human brainstem based on high resolution ex vivo diffusion tensor imaging (DTI) is introduced. The atlas consists of high resolution (125-255 μm isotropic) three-dimensional DT images of the formalin-fixed brainstem acquired at 11.7 T. The DTI data revealed microscopic neuroanatomical details, allowing three-dimensional visualization and reconstruction of fiber pathways including the decussation of the pyramidal tract fibers, and interdigitating fascicles of the corticospinal and transverse pontine fibers. Additionally, strong gray-white matter contrasts in the apparent diffusion coefficient (ADC) maps enabled precise delineation of gray matter nuclei in the brainstem, including the cranial nerve and the inferior olivary nuclei. Comparison with myelin-stained histology shows that at the level of resolution achieved in this study, the structural details resolved with DTI contrasts in the brainstem were comparable to anatomical delineation obtained with histological sectioning. Major neural structures delineated from DTI contrasts in the brainstem are segmented and three-dimensionally reconstructed. Further, the ex vivo DTI data are nonlinearly mapped to a widely-used in vivo human brain atlas, to construct a high-resolution atlas of the brainstem in the Montreal Neurological Institute (MNI) stereotaxic coordinate space. The results demonstrate the feasibility of developing a 3D DTI based atlas for detailed characterization of brainstem neuroanatomy with high resolution and contrasts, which will be a useful resource for research and clinical applications.
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Affiliation(s)
- Manisha Aggarwal
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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40
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Budde MD, Annese J. Quantification of anisotropy and fiber orientation in human brain histological sections. Front Integr Neurosci 2013; 7:3. [PMID: 23378830 PMCID: PMC3561729 DOI: 10.3389/fnint.2013.00003] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/11/2013] [Indexed: 11/16/2022] Open
Abstract
Diffusion weighted imaging (DWI) has provided unparalleled insight into the microscopic structure and organization of the central nervous system. Diffusion tensor imaging (DTI) and other models of the diffusion MRI signal extract microstructural properties of tissues with relevance to the normal and injured brain. Despite the prevalence of such techniques and applications, accurate and large-scale validation has proven difficult, particularly in the human brain. In this report, human brain sections obtained from a digital public brain bank were employed to quantify anisotropy and fiber orientation using structure tensor analysis. The derived maps depict the intricate complexity of white matter fibers at a resolution not attainable with current DWI experiments. Moreover, the effects of multiple fiber bundles (i.e., crossing fibers) and intravoxel fiber dispersion were demonstrated. Examination of the cortex and hippocampal regions validated-specific features of previous in vivo and ex vivo DTI studies of the human brain. Despite the limitation to two dimensions, the resulting images provide a unique depiction of white matter organization at resolutions currently unattainable with DWI. The method of analysis may be used to validate tissue properties derived from DTI and alternative models of the diffusion signal.
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Affiliation(s)
- Matthew D Budde
- Department of Neurosurgery, Medical College of Wisconsin Milwaukee, WI, USA
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41
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Examining brain microstructure using structure tensor analysis of histological sections. Neuroimage 2012; 63:1-10. [DOI: 10.1016/j.neuroimage.2012.06.042] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 06/20/2012] [Accepted: 06/22/2012] [Indexed: 11/22/2022] Open
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42
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Leergaard TB, Hilgetag CC, Sporns O. Mapping the connectome: multi-level analysis of brain connectivity. Front Neuroinform 2012; 6:14. [PMID: 22557964 PMCID: PMC3340894 DOI: 10.3389/fninf.2012.00014] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 04/03/2012] [Indexed: 02/03/2023] Open
Affiliation(s)
- Trygve B Leergaard
- Centre for Molecular Biology and Neuroscience, Institute of Basic Medical Sciences, University of Oslo Oslo, Norway
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