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Dent LG, Curry N, Sparks H, Bousgouni V, Maioli V, Kumar S, Munro I, Butera F, Jones I, Arias-Garcia M, Rowe-Brown L, Dunsby C, Bakal C. Environmentally dependent and independent control of 3D cell shape. Cell Rep 2024:114016. [PMID: 38636520 DOI: 10.1016/j.celrep.2024.114016] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/04/2024] [Accepted: 03/14/2024] [Indexed: 04/20/2024] Open
Abstract
How cancer cells determine their shape in response to three-dimensional (3D) geometric and mechanical cues is unclear. We develop an approach to quantify the 3D cell shape of over 60,000 melanoma cells in collagen hydrogels using high-throughput stage-scanning oblique plane microscopy (ssOPM). We identify stereotypic and environmentally dependent changes in shape and protrusivity depending on whether a cell is proximal to a flat and rigid surface or is embedded in a soft environment. Environmental sensitivity metrics calculated for small molecules and gene knockdowns identify interactions between the environment and cellular factors that are important for morphogenesis. We show that the Rho guanine nucleotide exchange factor (RhoGEF) TIAM2 contributes to shape determination in environmentally independent ways but that non-muscle myosin II, microtubules, and the RhoGEF FARP1 regulate shape in ways dependent on the microenvironment. Thus, changes in cancer cell shape in response to 3D geometric and mechanical cues are modulated in both an environmentally dependent and independent fashion.
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Affiliation(s)
- Lucas G Dent
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Nathan Curry
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Hugh Sparks
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Vicky Bousgouni
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Vincent Maioli
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Ian Munro
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Francesca Butera
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Ian Jones
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Mar Arias-Garcia
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
| | - Leo Rowe-Brown
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK
| | - Chris Dunsby
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK.
| | - Chris Bakal
- Dynamical Cell Systems Group, Division of Cancer Biology, Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK.
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Schofield H, Hill RM, Feys O, Holmes N, Osborne J, Doyle C, Bobela D, Corvilian P, Wens V, Rier L, Bowtell R, Ferez M, Mullinger KJ, Coleman S, Rhodes N, Rea M, Tanner Z, Boto E, de Tiège X, Shah V, Brookes MJ. A Novel, Robust, and Portable Platform for Magnetoencephalography using Optically Pumped Magnetometers. bioRxiv 2024:2024.03.06.583313. [PMID: 38558964 PMCID: PMC10979878 DOI: 10.1101/2024.03.06.583313] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Magnetoencephalography (MEG) measures brain function via assessment of magnetic fields generated by neural currents. Conventional MEG uses superconducting sensors, which place significant limitations on performance, practicality, and deployment; however, the field has been revolutionised in recent years by the introduction of optically-pumped-magnetometers (OPMs). OPMs enable measurement of the MEG signal without cryogenics, and consequently the conception of 'OPM-MEG' systems which ostensibly allow increased sensitivity and resolution, lifespan compliance, free subject movement, and lower cost. However, OPM-MEG remains in its infancy with limitations on both sensor and system design. Here, we report a new OPM-MEG design with miniaturised and integrated electronic control, a high level of portability, and improved sensor dynamic range (arguably the biggest limitation of existing instrumentation). We show that this system produces equivalent measures when compared to an established instrument; specifically, when measuring task-induced beta-band, gamma-band and evoked neuro-electrical responses, source localisations from the two systems were highly comparable and temporal correlation was >0.7 at the individual level and >0.9 for groups. Using an electromagnetic phantom, we demonstrate improved dynamic range by running the system in background fields up to 8 nT. We show that the system is effective in gathering data during free movement (including a sitting-to-standing paradigm) and that it is compatible with simultaneous electroencephalography (EEG - the clinical standard). Finally, we demonstrate portability by moving the system between two laboratories. Overall, our new system is shown to be a significant step forward for OPM-MEG technology and offers an attractive platform for next generation functional medical imaging.
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Affiliation(s)
- Holly Schofield
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - Ryan M. Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - Odile Feys
- Université libre de Bruxelles, ULB Neuroscience Institute, Laboratoire de neuroanatomie et neuroimagerie translationelles, Brussels, Belgium
- Université libre de Bruxelles, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Department of neurology, Brussels, Belgium
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - James Osborne
- QuSpin Inc. 331 South 104 Street, Suite 130, Louisville, Colorado, 80027, USA
| | - Cody Doyle
- QuSpin Inc. 331 South 104 Street, Suite 130, Louisville, Colorado, 80027, USA
| | - David Bobela
- QuSpin Inc. 331 South 104 Street, Suite 130, Louisville, Colorado, 80027, USA
| | - Pierre Corvilian
- Université libre de Bruxelles, ULB Neuroscience Institute, Laboratoire de neuroanatomie et neuroimagerie translationelles, Brussels, Belgium
| | - Vincent Wens
- Université libre de Bruxelles, ULB Neuroscience Institute, Laboratoire de neuroanatomie et neuroimagerie translationelles, Brussels, Belgium
- Université libre de Bruxelles, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Department of translational neuroimaging, Brussels, Belgium
| | - Lukas Rier
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Maxime Ferez
- Université libre de Bruxelles, ULB Neuroscience Institute, Laboratoire de neuroanatomie et neuroimagerie translationelles, Brussels, Belgium
| | - Karen J. Mullinger
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Centre for Human Brain Health, School of Psychology, University of Birmingham, UK
| | - Sebastian Coleman
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Natalie Rhodes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Molly Rea
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - Zoe Tanner
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
| | - Xavier de Tiège
- Université libre de Bruxelles, ULB Neuroscience Institute, Laboratoire de neuroanatomie et neuroimagerie translationelles, Brussels, Belgium
- Université libre de Bruxelles, Hôpital Universitaire de Bruxelles, Hôpital Erasme, Department of translational neuroimaging, Brussels, Belgium
| | - Vishal Shah
- QuSpin Inc. 331 South 104 Street, Suite 130, Louisville, Colorado, 80027, USA
| | - Matthew J. Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
- Cerca Magnetics Limited, 2 Castlebridge Office Village, Kirtley Drive, Nottingham, NG7 1LD, Nottingham, UK
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Geller AS, Teale P, Kronberg E, Ebersole JS. Magnetoencephalography for Epilepsy Presurgical Evaluation. Curr Neurol Neurosci Rep 2024; 24:35-46. [PMID: 38148387 DOI: 10.1007/s11910-023-01328-5] [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] [Accepted: 12/13/2023] [Indexed: 12/28/2023]
Abstract
PURPOSE OF THE REVIEW Magnetoencephalography (MEG) is a functional neuroimaging technique that records neurophysiology data with millisecond temporal resolution and localizes it with subcentimeter accuracy. Its capability to provide high resolution in both of these domains makes it a powerful tool both in basic neuroscience as well as clinical applications. In neurology, it has proven useful in its ability to record and localize epileptiform activity. Epilepsy workup typically begins with scalp electroencephalography (EEG), but in many situations, EEG-based localization of the epileptogenic zone is inadequate. The complementary sensitivity of MEG can be crucial in such cases, and MEG has been adopted at many centers as an important resource in building a surgical hypothesis. In this paper, we review recent work evaluating the extent of MEG influence of presurgical evaluations, novel analyses of MEG data employed in surgical workup, and new MEG instrumentation that will likely affect the field of clinical MEG. RECENT FINDINGS MEG consistently contributes to presurgical evaluation and these contributions often change the plan for epilepsy surgery. Extensive work has been done to develop new analytic methods for localizing the source of epileptiform activity with MEG. Systems using optically pumped magnetometry (OPM) have been successfully deployed to record and localize epileptiform activity. MEG remains an important noninvasive tool for epilepsy presurgical evaluation. Continued improvements in analytic methodology will likely increase the diagnostic yield of the test. Novel instrumentation with OPM may contribute to this as well, and may increase accessibility of MEG by decreasing cost.
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Affiliation(s)
- Aaron S Geller
- Department of Neurology, CU Anschutz Medical School, Aurora, CO, USA.
| | - Peter Teale
- Department of Neurology, CU Anschutz Medical School, Aurora, CO, USA
| | - Eugene Kronberg
- Department of Neurology, CU Anschutz Medical School, Aurora, CO, USA
| | - John S Ebersole
- Department of Neurology, Atlantic Neuroscience Institute, Summit, NJ, USA
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Alem O, Hughes KJ, Buard I, Cheung TP, Maydew T, Griesshammer A, Holloway K, Park A, Lechuga V, Coolidge C, Gerginov M, Quigg E, Seames A, Kronberg E, Teale P, Knappe S. An integrated full-head OPM-MEG system based on 128 zero-field sensors. Front Neurosci 2023; 17:1190310. [PMID: 37389367 PMCID: PMC10303922 DOI: 10.3389/fnins.2023.1190310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/24/2023] [Indexed: 07/01/2023] Open
Abstract
Compact optically-pumped magnetometers (OPMs) are now commercially available with noise floors reaching 10 fT/Hz1/2. However, to be used effectively for magnetoencephalography (MEG), dense arrays of these sensors are required to operate as an integrated turn-key system. In this study, we present the HEDscan, a 128-sensor OPM MEG system by FieldLine Medical, and evaluate its sensor performance with regard to bandwidth, linearity, and crosstalk. We report results from cross-validation studies with conventional cryogenic MEG, the Magnes 3,600 WH Biomagnetometer by 4-D Neuroimaging. Our results show high signal amplitudes captured by the OPM-MEG system during a standard auditory paradigm, where short tones at 1000 Hz were presented to the left ear of six healthy adult volunteers. We validate these findings through an event-related beamformer analysis, which is in line with existing literature results.
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Affiliation(s)
- Orang Alem
- FieldLine Medical, Boulder, CO, United States
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States
- FieldLine Industries, Boulder, CO, United States
| | - K. Jeramy Hughes
- FieldLine Medical, Boulder, CO, United States
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States
- FieldLine Industries, Boulder, CO, United States
| | - Isabelle Buard
- Anschutz Medical Campus, University of Colorado Denver, Denver, CO, United States
| | - Teresa P. Cheung
- FieldLine Medical, Boulder, CO, United States
- School of Engineering, Simon Fraser University, Burnaby, BC, Canada
- Surrey Memorial Hospital, Fraser Health Authority, Surrey, BC, Canada
| | | | | | | | - Aaron Park
- FieldLine Medical, Boulder, CO, United States
| | | | | | - Marja Gerginov
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States
| | - Erik Quigg
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States
| | - Alexander Seames
- Anschutz Medical Campus, University of Colorado Denver, Denver, CO, United States
| | - Eugene Kronberg
- Anschutz Medical Campus, University of Colorado Denver, Denver, CO, United States
| | - Peter Teale
- Anschutz Medical Campus, University of Colorado Denver, Denver, CO, United States
| | - Svenja Knappe
- FieldLine Medical, Boulder, CO, United States
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO, United States
- FieldLine Industries, Boulder, CO, United States
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5
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Wurm D, Ewert P, Fierlinger P, Wakai RT, Wallner V, Wunderl L, Wacker-Gußmann A. A Small Scale Optically Pumped Fetal Magnetocardiography System. J Clin Med 2023; 12:jcm12103380. [PMID: 37240486 DOI: 10.3390/jcm12103380] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/26/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
INTRODUCTION Fetal magnetocardiography (fMCG) is considered the best technique for diagnosis of fetal arrhythmia. It is superior to more widely used methods such as fetal, fetal electrocardiography, and cardiotocography for evaluation of fetal rhythm. The combination of fMCG and fetal echocardiography can provide a more comprehensive evaluation of fetal cardiac rhythm and function than is currently possible. In this study, we demonstrate a practical fMCG system based on optically pumped magnetometers (OPMs). METHODS Seven pregnant women with uncomplicated pregnancies underwent fMCG at 26-36 weeks' gestation. The recordings were made using an OPM-based fMCG system and a person-sized magnetic shield. The shield is much smaller than a shielded room and provides easy access with a large opening that allows the pregnant woman to lie comfortably in a prone position. RESULTS The data show no significant loss of quality compared to data acquired in a shielded room. Measurements of standard cardiac time intervals yielded the following results: PR = 104 ± 6 ms, QRS = 52.6 ± 1.5 ms, and QTc = 387 ± 19 ms. These results are compatible with those from prior studies performed using superconducting quantum interference device (SQUID) fMCG systems. CONCLUSIONS To our knowledge, this is the first European fMCG device with OPM technology commissioned for basic research in a pediatric cardiology unit. We demonstrated a patient-friendly, comfortable, and open fMCG system. The data yielded consistent cardiac intervals, measured from time-averaged waveforms, compatible with published SQUID and OPM data. This is an important step toward making the method widely accessible.
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Affiliation(s)
- David Wurm
- Chair E66, School of Natural Sciences, Technical University of Munich, 80636 Munich, Germany
| | - Peter Ewert
- Department of Congenital Heart Disease and Pediatric Cardiology, German Heart Center, 80636 Munich, Germany
| | - Peter Fierlinger
- Chair E66, School of Natural Sciences, Technical University of Munich, 80636 Munich, Germany
| | - Ronald T Wakai
- Department of Medical Physics, University of Wisconsin Madison, Madison, WI 53706, USA
| | - Verena Wallner
- Chair E66, School of Natural Sciences, Technical University of Munich, 80636 Munich, Germany
| | - Lena Wunderl
- Chair E66, School of Natural Sciences, Technical University of Munich, 80636 Munich, Germany
| | - Annette Wacker-Gußmann
- Department of Congenital Heart Disease and Pediatric Cardiology, German Heart Center, 80636 Munich, Germany
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Gutteling TP, Bonnefond M, Clausner T, Daligault S, Romain R, Mitryukovskiy S, Fourcault W, Josselin V, Le Prado M, Palacios-Laloy A, Labyt E, Jung J, Schwartz D. A New Generation of OPM for High Dynamic and Large Bandwidth MEG: The 4He OPMs-First Applications in Healthy Volunteers. Sensors (Basel) 2023; 23:s23052801. [PMID: 36905007 PMCID: PMC10006929 DOI: 10.3390/s23052801] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [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: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/24/2023] [Indexed: 06/06/2023]
Abstract
MagnetoEncephaloGraphy (MEG) provides a measure of electrical activity in the brain at a millisecond time scale. From these signals, one can non-invasively derive the dynamics of brain activity. Conventional MEG systems (SQUID-MEG) use very low temperatures to achieve the necessary sensitivity. This leads to severe experimental and economical limitations. A new generation of MEG sensors is emerging: the optically pumped magnetometers (OPM). In OPM, an atomic gas enclosed in a glass cell is traversed by a laser beam whose modulation depends on the local magnetic field. MAG4Health is developing OPMs using Helium gas (4He-OPM). They operate at room temperature with a large dynamic range and a large frequency bandwidth and output natively a 3D vectorial measure of the magnetic field. In this study, five 4He-OPMs were compared to a classical SQUID-MEG system in a group of 18 volunteers to evaluate their experimental performances. Considering that the 4He-OPMs operate at real room temperature and can be placed directly on the head, our assumption was that 4He-OPMs would provide a reliable recording of physiological magnetic brain activity. Indeed, the results showed that the 4He-OPMs showed very similar results to the classical SQUID-MEG system by taking advantage of a shorter distance to the brain, despite having a lower sensitivity.
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Affiliation(s)
- Tjerk P. Gutteling
- CERMEP-Imagerie du Vivant, MEG Departement, 69000 Lyon, France
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | | | - Tommy Clausner
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | | | | | | | - William Fourcault
- CEA LETI, Minatec Campus, Université Grenoble Alpes, 38000 Grenoble, France
| | - Vincent Josselin
- CEA LETI, Minatec Campus, Université Grenoble Alpes, 38000 Grenoble, France
| | | | | | | | - Julien Jung
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
| | - Denis Schwartz
- CERMEP-Imagerie du Vivant, MEG Departement, 69000 Lyon, France
- CRNL, UMR_S 1028, HCL, Université Lyon 1, 69000 Lyon, France
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Wengrowicz N, Lavi R, Kohen H, Dori D. Modeling with Real-Time Informative Feedback: Implementing and Evaluating a New Massive Open Online Course Component. J Sci Educ Technol 2022; 32:1-14. [PMID: 36573101 PMCID: PMC9771771 DOI: 10.1007/s10956-022-10019-8] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
As part of the design, development, and deployment of a massive open online course (MOOC) on model-based systems engineering, we introduced MORTIF-Modeling with Real-Time Informative Feedback, a new learning-by-doing feature that enables the learner to model, receive detailed feedback, and resubmit improved solutions. We examined the pedagogical usability of MORTIF by investigating characteristics of participants working with it, and their perceived contribution, preferred question type, and learning style. The research included 295 participants and applied the mixed-methods approach, using MOOC server data and online questionnaires. Analyzing 12,095 submissions, we found increasing frequency of using the model resubmitting option. Students ranked MORTIF as the highest of six question types in terms of preference and perceived contribution level. Nine learning style categories were identified and classified based on students' verbal explanations regarding their preference of MORTIF over the other question types. MORTIF has been effective in promoting meaningful learning, supporting our hypothesis that the combination of active learning with real-time informative feedback is a learning mode that students eagerly embrace and benefit from. The benefits we identified for using MORTIF include active learning, provision of meaningful immediate feedback to the learner, the option to use the feedback on the spot and resubmitting an improved model, and its suitability for a variety of learning styles.
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Affiliation(s)
- Niva Wengrowicz
- Faculty of Industrial Engineering and Management, Technion - Israel Institute of Technology, Haifa, Israel
| | - Rea Lavi
- School of Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Hanan Kohen
- Faculty of Industrial Engineering and Management, Technion - Israel Institute of Technology, Haifa, Israel
| | - Dov Dori
- Faculty of Industrial Engineering and Management, Technion - Israel Institute of Technology, Haifa, Israel
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8
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Hori S, Oida T, Moriya T, Saito A, Suyama M, Kobayashi T. Magnetic shieldless ultra-low-field MRI with an optically pumped magnetometer. J Magn Reson 2022; 343:107280. [PMID: 35998483 DOI: 10.1016/j.jmr.2022.107280] [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] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Among magnetic resonance imaging (MRI) techniques, ultra-low field (ULF) MRI has the potential to significantly lower the cost of implementation and maintenance, as well as the size of the scanning system. Due to the small amplitude of the signals produced by ULR-MRI, extremely sensitive magnetic sensors are required. Optically pumped magnetometers (OPMs) have been proposed for use in ULF-MRI as ultra-sensitive magnetic sensors capable of detecting very small signals. However, the cost of a ferromagnetic magnetic shield is often not affordable for many applications. By increasing the Larmor frequency, the influence of low-frequency magnetic noise can be mitigated, allowing OPM to be operated without the use of a magnetic shield chamber. This lowers the cost of the magnetic shield and further raises the signal strength, resulting in benefits such as non-prepolarization. We present a method for implementing the ULF-MRI using low-cost OPMs in this study. The Larmor frequency was adjusted to 300 kHz, and three-dimensional (3D) images of a phantom were acquired with a digital resolution of 3 × 3 × 3 mm3 using a static magnetic field of 7.05 mT without using a magnetic shield room or a prepolarization coil. Additionally, we corrected the frequency response to acquired images to consider the narrow bandwidth, and the SNR of 3D imaging was 18. The experimental results, we believe, establish a new guideline for higher-performance, lower-cost ULF-MRI that does not require expensive magnetic shielding.
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Affiliation(s)
- Sogo Hori
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takenori Oida
- Central Research Laboratory, Hamamatsu Photonics K.K., Japan
| | - Takahiro Moriya
- Central Research Laboratory, Hamamatsu Photonics K.K., Japan
| | - Akinori Saito
- Central Research Laboratory, Hamamatsu Photonics K.K., Japan
| | - Motohiro Suyama
- Central Research Laboratory, Hamamatsu Photonics K.K., Japan
| | - Tetsuo Kobayashi
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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9
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Seymour RA, Alexander N, Mellor S, O'Neill GC, Tierney TM, Barnes GR, Maguire EA. Interference suppression techniques for OPM-based MEG: Opportunities and challenges. Neuroimage 2022; 247:118834. [PMID: 34933122 PMCID: PMC8803550 DOI: 10.1016/j.neuroimage.2021.118834] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 09/30/2021] [Revised: 11/23/2021] [Accepted: 12/17/2021] [Indexed: 12/13/2022] Open
Abstract
One of the primary technical challenges facing magnetoencephalography (MEG) is that the magnitude of neuromagnetic fields is several orders of magnitude lower than interfering signals. Recently, a new type of sensor has been developed - the optically pumped magnetometer (OPM). These sensors can be placed directly on the scalp and move with the head during participant movement, making them wearable. This opens up a range of exciting experimental and clinical opportunities for OPM-based MEG experiments, including paediatric studies, and the incorporation of naturalistic movements into neuroimaging paradigms. However, OPMs face some unique challenges in terms of interference suppression, especially in situations involving mobile participants, and when OPMs are integrated with electrical equipment required for naturalistic paradigms, such as motion capture systems. Here we briefly review various hardware solutions for OPM interference suppression. We then outline several signal processing strategies aimed at increasing the signal from neuromagnetic sources. These include regression-based strategies, temporal filtering and spatial filtering approaches. The focus is on the practical application of these signal processing algorithms to OPM data. In a similar vein, we include two worked-through experiments using OPM data collected from a whole-head sensor array. These tutorial-style examples illustrate how the steps for suppressing external interference can be implemented, including the associated data and code so that researchers can try the pipelines for themselves. With the popularity of OPM-based MEG rising, there will be an increasing need to deal with interference suppression. We hope this practical paper provides a resource for OPM-based MEG researchers to build upon.
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Affiliation(s)
- Robert A Seymour
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK.
| | - Nicholas Alexander
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Stephanie Mellor
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - George C O'Neill
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Tim M Tierney
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Gareth R Barnes
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London WC1N 3AR, UK.
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10
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Borna A, Iivanainen J, Carter TR, McKay J, Taulu S, Stephen J, Schwindt PDD. Cross-Axis projection error in optically pumped magnetometers and its implication for magnetoencephalography systems. Neuroimage 2021; 247:118818. [PMID: 34915157 PMCID: PMC8929686 DOI: 10.1016/j.neuroimage.2021.118818] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/22/2021] [Accepted: 12/13/2021] [Indexed: 10/25/2022] Open
Abstract
Optically pumped magnetometers (OPMs) developed for magnetoencephalography (MEG) typically operate in the spin-exchange-relaxation-free (SERF) regime and measure a magnetic field component perpendicular to the propagation axis of the optical-pumping photons. The most common type of OPM for MEG employs alkali atoms, e.g. 87Rb, as the sensing element and one or more lasers for preparation and interrogation of the magnetically sensitive states of the alkali atoms ensemble. The sensitivity of the OPM can be greatly enhanced by operating it in the SERF regime, where the alkali atoms' spin exchange rate is much faster than the Larmor precession frequency. The SERF regime accommodates remnant static magnetic fields up to ±5 nT. However, in the presented work, through simulation and experiment, we demonstrate that multi-axis magnetic signals in the presence of small remnant static magnetic fields, not violating the SERF criteria, can introduce significant error terms in OPM's output signal. We call these deterministic errors cross-axis projection errors (CAPE), where magnetic field components of the MEG signal perpendicular to the nominal sensing axis contribute to the OPM signal giving rise to substantial amplitude and phase errors. Furthermore, through simulation, we have discovered that CAPE can degrade localization and calibration accuracy of OPM-based magnetoencephalography (OPM-MEG) systems.
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Affiliation(s)
- Amir Borna
- Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, NM 87123, United States.
| | - Joonas Iivanainen
- Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, NM 87123, United States
| | - Tony R Carter
- Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, NM 87123, United States
| | - Jim McKay
- Candoo Systems Inc., Port Coquitlam, BC V3C 5M2, Canada
| | - Samu Taulu
- University of Washington Seattle, WA 98195, United States
| | - Julia Stephen
- The Mind Research Network, Albuquerque, NM 87106, United States
| | - Peter D D Schwindt
- Sandia National Laboratories, 1515 Eubank Blvd SE, Albuquerque, NM 87123, United States
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11
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Clancy RJ, Gerginov V, Alem O, Becker S, Knappe S. A study of scalar optically-pumped magnetometers for use in magnetoencephalography without shielding. Phys Med Biol 2021; 66. [PMID: 34325403 DOI: 10.1088/1361-6560/ac18fb] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/29/2021] [Indexed: 11/11/2022]
Abstract
Scalar optically-pumped magnetometers (OPMs) are being developed in small packages with high sensitivities. The high common-mode rejection ratio of these sensors allows for detection of very small signals in the presence of large background fields making them ideally suited for brain imaging applications in unshielded environments. Despite a flurry of activity around the topic, questions remain concerning how well a dipolar source can be localized under such conditions, especially when using few sensors. In this paper, we investigate the source localization capabilities using an array of scalar OPMs in the presence of a large background field while varying dipole strength, sensor count, and forward model accuracy. We also consider localization performance as the orientation angle of the background field changes. Our results are validated experimentally through accurate localization using a phantom virtual array mimicking a current dipole in a conducting sphere in a large background field. Our results are intended to give researchers a general sense of the capabilities and limitations of scalar OPMs for magnetoencephalography systems.
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Affiliation(s)
- Richard J Clancy
- Department of Applied Mathematics, University of Colorado, Boulder, CO 80309, United States of America
| | - Vladislav Gerginov
- Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, United States of America
| | - Orang Alem
- Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, United States of America.,Fieldline Inc., Boulder, CO 80301, United States of America
| | - Stephen Becker
- Department of Applied Mathematics, University of Colorado, Boulder, CO 80309, United States of America
| | - Svenja Knappe
- Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, United States of America.,Fieldline Inc., Boulder, CO 80301, United States of America
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12
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Westner BU, Lubell JI, Jensen M, Hokland S, Dalal SS. Contactless measurements of retinal activity using optically pumped magnetometers. Neuroimage 2021; 243:118528. [PMID: 34464740 DOI: 10.1016/j.neuroimage.2021.118528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/20/2021] [Accepted: 08/27/2021] [Indexed: 11/23/2022] Open
Abstract
Optically pumped magnetometers (OPMs) have been adopted for the measurement of brain activity. Without the need to be cooled to cryogenic temperatures, an array of these sensors can be placed more flexibly, which allows for the recording of neuronal structures other than neocortex. Here we use eight OPM sensors to record human retinal activity following flash stimulation. We compare this magnetoretinographic (MRG) activity to the simultaneously recorded electroretinogram of the eight participants. The MRG shows the familiar flash-evoked potentials (a-wave and b-wave) and shares a highly significant amount of information with the electroretinogram (both in a simultaneous and separate measurement). We conclude that OPM sensors have the potential to become a contactless alternative to fiber electrodes for the measurement of retinal activity. Such a contactless solution can benefit both clinical and neuroscientific settings.
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13
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Rea M, Holmes N, Hill RM, Boto E, Leggett J, Edwards LJ, Woolger D, Dawson E, Shah V, Osborne J, Bowtell R, Brookes MJ. Precision magnetic field modelling and control for wearable magnetoencephalography. Neuroimage 2021; 241:118401. [PMID: 34273527 PMCID: PMC9248349 DOI: 10.1016/j.neuroimage.2021.118401] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 06/30/2021] [Accepted: 07/13/2021] [Indexed: 11/27/2022] Open
Abstract
Optically-pumped magnetometers (OPMs) are highly sensitive, compact magnetic field sensors, which offer a viable alternative to cryogenic sensors (superconducting quantum interference devices – SQUIDs) for magnetoencephalography (MEG). With the promise of a wearable system that offers lifespan compliance, enables movement during scanning, and provides higher quality data, OPMs could drive a step change in MEG instrumentation. However, this potential can only be realised if background magnetic fields are appropriately controlled, via a combination of optimised passive magnetic screening (i.e. enclosing the system in layers of high-permeability materials), and electromagnetic coils to further null the remnant magnetic field. In this work, we show that even in an OPM-optimised passive shield with extremely low (<2 nT) remnant magnetic field, head movement generates significant artefacts in MEG data that manifest as low-frequency interference. To counter this effect we introduce a magnetic field mapping technique, in which the participant moves their head to sample the background magnetic field using a wearable sensor array; resulting data are compared to a model to derive coefficients representing three uniform magnetic field components and five magnetic field gradient components inside the passive shield. We show that this technique accurately reconstructs the magnitude of known magnetic fields. Moreover, by feeding the obtained coefficients into a bi-planar electromagnetic coil system, we were able to reduce the uniform magnetic field experienced by the array from a magnitude of 1.3 ± 0.3 nT to 0.29 ± 0.07 nT. Most importantly, we show that this field compensation generates a five-fold reduction in motion artefact at 0–2 Hz, in a visual steady-state evoked response experiment using 6 Hz stimulation. We suggest that this technique could be used in future OPM-MEG experiments to improve the quality of data, especially in paradigms seeking to measure low-frequency oscillations, or in experiments where head movement is encouraged.
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Affiliation(s)
- Molly Rea
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - Ryan M Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - James Leggett
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Lucy J Edwards
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - David Woolger
- Magnetic Shields Limited, Headcorn Road, Staplehurst, Tonbridge, Kent, TN12 0DS, UK
| | - Eliot Dawson
- Magnetic Shields Limited, Headcorn Road, Staplehurst, Tonbridge, Kent, TN12 0DS, UK
| | - Vishal Shah
- QuSpin Inc., 331 South 104th Street, Suite 130, Louisville, 80027, Colorado, USA
| | - James Osborne
- QuSpin Inc., 331 South 104th Street, Suite 130, Louisville, 80027, Colorado, USA
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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14
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Marquetand J, Middelmann T, Dax J, Baek S, Sometti D, Grimm A, Lerche H, Martin P, Kronlage C, Siegel M, Braun C, Broser P. Optically pumped magnetometers reveal fasciculations non-invasively. Clin Neurophysiol 2021; 132:2681-2684. [PMID: 34274216 DOI: 10.1016/j.clinph.2021.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE This proof-of-principle-study evaluated the extent to which spontaneous activity (SA) of the muscle can be detected via non-invasive magnetomyography (MMG) with optically pumped magnetometers (OPM). METHODS Five patients, who together exhibited all forms of SA (fibrillations, positive sharp waves, fasciculations, myotonic discharges, complex-repetitive discharges) with conventional needle electromyography (EMG), were studied by OPM-MMG and simultaneous surface EMG (sEMG) while at rest, during light muscle activation, and when a muscle stretch reflex was elicited. Three healthy subjects were measured as controls. SA was considered apparent in the OPM-MMG if a signal could be visually detected that corresponded in shape and frequency to the SA in the respective needle EMG. RESULTS SA in the context of fasciculations could be detected in 2 of 5 patients by simultaneous OPM-MMG/sEMG. Other forms of SA could not be detected at rest, during light muscle activation, or after provocation of a muscle stretch reflex. CONCLUSIONS Results show that fasciculations could be detected non-invasively via a new method (OPM). SIGNIFICANCE We show that other forms of SA are not detectable with current OPM and propose necessary technical solutions to overcome this circumstance. Our results motivate to pursue OPM-MMG as a new clinical neurophysiological diagnostic.
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Affiliation(s)
- Justus Marquetand
- Department of Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany.
| | - Thomas Middelmann
- Department of Biosignals, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany
| | - Juergen Dax
- Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany
| | - Sangyeob Baek
- Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany
| | - Davide Sometti
- Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany
| | - Alexander Grimm
- Department of Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Pascal Martin
- Department of Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Cornelius Kronlage
- Department of Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Markus Siegel
- Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany; Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Christoph Braun
- Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; MEG-Center, University of Tübingen, Tübingen, Germany; CIMeC, Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy; DiPsCo, Department of Psychology and Cognitive Science, University of Trento, Rovereto, Italy
| | - Philip Broser
- Children's Hospital of Eastern Switzerland, Sankt Gallen, Switzerland
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15
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Brookes MJ, Boto E, Rea M, Shah V, Osborne J, Holmes N, Hill RM, Leggett J, Rhodes N, Bowtell R. Theoretical advantages of a triaxial optically pumped magnetometer magnetoencephalography system. Neuroimage 2021; 236:118025. [PMID: 33838266 DOI: 10.1016/j.neuroimage.2021.118025] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/10/2021] [Accepted: 03/25/2021] [Indexed: 01/10/2023] Open
Abstract
The optically pumped magnetometer (OPM) is a viable means to detect magnetic fields generated by human brain activity. Compared to conventional detectors (superconducting quantum interference devices) OPMs are small, lightweight, flexible, and operate without cryogenics. This has led to a step change in instrumentation for magnetoencephalography (MEG), enabling a "wearable" scanner platform, adaptable to fit any head size, able to acquire data whilst subjects move, and offering improved data quality. Although many studies have shown the efficacy of 'OPM-MEG', one relatively untapped advantage relates to improved array design. Specifically, OPMs enable the simultaneous measurement of magnetic field components along multiple axes (distinct from a single radial orientation, as used in most conventional MEG systems). This enables characterisation of the magnetic field vector at all sensors, affording extra information which has the potential to improve source reconstruction. Here, we conduct a theoretical analysis of the critical parameters that should be optimised for effective source reconstruction. We show that these parameters can be optimised by judicious array design incorporating triaxial MEG measurements. Using simulations, we demonstrate how a triaxial array offers a dramatic improvement on our ability to differentiate real brain activity from sources of magnetic interference (external to the brain). Further, a triaxial system is shown to offer a marked improvement in the elimination of artefact caused by head movement. Theoretical results are supplemented by an experimental recording demonstrating improved interference reduction. These findings offer new insights into how future OPM-MEG arrays can be designed with improved performance.
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16
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Boto E, Hill RM, Rea M, Holmes N, Seedat ZA, Leggett J, Shah V, Osborne J, Bowtell R, Brookes MJ. Measuring functional connectivity with wearable MEG. Neuroimage 2021; 230:117815. [PMID: 33524584 PMCID: PMC8216250 DOI: 10.1016/j.neuroimage.2021.117815] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/11/2020] [Accepted: 01/24/2021] [Indexed: 12/26/2022] Open
Abstract
Optically-pumped magnetometers (OPMs) offer the potential for a step change in magnetoencephalography (MEG) enabling wearable systems that provide improved data quality, accommodate any subject group, allow data capture during movement and potentially reduce cost. However, OPM-MEG is a nascent technology and, to realise its potential, it must be shown to facilitate key neuroscientific measurements, such as the characterisation of brain networks. Networks, and the connectivities that underlie them, have become a core area of neuroscientific investigation, and their importance is underscored by many demonstrations of their disruption in brain disorders. Consequently, a demonstration of network measurements using OPM-MEG would be a significant step forward. Here, we aimed to show that a wearable 50-channel OPM-MEG system enables characterisation of the electrophysiological connectome. To this end, we measured connectivity in the resting state and during a visuo-motor task, using both OPM-MEG and a state-of-the-art 275-channel cryogenic MEG device. Our results show that resting-state connectome matrices from OPM and cryogenic systems exhibit a high degree of similarity, with correlation values >70%. In addition, in task data, similar differences in connectivity between individuals (scanned multiple times) were observed in cryogenic and OPM-MEG data, again demonstrating the fidelity of the OPM-MEG device. This is the first demonstration of network connectivity measured using OPM-MEG, and results add weight to the argument that OPMs will ultimately supersede cryogenic sensors for MEG measurement.
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Affiliation(s)
- Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
| | - Ryan M Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Molly Rea
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Zelekha A Seedat
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - James Leggett
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Vishal Shah
- QuSpin Inc., 331 South 104th Street, Suite 130, Louisville, 80027, CO, USA
| | - James Osborne
- QuSpin Inc., 331 South 104th Street, Suite 130, Louisville, 80027, CO, USA
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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17
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Tierney TM, Levy A, Barry DN, Meyer SS, Shigihara Y, Everatt M, Mellor S, Lopez JD, Bestmann S, Holmes N, Roberts G, Hill RM, Boto E, Leggett J, Shah V, Brookes MJ, Bowtell R, Maguire EA, Barnes GR. Mouth magnetoencephalography: A unique perspective on the human hippocampus. Neuroimage 2020; 225:117443. [PMID: 33059052 PMCID: PMC8214102 DOI: 10.1016/j.neuroimage.2020.117443] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 09/02/2020] [Accepted: 10/09/2020] [Indexed: 02/07/2023] Open
Abstract
Traditional magnetoencephalographic (MEG) brain imaging scanners consist of a rigid sensor array surrounding the head; this means that they are maximally sensitive to superficial brain structures. New technology based on optical pumping means that we can now consider more flexible and creative sensor placement. Here we explored the magnetic fields generated by a model of the human hippocampus not only across scalp but also at the roof of the mouth. We found that simulated hippocampal sources gave rise to dipolar field patterns with one scalp surface field extremum at the temporal lobe and a corresponding maximum or minimum at the roof of the mouth. We then constructed a fitted dental mould to accommodate an Optically Pumped Magnetometer (OPM). We collected data using a previously validated hippocampal-dependant task to test the empirical utility of a mouth-based sensor, with an accompanying array of left and right temporal lobe OPMs. We found that the mouth sensor showed the greatest task-related theta power change. We found that this sensor had a mild effect on the reconstructed power in the hippocampus (~10% change) but that coherence images between the mouth sensor and reconstructed source images showed a global maximum in the right hippocampus. We conclude that augmenting a scalp-based MEG array with sensors in the mouth shows unique promise for both basic scientists and clinicians interested in interrogating the hippocampus.
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Affiliation(s)
- Tim M Tierney
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK.
| | - Andrew Levy
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Daniel N Barry
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Sofie S Meyer
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK; Institute of Cognitive Neuroscience, University College London, 17-19 Queen Square, London WC1N 3AZ, UK
| | | | - Matt Everatt
- S4S (UK) Limited & Smilelign Ltd, 151 Rutland Road, Sheffield S3 9PT, UK
| | - Stephanie Mellor
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Jose David Lopez
- Engineering Faculty, Universidad de Antioquia UDEA, calle 70 No 52-21, Medellín, Colombia
| | - Sven Bestmann
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Gillian Roberts
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Ryan M Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - James Leggett
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Vishal Shah
- QuSpin Inc., 2011 Cherry Street, Unit 112, Louisville, CO 80027, USA
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Eleanor A Maguire
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
| | - Gareth R Barnes
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, 12 Queen Square, London WC1N 3AR, UK
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18
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Abstract
Direct decoding of speech from the brain is a faster alternative to current electroencephalography (EEG) speller-based brain-computer interfaces (BCI) in providing communication assistance to locked-in patients. Magnetoencephalography (MEG) has recently shown great potential as a non-invasive neuroimaging modality for neural speech decoding, owing in part to its spatial selectivity over other high-temporal resolution devices. Standard MEG systems have a large number of cryogenically cooled channels/sensors (200 - 300) encapsulated within a fixed liquid helium dewar, precluding their use as wearable BCI devices. Fortunately, recently developed optically pumped magnetometers (OPM) do not require cryogens, and have the potential to be wearable and movable making them more suitable for BCI applications. This design is also modular allowing for customized montages to include only the sensors necessary for a particular task. As the number of sensors bears a heavy influence on the cost, size, and weight of MEG systems, minimizing the number of sensors is critical for designing practical MEG-based BCIs in the future. In this study, we sought to identify an optimal set of MEG channels to decode imagined and spoken phrases from the MEG signals. Using a forward selection algorithm with a support vector machine classifier we found that nine optimally located MEG gradiometers provided higher decoding accuracy compared to using all channels. Additionally, the forward selection algorithm achieved similar performance to dimensionality reduction using a stacked-sparse-autoencoder. Analysis of spatial dynamics of speech decoding suggested that both left and right hemisphere sensors contribute to speech decoding. Sensors approximately located near Broca's area were found to be commonly contributing among the higher-ranked sensors across all subjects.
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Affiliation(s)
- Debadatta Dash
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| | - Alan Wisler
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Paul Ferrari
- MEG Laboratory, Dell Children's Medical Center, Austin, TX 78723, USA
- Department of Psychology, The University of Texas at Austin, Austin, TX 78712, USA
| | | | - Joseph Maldjian
- Department of Radiology, University of Texas at Southwestern, Dallas, TX 75390, USA
| | - Jun Wang
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX 78712, USA
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19
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Hill RM, Boto E, Rea M, Holmes N, Leggett J, Coles LA, Papastavrou M, Everton SK, Hunt BAE, Sims D, Osborne J, Shah V, Bowtell R, Brookes MJ. Multi-channel whole-head OPM-MEG: Helmet design and a comparison with a conventional system. Neuroimage 2020; 219:116995. [PMID: 32480036 PMCID: PMC8274815 DOI: 10.1016/j.neuroimage.2020.116995] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [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: 03/12/2020] [Revised: 05/20/2020] [Accepted: 05/23/2020] [Indexed: 12/18/2022] Open
Abstract
Magnetoencephalography (MEG) is a powerful technique for functional
neuroimaging, offering a non-invasive window on brain electrophysiology. MEG
systems have traditionally been based on cryogenic sensors which detect the
small extracranial magnetic fields generated by synchronised current in neuronal
assemblies, however, such systems have fundamental limitations. In recent years,
non-cryogenic quantum-enabled sensors, called optically-pumped magnetometers
(OPMs), in combination with novel techniques for accurate background magnetic
field control, have promised to lift those restrictions offering an adaptable,
motion-robust MEG system, with improved data quality, at reduced cost. However,
OPM-MEG remains a nascent technology, and whilst viable systems exist, most
employ small numbers of sensors sited above targeted brain regions. Here,
building on previous work, we construct a wearable OPM-MEG system with
‘whole-head’ coverage based upon commercially available OPMs, and
test its capabilities to measure alpha, beta and gamma oscillations. We design
two methods for OPM mounting; a flexible (EEG-like) cap and rigid
(additively-manufactured) helmet. Whilst both designs allow for high quality
data to be collected, we argue that the rigid helmet offers a more robust option
with significant advantages for reconstruction of field data into 3D images of
changes in neuronal current. Using repeat measurements in two participants, we
show signal detection for our device to be highly robust. Moreover, via
application of source-space modelling, we show that, despite having 5 times
fewer sensors, our system exhibits comparable performance to an established
cryogenic MEG device. While significant challenges still remain, these
developments provide further evidence that OPM-MEG is likely to facilitate a
step change for functional neuroimaging.
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Affiliation(s)
- Ryan M Hill
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
| | - Elena Boto
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Molly Rea
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Niall Holmes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - James Leggett
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Laurence A Coles
- Added Scientific Limited, No 4, The Isaac Newton Centre, Nottingham Science Park, Nottingham, NG72RH, UK
| | - Manolis Papastavrou
- Added Scientific Limited, No 4, The Isaac Newton Centre, Nottingham Science Park, Nottingham, NG72RH, UK
| | - Sarah K Everton
- Added Scientific Limited, No 4, The Isaac Newton Centre, Nottingham Science Park, Nottingham, NG72RH, UK
| | - Benjamin A E Hunt
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Dominic Sims
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - James Osborne
- QuSpin Inc. 331 South 104th Street, Suite 130, Louisville, CO, 80027, USA
| | - Vishal Shah
- QuSpin Inc. 331 South 104th Street, Suite 130, Louisville, CO, 80027, USA
| | - Richard Bowtell
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Matthew J Brookes
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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Borna A, Carter TR, DeRego P, James CD, Schwindt PDD. Magnetic Source Imaging Using a Pulsed Optically Pumped Magnetometer Array. IEEE Trans Instrum Meas 2019; 68:493-501. [PMID: 31777404 PMCID: PMC6880808 DOI: 10.1109/tim.2018.2851458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have developed a pulsed optically pumped magnetometer (OPM) array for detecting magnetic field maps originated from an arbitrary current distribution. The presented magnetic source imaging (MSI) system features 24 OPM channels, has a data rate of 500 S/s, a sensitivity of 0.8 p T / H z , and a dynamic range of 72 dB. We have employed our pulsed- OPM MSI system for measuring the magnetic field map of a test coil structure. The coils are moved across the array in an indexed fashion to measure the magnetic field over an area larger than the array. The captured magnetic field maps show excellent agreement with the simulation results. Assuming a 2D current distribution, we have solved the inverse problem, using the measured magnetic field maps, and the reconstructed current distribution image is compared to that of the simulation.
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Affiliation(s)
- Amir Borna
- Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-1082, USA
| | - Tony R Carter
- Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-1082, USA
| | - Paul DeRego
- Kansas City National Security Campus, 2450 Alamo Ave SE, Albuquerque, NM 87106
| | - Conrad D James
- Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-1082, USA
| | - Peter D D Schwindt
- Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-1082, USA
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21
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Finch JTD, Power SA, Welbergen JA, Cook JM. Two's company, three's a crowd: co-occurring pollinators and parasite species in Breynia oblongifolia (Phyllanthaceae). BMC Evol Biol 2018; 18:193. [PMID: 30547744 PMCID: PMC6295073 DOI: 10.1186/s12862-018-1314-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 06/29/2018] [Accepted: 11/28/2018] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Obligate pollination mutualisms (OPMs) are specialized interactions in which female pollinators transport pollen between the male and female flowers of a single plant species and then lay eggs into those same flowers. The pollinator offspring hatch and feed upon some or all of the developing ovules pollinated by their mothers. Strong trait matching between plants and their pollinators in OPMs is expected to result in reciprocal partner specificity i.e., a single pollinator species using a single plant species and vice versa, and strict co-speciation. These issues have been studied extensively in figs and fig wasps, but little in the more recently discovered co-diversification of Epicephala moths and their Phyllanthaceae hosts. OPMs involving Epicephala moths are believed occur in approximately 500 species of Phyllanthaceae, making it the second largest OPM group after the Ficus radiation (> 750 species). In this study, we used a mixture of DNA barcoding, genital morphology and behavioral observations to determine the number of Epicephala moth species inhabiting the fruits of Breynia oblongifolia, their geographic distribution, pollinating behavior and phylogenetic relationships. RESULTS We found that B. oblongifolia hosts two species of pollinator that co-occurred at all study sites, violating the assumption of reciprocal specificity. Male and female genital morphologies both differed considerably between the two moth species. In particular, females differed in the shape of their ovipositors, eggs and oviposition sites. Phylogenetic analyses indicated that the two Epicephala spp. on B. oblongifolia likely co-exist due to a host switch. In addition, we discovered that Breynia fruits are also often inhabited by a third moth, an undescribed species of Herpystis, which is a non-pollinating seed parasite. CONCLUSIONS Our study reveals new complexity in interactions between Phyllantheae and Epicephala pollinators and highlights that host switching, co-speciation and non-pollinating seed parasites can shape species interactions in OPMs. Our finding that co-occurring Epicephala species have contrasting oviposition modes parallels other studies and suggests that such traits are important in Epicephala species coexistence.
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Affiliation(s)
- J. T. D. Finch
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Science Rd, Richmond, NSW 2753 Australia
| | - S. A. Power
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Science Rd, Richmond, NSW 2753 Australia
| | - J. A. Welbergen
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Science Rd, Richmond, NSW 2753 Australia
| | - J. M. Cook
- Hawkesbury Institute for the Environment, Hawkesbury Campus, Western Sydney University, Science Rd, Richmond, NSW 2753 Australia
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22
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Meier-Kolthoff JP, Hahnke RL, Petersen J, Scheuner C, Michael V, Fiebig A, Rohde C, Rohde M, Fartmann B, Goodwin LA, Chertkov O, Reddy TBK, Pati A, Ivanova NN, Markowitz V, Kyrpides NC, Woyke T, Göker M, Klenk HP. Complete genome sequence of DSM 30083(T), the type strain (U5/41(T)) of Escherichia coli, and a proposal for delineating subspecies in microbial taxonomy. Stand Genomic Sci 2014; 9:2. [PMID: 25780495 PMCID: PMC4334874 DOI: 10.1186/1944-3277-9-2] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/16/2014] [Indexed: 12/02/2022] Open
Abstract
Although Escherichia coli is the most widely studied bacterial model organism and often considered to be the model bacterium per se, its type strain was until now forgotten from microbial genomics. As a part of the G enomic E ncyclopedia of B acteria and A rchaea project, we here describe the features of E. coli DSM 30083(T) together with its genome sequence and annotation as well as novel aspects of its phenotype. The 5,038,133 bp containing genome sequence includes 4,762 protein-coding genes and 175 RNA genes as well as a single plasmid. Affiliation of a set of 250 genome-sequenced E. coli strains, Shigella and outgroup strains to the type strain of E. coli was investigated using digital DNA:DNA-hybridization (dDDH) similarities and differences in genomic G+C content. As in the majority of previous studies, results show Shigella spp. embedded within E. coli and in most cases forming a single subgroup of it. Phylogenomic trees also recover the proposed E. coli phylotypes as monophyla with minor exceptions and place DSM 30083(T) in phylotype B2 with E. coli S88 as its closest neighbor. The widely used lab strain K-12 is not only genomically but also physiologically strongly different from the type strain. The phylotypes do not express a uniform level of character divergence as measured using dDDH, however, thus an alternative arrangement is proposed and discussed in the context of bacterial subspecies. Analyses of the genome sequences of a large number of E. coli strains and of strains from > 100 other bacterial genera indicate a value of 79-80% dDDH as the most promising threshold for delineating subspecies, which in turn suggests the presence of five subspecies within E. coli.
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Affiliation(s)
- Jan P Meier-Kolthoff
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Richard L Hahnke
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Jörn Petersen
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Carmen Scheuner
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Victoria Michael
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Anne Fiebig
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Christine Rohde
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Manfred Rohde
- />Helmholtz Centre for Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | | | | | | | - TBK Reddy
- />DOE Joint Genome Institute, Walnut Creek, Ca USA
| | - Amrita Pati
- />DOE Joint Genome Institute, Walnut Creek, Ca USA
| | | | | | - Nikos C Kyrpides
- />DOE Joint Genome Institute, Walnut Creek, Ca USA
- />Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Tanja Woyke
- />DOE Joint Genome Institute, Walnut Creek, Ca USA
| | - Markus Göker
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
| | - Hans-Peter Klenk
- />Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124 Braunschweig, Germany
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23
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Andrade F, Rafael D, Videira M, Ferreira D, Sosnik A, Sarmento B. Nanotechnology and pulmonary delivery to overcome resistance in infectious diseases. Adv Drug Deliv Rev 2013; 65:1816-27. [PMID: 23932923 PMCID: PMC7103277 DOI: 10.1016/j.addr.2013.07.020] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/18/2013] [Indexed: 12/22/2022]
Abstract
Used since ancient times especially for the local treatment of pulmonary diseases, lungs and airways are a versatile target route for the administration of both local and systemic drugs. Despite the existence of different platforms and devices for the pulmonary administration of drugs, only a few formulations are marketed, partly due to physiological and technological limitations. Respiratory infections represent a significant burden to health systems worldwide mainly due to intrahospital infections that more easily affect immune-compromised patients. Moreover, tuberculosis (TB) is an endemic infectious disease in many developing nations and it has resurged in the developed world associated with the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic. Currently, medicine faces the specter of antibiotic resistance. Besides the development of new anti-infectious drugs, the development of innovative and more efficient delivery systems for drugs that went off patent appears as a promising strategy pursued by the pharmaceutical industry to improve the therapeutic outcomes and to prolong the utilities of their intellectual property portfolio. In this context, nanotechnology-based drug delivery systems (nano-DDS) emerged as a promising approach to circumvent the limitations of conventional formulations and to treat drug resistance, opening the hypothesis for new developments in this area.
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