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Raabe W, Walk D. Multiple averaged records to identify Aδ-fibers in sensory nerves. J Neurosci Methods 2024; 405:110081. [PMID: 38369028 DOI: 10.1016/j.jneumeth.2024.110081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/08/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
BACKGROUND Existing methods identify only ≈10 Aδ-fibers in human sensory nerves per recording. This study examines methods to increase the detection of Aδ-fibers. NEW METHOD Two to 20 averages of 500 replicate responses to epidermal nerve stimulation are obtained. Pairs of different averages are constructed. Each pair is analyzed with algorithms applied to amplitude and frequency to detect replication of responses to stimulation as "simultaneous similarities in two averages" (SS2AVs) at ≥99.5th percentile of control. In a pair of averages the latencies of amplitude and frequency SS2AVs for the same response to stimulation may differ by ≤0.25 ms. Therefore, Aδ-fibers are identified by the 0.25 ms moving sum of SS2AV latencies of the pairs of averages. RESULTS Increasing averages increases pairs of different averages and detection of Aδ-fibers: from 2 to 10 Aδ-fibers with two averages (one pair) to >50 Aδ-fibers with 12-20 averages (66-190 pairs). COMPARISON WITH EXISTING METHOD(S) Existing methods identify ≤10 Aδ-fibers in 10 averages/45 pairs with the medians of amplitude and frequency algorithms applied to all 45 pairs. This study identifies Aδ-fibers (i) by applying these algorithms at the 99.5th percentile of control, (ii) to each pair of averages and (iii) by the 0.25 ms sum of algorithm identified events (SS2AVs) in all pairs. These three changes significantly increase the detection of Aδ-fibers, e.g., in 10 averages/45pairs from 10 to 45. CONCLUSIONS Three modifications of existing methods can increase the detection of Aδ-fibers to an amount suitable (>50 with ≥12 averages) for statistical comparison of different nerves.
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Affiliation(s)
- W Raabe
- Department of Neurology, University of Minnesota, Minneapolis, MN, USA.
| | - D Walk
- Department of Neurology, University of Minnesota, Minneapolis, MN, USA
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2
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Wernisch L, Edwards T, Berthon A, Tessier-Lariviere O, Sarkans E, Stoukidi M, Fortier-Poisson P, Pinkney M, Thornton M, Hanley C, Lee S, Jennings J, Appleton B, Garsed P, Patterson B, Buttinger W, Gonshaw S, Jakopec M, Shunmugam S, Mamen J, Tukiainen A, Lajoie G, Armitage O, Hewage E. Online Bayesian optimization of vagus nerve stimulation. J Neural Eng 2024; 21:026019. [PMID: 38479016 DOI: 10.1088/1741-2552/ad33ae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Objective.In bioelectronic medicine, neuromodulation therapies induce neural signals to the brain or organs, modifying their function. Stimulation devices capable of triggering exogenous neural signals using electrical waveforms require a complex and multi-dimensional parameter space to control such waveforms. Determining the best combination of parameters (waveform optimization or dosing) for treating a particular patient's illness is therefore challenging. Comprehensive parameter searching for an optimal stimulation effect is often infeasible in a clinical setting due to the size of the parameter space. Restricting this space, however, may lead to suboptimal therapeutic results, reduced responder rates, and adverse effects.Approach. As an alternative to a full parameter search, we present a flexible machine learning, data acquisition, and processing framework for optimizing neural stimulation parameters, requiring as few steps as possible using Bayesian optimization. This optimization builds a model of the neural and physiological responses to stimulations, enabling it to optimize stimulation parameters and provide estimates of the accuracy of the response model. The vagus nerve (VN) innervates, among other thoracic and visceral organs, the heart, thus controlling heart rate (HR), making it an ideal candidate for demonstrating the effectiveness of our approach.Main results.The efficacy of our optimization approach was first evaluated on simulated neural responses, then applied to VN stimulation intraoperatively in porcine subjects. Optimization converged quickly on parameters achieving target HRs and optimizing neural B-fiber activations despite high intersubject variability.Significance.An optimized stimulation waveform was achieved in real time with far fewer stimulations than required by alternative optimization strategies, thus minimizing exposure to side effects. Uncertainty estimates helped avoiding stimulations outside a safe range. Our approach shows that a complex set of neural stimulation parameters can be optimized in real-time for a patient to achieve a personalized precision dosing.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Guillaume Lajoie
- Université de Montréal and Mila-Quebec AI Institute, Montréal, Canada
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Sell LB, Shi Q, Bhat MA. Protocol for isolating and processing mouse sciatic nerve fibers for confocal immunohistochemistry. STAR Protoc 2024; 5:102852. [PMID: 38277269 PMCID: PMC10840394 DOI: 10.1016/j.xpro.2024.102852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/15/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024] Open
Abstract
Many motor and neurodegenerative diseases affect the peripheral nervous system (PNS). The myelinated axons in the sciatic nerves offer valuable insights into the pathology of these diseases. Here, we present a protocol for isolating and processing mouse sciatic nerves for confocal immunohistochemistry. We describe steps for mouse perfusion, removing and fixing the sciatic nerve, transferring nerves onto slides, staining, and imaging. This protocol can assist in characterizing pathologies of myelinated fibers resulting from diseases affecting the PNS. For complete details on the use and execution of this protocol, please refer to Chang et al. (2023).1.
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Affiliation(s)
- Lacey B Sell
- Department of Cellular and Integrative Physiology, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
| | - Qian Shi
- Department of Cellular and Integrative Physiology, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA; IBMS Neuroscience Graduate Program, Joe R. and Teresa Lozano Long School of Medicine, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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Negrete FJM, Casanova VA, Ramón PVM, Mariscal MG, Palomeque TS, Rebolleda G. Partial regression of peripapillary myelinated nerve fibers after non-arteritic anterior ischemic optic neuropathy. Arq Bras Oftalmol 2024; 87:e20220237. [PMID: 38451679 DOI: 10.5935/0004-2749.2022-0237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/10/2022] [Indexed: 03/08/2024] Open
Abstract
A 71-year-old woman presented a non-arteritic anterior ischemic optic neuropathy in an optic nerve with previously registered superonasal peripapillary myelinated nerve fibers. Her past medical history was significant for controlled systemic hypertension, hyperlipidemia, and diabetes mellitus. The physiologic cup was absent in both optic discs. Non-arteritic anterior ischemic optic neuropathy mainly affected the temporal and inferior sectors of the peripapillary retinal nerve fiber layer, as could be demonstrated by retinal nerve fiber layer optical coherence tomography and optic disc optical coherence tomography angiography. Unlike other published reports, just a slight regression of the myelinated nerve fibers was observed after 1 year of follow-up. This occurred because ischemia mainly affected the temporal and inferior peripapillary sectors, whereas myelinated nerve fibers were superonasal to the optic disc.
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Affiliation(s)
- Francisco J Muñoz Negrete
- Ophthalmology Department, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Surgery Department, Universidad de Alcalá School of Medicine, Madrid, Spain
| | | | | | - Marta Gomez Mariscal
- Ophthalmology Department, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | | | - Gema Rebolleda
- Ophthalmology Department, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Surgery Department, Universidad de Alcalá School of Medicine, Madrid, Spain
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5
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Zhao H, Li Y, Zhang Y, Zhang C. Changes in myelinated nerve fibers induced by pulsed electrical stimulation: A microstructural perspective on the causes of electrical stimulation side effects. Biochem Biophys Res Commun 2024; 691:149331. [PMID: 38039835 DOI: 10.1016/j.bbrc.2023.149331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 10/17/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023]
Abstract
Electrical brain stimulation technology is widely used in the clinic to treat brain neurological disorders. However, during treatment, patients may experience side effects such as pain, poor limb coordination, and skin rash. Previous reports have focused on the brilliant chapter on electrical brain stimulation technology and have not paid attention to patients' suffering caused by side effects during treatment. In this study, electrodes were arranged on the medulla oblongata. Pulsed electric fields of different frequencies were used to perform electrical stimulation to study the impact of electric fields on myelinated nerve fibers and reveal the possible microstructural origin of side effects. Transmission electron microscopy was used to analyze and quantify the changes in microstructure. The results illustrated that myelinated nerve fibers underwent atrophy under pulsed electric fields, with the mildest degree of atrophy under high-frequency (400 Hz) electric fields. Myelin sheaths experienced plate separation under pulsed electric fields, and a distinct laminar structure appeared. The microstructure changes may be related to the side effects of clinical electrical stimulation. This study can provide pathological possibilities for exploring the causes of the side effects of electrical stimulation and supply guidance for selecting electrical parameters for clinical electrical stimulation therapy from a distinctive perspective.
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Affiliation(s)
- Hongwei Zhao
- Key Laboratory of CNC Equipment Reliability, Ministry of Education, Jilin University, Changchun, 130025, PR China; School of Mechanical & Aerospace Engineering, Jilin University, Changchun, 130025, PR China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang, 110167, PR China; Chongqing Research Institute of Jilin University, Chongqing, 401120, PR China
| | - Yiqiang Li
- Key Laboratory of CNC Equipment Reliability, Ministry of Education, Jilin University, Changchun, 130025, PR China; School of Mechanical & Aerospace Engineering, Jilin University, Changchun, 130025, PR China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang, 110167, PR China; Chongqing Research Institute of Jilin University, Chongqing, 401120, PR China
| | - Yibo Zhang
- Key Laboratory of CNC Equipment Reliability, Ministry of Education, Jilin University, Changchun, 130025, PR China; School of Mechanical & Aerospace Engineering, Jilin University, Changchun, 130025, PR China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang, 110167, PR China; Chongqing Research Institute of Jilin University, Chongqing, 401120, PR China
| | - Chi Zhang
- Key Laboratory of CNC Equipment Reliability, Ministry of Education, Jilin University, Changchun, 130025, PR China; School of Mechanical & Aerospace Engineering, Jilin University, Changchun, 130025, PR China; Institute of Structured and Architected Materials, Liaoning Academy of Materials, Shenyang, 110167, PR China; Chongqing Research Institute of Jilin University, Chongqing, 401120, PR China.
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Wu D, Wu Q, Li F, Wang Y, Zeng J, Tang B, Bishop JR, Xiao L, Lui S. Free water alterations in different inflammatory subgroups in schizophrenia. Brain Behav Immun 2024; 115:557-564. [PMID: 37972880 DOI: 10.1016/j.bbi.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 09/09/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Accumulating evidence suggests that inflammatory dysregulation both in blood and the brain is implicated in the pathogenesis of schizophrenia. Alterations in peripheral cytokines are not evident in all patients and there may be discrete altered inflammatory subgroups in schizophrenia. Recent studies using a novel and in vivo free-water imaging to detect inflammatory processes, have shown increased free water in white matter in schizophrenia. However, no studies to date have investigated the free water alterations in different inflammatory subgroups in schizophrenia. METHODS Forty-four patients with schizophrenia and 49 controls were recruited. The serum levels of interleukin-1 beta (IL-1β), IL-6, IL-10, and IL-12p70 were measured and used for cluster analysis with K-means and hierarchical algorithms. Diffusion tensor imaging (DTI) images were collected for all participants and voxel-wise free water and fractional anisotropy of tissue (FA-t) were compared between groups with Randomise running in FSL. Partial correlation analysis was employed to explore the association of the peripheral cytokine levels with free water. RESULTS We identified two statistically quantifiable discrete subgroups of patients based on the cluster analysis of cytokine measures. The peripheral levels of IL-1β (P < 0.001), IL-10 (P = 0.041), and IL-12p70 (P < 0.001) showed significant differences between the two different inflammatory subgroups. In the inflammatory subgroup with a predominantly higher IL-1β level, increased free water values in white matter were found mainly in the left posterior limb of the internal capsule, posterior corona radiata, and partly in the left sagittal stratum. These affected areas did not overlap with the regions that showed significant free water differences between patients and healthy controls. In the inflammatory subgroup with lower IL-1β levels, peripheral IL-1β was significantly associated with free water values in white matter while no such association was detected in the patient group. CONCLUSIONS Localized free water differences were demonstrated between the two identified inflammatory subgroups in our data, and free water appears to be a feasible in vivo neuroimaging biomarker guiding the target of inflammatory intervention and development of new therapeutic strategies in an individualized manner in schizophrenia.
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Affiliation(s)
- Dongsheng Wu
- Department of Radiology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan, China; West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, Sichuan, China.
| | - Qi Wu
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China.
| | - Fei Li
- Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China; Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, China.
| | - Yaxuan Wang
- Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China; Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, China
| | - Jiaxin Zeng
- Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China; Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, China
| | - Biqiu Tang
- Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China; Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, China
| | - Jeffrey R Bishop
- Department of Experimental and Clinical Pharmacology and Department of Psychiatry and Behavioral Sciences, University of Minnesota, Minneapolis, MN, United States.
| | - Li Xiao
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China; School of Artificial Intelligence, Beijing University of Posts and Telecommunications, Beijing, China.
| | - Su Lui
- Huaxi MR Research Center (HMRRC), Functional and Molecular Imaging Key Laboratory of Sichuan Province, Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China; Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, China.
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7
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Oncel D, MacCumber M. Geleophysic dysplasia, unilateral choroidal folds and myelinated nerve fiber layer: A case report. J Fr Ophtalmol 2024; 47:103906. [PMID: 37661493 DOI: 10.1016/j.jfo.2023.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 05/28/2023] [Indexed: 09/05/2023]
Affiliation(s)
- D Oncel
- Loyola Stritch School of Medicine, Maywood, IL, United States
| | - M MacCumber
- Rush University Medical Center, Chicago, IL, United States.
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8
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Smrkolj V, Pregeljc D, Kavčič H, Umek N, Mavri J. Micro-pharmacokinetics of lidocaine and bupivacaine transfer across a myelinated nerve fiber. Comput Biol Med 2023; 165:107375. [PMID: 37611421 DOI: 10.1016/j.compbiomed.2023.107375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/20/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023]
Abstract
BACKGROUND The aim of the present study was to predict the time to onset and duration of action of two local anesthetics (lidocaine and bupivacaine) based on experimental dimensions of a typical nerve and experimental octanol/water partition coefficients. METHODS We began our compilation of experimental data with a numerical solution of the Smoluchowski equation for the transfer of lidocaine and bupivacaine across the axon membrane in the region of the node of Ranvier (axolemma) and across the Schwann cell. The difference between the aqueous and lipid environments of the neuron was simulated by including the coordinate-dependent chemical potential. In the second step, the permeation rates calculated using the diffusion equation were used to solve a system of four ordinary differential equations. This approach allowed us to simulate the cellular environment for a longer time and to compare our model with pharmacokinetic properties (time to onset and duration of action) of local anesthetics from the literature. The behavior of local anesthetics under physiological conditions and in case of local acidosis was also simulated. RESULTS We demonstrated that local anesthetics cross the axolemma in a time span of less than 1 μs. The time to onset of action, controlled by diffusion from the epineurium to an axon with a typical distance of 500 μm, was 167 s and 186 s for lidocaine and bupivacaine, respectively. The calculated half-life, which is a measure of the duration of action, was 41 min and 328 min for lidocaine and bupivacaine, respectively. CONCLUSIONS Duration of action is controlled by the storage capacity of lipophilic compartments around the axon, which is higher for bupivacaine but lower in local acidosis. For the latter case, the literature, including textbooks, provides a misinterpretation, namely that protonated species cannot penetrate the membrane.
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Affiliation(s)
- Vladimir Smrkolj
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; Laboratory of Computational Biochemistry and Drug Design, National Institute of Chemistry, Ljubljana, Slovenia
| | - Domen Pregeljc
- Department of Chemistry, Imperial College London, London, United Kingdom
| | - Hana Kavčič
- Clinical Department for Anesthesiology and Surgical Intensive Therapy of University Medical Center Ljubljana, Ljubljana, Slovenia; Department of Anesthesiology and Reanimatology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Nejc Umek
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Janez Mavri
- Laboratory of Computational Biochemistry and Drug Design, National Institute of Chemistry, Ljubljana, Slovenia.
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RaviChandran N, Hope J, Aw K, McDaid A. Modeling the excitation of nerve axons under transcutaneous stimulation. Comput Biol Med 2023; 165:107463. [PMID: 37699322 DOI: 10.1016/j.compbiomed.2023.107463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 08/15/2023] [Accepted: 09/04/2023] [Indexed: 09/14/2023]
Abstract
Computational models enable a safe and convenient way to study the excitation of nerve fibers under external stimulation. Contemporary models calculate the electric field distribution from transcutaneous stimulation and the resulting neuronal response separately. This study uses finite element methods to develop a multi-scale model that couples electric fields within macroscopic tissue layers and microscopic nerve fibers in a single-stage computational framework. The model included a triaxial myelinated nerve fiber bundle embedded within a volume conductor of tissue layers to represent the median nerve innervating the forearm muscles. The model captured the excitability of nerve fibers under transcutaneous stimulation and their nerve-tissue interactions to a transient external stimulus. The determinants of the strength-duration curve, rheobase, and chronaxie for the proposed model had close correlations with in-vivo experimentation on human participants. Additionally, the excitability indices for the triaxial myelinated nerve fiber implemented using the finite element method agreed well with experimental data from the literature. The validity of the proposed model encourages its use for applications involving transcutaneous stimulation. Capable of capturing field distribution across realistic morphologies, the model can serve as a testbed to improve stimulation protocols and electrode designs with subject-level specificity.
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Affiliation(s)
- Narrendar RaviChandran
- Medical Devices and Technologies Group, Department of Mechanical and Mechatronics Engineering, The University of Auckland, Auckland 1010, New Zealand; Singapore Eye Research Institute, Singapore 169856, Singapore.
| | - James Hope
- Medical Devices and Technologies Group, Department of Mechanical and Mechatronics Engineering, The University of Auckland, Auckland 1010, New Zealand; Department of Mechanical Engineering, The University of Minnesota, Minneapolis, MN 55455, United States
| | - Kean Aw
- Smart Materials and Microtechnologies Group, Department of Mechanical and Mechatronics Engineering, The University of Auckland, Auckland 1010, New Zealand
| | - Andrew McDaid
- Medical Devices and Technologies Group, Department of Mechanical and Mechatronics Engineering, The University of Auckland, Auckland 1010, New Zealand
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Blanca CP, Isabel PC, Sergio IM, Candela CL, Honorio BG, Enrique EG. Straatsma Syndrome and cataract: case report and review of the literature. Rom J Ophthalmol 2023; 67:416-418. [PMID: 38239417 PMCID: PMC10793372 DOI: 10.22336/rjo.2023.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2023] [Indexed: 01/22/2024] Open
Abstract
Straatsma Syndrome is known as unilateral myopia, amblyopia, and myelinated retinal nerve fibers (MRNF). The syndrome can be associated with other findings such as nystagmus, strabismus, and optic nerve hypoplasia among others. However, no cases associated with cataract have been reported. The visual prognosis depends on the myelinated retinal nerve fibers extension, the early amblyopia therapy, and the coexistence of other signs. We present the case of a 4-year-old girl with Straatsma Syndrome and cataract in the left eye. Despite the cataract surgical treatment with the refractive error correction and the amblyopia therapy, no visual improvement has been reported. Abbreviations: MRNF = Myelinated retinal nerve fibers, LE = Left eye, PD = Prism dioptres, BCVA = Best-corrected visual acuity, RE = Right eye, HM = Hand movement, CF = Counting fingers.
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Affiliation(s)
- Casado-Pelaez Blanca
- Department of Ophthalmology, La Fe University and Polytechnic Hospital, Valencia, Spain
| | - Pascual-Camps Isabel
- Department of Ophthalmology, La Fe University and Polytechnic Hospital, Valencia, Spain
| | - Inat-Moreno Sergio
- Department of Ophthalmology, La Fe University and Polytechnic Hospital, Valencia, Spain
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Ma M, Sun T. Progressive Retinal Medullated Nerve Fiber Layer in a Young Boy. JAMA Ophthalmol 2023; 141:e231863. [PMID: 37855841 DOI: 10.1001/jamaophthalmol.2023.1863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
This case report documents progression of myelinated retinal nerve fibers in a young boy from age 6 months to 2 years.
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Affiliation(s)
- Mingming Ma
- Department of Ophthalmology, Shanghai General Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Tao Sun
- Shanghai Eye Diseases Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
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Pauziene N, Ranceviene D, Rysevaite-Kyguoliene K, Inokaitis H, Saburkina I, Plekhanova K, Sabeckiene D, Sabeckis I, Martinaityte R, Pilnikovaite E, Pauza DH. Comparative analysis of intracardiac neural structures in the aged rats with essential hypertension. Anat Rec (Hoboken) 2023; 306:2313-2332. [PMID: 36342958 DOI: 10.1002/ar.25109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/16/2022] [Accepted: 10/09/2022] [Indexed: 11/09/2022]
Abstract
Persistent arterial hypertension initiates cardiac autonomic imbalance and alters cardiac tissues. Previous studies have shown that neural component contributes to arterial hypertension etiology, maintenance, and progression and leads to brain damage, peripheral neuropathy, and remodeling of intrinsic cardiac neural plexus. Recently, significant structural changes of the intracardiac neural plexus were demonstrated in young prehypertensive and adult hypertensive spontaneously hypertensive rats (SHR), yet structural alterations of intracardiac neural plexus that occur in the aged SHR remain undetermined. Thus, we analyzed the impact of uncontrolled arterial hypertension in old (48-52 weeks) SHR and the age-matched Wistar-Kyoto rats (WKY). Intrinsic cardiac neural plexus was examined using a combination of immunofluorescence confocal microscopy and transmission electron microscopy in cardiac sections and whole-mount preparations. Our findings demonstrate that structural changes of intrinsic cardiac neural plexus caused by arterial hypertension are heterogeneous and may support recent physiological implications about cardiac denervation occurring together with the hyperinnervation of the SHR heart. We conclude that arterial hypertension leads to (i) the decrease of the neuronal body area, the thickness of atrial nerves, the number of myelinated nerve fibers, unmyelinated axon area and cumulative axon area in the nerve, and the density of myocardial nerve fibers, and (ii) the increase in myelinated nerve fiber area and density of neuronal bodies within epicardiac ganglia. Despite neuropathic alterations of myelinated fibers were exposed within intracardiac nerves of both groups, SHR and WKY, we consider that the determined significant changes in structure of intrinsic cardiac neural plexus were predisposed by arterial hypertension.
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Affiliation(s)
| | | | | | | | - Inga Saburkina
- Lithuanian University of Health Sciences, Kaunas, Lithuania
| | | | | | - Ignas Sabeckis
- Lithuanian University of Health Sciences, Kaunas, Lithuania
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Sarıgül Sezenöz A, Oto S, Akkoyun İ, Akça Bayar S, Yılmaz G, Çolak MY. Macular Imaging Characteristics in Children with Myelinated Retinal Nerve Fiber and High Myopia Syndrome. Turk J Ophthalmol 2023; 53:234-240. [PMID: 37602641 PMCID: PMC10442755 DOI: 10.4274/tjo.galenos.2023.27612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 01/05/2023] [Indexed: 08/22/2023] Open
Abstract
Objectives To investigate the macular imaging features in patients with unilateral myelinated retinal nerve fiber (MRNF) and high myopia syndrome. Materials and Methods Six patients with unilateral MRNF and high myopia syndrome and 13 myopic controls were enrolled in this study. Spectral domain (SD) optical coherence tomography (OCT), SD enhanced depth imaging OCT, and OCT angiography (OCTA) imaging results of MRNF-affected eyes were compared with the fellow eyes and myopic controls. Results All patients had abnormal foveal reflex and/or ectopia. No significant difference in retinal thickness parameters were noted between the groups. In OCT scans, posterior vitreous detachment (PVD) was observed in 4 out of the 6 MRNF-affected eyes. Regarding OCTA parameters, only a significant increase in acircularity index was noted in myelinated eyes (p=0.01). Conclusion All patients demonstrated normal foveal contours, macular structure, and OCTA features except for a higher acircularity index. The incidence of PVD was notably increased in the myelinated eyes.
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Affiliation(s)
| | - Sibel Oto
- Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Türkiye
| | - İmren Akkoyun
- Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Türkiye
| | - Sezin Akça Bayar
- Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Türkiye
| | - Gürsel Yılmaz
- Başkent University Faculty of Medicine, Department of Ophthalmology, Ankara, Türkiye
| | - Meriç Yavuz Çolak
- Başkent University Faculty of Medicine, Department of Biostatistics, Ankara, Türkiye
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14
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Abstract
Despite the large number of immunomodulatory or immunosuppressive treatments available to treat relapsing-remitting multiple sclerosis (MS), treatment of the progressive phase of the disease has not yet been achieved. This lack of successful treatment approaches is caused by our poor understanding of the mechanisms driving disease progression. Emerging concepts suggest that a combination of persisting focal and diffuse inflammation within the CNS and a gradual failure of compensatory mechanisms, including remyelination, result in disease progression. Therefore, promotion of remyelination presents a promising intervention approach. However, despite our increasing knowledge regarding the cellular and molecular mechanisms regulating remyelination in animal models, therapeutic increases in remyelination remain an unmet need in MS, which suggests that mechanisms of remyelination and remyelination failure differ fundamentally between humans and demyelinating animal models. New and emerging technologies now allow us to investigate the cellular and molecular mechanisms underlying remyelination failure in human tissue samples in an unprecedented way. The aim of this Review is to summarize our current knowledge regarding mechanisms of remyelination and remyelination failure in MS and in animal models of the disease, identify open questions, challenge existing concepts, and discuss strategies to overcome the translational roadblock in the field of remyelination-promoting therapies.
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Affiliation(s)
- Luisa Klotz
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada
| | - Tanja Kuhlmann
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Québec, Canada.
- Institute of Neuropathology, University Hospital Münster, Münster, Germany.
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15
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Janssen N, Kessels RPC, Mars RB, Llera A, Beckmann CF, Roelofs A. Dissociating the functional roles of arcuate fasciculus subtracts in speech production. Cereb Cortex 2023; 33:2539-2547. [PMID: 35709759 PMCID: PMC10016035 DOI: 10.1093/cercor/bhac224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 11/12/2022] Open
Abstract
Recent tractography and microdissection studies have shown that the left arcuate fasciculus (AF)-a fiber tract thought to be crucial for speech production-consists of a minimum of 2 subtracts directly connecting the temporal and frontal cortex. These subtracts link the posterior superior temporal gyrus (STG) and middle temporal gyrus (MTG) to the inferior frontal gyrus. Although they have been hypothesized to mediate different functions in speech production, direct evidence for this hypothesis is lacking. To functionally segregate the 2 AF segments, we combined functional magnetic resonance imaging with diffusion-weighted imaging and probabilistic tractography using 2 prototypical speech production tasks, namely spoken pseudoword repetition (tapping sublexical phonological mapping) and verb generation (tapping lexical-semantic mapping). We observed that the repetition of spoken pseudowords is mediated by the subtract of STG, while generating an appropriate verb to a spoken noun is mediated by the subtract of MTG. Our findings provide strong evidence for a functional dissociation between the AF subtracts, namely a sublexical phonological mapping by the STG subtract and a lexical-semantic mapping by the MTG subtract. Our results contribute to the unraveling of a century-old controversy concerning the functional role in speech production of a major fiber tract involved in language.
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Affiliation(s)
- Nikki Janssen
- Corresponding author: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Thomas van Aquinostraat 3, 6525 GD, Nijmegen, the Netherlands.
| | - Roy P C Kessels
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, PO Box 9104, 6500 HE Nijmegen, the Netherlands
- Department of Medical Psychology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
- Vincent van Gogh Institute for Psychiatry, Centre of Excellence for Korsakoff and Alcohol-Related Cognitive Disorders, D'n Herk 90, 5803 DN, Venray, the Netherlands
| | - Rogier B Mars
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, PO Box 9104, 6500 HE Nijmegen, the Netherlands
- Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX39DU, United Kingdom
| | - Alberto Llera
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, PO Box 9104, 6500 HE Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Medical Centre Nijmegen, Postbus 9101, Nijmegen, 6500 HB, the Netherlands
| | - Christian F Beckmann
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, PO Box 9104, 6500 HE Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Medical Centre Nijmegen, Postbus 9101, Nijmegen, 6500 HB, the Netherlands
- Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford OX39DU, United Kingdom
| | - Ardi Roelofs
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognition, Radboud University, PO Box 9104, 6500 HE Nijmegen, the Netherlands
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Sharma A, Wu L, Bloom S, Stanga P, Rachitskaya AV, Gibson W, Rezaei KA. RWC Update: DRCR Retina Network Protocol AC, Step Therapy, and Clinical Practice Implications; Central Retinal Vein Occlusion with Secondary Branch Retinal Artery Occlusion and Incidental Myelinated Nerve Fiber Layer and CHRPE. Ophthalmic Surg Lasers Imaging Retina 2023; 54:127-130. [PMID: 36944069 DOI: 10.3928/23258160-20230130-05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
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17
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Wang J, Wen C, Li J, Chen J, Feng Y. Automated quantification of brain connectivity in Alzheimer's disease using ClusterMetric. Neurosci Lett 2022; 785:136724. [PMID: 35697157 DOI: 10.1016/j.neulet.2022.136724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/26/2022] [Accepted: 06/08/2022] [Indexed: 11/18/2022]
Abstract
Diffusion magnetic resonance imaging tractography allows investigating brain structural connections in a noninvasive way and has been widely used for understanding neurological disease. Quantification of brain connectivity along with its length by dividing a fiber bundle into multiple segments (node) is a powerful approach to assess biological properties, which is termed as tractometry. However, current tractometry methods face challenges in node identification along with the length of complex bundles whose morphology is difficult to summarize. In addition, the anatomic measure reflecting the macroscopic fiber cross-section has not been followed in previous tractometry. In this paper, we propose an automated fiber bundle quantification, which we refer to as ClusterMetric. The ClusterMetric uses a data-driven approach to identify fiber clusters corresponding to subdivisions of the white matter anatomy and identify consistent space nodes along the length of clusters across individuals. The proposed method is demonstrated by applicating to our collected dataset including 23 Alzheimer's disease (AD) patients and 22 healthy controls (HCs) and a public dataset of ADNI including 53 AD patients and 85 HCs. The altered white matter tracts in AD group are observed using both datasets, which involve several major fiber tracts including the corpus callosum, corona-radiata-frontal, arcuate fasciculus, inferior occipito-frontal fasciculus, uncinate fasciculus, thalamo-frontal, superior longitudinal fasciculus, inferior cerebellar peduncle, cingulum bundle, and extreme capsule. These fiber clusters represent the white matter connections that could be most affected in AD, suggesting the ability of our method in identifying potential abnormalities specific to local regions within a fiber cluster.
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Affiliation(s)
- Jingqiang Wang
- Institution of Information Processing and Automation, College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Caiyun Wen
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jinwen Li
- Institution of Information Processing and Automation, College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
| | | | - Yuanjing Feng
- Institution of Information Processing and Automation, College of Information Engineering, Zhejiang University of Technology, Hangzhou, China.
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18
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Wang G, Dokos S. Selective myelinated nerve fiber stimulation via temporal interfering electric fields. Annu Int Conf IEEE Eng Med Biol Soc 2021; 2021:6033-6036. [PMID: 34892492 DOI: 10.1109/embc46164.2021.9630073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We have investigated selective electrical stimulation of myelinated nerve fibers using a computational model of temporal interfering (TI) fields. The model consists of two groups of electrodes placed on the outer bundle surface, each group stimulated at a different frequency. We manipulated the stimulus waveform, magnitude and frequency of short-duration stimuli (70ms), and investigated fiber-specific stimulus-elicited compound action potentials. Results show that under 100Hz & 200Hz TI stimulation with 0.6mA total current shared by the electrodes, continuous action potentials were generated in deeper nerve fibers, and that the firing region was steerable by changing individual electrode currents. This study provides a promising platform for non-invasive nerve bundle stimulation by TI fields.
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19
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Mendoza C, Roman C, Vazquez A, Poupon C, Mangin JF, Hernandez C, Guevara P. Enhanced Automatic Segmentation for Superficial White Matter Fiber Bundles for Probabilistic Tractography Datasets. Annu Int Conf IEEE Eng Med Biol Soc 2021; 2021:3654-3658. [PMID: 34892029 DOI: 10.1109/embc46164.2021.9630529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
This paper presents an enhanced algorithm for automatic segmentation of superficial white matter (SWM) bundles from probabilistic dMRI tractography datasets, based on a multi-subject bundle atlas. Previous segmentation methods use the maximum Euclidean distance between corresponding points of the subject fibers and the atlas centroids. However, this scheme might include noisy fibers. Here, we propose a three step approach to discard noisy fibers improving the identification of fibers. The first step applies a fiber clustering and the segmentation is performed between the centroids of the clusters and the atlas centroids. This step removes outliers and enables a better identification of fibers with similar shapes. The second step applies a fiber filter based on two different fiber similarities. One is the Symmetrized Segment-Path Distance (SSPD) over 2D ISOMAP and the other is an adapted version of SSPD for 3D space. The last step eliminates noisy fibers by removing those that connect regions that are far from the main atlas bundle connections. We perform an experimental evaluation using ten subjects of the Human Connectome (HCP) database. The evaluation only considers the bundles connecting precentral and postcentral gyri, with a total of seven bundles per hemisphere. For comparison, the bundles of the ten subjects were manually segmented. Bundles segmented with our method were evaluated in terms of similarity to manually segmented bundles and the final number of fibers. The results show that our approach obtains bundles with a higher similarity score than the state-of-the-art method and maintains a similar number of fibers.Clinical relevance-Many brain pathologies or disorders can occur in specific regions of the SWM automatic segmentation of reliable SWM bundles would help applications to clinical research.
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20
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Chung SA, Kim CW, Kim SW. Progressive Myelinated Retinal Nerve Fibers in Children With Craniosynostosis. J Pediatr Ophthalmol Strabismus 2021; 58:e40-e41. [PMID: 34851788 DOI: 10.3928/01913913-20210824-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The authors found the changes of myelinated retinal nerve fibers in one pair of identical twins with nonsyndromic craniosynostosis and two patients with Crouzon syndrome, who were at risk for impaired lamina cribrosa barrier function. This is the first report of progressive and presumed acquired myelinated retinal nerve fibers in craniosynostosis. [J Pediatr Ophthalmol Strabismus. 2021;58(6):e40-e43.].
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21
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Preziosa C, Milani P, Ciasca P, Bergamini F, Staurenghi G, Pellegrini M. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FINDINGS IN A CASE OF CONGENITAL RETINAL MACROVESSEL WITH ANOMALOUS RETINAL ANASTOMOSIS ASSOCIATED WITH CONTRALATERAL MYELINATED NERVE FIBERS AND RETINAL VASCULAR ABNORMALITIES. Retin Cases Brief Rep 2021; 15:605-610. [PMID: 30830007 DOI: 10.1097/icb.0000000000000861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To describe a case of congenital retinal macrovessel complicated by cystoid macular edema associated with contralateral myelinated retinal nerve fibers and retinal vascular abnormalities studied with optical coherence tomography angiography (OCTA). METHODS Case report. RESULTS A healthy 25-year-old woman with decreased vision in her right eye was found to have a congenital retinal venous macrovessel in the macula associated with cystoid edema. In the contralateral amblyopic eye, the examination revealed a tuft of myelinated retinal nerve fibers along the superotemporal vascular arcade associated with superficial vascular abnormalities. A complete multi-imaging examination was obtained, including fundus color photography, fluorescein angiography, indocyanine green angiography, optical coherence tomography (OCT), and optical coherence tomography angiography. At 1-week follow-up, the optical coherence tomography displayed spontaneous resolution of the edema that remained stable at consecutive 1-month follow-up. CONCLUSION Congenital retinal macrovessels can be associated with other ocular developmental anomalies. Vascular complications can occur, leading to macular edema and retinal ischemia. Optical coherence tomography angiography can be useful for the diagnosis and follow-up of this condition.
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Affiliation(s)
- Chiara Preziosa
- Department of Biomedical and Clinical Science "Luigi Sacco," Eye Clinic, Luigi Sacco Hospital, University of Milan, Milan, Italy ; and
| | - Paolo Milani
- Department of Ophthalmology, Scientific Institute Capitanio Hospital, IRCCS Foundation, Istituto Auxologico Italiano, Milan, Italy
| | - Paola Ciasca
- Department of Ophthalmology, Scientific Institute Capitanio Hospital, IRCCS Foundation, Istituto Auxologico Italiano, Milan, Italy
| | - Fulvio Bergamini
- Department of Ophthalmology, Scientific Institute Capitanio Hospital, IRCCS Foundation, Istituto Auxologico Italiano, Milan, Italy
| | - Giovanni Staurenghi
- Department of Biomedical and Clinical Science "Luigi Sacco," Eye Clinic, Luigi Sacco Hospital, University of Milan, Milan, Italy ; and
| | - Marco Pellegrini
- Department of Biomedical and Clinical Science "Luigi Sacco," Eye Clinic, Luigi Sacco Hospital, University of Milan, Milan, Italy ; and
- Department of Ophthalmology, Scientific Institute Capitanio Hospital, IRCCS Foundation, Istituto Auxologico Italiano, Milan, Italy
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22
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Guo F, de Luca A, Parker G, Jones DK, Viergever MA, Leemans A, Tax CMW. The effect of gradient nonlinearities on fiber orientation estimates from spherical deconvolution of diffusion magnetic resonance imaging data. Hum Brain Mapp 2021; 42:367-383. [PMID: 33035372 PMCID: PMC7776002 DOI: 10.1002/hbm.25228] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 12/12/2022] Open
Abstract
Gradient nonlinearities in magnetic resonance imaging (MRI) cause spatially varying mismatches between the imposed and the effective gradients and can cause significant biases in rotationally invariant diffusion MRI measures derived from, for example, diffusion tensor imaging. The estimation of the orientational organization of fibrous tissue, which is nowadays frequently performed with spherical deconvolution techniques ideally using higher diffusion weightings, can likewise be biased by gradient nonlinearities. We explore the sensitivity of two established spherical deconvolution approaches to gradient nonlinearities, namely constrained spherical deconvolution (CSD) and damped Richardson-Lucy (dRL). Additionally, we propose an extension of dRL to take into account gradient imperfections, without the need of data interpolation. Simulations show that using the effective b-matrix can improve dRL fiber orientation estimation and reduces angular deviations, while CSD can be more robust to gradient nonlinearity depending on the implementation. Angular errors depend on a complex interplay of many factors, including the direction and magnitude of gradient deviations, underlying microstructure, SNR, anisotropy of the effective response function, and diffusion weighting. Notably, angular deviations can also be observed at lower b-values in contrast to the perhaps common assumption that only high b-value data are affected. In in vivo Human Connectome Project data and acquisitions from an ultrastrong gradient (300 mT/m) scanner, angular differences are observed between applying and not applying the effective gradients in dRL estimation. As even small angular differences can lead to error propagation during tractography and as such impact connectivity analyses, incorporating gradient deviations into the estimation of fiber orientations should make such analyses more reliable.
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Affiliation(s)
- Fenghua Guo
- Image Sciences InstituteUniversity Medical Center Utrecht, Utrecht UniversityUtrechtThe Netherlands
| | - Alberto de Luca
- Image Sciences InstituteUniversity Medical Center Utrecht, Utrecht UniversityUtrechtThe Netherlands
| | - Greg Parker
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff UniversityCardiffUK
| | - Derek K. Jones
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff UniversityCardiffUK
| | - Max A. Viergever
- Image Sciences InstituteUniversity Medical Center Utrecht, Utrecht UniversityUtrechtThe Netherlands
| | - Alexander Leemans
- Image Sciences InstituteUniversity Medical Center Utrecht, Utrecht UniversityUtrechtThe Netherlands
| | - Chantal M. W. Tax
- Image Sciences InstituteUniversity Medical Center Utrecht, Utrecht UniversityUtrechtThe Netherlands
- Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff UniversityCardiffUK
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23
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Pidlisetskyy А, Savosko S, Dolhopolov О, Makarenko O. PERIPHERAL NERVE LESIONS AFTER A MECHANICALLY INDUCED LIMB ISCHEMIA. Georgian Med News 2021:165-169. [PMID: 33658426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The article describes the results of studying the changes in peripheral nerves of a limb after a mechanically induced ischemia. It assessed myelinated nerve fibers in sciatic and tibial nerves after 6 hours of ischemia, simulated by a tourniquet on the level of a tibial, knee, and a lower third of a femur. Fasciculi of the sciatic nerve have shown no changes in the density of nerve fibers in 5th, 15th, and 30th days after the simulated ischemia, but we revealed the deformed fibers with the different thickness of myelin sheath. In a tibial nerve, myelin loss and deformations occurred on the 5th and 15th day, and atrophy of nerve fibers - on the 15th and 30th days. Neurolemmocytes of the injured myelin nerve fibers demonstrate the signs of dystrophic processes and autophagy. After the insertion of platelet-rich plasma, concentrated bone marrow aspirate, and homogenized adipose tissue in the ischemically damaged muscles, not a significant difference appeared between the extent of damage to the nerve. Consequently, the structural signs of the damage to peripheral nerves depend more on the level of injury to a limb than on therapy with autologous cellular technologies.
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Affiliation(s)
- А Pidlisetskyy
- Lviv Regional Hospital for War Veterans and Repressed named after Yu. Lypa; Ukraine
| | - S Savosko
- Bogomolets National Medical University, Department of Histology and Embryology; Ukraine
| | - О Dolhopolov
- SI "Institute of Traumatology and Orthopedics under NAMS of Ukraine; Ukraine
| | - O Makarenko
- Interregional Academy of Personnel Management, Ukraine
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Abdolalizadeh A, Ostadrahimi H, Mohajer B, Darvishi A, Sattarian M, Bayani Ershadi AS, Abbasi N. White Matter Microstructural Properties Associated with Impaired Attention in Chronic Schizophrenia: A Multi-Center Study. Psychiatry Res Neuroimaging 2020; 302:111105. [PMID: 32498000 DOI: 10.1016/j.pscychresns.2020.111105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 04/24/2020] [Accepted: 05/01/2020] [Indexed: 12/17/2022]
Abstract
Attention as a key cognitive function is impaired in schizophrenia, interfering with the normal daily life of the patients. Previous studies on the microstructural correlates of attention in schizophrenia were limited to single fibers, did not include a control group, or did not adjust for drug dosage. In the current study, we investigated the association between microstructural properties of the white matter fibers and attention tests in 81 patients and 79 healthy controls from the Mind Clinical Imaging Consortium database. Integrity measures of superior longitudinal fasciculus, cingulum, genu, and splenium were extracted after tractography. Using an interaction model between diagnosis and microstructural properties, and adjusting for age, gender, acquisition site, education, and cumulative drug usage dose, and after correcting for family-wise error, we showed decreased integrity in the patients and a significant negative association between fractional anisotropy of the tracts and trail making test part A with a greater expected decrease in the attention per unit of decrease of integrity in the patients compared to the healthy controls. Our findings suggest that decreased integrity of the bilateral cingulum, and splenium, are independent of the cumulative drug dosage, age, gender, and site, and may underlie the impaired attention in the schizophrenia.
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Affiliation(s)
| | - Hamidreza Ostadrahimi
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Mohajer
- Non-Communicable Diseases Research Center, Endocrinology and Metabolism Population Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Asma Darvishi
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahta Sattarian
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Nooshin Abbasi
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Canada
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25
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Shakeel MK, MacQueen G, Addington J, Metzak PD, Georgopoulos G, Bray S, Goldstein BI, MacIntosh BJ, Wang J, Kennedy SH, Lebel C. White Matter Connectivity in Youth at Risk for Serious Mental Illness: A Longitudinal Analysis. Psychiatry Res Neuroimaging 2020; 302:111106. [PMID: 32505905 DOI: 10.1016/j.pscychresns.2020.111106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/28/2020] [Accepted: 05/04/2020] [Indexed: 11/28/2022]
Abstract
Longitudinal changes in white matter connectivity were assessed in a sample of youth at-risk for serious mental illness (n=183; age 12-25). Diffusion tensor imaging (DTI) was acquired at baseline and 12 months from youth recruited across two sites and classified as healthy controls (n=36), familial risk (n=30), mild-symptoms (n=41), attenuated syndromes (n=70), or transition (n=9) based on clinical assessments. Fractional anisotropy (FA) and mean diffusivity (MD) values were derived for the whole brain white matter, forceps minor, anterior cingulate, anterior thalamic radiations, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, and uncinate fasciculus. MANCOVA analysis controlling for site, sex, and age showed no significant group differences in FA and MD at baseline or at 12 months. Linear mixed effects analysis showed a significant effect for time for most white matter tracts, but no effect for group, or group by time interaction. Transdiagnostic risk groups have similar profiles of WM connectivity and similar rates of change over time.
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Affiliation(s)
- Mohammed K Shakeel
- Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Glenda MacQueen
- Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jean Addington
- Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
| | - Paul D Metzak
- Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Grace Georgopoulos
- Department of Psychiatry, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Signe Bray
- Department of Radiology, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Department of Radiology, Child and Adolescent Imaging Research Program, Calgary, Alberta, Canada
| | - Benjamin I Goldstein
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Bradley J MacIntosh
- Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - JianLi Wang
- Work and Mental Health Research Unit, Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada; School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Sidney H Kennedy
- Department of Psychiatry, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, St. Michael's Hospital, Toronto, Ontario, Canada; Arthur Sommer Rotenberg Chair in Suicide and Depression Studies, St. Michael's Hospital, Toronto, Ontario, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Catherine Lebel
- Department of Radiology, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Department of Radiology, Child and Adolescent Imaging Research Program, Calgary, Alberta, Canada
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Melo-Carrillo A, Schain AJ, Strassman AM, Burstein R. Activation of Peripheral and Central Trigeminovascular Neurons by Seizure: Implications for Ictal and Postictal Headache. J Neurosci 2020; 40:5314-5326. [PMID: 32527981 PMCID: PMC7329305 DOI: 10.1523/jneurosci.0283-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/12/2020] [Accepted: 04/15/2020] [Indexed: 11/21/2022] Open
Abstract
An epileptic seizure can trigger a headache during (ictal) or after (postictal) the termination of the event. Little is known about the pathophysiology of seizure-induced headaches. In the current study, we determined whether a seizure can activate nociceptive pathways that carry pain signals from the meninges to the spinal cord, and if so, to what extent and through which classes of peripheral and central neurons. To achieve these goals, we used single-unit recording techniques and an established animal model of seizure (picrotoxin) to determine the effects of epileptic seizure on the activity of trigeminovascular Aδ-, C-, wide-dynamic range, and high-threshold neurons in male and female rats. Occurrence of seizure activated 54%, 50%, 68%, and 39% of the Aδ-, C-, wide-dynamic range, and high-threshold neurons, respectively. Regardless of their class, activated neurons exhibited a twofold to fourfold increase in their firing, which started immediately (1 min) or up to 90 min after seizure initiation, and lasted as short as 10 min or as long as 120 min. Administration of lidocaine to the dura prevented activation of all neuronal classes but not the initiation or maintenance of the seizure. These findings suggest that all neuronal classes may be involved in the initiation and maintenance of seizure-induced headache, and that their activation patterns can provide a neural substrate for explaining the timing and duration of ictal and possibly postictal headaches. By using seizure, which is evident in humans, this study bypasses controversies associated with cortical spreading depression, which is less readily observed in humans.SIGNIFICANCE STATEMENT This preclinical study provides a neural substrate for ictal and postictal headache. By studying seizure effects on the activity of peripheral (C and Aδ) and central (wide dynamic range and high-threshold) trigeminovascular neurons in intact and anesthetized dura, the findings help resolve two outstanding questions about the pathophysiology of headaches of intracranial origin. The first is that abnormal brain activity (i.e., seizure) that is evident in human (unlike cortical spreading depression) gives rise to specific and selective activation of the different components of the trigeminovascular system, and the second is that the activation of all components of the trigeminovascular pathway (i.e., peripheral and central neurons) depends on activation of the meningeal nociceptors from their receptors in the dura.
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Affiliation(s)
- Agustin Melo-Carrillo
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02215
| | - Aaron J Schain
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02215
| | - Andrew M Strassman
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02215
| | - Rami Burstein
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
- Harvard Medical School, Boston, Massachusetts 02215
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Garcia-Egan PM, Preston-Campbell RN, Salminen LE, Heaps-Woodruff JM, Balla L, Cabeen RP, Laidlaw DH, Conturo TE, Paul RH. Behavioral inhibition corresponds to white matter fiber bundle integrity in older adults. Brain Imaging Behav 2020; 13:1602-1611. [PMID: 31209835 DOI: 10.1007/s11682-019-00144-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Little is known about the contribution of white matter integrity to inhibitory cognitive control, particularly in healthy aging. The present study examines the correspondence between white matter fiber bundle length and behavioral inhibition in 37 community-dwelling older adults (aged 51-78 years). Participants underwent neuroimaging with 3 Tesla MRI, and completed a behavioral test of inhibition (i.e., Go/NoGo task). Quantitative tractography derived from diffusion tensor imaging (qtDTI) was used to measure white matter fiber bundle lengths (FBLs) in tracts known to innervate frontal brain regions, including the anterior corpus callosum (AntCC), the cingulate gyrus segment of the cingulum bundle (CING), uncinate fasciculus (UNC), and the superior longitudinal fasciculus (SLF). Performance on the Go/NoGo task was measured by the number of commission errors standardized to reaction time. Hierarchical regression models revealed that shorter FBLs in the CING (p < 0.05) and the bilateral UNC (p < 0.01) were associated with lower inhibitory performance after adjusting for multiple comparisons, supporting a disconnection model of response inhibition in older adults. Prospective longitudinal studies are needed to examine the evolution of inhibitory errors in older adult populations and potential for therapeutic intervention.
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Affiliation(s)
- Paola M Garcia-Egan
- Department of Psychological Sciences, University of Missouri, St. Louis, MO, 63121, USA
| | | | - Lauren E Salminen
- Imaging Genetics Center, Stevens Neuroimaging and Informatics Institute, University of Southern California, Marina del Rey, CA, 90292, USA
| | | | - Lila Balla
- Missouri Institute of Mental Health, St. Louis, MO, 63134, USA
| | - Ryan P Cabeen
- Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, Keck School of Medicine of USC, University of Southern California, LosAngeles, CA, 90033, USA
| | - David H Laidlaw
- Department of Computer Science, Brown University, Providence, RI, 02906, USA
| | - Thomas E Conturo
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Robert H Paul
- Department of Psychological Sciences, University of Missouri, St. Louis, MO, 63121, USA.
- Missouri Institute of Mental Health, St. Louis, MO, 63134, USA.
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Sadashivaiah V, Sacre P, Guan Y, Anderson WS, Sarma SV. Studying the interactions in a mammalian nerve fiber: a functional modeling approach. Annu Int Conf IEEE Eng Med Biol Soc 2019; 2018:3525-3528. [PMID: 30441139 DOI: 10.1109/embc.2018.8512975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Modern therapeutic interventions are increasingly favoring electrical stimulation to treat neurophysiological dis-orders. These therapies are associated with suboptimal efficacy since most neurostimulation devices operate in an open-loop manner $(i.e.$, stimulation settings like frequency, amplitude are preprogrammed). A closed-loop system can dynamically adjust stimulation parameters and may provide efficient therapies. Computational models used to design these systems vary in complexity which can adversely affect their real-time performance. In this study, we compare two models of varying degrees of complexity. We constructed two computational models of a myelinated nerve fiber (functional versus mechanistic) each receiving two inputs: the underlying physiological activity at one end of the fiber, and the external stimulus applied to the middle of the fiber. We then defined relay reliability as the percentage of physiological action potentials that make it to the other end of the nerve fiber. We applied the two inputs to the fiber at various frequencies and analyze reliability. We found that the functional model and the mechanistic model have similar reliability properties, but the functional model significantly decreases the computational complexity and simulation run time. This modeling effort is the first step towards understanding and designing closed loop, real-time neurostimulation devices.
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29
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Grotheer M, Zhen Z, Lerma-Usabiaga G, Grill-Spector K. Separate lanes for adding and reading in the white matter highways of the human brain. Nat Commun 2019; 10:3675. [PMID: 31417075 PMCID: PMC6695422 DOI: 10.1038/s41467-019-11424-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 07/09/2019] [Indexed: 01/11/2023] Open
Abstract
Math and reading involve distributed brain networks and have both shared (e.g. encoding of visual stimuli) and dissociated (e.g. quantity processing) cognitive components. Yet, to date, the shared vs. dissociated gray and white matter substrates of the math and reading networks are unknown. Here, we define these networks and evaluate the structural properties of their fascicles using functional MRI, diffusion MRI, and quantitative MRI. Our results reveal that there are distinct gray matter regions which are preferentially engaged in either math (adding) or reading, and that the superior longitudinal and arcuate fascicles are shared across the math and reading networks. Strikingly, within these fascicles, reading- and math-related tracts are segregated into parallel sub-bundles and show structural differences related to myelination. These findings open a new avenue of research that examines the contribution of sub-bundles within fascicles to specific behaviors.
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Affiliation(s)
- Mareike Grotheer
- Psychology Department, Stanford University, Stanford, CA, 94305, USA.
| | - Zonglei Zhen
- Beijing Key Laboratory of Applied Experimental Psychology, Faculty of Psychology, Beijing Normal University, Beijing, 100875, China
| | - Garikoitz Lerma-Usabiaga
- Psychology Department, Stanford University, Stanford, CA, 94305, USA
- BCBL. Basque Center on Cognition, Brain and Language, Mikeletegi Pasealekua 69, Donostia - San Sebastián, 20009, Gipuzkoa, Spain
| | - Kalanit Grill-Spector
- Psychology Department, Stanford University, Stanford, CA, 94305, USA
- Stanford Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
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Zhang F, Wu Y, Norton I, Rathi Y, Golby AJ, O'Donnell LJ. Test-retest reproducibility of white matter parcellation using diffusion MRI tractography fiber clustering. Hum Brain Mapp 2019; 40:3041-3057. [PMID: 30875144 PMCID: PMC6548665 DOI: 10.1002/hbm.24579] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/28/2019] [Accepted: 03/07/2019] [Indexed: 01/22/2023] Open
Abstract
There are two popular approaches for automated white matter parcellation using diffusion MRI tractography, including fiber clustering strategies that group white matter fibers according to their geometric trajectories and cortical-parcellation-based strategies that focus on the structural connectivity among different brain regions of interest. While multiple studies have assessed test-retest reproducibility of automated white matter parcellations using cortical-parcellation-based strategies, there are no existing studies of test-retest reproducibility of fiber clustering parcellation. In this work, we perform what we believe is the first study of fiber clustering white matter parcellation test-retest reproducibility. The assessment is performed on three test-retest diffusion MRI datasets including a total of 255 subjects across genders, a broad age range (5-82 years), health conditions (autism, Parkinson's disease and healthy subjects), and imaging acquisition protocols (three different sites). A comprehensive evaluation is conducted for a fiber clustering method that leverages an anatomically curated fiber clustering white matter atlas, with comparison to a popular cortical-parcellation-based method. The two methods are compared for the two main white matter parcellation applications of dividing the entire white matter into parcels (i.e., whole brain white matter parcellation) and identifying particular anatomical fiber tracts (i.e., anatomical fiber tract parcellation). Test-retest reproducibility is measured using both geometric and diffusion features, including volumetric overlap (wDice) and relative difference of fractional anisotropy. Our experimental results in general indicate that the fiber clustering method produced more reproducible white matter parcellations than the cortical-parcellation-based method.
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Affiliation(s)
- Fan Zhang
- Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Ye Wu
- Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Isaiah Norton
- Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
| | - Yogesh Rathi
- Brigham and Women's HospitalHarvard Medical SchoolBostonMassachusetts
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31
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Mottahedin A, Zhang X, Zelco A, Ardalan M, Lai JCY, Mallard C, Wang X, Ahmady Phoulady H. A novel image segmentation method for the evaluation of inflammation-induced cortical and hippocampal white matter injury in neonatal mice. J Chem Neuroanat 2018; 96:79-85. [PMID: 30586607 DOI: 10.1016/j.jchemneu.2018.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 11/30/2018] [Accepted: 12/21/2018] [Indexed: 01/20/2023]
Abstract
The developing brain is very susceptible to environmental insults, and very immature infants often suffer from long-term neurological syndromes associated with white matter injuries such as periventricular leukomalacia. Infection and inflammation are important risk factors for neonatal brain white matter injuries, but the evaluation of white matter injury in animal models, especially the quantification of myelinated axons, has long been problematic due to the lack of ideal measurement methods. Here, we present an automated segmentation method, which we call MyelinQ, for the quantification of myelinated white matter in immunohistochemical DAB-stained sections of the neonatal mouse brain. Using MyelinQ, we show that a viral infection mimic agent, the Toll-like receptor 3 ligand Poly I:C, causes significant hypomyelination of white matter in the cortical and hippocampal fimbria regions, but not in the striatal caudoputamen region. We showed that MyelinQ can reliably produce results that are comparable to a method used in our previous publications. However, in comparison to the conventional method, MyelinQ has the advantages of being automated, objective and accurate. MyelinQ can analyze white matter in various specific brain regions and therefore provides a useful platform for the quantification of myelin and the evaluation of white matter injuries in animal models. MyelinQ and its code together with instructions for use can be found at: https://github.com/parham-ap/myelinq.
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Affiliation(s)
- Amin Mottahedin
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Xiaoli Zhang
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden; Henan Key Laboratory of Child Brain Injury, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Aura Zelco
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Maryam Ardalan
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Jacqueline C Y Lai
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Carina Mallard
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden; Henan Key Laboratory of Child Brain Injury, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaoyang Wang
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden; Henan Key Laboratory of Child Brain Injury, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hady Ahmady Phoulady
- Department of Computer Science, University of Southern Maine, Portland, ME, USA.
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32
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Pinto D, Roman C, Guevara M, Poupon C, Mangin JF, Guevara P. A stringent fiber distance measure for dMRI tractography clustering and segmentation. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:1-4. [PMID: 30440248 DOI: 10.1109/embc.2018.8512333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most analysis and segmentation methods for diffusion MRI tractography datasets require a fiber distance measure able to determine the similarity between a pair of fibers. We present a stringent fiber distance measure able to perform a good discrimination between fiber shapes and lengths. It uses three terms: (i) a fiber maximum Euclidean distance, (ii) a fiber shape distance, and (iii) a fiber length distance. The distance was evaluated applying a hierarchical clustering of fibers connecting the pre-and post-central gyri of a subject. Results where compared with other known fiber distance measures. A better sensitivity to differences in fiber shape and length was found for the proposed distance. This will be very useful for the detailed study and description of white matter bundles. Known bundles will be better decomposed into sub-bundles, with more precision on the bundle shape and on the regions connected by the fibers. For short association bundles, this distance will be a real improvement, as even the most stringent distance used until now shows some limitations when evaluating the similarity of these fibers.
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33
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Abstract
A rapidly developing application of high field MRI is the study of brain anatomy and function with contrast based on the magnetic susceptibility of tissues. To study the subtle variations in susceptibility contrast between tissues and with changes in brain activity, dedicated scan techniques such as susceptibility-weighted MRI and blood-oxygen level dependent functional MRI have been developed. Particularly strong susceptibility contrast has been observed with systems that operate at 7T and above, and their recent widespread use has led to an improved understanding of contributing sources and mechanisms. To interpret magnetic susceptibility contrast, analysis approaches have been developed with the goal of extracting measures that report on local tissue magnetic susceptibility, a physical quantity that, under certain conditions, allows estimation of blood oxygenation, local tissue iron content, and quantification of its changes with disease. Interestingly, high field studies have also brought to light that not only the makeup of tissues affects MRI susceptibility contrast, but that also a tissue's sub-voxel structure at scales all the way down to the molecular level plays an important role as well. In this review, various ways will be discussed by which sub-voxel structure can affect the MRI signal in general, and magnetic susceptibility in particular, sometimes in a complex fashion. In the light of this complexity, it appears likely that accurate, brain-wide quantification of iron will require the combination of multiple contrasts that may include diffusion and magnetization transfer information with susceptibility-weighted contrast. On the other hand, this complexity also offers opportunities to use magnetic susceptibility contrast to inform about specific microstructural aspects of brain tissue. Details and several examples will be presented in this review.
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Affiliation(s)
- Jeff H Duyn
- Advanced MRI Section, Laboratory of Functional and Molecular Imaging, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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34
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Glozman T, Bruckert L, Pestilli F, Yecies DW, Guibas LJ, Yeom KW. Framework for shape analysis of white matter fiber bundles. Neuroimage 2018; 167:466-477. [PMID: 29203454 PMCID: PMC5845796 DOI: 10.1016/j.neuroimage.2017.11.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 10/26/2017] [Accepted: 11/22/2017] [Indexed: 12/24/2022] Open
Abstract
Diffusion imaging coupled with tractography algorithms allows researchers to image human white matter fiber bundles in-vivo. These bundles are three-dimensional structures with shapes that change over time during the course of development as well as in pathologic states. While most studies on white matter variability focus on analysis of tissue properties estimated from the diffusion data, e.g. fractional anisotropy, the shape variability of white matter fiber bundle is much less explored. In this paper, we present a set of tools for shape analysis of white matter fiber bundles, namely: (1) a concise geometric model of bundle shapes; (2) a method for bundle registration between subjects; (3) a method for deformation estimation. Our framework is useful for analysis of shape variability in white matter fiber bundles. We demonstrate our framework by applying our methods on two datasets: one consisting of data for 6 normal adults and another consisting of data for 38 normal children of age 11 days to 8.5 years. We suggest a robust and reproducible method to measure changes in the shape of white matter fiber bundles. We demonstrate how this method can be used to create a model to assess age-dependent changes in the shape of specific fiber bundles. We derive such models for an ensemble of white matter fiber bundles on our pediatric dataset and show that our results agree with normative human head and brain growth data. Creating these models for a large pediatric longitudinal dataset may improve understanding of both normal development and pathologic states and propose novel parameters for the examination of the pediatric brain.
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Affiliation(s)
- Tanya Glozman
- Electrical Engineering, Stanford University, Stanford, CA, USA.
| | | | - Franco Pestilli
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Derek W Yecies
- Pediatric Neurosurgery, Stanford University, Stanford, CA, USA
| | | | - Kristen W Yeom
- Department of Radiology, Lucile Packard Children's Hospital, Stanford University, Stanford, CA, USA
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35
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36
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Capllonch-Juan M, Kolbl F, Sepulveda F. Unidirectional ephaptic stimulation between two myelinated axons. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2017:230-233. [PMID: 29059852 DOI: 10.1109/embc.2017.8036804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Providing realistic sensory feedback for prosthetic devices strongly relies on an accurate modelling of machine-nerve interfaces. Models of these interfaces in the peripheral nervous system usually neglect the effects that ephaptic coupling can have on the selectivity of stimulating electrodes. In this contribution, we study the ephaptic stimulation between myelinated axons and show its relation with the separation between fibers and the conductivity of the medium that surrounds them.
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37
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Potocnik I, Tomsic M, Sketelj J, Bajrovic FF. Articaine is More Effective than Lidocaine or Mepivacaine in Rat Sensory Nerve Conduction Block in vitro. J Dent Res 2016; 85:162-6. [PMID: 16434735 DOI: 10.1177/154405910608500209] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The reasons for the relatively high failure rate after inferior alveolar nerve block in dentistry are not fully understood. Therefore, the effectiveness of different anesthetic solutions (2% and 4% lidocaine, 3% mepivacine, 2% and 4% articaine) in depressing the compound action potential amplitude of the sensory fibers in the rat sural nerve was examined under strictly controlled conditions in vitro. After application of an anesthetic solution and stimulation of the nerve with a supramaximal electrical stimulus, a complete disappearance of the compound action potential of the C fibers, but not of the A fibers, was observed in all the experimental groups. Both 2% and 4% articaine more effectively depressed the compound action potential of the A fibers than did other anesthetic solutions. These results are discussed in the light of recent clinical reports finding no differences in the effectiveness between 4% articaine and 2% lidocaine regarding the inferior alveolar nerve block.
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Affiliation(s)
- I Potocnik
- Department of Restorative Dentistry & Endodontics, University of Ljubljana, Dental School, Hrvatski trg 6,1000 Ljubljana, Slovenia.
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Yeh CH, Smith RE, Liang X, Calamante F, Connelly A. Correction for diffusion MRI fibre tracking biases: The consequences for structural connectomic metrics. Neuroimage 2016; 142:150-162. [PMID: 27211472 DOI: 10.1016/j.neuroimage.2016.05.047] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/27/2016] [Accepted: 05/18/2016] [Indexed: 12/13/2022] Open
Affiliation(s)
- Chun-Hung Yeh
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
| | - Robert E Smith
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
| | - Xiaoyun Liang
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia
| | - Fernando Calamante
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Alan Connelly
- Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia; Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, Victoria, Australia
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Abstract
Andreas Vesalius is attributed the discovery of white matter in the 16th century but van Leeuwenhoek is arguably the first to have observed myelinated fibers in 1717. A globular myelin theory followed, claiming all elements of the nervous system except for Fontana's primitive cylinder with outer sheath in 1781. Remak's axon revolution in 1836 relegated myelin to the unknown. Ehrenberg described nerve tubes with double borders in 1833, and Schwann with nuclei in 1839, but the medullary sheath acquired its name of myelin, coined by Virchow, only in 1854. Thanks to Schultze's osmium specific staining in 1865, myelin designates the structure known today. The origin of myelin though was baffling. Only after Ranvier discovered a periodic segmentation, which came to us as nodes of Ranvier, did he venture suggesting in 1872 that the nerve internode was a fatty cell secreting myelin in cytoplasm. Ranvier's hypothesis was met with high skepticism, because nobody could see the cytoplasm, and the term Schwann cell very slowly emerged into the vocabulary with von Lenhossék in 1895. When Cajal finally admitted the concept of Schwann cell internode in 1912, he still firmly believed myelin was secreted by the axon. Del Río-Hortega re-discovered oligodendrocytes in 1919 (after Robertson in 1899) and named them oligodendroglia in 1921, thereby antagonizing Cajal for discovering a second cell type in his invisible third element. Penfield had to come to del Río-Hortega's rescue in 1924 for oligodendrocytes to be accepted. They jointly hypothesized myelin could be made by oligodendrocytes, considered the central equivalent of Schwann cells. Meanwhile myelin birefringence properties observed by Klebs in 1865 then Schmidt in 1924 confirmed its high fatty content, ascertained by biochemistry by Thudichum in 1884. The 20th century saw X-ray diffraction developed by Schmitt, who discovered in 1935 the crystal-like organization of this most peculiar structure, and devised the g-ratio concept in 1937. A revolution happened around the same time: saltatory conduction, the very reason for myelin existence, discovered by Tasaki in 1939 and confirmed by Huxley and Stämpfli in 1949. After the second world war, widely available electron microscopes allowed Geren to finally discover the origin of myelin in 1954, exactly a century after Virchow coined 'myelin' in 1854. Geren had the genial insight that the Schwann cell wraps around the axon and generates a spiral of compacted membrane-myelin. The central origin of myelin took a little longer due to the special configuration of oligodendrocyte distanced from the axon, but in 1962 the Bunges established the definitive proof that oligodendrocyte secretes myelin. The era of myelin biology had begun. In 1973 Norton devised a method to purify myelin which launched the modern molecular era.
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Affiliation(s)
- Anne Isabelle Boullerne
- 835 South Wolcott Ave. M/C 513 room E720, University of Illinois at Chicago, Department of Anesthesiology, Chicago, IL 60612, United States.
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Ream JM, Glielmi C, Lazar M, Campbell N, Pfeuffer J, Schneider R, Rosenkrantz AB. Zoomed echo-planar diffusion tensor imaging for MR tractography of the prostate gland neurovascular bundle without an endorectal coil: a feasibility study. Abdom Radiol (NY) 2016; 41:919-25. [PMID: 27193790 DOI: 10.1007/s00261-015-0587-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE The purpose of this study was to assess the feasibility of zoomed echo-planar imaging (EPI) diffusion tensor imaging (DTI) with 2-channel parallel transmission (pTx) for MR tractography of the periprostatic neurovascular bundle (NVB) without an endorectal coil, and to compare its performance to that of conventionally acquired DTI. METHODS 8 healthy males (28.9 ± 4.6 years) underwent pelvic phased-array coil prostate MRI on a 3T system using both zoomed-EPI DTI (z-DTI) with 2-channel pTx and conventional single-shot spin-echo EPI DTI (c-DTI) acquisitions with 6 encoding directions and b-values of 0 and 1000 s/mm(2). Fractional anisotropy (FA) maps and tractography analysis incorporating 3D visualization of the NVB were performed from each acquisition. Fiber tract counts, estimated signal-to-noise ratio (eSNR), and image quality measures of the FA maps and NVB tractography were compared. Quantitative and image quality measures were compared using Wilcoxon signed rank tests. RESULTS 3 of 8 subjects had no tracts detected with c-DTI acquisition, while all 8 had tracts detected with z-DTI. z-DTI acquisition yielded significantly more fiber tracts (c-DTI: 77 ± 116 tracts; z-DTI: 430 ± 228 tracts; p = 0.019) and higher eSNR (c-DTI: 2.9 ± 1.2; z-DTI: 13.17 ± 9.9; p = 0.014). Relative to c-DTI acquisitions, z-DTI FA maps showed significantly reduced artifact (p = 0.008) and reduced anatomic distortion of the prostate (p = 0.010), while z-DTI tractography showed significantly better overall visual quality (p = 0.011), tract symmetry (p = 0.010), tract coherence (p = 0.011), and subjective similarity to the actual NVB (p = 0.011). CONCLUSION Zoomed-EPI DTI acquisition for tractography of the prostate gland NVB improves quantitative and qualitative measures of image and tract fiber quality, allowing tractography of the NVB at 3T without using an endorectal coil.
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Affiliation(s)
- Justin M Ream
- Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA.
| | | | - Mariana Lazar
- Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA
| | - Naomi Campbell
- Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Josef Pfeuffer
- Imaging and Therapy Division, Siemens AG Healthcare Sector, Erlangen, Germany
| | - Rainer Schneider
- Imaging and Therapy Division, Siemens AG Healthcare Sector, Erlangen, Germany
| | - Andrew B Rosenkrantz
- Department of Radiology, New York University School of Medicine, NYU Langone Medical Center, 660 1st Avenue, New York, NY, 10016, USA
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Kent AR. Modeling the impact of spinal cord stimulation paddle lead position on impedance, stimulation threshold, and activation region. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:5801-4. [PMID: 26737610 DOI: 10.1109/embc.2015.7319710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The effectiveness of spinal cord stimulation (SCS) for chronic pain treatment depends on selection of appropriate stimulation settings, which can be especially challenging following posture change or SCS lead migration. The objective of this work was to investigate the feasibility of using SCS lead impedance for determining the location of a SCS lead and for detecting lead migration, as well as the impact of axial movement and rotation of the St. Jude Medical PENTA™ paddle in the dorsal-ventral or medial-lateral directions on dorsal column (DC) stimulation thresholds and neural activation regions. We used a two-stage computational model, including a finite element method model of field potentials in the spinal cord during stimulation, coupled to a biophysical cable model of mammalian, myelinated nerve fibers to calculate tissue impedance and nerve fiber activation within the DC. We found that SCS lead impedance was highly sensitive to the distance between the lead and cerebrospinal fluid (CSF) layer. In addition, among all the lead positions studied, medial-lateral movement resulted in the most substantial changes to SC activation regions. These results suggest that impedance can be used for detecting paddle position and lead migration, and therefore for guiding SCS programming.
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Serra M, De Pisapia N, Rigo P, Papinutto N, Jager J, Bornstein MH, Venuti P. Secure attachment status is associated with white matter integrity in healthy young adults. Neuroreport 2015; 26:1106-11. [PMID: 26559724 PMCID: PMC4646732 DOI: 10.1097/wnr.0000000000000479] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study investigates associations between security of attachment in the mother-child relationship and patterns of brain connectivity in young adults. We hypothesized that secure attachment would relate to more efficient connectivity in white matter association fibers due to increased myelination. Attachment security was measured in 53 young adults using the Kerns Security Scale; anatomical information was acquired using diffusion tensor imaging. Higher fractional anisotropy, an index of directionality of diffusion, related to security of attachment in four left-hemisphere white matter association fibers (uncinate fasciculus, cingulum, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus). As expected, this result was mainly ascribable to increased myelination, which has been independently associated with attachment security. Security of attachment may have an identifiable biological basis. Our research demonstrates the feasibility of coupling neuroimaging tools with clinical investigation.
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Affiliation(s)
- Mauro Serra
- Department of Psychology and cognitive science, University of Trento, Rovereto, Italy
| | - Nicola De Pisapia
- Department of Psychology and cognitive science, University of Trento, Rovereto, Italy
| | - Paola Rigo
- Department of Psychology and cognitive science, University of Trento, Rovereto, Italy
| | | | - Justin Jager
- T. Denny Sanford School of Social and Family Dynamics, Arizona State University, Phoenix, AZ, United States
| | - Marc H. Bornstein
- National Institutes of Health, Department of Health and Human Services, Rockville, MD, United States
| | - Paola Venuti
- Department of Psychology and cognitive science, University of Trento, Rovereto, Italy
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Meng L, Liu J, Liu X, Wang Z, Yuan Y, Zhang W. [Pathological features of muscles and peripheral nerves of Kennedy's disease: a report of 12 cases]. Zhonghua Yi Xue Za Zhi 2015; 95:1681-1685. [PMID: 26675799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To explore the pathological features of muscles and peripheral nerves of Kennedy's disease (KD). METHODS A total of 12 male patients were selected at our department from January 2006 to October 2014. Their definite diagnoses of KD were made by genetic testing of androgen receptor. Their average age was (52 ± 10) years old. All onset sites were lower limbs. Serum creatine kinase levels were elevated in varying degrees of 209-3 600 U/L. Electrophysiological examination revealed generalized neurogenic damage and impaired peripheral motor and sensory nerves. Biopsies were performed on biceps brachii (n=8), gastrocnemius (n=3), quadriceps femoris (n=1) and sural nerve (n=4). RESULTS The major muscular pathological features were neurogenic pathological changes. Some patients had myopathic changes, showing necrotic fibers, regenerating fibers, fiber splitting, vortex-like fibers, central nuclei and reduced oxidase activities. Sural nerve pathology of 4 patients showed a loss of myelinated nerve fibers, as well as axonal degeneration, regeneration clusters and thin myelinated fibers. Electron microscopy examination showed axonal degeneration, regeneration clusters, thin myelinated fibers and onion bulbs-like pathological changes. CONCLUSION KD has myopathic changes with an impairment of chronic axonal and demyelinating sensory nerves.
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Affiliation(s)
- Lingchao Meng
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Jing Liu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Xiao Liu
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing 100034, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing 100034, China;
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O'Leary JL, Smith JM, Inukai J, O'Leary M. The inferior olive as a source of climbing fibers in the rat. Bibl Psychiatr 2015; 143:128-37. [PMID: 5411696 DOI: 10.1159/000385824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Truini A, Gerardi MC, Di Stefano G, La Cesa S, Iannuccelli C, Pepe A, Sarzi-Puttini P, Cruccu G, Di Franco M. Hyperexcitability in pain matrices in patients with fibromyalgia. Clin Exp Rheumatol 2015; 33:S68-S72. [PMID: 25786046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/10/2015] [Indexed: 06/04/2023]
Abstract
OBJECTIVES Emerging evidence associates fibromyalgia (FM) with pain system dysfunction. In this study, using laser evoked potentials (LEPs) and paired laser stimuli, we tested excitability in the pain matrices and sought possible changes in patients with FM. METHODS In 20 patients with FM and 15 healthy subjects, after recording control nociceptive system-mediated Aδ- and C-fibre-related LEPs, we measured excitability in the pain matrices by testing the Aδ-LEP conditioned by a preceding C-LEP. RESULTS No difference was found in control LEP amplitudes for Aδ- or C-fibres between patients and healthy subjects. Conversely, the Aδ-LEP amplitude, conditioned by a preceding C-LEP, was significantly higher in patients than in healthy subjects (p<0.001). CONCLUSIONS Objective evidence from increased conditioned Aδ-LEP amplitudes reflecting hyperexcitability in the pain matrices in FM, provides diagnostically useful information and might help in developing new therapeutic approaches.
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Affiliation(s)
- Andrea Truini
- Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Maria Chiara Gerardi
- Rheumatology Unit, Department of Internal Medicine and Medical Specialities, Sapienza University of Rome, Rome, Italy
| | - Giulia Di Stefano
- Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Silvia La Cesa
- Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Cristina Iannuccelli
- Rheumatology Unit, Department of Internal Medicine and Medical Specialities, Sapienza University of Rome, Rome, Italy
| | - Alessia Pepe
- Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Piercarlo Sarzi-Puttini
- Rheumatology Unit, Department of Internal Medicine, Luigi Sacco University Hospital, Milan, Italy
| | - Giorgio Cruccu
- Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Manuela Di Franco
- Rheumatology Unit, Department of Internal Medicine and Medical Specialities, Sapienza University of Rome, Rome, Italy
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Tudorascu DL, Rosano C, Venkatraman VK, MacCloud RL, Harris T, Yaffe K, Newman AB, Aizenstein HJ. Multimodal MRI markers support a model of small vessel ischemia for depressive symptoms in very old adults. Psychiatry Res 2014; 224:73-80. [PMID: 25205441 PMCID: PMC4195799 DOI: 10.1016/j.pscychresns.2014.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 06/25/2014] [Accepted: 08/15/2014] [Indexed: 01/15/2023]
Abstract
In older adults, depressive symptoms are associated with lower quality of life, high morbidity and mortality. This study aims to identify brain magnetic resonance imaging (MRI) features associated with late-life depressive symptoms in the population. Older community-dwelling adults (n=314) from the Health ABC study underwent brain MRI. Logistic regression was used to characterize the relationships between depressive symptoms (Center for Epidemiologic Studies of Depression scale, CES-D) and the following whole-brain variables: white matter hyperintensity (WMH) burden, fractional anisotropy (FA), and gray matter volume (GMV). Analyses examining possible regional differences between the CES-D groups controlled for Modified Mini-Mental State Examination score and diabetes status. The relative importance of localization of the markers was examined by comparing the distribution of significant peaks across the brain. Each whole-brain variable showed loss of integrity associated with high CES-D. For GMV, the odds ratio (OR)=0.84 (95% confidence interval (CI) 0.74, 0.96); for FA, OR=0.714 (95% CI 0.57, 0.88); for WMH, OR=1.89 (95%CI 1.33, 2.69). Voxel-wise analyses and patterns of peak significance showed non-specific patterns for white matter measures. Loss of GMV was most significant in the bilateral insula and anterior cingulate cortex. This study supports a cerebrovascular pattern for depressive symptoms in older adults. The localization of gray matter changes to the insula, a watershed area and a hub of affective circuits, suggests an etiological pathway from ischemia to increased depressive burden.
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Affiliation(s)
- Dana L Tudorascu
- Department of Internal Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, USA; Geriatric Psychiatric Neuroimaging, Western Psychiatric Institute and Clinic, University of Pittsburgh, Pittsburgh, PA, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Caterina Rosano
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Vijay K Venkatraman
- Department of Neurosciences, School of Medicine, University of California, San Diego, CA, USA
| | - Rebecca L MacCloud
- Geriatric Psychiatric Neuroimaging, Western Psychiatric Institute and Clinic, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tamara Harris
- Laboratory of Epidemiology, Demography, and Biometry, National Institute of Health, Bethesda, MD, USA
| | - Kristine Yaffe
- Department of Psychiatry, Neurology and Epidemiology and Biostatistics, University of California, San Francisco, CA, USA
| | - Anne B Newman
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Howard J Aizenstein
- Geriatric Psychiatric Neuroimaging, Western Psychiatric Institute and Clinic, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
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Wu M, Lu LH, Lowes A, Yang S, Passarotti AM, Zhou XJ, Pavuluri MN. Development of superficial white matter and its structural interplay with cortical gray matter in children and adolescents. Hum Brain Mapp 2014; 35:2806-16. [PMID: 24038932 PMCID: PMC6869421 DOI: 10.1002/hbm.22368] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/11/2013] [Accepted: 07/01/2013] [Indexed: 11/09/2022] Open
Abstract
Healthy human brain undergoes significant changes during development. The developmental trajectory of superficial white matter (SWM) is less understood relative to cortical gray matter (GM) and deep white matter. In this study, a multimodal imaging strategy was applied to vertexwise map SWM microstructure and cortical thickness to characterize their developmental pattern and elucidate SWM-GM associations in children and adolescents. Microscopic changes in SWM were evaluated with water diffusion parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in 133 healthy subjects aged 10-18 years. Results demonstrated distinct maturational patterns in SWM and GM. SWM showed increasing FA and decreasing MD and RD underneath bilateral motor sensory cortices and superior temporal auditory cortex, suggesting increasing myelination. A second developmental pattern in SWM was increasing FA and AD in bilateral orbitofrontal regions and insula, suggesting improved axonal coherence. These SWM patterns diverge from the more widespread GM maturation, suggesting that cortical thickness changes in adolescence are not explained by the encroachment of SWM myelin into the GM-WM boundary. Interestingly, age-independent intrinsic association between SWM and cortical GM seems to follow functional organization of polymodal and unimodal brain regions. Unimodal sensory areas showed positive correlation between GM thickness and FA whereas polymodal regions showed negative correlation. Axonal coherence and differences in interstitial neuron composition between unimodal and polymodal regions may account for these SWM-GM association patterns. Intrinsic SWM-GM relationships unveiled by neuroimaging in vivo can be useful for examining psychiatric disorders with known WM/GM disturbances.
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Affiliation(s)
- Minjie Wu
- Pediatric Brain Research and Intervention Center, Institute for Juvenile Research and Colbeth Clinic, Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Department of PsychiatryUniversity of Illinois at ChicagoIllinois
| | - Lisa H. Lu
- Pediatric Brain Research and Intervention Center, Institute for Juvenile Research and Colbeth Clinic, Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Department of PsychologyRoosevelt UniversityIllinois
| | - Allison Lowes
- Pediatric Brain Research and Intervention Center, Institute for Juvenile Research and Colbeth Clinic, Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Department of PsychiatryUniversity of Illinois at ChicagoIllinois
| | - Shaolin Yang
- Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Departments of Radiology and BioengineeringUniversity of Illinois at ChicagoIllinois
| | - Alessandra M. Passarotti
- Pediatric Brain Research and Intervention Center, Institute for Juvenile Research and Colbeth Clinic, Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Department of PsychiatryUniversity of Illinois at ChicagoIllinois
| | - Xiaohong J. Zhou
- Departments of Radiology and BioengineeringUniversity of Illinois at ChicagoIllinois
- Department of NeurosurgeryUniversity of Illinois at ChicagoIllinois
- Center for Magnetic Resonance ResearchUniversity of Illinois at ChicagoIllinois
| | - Mani N. Pavuluri
- Pediatric Brain Research and Intervention Center, Institute for Juvenile Research and Colbeth Clinic, Department of PsychiatryUniversity of Illinois at ChicagoIllinois
- Department of PsychiatryUniversity of Illinois at ChicagoIllinois
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Wang L, Shi F, Gao Y, Li G, Gilmore JH, Lin W, Shen D. Integration of sparse multi-modality representation and anatomical constraint for isointense infant brain MR image segmentation. Neuroimage 2014; 89:152-64. [PMID: 24291615 PMCID: PMC3944142 DOI: 10.1016/j.neuroimage.2013.11.040] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/21/2013] [Accepted: 11/18/2013] [Indexed: 01/18/2023] Open
Abstract
Segmentation of infant brain MR images is challenging due to poor spatial resolution, severe partial volume effect, and the ongoing maturation and myelination processes. During the first year of life, the brain image contrast between white and gray matters undergoes dramatic changes. In particular, the image contrast inverses around 6-8months of age, where the white and gray matter tissues are isointense in T1 and T2 weighted images and hence exhibit the extremely low tissue contrast, posing significant challenges for automated segmentation. In this paper, we propose a general framework that adopts sparse representation to fuse the multi-modality image information and further incorporate the anatomical constraints for brain tissue segmentation. Specifically, we first derive an initial segmentation from a library of aligned images with ground-truth segmentations by using sparse representation in a patch-based fashion for the multi-modality T1, T2 and FA images. The segmentation result is further iteratively refined by integration of the anatomical constraint. The proposed method was evaluated on 22 infant brain MR images acquired at around 6months of age by using a leave-one-out cross-validation, as well as other 10 unseen testing subjects. Our method achieved a high accuracy for the Dice ratios that measure the volume overlap between automated and manual segmentations, i.e., 0.889±0.008 for white matter and 0.870±0.006 for gray matter.
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Affiliation(s)
- Li Wang
- IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA
| | - Feng Shi
- IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA
| | - Yaozong Gao
- IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA; Department of Computer Science, University of North Carolina at Chapel Hill, NC, USA
| | - Gang Li
- IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA
| | - John H Gilmore
- Department of Psychiatry, University of North Carolina at Chapel Hill, NC, USA
| | - Weili Lin
- MRI Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA
| | - Dinggang Shen
- IDEA Lab, Department of Radiology and BRIC, University of North Carolina at Chapel Hill, NC, USA; Department of Brain and Cognitive Engineering, Korea University, Seoul, Korea.
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Krestel H, Annoni JM, Jagella C. White matter in aphasia: a historical review of the Dejerines' studies. Brain Lang 2013; 127:526-532. [PMID: 23895939 DOI: 10.1016/j.bandl.2013.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/23/2013] [Accepted: 05/29/2013] [Indexed: 06/02/2023]
Abstract
The Objective was to describe the contributions of Joseph Jules Dejerine and his wife Augusta Dejerine-Klumpke to our understanding of cerebral association fiber tracts and language processing. The Dejerines (and not Constantin von Monakow) were the first to describe the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) as an association fiber tract uniting Broca's area, Wernicke's area, and a visual image center in the angular gyrus of a left hemispheric language zone. They were also the first to attribute language-related functions to the fasciculi occipito-frontalis (FOF) and the inferior longitudinal fasciculus (ILF) after describing aphasia patients with degeneration of the SLF/AF, ILF, uncinate fasciculus (UF), and FOF. These fasciculi belong to a functional network known as the Dejerines' language zone, which exceeds the borders of the classically defined cortical language centers. The Dejerines provided the first descriptions of the anatomical pillars of present-day language models (such as the SLF/AF). Their anatomical descriptions of fasciculi in aphasia patients provided a foundation for our modern concept of the dorsal and ventral streams in language processing.
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Affiliation(s)
- Heinz Krestel
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland; Department of Neuropediatrics, Inselspital, Bern University Hospital, University of Bern, Switzerland.
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Du J, Ma G, Li S, Carl M, Szeverenyi NM, VandenBerg S, Corey-Bloom J, Bydder GM. Ultrashort echo time (UTE) magnetic resonance imaging of the short T2 components in white matter of the brain using a clinical 3T scanner. Neuroimage 2013; 87:32-41. [PMID: 24188809 DOI: 10.1016/j.neuroimage.2013.10.053] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/01/2013] [Accepted: 10/24/2013] [Indexed: 11/19/2022] Open
Abstract
White matter of the brain contains a majority of long T2 components as well as a minority of short T2 components. These are not detectable using clinical magnetic resonance imaging (MRI) sequences with conventional echo times (TEs). In this study we used ultrashort echo time (UTE) sequences to investigate the ultrashort T2 components in white matter of the brain and quantify their T2*s and relative proton densities (RPDs) (relative to water with a proton density of 100%) using a clinical whole body 3T scanner. An adiabatic inversion recovery prepared dual echo UTE (IR-dUTE) sequence was used for morphological imaging of the ultrashort T2 components in white matter. IR-dUTE acquisitions at a constant TR of 1000 ms and a series of TIs were performed to determine the optimal TI which corresponded to the minimum signal to noise ratio (SNR) in white matter of the brain on the second echo image. T2*s of the ultrashort T2 components were quantified using mono-exponential decay fitting of the IR-dUTE signal at a series of TEs. RPD was quantified by comparing IR-dUTE signal of the ultrashort T2 components with that of a rubber phantom. Nine healthy volunteers were studied. The IR-dUTE sequence provided excellent image contrast for the ultrashort T2 components in white matter of the brain with a mean signal to noise ratio of 18.7 ± 3.7 and a contrast to noise ratio of 14.6 ± 2.4 between the ultrashort T2 white matter and gray matter in a 4.4 min scan time with a nominal voxel size of 1.25 × 1.25 × 5.0mm(3). On average a T2* value of 0.42 ± 0.08 ms and a RPD of 4.05 ± 0.88% were demonstrated for the ultrashort T2 components in white matter of the brain of healthy volunteers at 3T.
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Affiliation(s)
- Jiang Du
- Department of Radiology, University of California, San Diego, USA.
| | - Guolin Ma
- Department of Radiology, University of California, San Diego, USA; Department of Radiology, China-Japan Friendship Hospital, Beijing, China
| | - Shihong Li
- Department of Radiology, University of California, San Diego, USA; Department of Radiology, Huadong Hospital, Fudan University, Shanghai, China
| | - Michael Carl
- Global Applied Science Laboratory, GE Healthcare, San Diego, USA
| | | | - Scott VandenBerg
- Department of Pathology, University of California, San Diego, USA
| | - Jody Corey-Bloom
- Department of Neurosciences, University of California, San Diego, USA
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, USA
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