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Srivastava S, Seamon BA, Marebwa BK, Wilmskoetter J, Bowden MG, Gregory CM, Seo NJ, Hanlon CA, Bonilha L, Brown TR, Neptune RR, Kautz SA. The relationship between motor pathway damage and flexion-extension patterns of muscle co-excitation during walking. Front Neurol 2022; 13:968385. [PMID: 36388195 PMCID: PMC9650203 DOI: 10.3389/fneur.2022.968385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 10/12/2022] [Indexed: 01/16/2023] Open
Abstract
Background Mass flexion-extension co-excitation patterns during walking are often seen as a consequence of stroke, but there is limited understanding of the specific contributions of different descending motor pathways toward their control. The corticospinal tract is a major descending motor pathway influencing the production of normal sequential muscle coactivation patterns for skilled movements. However, control of walking is also influenced by non-corticospinal pathways such as the corticoreticulospinal pathway that possibly contribute toward mass flexion-extension co-excitation patterns during walking. The current study sought to investigate the associations between damage to corticospinal (CST) and corticoreticular (CRP) motor pathways following stroke and the presence of mass flexion-extension patterns during walking as evaluated using module analysis. Methods Seventeen healthy controls and 44 stroke survivors were included in the study. We used non-negative matrix factorization for module analysis of paretic leg electromyographic activity. We typically have observed four modules during walking in healthy individuals. Stroke survivors often have less independently timed modules, for example two-modules presented as mass flexion-extension pattern. We used diffusion tensor imaging-based analysis where streamlines connecting regions of interest between the cortex and brainstem were computed to evaluate CST and CRP integrity. We also used a coarse classification tree analysis to evaluate the relative CST and CRP contribution toward module control. Results Interhemispheric CST asymmetry was associated with worse lower extremity Fugl-Meyer score (p = 0.023), propulsion symmetry (p = 0.016), and fewer modules (p = 0.028). Interhemispheric CRP asymmetry was associated with worse lower extremity Fugl-Meyer score (p = 0.009), Dynamic gait index (p = 0.035), Six-minute walk test (p = 0.020), Berg balance scale (p = 0.048), self-selected walking speed (p = 0.041), and propulsion symmetry (p = 0.001). The classification tree model reveled that substantial ipsilesional CRP or CST damage leads to a two-module pattern and poor walking ability with a trend toward increased compensatory contralesional CRP based control. Conclusion Both CST and CRP are involved with control of modules during walking and damage to both may lead to greater reliance on the contralesional CRP, which may contribute to a two-module pattern and be associated with worse walking performance.
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Affiliation(s)
- Shraddha Srivastava
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,*Correspondence: Shraddha Srivastava
| | - Bryant A. Seamon
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Barbara K. Marebwa
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Janina Wilmskoetter
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Mark G. Bowden
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Chris M. Gregory
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Na Jin Seo
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,Division of Occupational Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Colleen A. Hanlon
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Leonardo Bonilha
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Truman R. Brown
- Department of Radiology and Radiological Science, College of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Richard R. Neptune
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Steven A. Kautz
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States,Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
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2
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Kindred JH, Wonsetler EC, Charalambous CC, Srivastava S, Marebwa BK, Bonilha L, Kautz SA, Bowden MG. Individualized Responses to Ipsilesional High-Frequency and Contralesional Low-Frequency rTMS in Chronic Stroke: A Pilot Study to Support the Individualization of Neuromodulation for Rehabilitation. Front Hum Neurosci 2020; 14:578127. [PMID: 33328932 PMCID: PMC7717949 DOI: 10.3389/fnhum.2020.578127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/21/2020] [Indexed: 12/31/2022] Open
Abstract
Background: In this pilot study, we examined the effects of ipsilesional high-frequency rTMS (iHF-rTMS) and contralesional low-frequency rTMS (cLF-rTMS) applied via a double-cone coil on neurophysiological and gait variables in patients with chronic stroke. Objective/Hypothesis: To determine the group and individual level effects of two types of stimulation to better individualize neuromodulation for rehabilitation. Methods: Using a randomized, within-subject, double-blind, sham-controlled trial with 14 chronic stroke participants iHF-rTMS and cLF-rTMS were applied via a double-cone coil to the tibialis anterior cortical representation. Neurophysiological and gait variables were compared pre-post rTMS. Results: A small effect of cLF-rTMS indicated increased MEP amplitudes (Cohen’s D; cLF-rTMS, d = −0.30). Group-level analysis via RMANOVA showed no significant group effects of stimulation (P > 0.099). However, secondary analyses of individual data showed a high degree of response variability to rTMS. Individual percent changes in resting motor threshold and normalized MEP latency correlated with changes in gait propulsive forces and walking speed (iHF-rTMS, nLAT:Pp, R = 0.632 P = 0.015; cLF-rTMS, rMT:SSWS, R = −0.557, P = 0.039; rMT:Pp, R = 0.718, P = 0.004). Conclusions: Changes in propulsive forces and walking speed were seen in some individuals that showed neurophysiological changes in response to rTMS. The neurological consequences of stroke are heterogeneous making a “one type fits all” approach to neuromodulation for rehabilitation unlikely. This pilot study suggests that an individual’s unique response to rTMS should be considered before the application/selection of neuromodulatory therapies. Before neuromodulatory therapies can be incorporated into standard clinical practice, additional work is needed to identify biomarkers of response and how best to prescribe neuromodulation for rehabilitation for post-stroke gait.
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Affiliation(s)
- John Harvey Kindred
- Department of Research and Development, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States.,Division of Physical Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Elizabeth Carr Wonsetler
- Department of Public Health and Community Medicine, School of Medicine, Tufts University, Boston, MA, United States
| | - Charalambos Costas Charalambous
- Department of Basic and Clinical Sciences, Medical School, University of Nicosia, Nicosia, Cyprus.,Center for Neuroscience and Integrative Brain Research (CENIBRE), Medical School, University of Nicosia, Nicosia, Cyprus
| | - Shraddha Srivastava
- Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Barbara Khalibinzwa Marebwa
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Leonardo Bonilha
- Department of Neurology, College of Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Steven A Kautz
- Department of Research and Development, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States.,Division of Physical Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States.,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
| | - Mark G Bowden
- Department of Research and Development, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States.,Division of Physical Therapy, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States.,Department of Health Sciences and Research, College of Health Professions, Medical University of South Carolina, Charleston, SC, United States
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3
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Levman J, Fang Z, Zumwalt K, Cogger L, Vasung L, MacDonald P, Lim A, Takahashi E. Asymmetric Insular Connectomics Revealed by Diffusion Magnetic Resonance Imaging Analysis of Healthy Brain Development. Brain Connect 2019; 9:2-12. [PMID: 30501515 DOI: 10.1089/brain.2018.0582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The insula has been implicated in playing important roles in various brain functions including consciousness, homeostasis, perception, self-awareness, language processing, and interpersonal experience. Abnormalities of the insula have been observed in patients suffering from addiction, deteriorating language function, anorexia, and emotional dysregulation. We analyzed typical development of insular connections in a large-scale pediatric population using 642 magnetic resonance imaging examinations. Interpreting large quantities of acquired data is one of the major challenges in connectomics. This article focuses its analysis on the connectivity observed between the insula and many other regions throughout the brain and performs a hemispheric asymmetry analysis comparing localized connectome measurements. Results demonstrate asymmetries in the pathways connecting the insula to the superior temporal region, pars opercularis, etc. that may be representative of language lateralization in the brain. Results also demonstrate multiple fiber pathways that exhibit hemispheric dominance in tract length and an inverted hemispheric dominance in tract counts, implying the presence of asymmetric lateralization of some of the brain's insular pathways. This study illustrates the investigative potential of performing connectomics-style analyses in a clinical context across a large population of children as part of routine imaging, demonstrating the feasibility of using current technologies to perform regionally focused clinical connectivity studies.
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Affiliation(s)
- Jacob Levman
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,2 Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts.,3 Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,4 Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University, Antigonish, Canada
| | - Zihang Fang
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts
| | - Katarina Zumwalt
- 5 OceanPath Fellow, Coady International Institute, St. Francis Xavier University, Antigonish, Canada
| | - Liam Cogger
- 4 Department of Mathematics, Statistics and Computer Science, St. Francis Xavier University, Antigonish, Canada
| | - Lana Vasung
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,3 Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Patrick MacDonald
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts
| | - Ashley Lim
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts
| | - Emi Takahashi
- 1 Division of Newborn Medicine, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,2 Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts.,3 Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
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Ledig C, Kamnitsas K, Koikkalainen J, Posti JP, Takala RSK, Katila A, Frantzén J, Ala-Seppälä H, Kyllönen A, Maanpää HR, Tallus J, Lötjönen J, Glocker B, Tenovuo O, Rueckert D. Regional brain morphometry in patients with traumatic brain injury based on acute- and chronic-phase magnetic resonance imaging. PLoS One 2017; 12:e0188152. [PMID: 29182625 PMCID: PMC5705131 DOI: 10.1371/journal.pone.0188152] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 11/01/2017] [Indexed: 02/02/2023] Open
Abstract
Traumatic brain injury (TBI) is caused by a sudden external force and can be very heterogeneous in its manifestation. In this work, we analyse T1-weighted magnetic resonance (MR) brain images that were prospectively acquired from patients who sustained mild to severe TBI. We investigate the potential of a recently proposed automatic segmentation method to support the outcome prediction of TBI. Specifically, we extract meaningful cross-sectional and longitudinal measurements from acute- and chronic-phase MR images. We calculate regional volume and asymmetry features at the acute/subacute stage of the injury (median: 19 days after injury), to predict the disability outcome of 67 patients at the chronic disease stage (median: 229 days after injury). Our results indicate that small structural volumes in the acute stage (e.g. of the hippocampus, accumbens, amygdala) can be strong predictors for unfavourable disease outcome. Further, group differences in atrophy are investigated. We find that patients with unfavourable outcome show increased atrophy. Among patients with severe disability outcome we observed a significantly higher mean reduction of cerebral white matter (3.1%) as compared to patients with low disability outcome (0.7%).
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Affiliation(s)
- Christian Ledig
- Imperial College London, Department of Computing, London, United Kingdom
- * E-mail:
| | | | - Juha Koikkalainen
- Combinostics, Tampere, Finland
- VTT Technical Research Centre of Finland, Tampere, Finland
| | - Jussi P. Posti
- Department of Clinical Medicine, University of Turku, Turku, Finland
- Division of Clinical Neurosciences, Turku Brain Injury Centre, Turku University Hospital, Turku, Finland
- Division of Clinical Neurosciences, Department of Neurosurgery, Turku University Hospital, Turku, Finland
| | - Riikka S. K. Takala
- Perioperative Services, Intensive Care Medicine and Pain Management, Turku University Hospital and University of Turku, Turku, Finland
| | - Ari Katila
- Perioperative Services, Intensive Care Medicine and Pain Management, Turku University Hospital and University of Turku, Turku, Finland
| | - Janek Frantzén
- Department of Clinical Medicine, University of Turku, Turku, Finland
- Division of Clinical Neurosciences, Turku Brain Injury Centre, Turku University Hospital, Turku, Finland
- Division of Clinical Neurosciences, Department of Neurosurgery, Turku University Hospital, Turku, Finland
| | - Henna Ala-Seppälä
- Department of Clinical Medicine, University of Turku, Turku, Finland
| | - Anna Kyllönen
- Department of Clinical Medicine, University of Turku, Turku, Finland
| | | | - Jussi Tallus
- Department of Clinical Medicine, University of Turku, Turku, Finland
| | - Jyrki Lötjönen
- Combinostics, Tampere, Finland
- VTT Technical Research Centre of Finland, Tampere, Finland
| | - Ben Glocker
- Imperial College London, Department of Computing, London, United Kingdom
| | - Olli Tenovuo
- Department of Clinical Medicine, University of Turku, Turku, Finland
- Division of Clinical Neurosciences, Turku Brain Injury Centre, Turku University Hospital, Turku, Finland
| | - Daniel Rueckert
- Imperial College London, Department of Computing, London, United Kingdom
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5
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Peters DM, Fridriksson J, Stewart JC, Richardson JD, Rorden C, Bonilha L, Middleton A, Gleichgerrcht E, Fritz SL. Cortical disconnection of the ipsilesional primary motor cortex is associated with gait speed and upper extremity motor impairment in chronic left hemispheric stroke. Hum Brain Mapp 2017; 39:120-132. [PMID: 28980355 DOI: 10.1002/hbm.23829] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/14/2017] [Accepted: 09/18/2017] [Indexed: 12/11/2022] Open
Abstract
Advances in neuroimaging have enabled the mapping of white matter connections across the entire brain, allowing for a more thorough examination of the extent of white matter disconnection after stroke. To assess how cortical disconnection contributes to motor impairments, we examined the relationship between structural brain connectivity and upper and lower extremity motor function in individuals with chronic stroke. Forty-three participants [mean age: 59.7 (±11.2) years; time poststroke: 64.4 (±58.8) months] underwent clinical motor assessments and MRI scanning. Nonparametric correlation analyses were performed to examine the relationship between structural connectivity amid a subsection of the motor network and upper/lower extremity motor function. Standard multiple linear regression analyses were performed to examine the relationship between cortical necrosis and disconnection of three main cortical areas of motor control [primary motor cortex (M1), premotor cortex (PMC), and supplementary motor area (SMA)] and motor function. Anatomical connectivity between ipsilesional M1/SMA and the (1) cerebral peduncle, (2) thalamus, and (3) red nucleus were significantly correlated with upper and lower extremity motor performance (P ≤ 0.003). M1-M1 interhemispheric connectivity was also significantly correlated with gross manual dexterity of the affected upper extremity (P = 0.001). Regression models with M1 lesion load and M1 disconnection (adjusted for time poststroke) explained a significant amount of variance in upper extremity motor performance (R2 = 0.36-0.46) and gait speed (R2 = 0.46), with M1 disconnection an independent predictor of motor performance. Cortical disconnection, especially of ipsilesional M1, could significantly contribute to variability seen in locomotor and upper extremity motor function and recovery in chronic stroke. Hum Brain Mapp 39:120-132, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Denise M Peters
- Department of Exercise Science, Physical Therapy Program, University of South Carolina, 921 Assembly Street, Columbia, South Carolina
| | - Julius Fridriksson
- Department of Communication Sciences and Disorders, University of South Carolina, 915 Greene Street, Columbia, South Carolina
| | - Jill C Stewart
- Department of Exercise Science, Physical Therapy Program, University of South Carolina, 921 Assembly Street, Columbia, South Carolina
| | - Jessica D Richardson
- Department of Communication Sciences and Disorders, University of South Carolina, 915 Greene Street, Columbia, South Carolina
| | - Chris Rorden
- Department of Psychology, University of South Carolina, 1512 Pendleton Street, Columbia, South Carolina
| | - Leonardo Bonilha
- Department of Neurology, Medical University of South Carolina, 96 Jonathan Lucas Street, Charleston, South Carolina
| | - Addie Middleton
- Department of Exercise Science, Physical Therapy Program, University of South Carolina, 921 Assembly Street, Columbia, South Carolina
| | - Ezequiel Gleichgerrcht
- Department of Neurology, Medical University of South Carolina, 96 Jonathan Lucas Street, Charleston, South Carolina
| | - Stacy L Fritz
- Department of Exercise Science, Physical Therapy Program, University of South Carolina, 921 Assembly Street, Columbia, South Carolina
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6
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Reduced Hemispheric Asymmetry of White Matter Microstructure in Autism Spectrum Disorder. J Am Acad Child Adolesc Psychiatry 2016; 55:1073-1080. [PMID: 27871642 PMCID: PMC5125511 DOI: 10.1016/j.jaac.2016.09.491] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/11/2016] [Accepted: 09/21/2016] [Indexed: 01/26/2023]
Abstract
OBJECTIVE Many past studies have suggested atypical functional and anatomical hemispheric asymmetries in autism spectrum disorder (ASD). However, almost all of these have examined only language-related asymmetries. Here, we conduct a comprehensive investigation of microstructural asymmetries across a large number of fiber tracts in ASD. METHOD We used diffusion tensor imaging for a comprehensive investigation of anatomical white matter asymmetries across the entire white matter skeleton, using tract-based spatial statistics in 41 children and adolescents with ASD and a matched group of 44 typically developing (TD) participants. RESULTS We found significant asymmetries in the TD group, being rightward for fractional anisotropy and leftward for mean diffusivity (with concordant asymmetries for radial and axial diffusivity). These asymmetries were significantly reduced in the group with ASD: in whole brain analysis for fractional anisotropy, and in a region where several major association and projection tracts travel in close proximity within occipital white matter for mean diffusivity, axial diffusivity, and radial diffusivity. No correlations between global white matter asymmetry and age or socio-communicative abilities were detected. CONCLUSION Our findings in TD children and adolescents can be interpreted as reflecting different processing modes (more integrative in the right and more specialized in the left hemisphere). These asymmetries and the "division of labor" between hemispheres implied by them appear to be diminished in autism spectrum disorder.
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7
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Future advances. HANDBOOK OF CLINICAL NEUROLOGY 2015. [PMID: 25726297 DOI: 10.1016/b978-0-444-62630-1.00038-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Future advances in the auditory systems are difficult to predict, and only educated guesses are possible. It is expected that innovative technologies in the field of neuroscience will be applied to the auditory system. Optogenetics, Brainbow, and CLARITY will improve our knowledge of the working of neural auditory networks and the relationship between sound and language, providing a dynamic picture of the brain in action. CLARITY makes brain tissue transparent and offers a three-dimensional view of neural networks, which, combined with genetically labeling neurons with multiple, distinct colors (Optogenetics), will provide detailed information of the complex brain system. Molecular functional magnetic resonance imaging (MRI) will allow the study of neurotransmitters detectable by MRI and their function in the auditory pathways. The Human Connectome project will study the patterns of distributed brain activity that underlie virtually all aspects of cognition and behavior and determine if abnormalities in the distributed patterns of activity may result in hearing and behavior disorders. Similarly, the programs of Big Brain and ENIGMA will improve our understanding of auditory disorders. New stem-cell therapy and gene therapies therapy may bring about a partial restoration of hearing for impaired patients by inducing regeneration of cochlear hair cells.
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Kellermann TS, Bonilha L, Lin JJ, Hermann BP. Mapping the landscape of cognitive development in children with epilepsy. Cortex 2015; 66:1-8. [PMID: 25776901 DOI: 10.1016/j.cortex.2015.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 12/12/2014] [Accepted: 02/06/2015] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Normal childhood development is defined by age-dependent improvement across cognitive abilities, including language, memory, psychomotor speed and executive function. Epilepsy is often associated with a global disruption in cognitive development, however, it is still largely unknown how epilepsy affects the overall organization of overlapping cognitive domains. The aim of the study was to evaluate how childhood epilepsy affects the developmental interrelationships between cognitive domains. METHODS We performed a comprehensive assessment of neuropsychological function in 127 children with new onset epilepsy and 80 typically developing children matched for age, gender, and socio-demographic status. A cross-correlation matrix between the performances across multiple cognitive tests was used to assess the interrelationship between cognitive modalities for each group (patients and controls). A weighted network composed by the cognitive domains as nodes, and pair-wise domain correlation as links, was assessed using graph theory analyses, with focus on global network structure, network hubs and community structure. RESULTS Normally developing children exhibited a cognitive network with well-defined modules, with verbal intelligence, reading and spelling skills occupying a central position in the developing network. Conversely, children with epilepsy demonstrated a less well-organized network with less clear separation between modules, and relative isolation of measures of attention and executive function. CONCLUSION Our findings demonstrate that childhood-onset epilepsy, even within its early course, is associated with an extensive disruption of cognitive neurodevelopmental organization. The approach used in this study may be useful to assess the effectiveness of future interventions aimed at mitigating the cognitive consequences of epilepsy.
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Affiliation(s)
- Tanja S Kellermann
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - Leonardo Bonilha
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - Jack J Lin
- Department of Neurology, University of California Irvine, Irvine, CA, USA
| | - Bruce P Hermann
- Department of Neurology, University of Wisconsin, Madison, WI, USA.
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Robust whole-brain segmentation: application to traumatic brain injury. Med Image Anal 2014; 21:40-58. [PMID: 25596765 DOI: 10.1016/j.media.2014.12.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 12/14/2014] [Accepted: 12/15/2014] [Indexed: 11/23/2022]
Abstract
We propose a framework for the robust and fully-automatic segmentation of magnetic resonance (MR) brain images called "Multi-Atlas Label Propagation with Expectation-Maximisation based refinement" (MALP-EM). The presented approach is based on a robust registration approach (MAPER), highly performant label fusion (joint label fusion) and intensity-based label refinement using EM. We further adapt this framework to be applicable for the segmentation of brain images with gross changes in anatomy. We propose to account for consistent registration errors by relaxing anatomical priors obtained by multi-atlas propagation and a weighting scheme to locally combine anatomical atlas priors and intensity-refined posterior probabilities. The method is evaluated on a benchmark dataset used in a recent MICCAI segmentation challenge. In this context we show that MALP-EM is competitive for the segmentation of MR brain scans of healthy adults when compared to state-of-the-art automatic labelling techniques. To demonstrate the versatility of the proposed approach, we employed MALP-EM to segment 125 MR brain images into 134 regions from subjects who had sustained traumatic brain injury (TBI). We employ a protocol to assess segmentation quality if no manual reference labels are available. Based on this protocol, three independent, blinded raters confirmed on 13 MR brain scans with pathology that MALP-EM is superior to established label fusion techniques. We visually confirm the robustness of our segmentation approach on the full cohort and investigate the potential of derived symmetry-based imaging biomarkers that correlate with and predict clinically relevant variables in TBI such as the Marshall Classification (MC) or Glasgow Outcome Score (GOS). Specifically, we show that we are able to stratify TBI patients with favourable outcomes from non-favourable outcomes with 64.7% accuracy using acute-phase MR images and 66.8% accuracy using follow-up MR images. Furthermore, we are able to differentiate subjects with the presence of a mass lesion or midline shift from those with diffuse brain injury with 76.0% accuracy. The thalamus, putamen, pallidum and hippocampus are particularly affected. Their involvement predicts TBI disease progression.
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Ribolsi M, Daskalakis ZJ, Siracusano A, Koch G. Abnormal asymmetry of brain connectivity in schizophrenia. Front Hum Neurosci 2014; 8:1010. [PMID: 25566030 PMCID: PMC4273663 DOI: 10.3389/fnhum.2014.01010] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/26/2014] [Indexed: 01/09/2023] Open
Abstract
Recently, a growing body of data has revealed that beyond a dysfunction of connectivity among different brain areas in schizophrenia patients (SCZ), there is also an abnormal asymmetry of functional connectivity compared with healthy subjects. The loss of the cerebral torque and the abnormalities of gyrification, with an increased or more complex cortical folding in the right hemisphere may provide an anatomical basis for such aberrant connectivity in SCZ. Furthermore, diffusion tensor imaging studies have shown a significant reduction of leftward asymmetry in some key white-matter tracts in SCZ. In this paper, we review the studies that investigated both structural brain asymmetry and asymmetry of functional connectivity in healthy subjects and SCZ. From an analysis of the existing literature on this topic, we can hypothesize an overall generally attenuated asymmetry of functional connectivity in SCZ compared to healthy controls. Such attenuated asymmetry increases with the duration of the disease and correlates with psychotic symptoms. Finally, we hypothesize that structural deficits across the corpus callosum may contribute to the abnormal asymmetry of intra-hemispheric connectivity in schizophrenia.
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Affiliation(s)
- Michele Ribolsi
- Dipartimento di Medicina dei Sistemi, Clinica Psichiatrica, Università di Roma Tor Vergata , Rome , Italy ; Laboratorio di Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS , Rome , Italy
| | - Zafiris J Daskalakis
- Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto , Toronto, ON , Canada
| | - Alberto Siracusano
- Dipartimento di Medicina dei Sistemi, Clinica Psichiatrica, Università di Roma Tor Vergata , Rome , Italy
| | - Giacomo Koch
- Laboratorio di Neurologia Clinica e Comportamentale, Fondazione Santa Lucia IRCCS , Rome , Italy
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11
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Lee CY, Tabesh A, Nesland T, Jensen JH, Helpern JA, Spampinato MV, Bonilha L. Human brain asymmetry in microstructural connectivity demonstrated by diffusional kurtosis imaging. Brain Res 2014; 1588:73-80. [PMID: 25239477 DOI: 10.1016/j.brainres.2014.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/30/2014] [Accepted: 09/01/2014] [Indexed: 10/24/2022]
Abstract
Structural asymmetry of whole brain white matter (WM) pathways, i.e., the connectome, has been demonstrated using fiber tractography based on diffusion tensor imaging (DTI). However, DTI-based tractography fails to resolve axonal fiber bundles that intersect within an imaging voxel, and therefore may not fully characterize the extent of asymmetry. The goal of this study was to assess structural asymmetry with tractography based on diffusional kurtosis imaging (DKI), which improves upon DTI-based tractography by delineating intravoxel crossing fibers. DKI images were obtained from 42 healthy subjects. By using automatic segmentation, gray matter (GM) was parcellated into anatomically defined regions of interest (ROIs). WM pathways were reconstructed with both DKI- and DTI-based tractography. The connectivity between the ROIs was quantified with the streamlines connecting the ROIs. The asymmetry index (AI) was utilized to quantify hemispheric differences in the connectivity of cortical ROIs and of links interconnecting cortical ROIs. Our results demonstrated that leftward asymmetrical ROIs and links were observed in frontal, parietal, temporal lobes, and insula. Rightward asymmetrical ROI and links were observed in superior frontal lobe, cingulate cortex, fusiform, putamen, and medial temporal lobe. Interestingly, these observed structural asymmetries were incompletely identified with DTI-based tractography. These results suggest that DKI-based tractography can improve the identification of asymmetrical connectivity patterns, thereby serving as an additional tool in the evaluation of the structural bases of functional lateralization.
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Affiliation(s)
- Chu-Yu Lee
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Ali Tabesh
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Travis Nesland
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA; Department of Neurology, Comprehensive Epilepsy Center, Medical University of South Carolina, Charleston, SC, USA
| | - Jens H Jensen
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Joseph A Helpern
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Maria V Spampinato
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA; Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA
| | - Leonardo Bonilha
- Center for Biomedical Imaging, Medical University of South Carolina, Charleston, SC, USA; Department of Neurology, Comprehensive Epilepsy Center, Medical University of South Carolina, Charleston, SC, USA.
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Bonilha L, Rorden C, Fridriksson J. Assessing the clinical effect of residual cortical disconnection after ischemic strokes. Stroke 2014; 45:988-93. [PMID: 24619391 DOI: 10.1161/strokeaha.113.004137] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND PURPOSE Studies assessing the relationship between chronic poststroke language impairment (aphasia) and ischemic brain damage usually rely on measuring the extent of brain necrosis observed on MRI. Nonetheless, clinical observation suggests that patients can exhibit deficits that are more severe than what would be expected based on lesion location and size. This phenomenon is commonly explained as being the result of cortical disconnection. To understand whether disconnection contributes to clinical symptoms, we assessed the relationship between language impairments and structural brain connectivity (the connectome) in patients with chronic aphasia after a stroke. METHODS Thirty-nine patients with chronic aphasia underwent language assessment and MRI scanning. Relying on MRI data, we reconstructed the individual connectome from T1-weighted and diffusion tensor imaging. Deterministic fiber tractography was used to assess connectivity between each possible pair of cortical Brodmann areas. Multiple linear regression analyses were performed to evaluate the relationship between language performance and cortical necrosis and cortical disconnection. RESULTS We observed that structural disconnection of Brodmann area 45 (spared by the necrotic tissue) was independently associated with naming performance, controlling for the extent of Brodmann area 45 necrosis (F=4.62; P<0.01; necrosis: β=0.43; P=0.03; disconnection β=1.21; P<0.001). CONCLUSIONS We suggest that cortical disconnection, as measured by the structural connectome, is an independent predictor of naming impairment in patients with chronic aphasia. The full extent of clinically relevant brain damage after an ischemic stroke may be underappreciated by visual inspection of cortical necrosis alone.
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Affiliation(s)
- Leonardo Bonilha
- From the Department of Neurology, Medical University of South Carolina, Charleston (L.B.); and Departments of Psychology (C.R.) and Communication Sciences and Disorders (J.F.), University of South Carolina, Columbia
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