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Bernard R, Valverde Salzmann M, Scheffler K, Pohmann R. Concurrent intrinsic optical imaging and fMRI at ultra-high field using magnetic field proof optical components. NMR IN BIOMEDICINE 2023; 36:e4909. [PMID: 36669650 DOI: 10.1002/nbm.4909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 06/15/2023]
Abstract
Intrinsic optical imaging (IOI) is a well established technique to quantify activation-related hemodynamical changes at the surface of the brain, which can be used to investigate the underlying processes of BOLD signal formation. To directly and quantitatively relate IOI and fMRI, simultaneous measurements with the two modalities are necessary. Here, a novel technical solution for a completely in-bore setup is presented, which uses only magnetic field proof components and thus allows concurrent recordings with a quality similar to that obtained in separate experiments. Measurements of the somatosensory cortex of rats with electrical forepaw stimulation were used to verify this approach. The high spatial and temporal resolution of the fMRI data, which is possible due to the high magnetic field of 14.1 T, the use of a point-spread function-based distortion correction and optimized additional anatomical images, allowed accurate colocalization of the images of the two modalities. Accordingly, detailed investigations of the temporal and spatial relationships between the hemodynamic parameters and the fMRI signal, which demonstrate the linear dependence of the BOLD effect on changes in the concentrations of oxygenated and deoxygenated hemoglobin, are possible. Comparisons between the signals emerging from arterial, venous and parenchymal areas are possible and show clearly distinct characteristics. The presented setup allows combining MRI measurements and optical recordings without serious losses in the data quality of either modality. While the proposed combination of fMRI and IOI can help to gain valuable insight into the generation of the BOLD effect, the setup can be easily modified to include different types of optical or MRI measurements.
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Affiliation(s)
- Rebekka Bernard
- Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
| | | | - Klaus Scheffler
- Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
- Department for Neuroimaging, University of Tübingen, Tübingen, Germany
| | - Rolf Pohmann
- Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany
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2
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The effects of locomotion on sensory-evoked haemodynamic responses in the cortex of awake mice. Sci Rep 2022; 12:6236. [PMID: 35422473 PMCID: PMC9010417 DOI: 10.1038/s41598-022-10195-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/04/2022] [Indexed: 12/22/2022] Open
Abstract
Investigating neurovascular coupling in awake rodents is becoming ever more popular due, in part, to our increasing knowledge of the profound impacts that anaesthesia can have upon brain physiology. Although awake imaging brings with it many advantages, we still do not fully understand how voluntary locomotion during imaging affects sensory-evoked haemodynamic responses. In this study we investigated how evoked haemodynamic responses can be affected by the amount and timing of locomotion. Using an awake imaging set up, we used 2D-Optical Imaging Spectroscopy (2D-OIS) to measure changes in cerebral haemodynamics within the sensory cortex of the brain during either 2 s whisker stimulation or spontaneous (no whisker stimulation) experiments, whilst animals could walk on a spherical treadmill. We show that locomotion alters haemodynamic responses. The amount and timing of locomotion relative to whisker stimulation is important, and can significantly impact sensory-evoked haemodynamic responses. If locomotion occurred before or during whisker stimulation, the amplitude of the stimulus-evoked haemodynamic response was significantly altered. Therefore, monitoring of locomotion during awake imaging is necessary to ensure that conclusions based on comparisons of evoked haemodynamic responses (e.g., between control and disease groups) are not confounded by the effects of locomotion.
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Guinto MC, Haruta M, Kurauchi Y, Saigo T, Kurasawa K, Ryu S, Ohta Y, Kawahara M, Takehara H, Tashiro H, Sasagawa K, Katsuki H, Ohta J. Modular head-mounted cortical imaging device for chronic monitoring of intrinsic signals in mice. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:026501. [PMID: 35166087 PMCID: PMC8843356 DOI: 10.1117/1.jbo.27.2.026501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
SIGNIFICANCE Intrinsic optical signals (IOS) generated in the cortical tissue as a result of various interacting metabolic processes are used extensively to elucidate the underlying mechanisms that govern neurovascular coupling. However, current IOS measurements still often rely on bulky, tabletop imaging systems, and there remains a dearth of studies in freely moving subjects. Lightweight, miniature head-mounted imaging devices provide unique opportunities for investigating cortical dynamics in small animals under a variety of naturalistic behavioral settings. AIM The aim of this work was to monitor IOS in the somatosensory cortex of wild-type mice by developing a lightweight, biocompatible imaging device that readily lends itself to animal experiments in freely moving conditions. APPROACH Herein we describe a method for realizing long-term IOS imaging in mice using a 0.54-g, compact, CMOS-based, head-mounted imager. The two-part module, consisting of a tethered sensor plate and a base plate, allows facile assembly prior to imaging sessions and disassembly when the sensor is not in use. LEDs integrated into the device were chosen to illuminate the cortical mantle at two different wavelengths in the visible regime (λcenter: 535 and 625 nm) for monitoring volume- and oxygenation state-dependent changes in the IOS, respectively. To test whether the system can detect robust cortical responses, we recorded sensory-evoked IOS from mechanical stimulation of the hindlimbs (HL) of anesthetized mice in both acute and long-term implantation conditions. RESULTS Cortical IOS recordings in the primary somatosensory cortex hindlimb receptive field (S1HL) of anesthetized mice under green and red LED illumination revealed robust, multiphasic profiles that were time-locked to the mechanical stimulation of the contralateral plantar hindpaw. Similar intrinsic signal profiles observed in S1HL at 40 days postimplantation demonstrated the viability of the approach for long-term imaging. Immunohistochemical analysis showed that the brain tissue did not exhibit appreciable immune response due to the device implantation and operation. A proof-of-principle imaging session in a freely behaving mouse showed minimal locomotor impediment for the animal and also enabled estimation of blood flow speed. CONCLUSIONS We demonstrate the utility of a miniature cortical imaging device for monitoring IOS and related hemodynamic processes in both anesthetized and freely moving mice, cueing potential for applications to some neuroscientific studies of sensation and naturalistic behavior.
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Affiliation(s)
- Mark Christian Guinto
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Makito Haruta
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Yuki Kurauchi
- Kumamoto University, Graduate School of Pharmaceutical Sciences, Department of Chemico-Pharmacological Sciences, Kumamoto, Japan
| | - Taisuke Saigo
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Kazuki Kurasawa
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Sumika Ryu
- Kumamoto University, Graduate School of Pharmaceutical Sciences, Department of Chemico-Pharmacological Sciences, Kumamoto, Japan
| | - Yasumi Ohta
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Mamiko Kawahara
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Hironari Takehara
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Hiroyuki Tashiro
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
- Kyushu University, Division of Medical Technology, Department of Health Sciences, Faculty of Medical Sciences, Fukuoka, Japan
| | - Kiyotaka Sasagawa
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
| | - Hiroshi Katsuki
- Kumamoto University, Graduate School of Pharmaceutical Sciences, Department of Chemico-Pharmacological Sciences, Kumamoto, Japan
| | - Jun Ohta
- Nara Institute of Science and Technology, Graduate School of Science and Technology, Division of Materials Science, Ikoma, Japan
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Shabir O, Pendry B, Lee L, Eyre B, Sharp PS, Rebollar MA, Drew D, Howarth C, Heath PR, Wharton SB, Francis SE, Berwick J. Assessment of neurovascular coupling and cortical spreading depression in mixed mouse models of atherosclerosis and Alzheimer's disease. eLife 2022; 11:e68242. [PMID: 35014950 PMCID: PMC8752088 DOI: 10.7554/elife.68242] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022] Open
Abstract
Neurovascular coupling is a critical brain mechanism whereby changes to blood flow accompany localised neural activity. The breakdown of neurovascular coupling is linked to the development and progression of several neurological conditions including dementia. In this study, we examined cortical haemodynamics in mouse preparations that modelled Alzheimer's disease (J20-AD) and atherosclerosis (PCSK9-ATH) between 9 and 12 m of age. We report novel findings with atherosclerosis where neurovascular decline is characterised by significantly reduced blood volume, altered levels of oxyhaemoglobin and deoxyhaemoglobin, in addition to global neuroinflammation. In the comorbid mixed model (J20-PCSK9-MIX), we report a 3 x increase in hippocampal amyloid-beta plaques. A key finding was that cortical spreading depression (CSD) due to electrode insertion into the brain was worse in the diseased animals and led to a prolonged period of hypoxia. These findings suggest that systemic atherosclerosis can be detrimental to neurovascular health and that having cardiovascular comorbidities can exacerbate pre-existing Alzheimer's-related amyloid-plaques.
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Affiliation(s)
- Osman Shabir
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
| | - Ben Pendry
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Llywelyn Lee
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Beth Eyre
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Paul S Sharp
- Medicines Discovery CatapultAlderley EdgeUnited Kingdom
| | - Monica A Rebollar
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - David Drew
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
| | - Clare Howarth
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Stephen B Wharton
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Sheila E Francis
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
| | - Jason Berwick
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
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5
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Wang X, Ma LC, Shahdadian S, Wu A, Truong NCD, Liu H. Metabolic Connectivity and Hemodynamic-Metabolic Coherence of Human Prefrontal Cortex at Rest and Post Photobiomodulation Assessed by Dual-Channel Broadband NIRS. Metabolites 2022; 12:42. [PMID: 35050164 PMCID: PMC8778041 DOI: 10.3390/metabo12010042] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/27/2021] [Accepted: 01/04/2022] [Indexed: 02/05/2023] Open
Abstract
Billions of neurons in the human brain form neural networks with oscillation rhythms. Infra-slow oscillation (ISO) presents three main physiological sources: endogenic, neurogenic, and myogenic vasomotions. Having an in vivo methodology for the absolute quantification of ISO from the human brain can facilitate the detection of brain abnormalities in cerebral hemodynamic and metabolic activities. In this study, we introduced a novel measurement-plus-analysis framework for the non-invasive quantification of prefrontal ISO by (1) taking dual-channel broadband near infrared spectroscopy (bbNIRS) measurements from 12 healthy humans during a 6-min rest and 4-min post transcranial photobiomodulation (tPBM) and (2) performing wavelet transform coherence (WTC) analysis on the measured time series data. The WTC indexes (IC, between 0 and 1) enabled the assessment of ipsilateral hemodynamic-metabolic coherence and bilateral functional connectivity in each ISO band of the human prefrontal cortex. At rest, bilateral hemodynamic connectivity was consistent across the three ISO bands (IC ≅ 0.66), while bilateral metabolic connectivity was relatively weaker. For post-tPBM/sham comparison, our analyses revealed three key findings: 8-min, right-forehead, 1064-nm tPBM (1) enhanced the amplitude of metabolic oscillation bilaterally, (2) promoted the bilateral metabolic connectivity of neurogenic rhythm, and (3) made the main effect on endothelial cells, causing alteration of hemodynamic-metabolic coherence on each side of the prefrontal cortex.
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Affiliation(s)
| | | | | | | | | | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, 500 UTA Blvd, Arlington, TX 76019, USA; (X.W.); (L.-C.M.); (S.S.); (A.W.); (N.C.D.T.)
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6
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Abdelfattah AS, Ahuja S, Akkin T, Allu SR, Brake J, Boas DA, Buckley EM, Campbell RE, Chen AI, Cheng X, Čižmár T, Costantini I, De Vittorio M, Devor A, Doran PR, El Khatib M, Emiliani V, Fomin-Thunemann N, Fainman Y, Fernandez-Alfonso T, Ferri CGL, Gilad A, Han X, Harris A, Hillman EMC, Hochgeschwender U, Holt MG, Ji N, Kılıç K, Lake EMR, Li L, Li T, Mächler P, Miller EW, Mesquita RC, Nadella KMNS, Nägerl UV, Nasu Y, Nimmerjahn A, Ondráčková P, Pavone FS, Perez Campos C, Peterka DS, Pisano F, Pisanello F, Puppo F, Sabatini BL, Sadegh S, Sakadzic S, Shoham S, Shroff SN, Silver RA, Sims RR, Smith SL, Srinivasan VJ, Thunemann M, Tian L, Tian L, Troxler T, Valera A, Vaziri A, Vinogradov SA, Vitale F, Wang LV, Uhlířová H, Xu C, Yang C, Yang MH, Yellen G, Yizhar O, Zhao Y. Neurophotonic tools for microscopic measurements and manipulation: status report. NEUROPHOTONICS 2022; 9:013001. [PMID: 35493335 PMCID: PMC9047450 DOI: 10.1117/1.nph.9.s1.013001] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Neurophotonics was launched in 2014 coinciding with the launch of the BRAIN Initiative focused on development of technologies for advancement of neuroscience. For the last seven years, Neurophotonics' agenda has been well aligned with this focus on neurotechnologies featuring new optical methods and tools applicable to brain studies. While the BRAIN Initiative 2.0 is pivoting towards applications of these novel tools in the quest to understand the brain, this status report reviews an extensive and diverse toolkit of novel methods to explore brain function that have emerged from the BRAIN Initiative and related large-scale efforts for measurement and manipulation of brain structure and function. Here, we focus on neurophotonic tools mostly applicable to animal studies. A companion report, scheduled to appear later this year, will cover diffuse optical imaging methods applicable to noninvasive human studies. For each domain, we outline the current state-of-the-art of the respective technologies, identify the areas where innovation is needed, and provide an outlook for the future directions.
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Affiliation(s)
- Ahmed S. Abdelfattah
- Brown University, Department of Neuroscience, Providence, Rhode Island, United States
| | - Sapna Ahuja
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Taner Akkin
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Srinivasa Rao Allu
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Joshua Brake
- Harvey Mudd College, Department of Engineering, Claremont, California, United States
| | - David A. Boas
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Erin M. Buckley
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University, Department of Pediatrics, Atlanta, Georgia, United States
| | - Robert E. Campbell
- University of Tokyo, Department of Chemistry, Tokyo, Japan
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Anderson I. Chen
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Tomáš Čižmár
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Irene Costantini
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Biology, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Massimo De Vittorio
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Anna Devor
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Patrick R. Doran
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Mirna El Khatib
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | | | - Natalie Fomin-Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Yeshaiahu Fainman
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Tomas Fernandez-Alfonso
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Christopher G. L. Ferri
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Ariel Gilad
- The Hebrew University of Jerusalem, Institute for Medical Research Israel–Canada, Department of Medical Neurobiology, Faculty of Medicine, Jerusalem, Israel
| | - Xue Han
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Andrew Harris
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | | | - Ute Hochgeschwender
- Central Michigan University, Department of Neuroscience, Mount Pleasant, Michigan, United States
| | - Matthew G. Holt
- University of Porto, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
| | - Na Ji
- University of California Berkeley, Department of Physics, Berkeley, California, United States
| | - Kıvılcım Kılıç
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evelyn M. R. Lake
- Yale School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, Connecticut, United States
| | - Lei Li
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Tianqi Li
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Philipp Mächler
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evan W. Miller
- University of California Berkeley, Departments of Chemistry and Molecular & Cell Biology and Helen Wills Neuroscience Institute, Berkeley, California, United States
| | | | | | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience University of Bordeaux & CNRS, Bordeaux, France
| | - Yusuke Nasu
- University of Tokyo, Department of Chemistry, Tokyo, Japan
| | - Axel Nimmerjahn
- Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, California, United States
| | - Petra Ondráčková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Francesco S. Pavone
- National Institute of Optics, National Research Council, Rome, Italy
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Physics, Florence, Italy
| | - Citlali Perez Campos
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Darcy S. Peterka
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Filippo Pisano
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Francesca Puppo
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Bernardo L. Sabatini
- Harvard Medical School, Howard Hughes Medical Institute, Department of Neurobiology, Boston, Massachusetts, United States
| | - Sanaz Sadegh
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Sava Sakadzic
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Shy Shoham
- New York University Grossman School of Medicine, Tech4Health and Neuroscience Institutes, New York, New York, United States
| | - Sanaya N. Shroff
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - R. Angus Silver
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Ruth R. Sims
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Spencer L. Smith
- University of California Santa Barbara, Department of Electrical and Computer Engineering, Santa Barbara, California, United States
| | - Vivek J. Srinivasan
- New York University Langone Health, Departments of Ophthalmology and Radiology, New York, New York, United States
| | - Martin Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Lei Tian
- Boston University, Departments of Electrical Engineering and Biomedical Engineering, Boston, Massachusetts, United States
| | - Lin Tian
- University of California Davis, Department of Biochemistry and Molecular Medicine, Davis, California, United States
| | - Thomas Troxler
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Antoine Valera
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Alipasha Vaziri
- Rockefeller University, Laboratory of Neurotechnology and Biophysics, New York, New York, United States
- The Rockefeller University, The Kavli Neural Systems Institute, New York, New York, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Flavia Vitale
- Center for Neuroengineering and Therapeutics, Departments of Neurology, Bioengineering, Physical Medicine and Rehabilitation, Philadelphia, Pennsylvania, United States
| | - Lihong V. Wang
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Hana Uhlířová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Chris Xu
- Cornell University, School of Applied and Engineering Physics, Ithaca, New York, United States
| | - Changhuei Yang
- California Institute of Technology, Departments of Electrical Engineering, Bioengineering and Medical Engineering, Pasadena, California, United States
| | - Mu-Han Yang
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Gary Yellen
- Harvard Medical School, Department of Neurobiology, Boston, Massachusetts, United States
| | - Ofer Yizhar
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | - Yongxin Zhao
- Carnegie Mellon University, Department of Biological Sciences, Pittsburgh, Pennsylvania, United States
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7
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Huber LR, Poser BA, Kaas AL, Fear EJ, Dresbach S, Berwick J, Goebel R, Turner R, Kennerley AJ. Validating layer-specific VASO across species. Neuroimage 2021; 237:118195. [PMID: 34038769 DOI: 10.1016/j.neuroimage.2021.118195] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 01/27/2023] Open
Abstract
Cerebral blood volume (CBV) has been shown to be a robust and important physiological parameter for quantitative interpretation of functional (f)MRI, capable of delivering highly localized mapping of neural activity. Indeed, with recent advances in ultra-high-field (≥7T) MRI hardware and associated sequence libraries, it has become possible to capture non-invasive CBV weighted fMRI signals across cortical layers. One of the most widely used approaches to achieve this (in humans) is through vascular-space-occupancy (VASO) fMRI. Unfortunately, the exact contrast mechanisms of layer-dependent VASO fMRI have not been validated for human fMRI and thus interpretation of such data is confounded. Here we validate the signal source of layer-dependent SS-SI VASO fMRI using multi-modal imaging in a rat model in response to neuronal activation (somatosensory cortex) and respiratory challenge (hypercapnia). In particular VASO derived CBV measures are directly compared to concurrent measures of total haemoglobin changes from high resolution intrinsic optical imaging spectroscopy (OIS). Quantified cortical layer profiling is demonstrated to be in agreement between VASO and contrast enhanced fMRI (using monocrystalline iron oxide nanoparticles, MION). Responses show high spatial localisation to layers of cortical processing independent of confounding large draining veins which can hamper BOLD fMRI studies, (depending on slice positioning). Thus, a cross species comparison is enabled using VASO as a common measure. We find increased VASO based CBV reactivity (3.1 ± 1.2 fold increase) in humans compared to rats. Together, our findings confirm that the VASO contrast is indeed a reliable estimate of layer-specific CBV changes. This validation study increases the neuronal interpretability of human layer-dependent VASO fMRI as an appropriate method in neuroscience application studies, in which the presence of large draining intracortical and pial veins limits neuroscientific inference with BOLD fMRI.
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Affiliation(s)
- Laurentius Renzo Huber
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands.
| | - Benedikt A Poser
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Amanda L Kaas
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Elizabeth J Fear
- Hull-York-Medical-School (HYMS), University of York, York, United Kingdom
| | - Sebastian Dresbach
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Jason Berwick
- Department of Psychology, University of Sheffield, Sheffield, United Kingdom
| | - Rainer Goebel
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Robert Turner
- Neurophysics Department Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom
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8
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Shabir O, Sharp P, Rebollar MA, Boorman L, Howarth C, Wharton SB, Francis SE, Berwick J. Enhanced Cerebral Blood Volume under Normobaric Hyperoxia in the J20-hAPP Mouse Model of Alzheimer's Disease. Sci Rep 2020; 10:7518. [PMID: 32371859 PMCID: PMC7200762 DOI: 10.1038/s41598-020-64334-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/14/2020] [Indexed: 11/14/2022] Open
Abstract
Early impairments to neurovascular coupling have been proposed to be a key pathogenic factor in the onset and progression of Alzheimer's disease (AD). Studies have shown impaired neurovascular function in several mouse models of AD, including the J20-hAPP mouse. In this study, we aimed to investigate early neurovascular changes using wild-type (WT) controls and J20-hAPP mice at 6 months of age, by measuring cerebral haemodynamics and neural activity to physiological sensory stimulations. A thinned cranial window was prepared to allow access to cortical vasculature and imaged using 2D-optical imaging spectroscopy (2D-OIS). After chronic imaging sessions where the skull was intact, a terminal acute imaging session was performed where an electrode was inserted into the brain to record simultaneous neural activity. We found that cerebral haemodynamic changes were significantly enhanced in J20-hAPP mice compared with controls in response to physiological stimulations, potentially due to the significantly higher neural activity (hyperexcitability) seen in the J20-hAPP mice. Thus, neurovascular coupling remained preserved under a chronic imaging preparation. Further, under hyperoxia, the baseline blood volume and saturation of all vascular compartments in the brains of J20-hAPP mice were substantially enhanced compared to WT controls, but this effect disappeared under normoxic conditions. This study highlights novel findings not previously seen in the J20-hAPP mouse model, and may point towards a potential therapeutic strategy.
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Affiliation(s)
- Osman Shabir
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Paul Sharp
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Monica A Rebollar
- Sheffield Institute for Translational Neuroscience (SITraN), 385a Glossop Road, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Luke Boorman
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Clare Howarth
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Stephen B Wharton
- Sheffield Institute for Translational Neuroscience (SITraN), 385a Glossop Road, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Sheila E Francis
- Department of Infection, Immunity & Cardiovascular Disease (IICD), University of Sheffield, Medical School, Beech Hill Road, Sheffield, S10 2RX, UK
| | - Jason Berwick
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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Lee L, Boorman L, Glendenning E, Christmas C, Sharp P, Redgrave P, Shabir O, Bracci E, Berwick J, Howarth C. Key Aspects of Neurovascular Control Mediated by Specific Populations of Inhibitory Cortical Interneurons. Cereb Cortex 2020; 30:2452-2464. [PMID: 31746324 PMCID: PMC7174996 DOI: 10.1093/cercor/bhz251] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 01/21/2023] Open
Abstract
Inhibitory interneurons can evoke vasodilation and vasoconstriction, making them potential cellular drivers of neurovascular coupling. However, the specific regulatory roles played by particular interneuron subpopulations remain unclear. Our purpose was therefore to adopt a cell-specific optogenetic approach to investigate how somatostatin (SST) and neuronal nitric oxide synthase (nNOS)-expressing interneurons might influence the neurovascular relationship. In mice, specific activation of SST- or nNOS-interneurons was sufficient to evoke hemodynamic changes. In the case of nNOS-interneurons, robust hemodynamic changes occurred with minimal changes in neural activity, suggesting that the ability of blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) to reliably reflect changes in neuronal activity may be dependent on type of neuron recruited. Conversely, activation of SST-interneurons produced robust changes in evoked neural activity with shallow cortical excitation and pronounced deep layer cortical inhibition. Prolonged activation of SST-interneurons often resulted in an increase in blood volume in the centrally activated area with an accompanying decrease in blood volume in the surrounding brain regions, analogous to the negative BOLD signal. These results demonstrate the role of specific populations of cortical interneurons in the active control of neurovascular function.
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Affiliation(s)
- L Lee
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - L Boorman
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - E Glendenning
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - C Christmas
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - P Sharp
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - P Redgrave
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - O Shabir
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - E Bracci
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - J Berwick
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - C Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
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10
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Kang S, Hayashi Y, Bruyns-Haylett M, Baker DH, Boura M, Wang X, Karatzas KA, Serra I, Bithell A, Williams C, Field DT, Zheng Y. Supplemental Vitamin B-12 Enhances the Neural Response to Sensory Stimulation in the Barrel Cortex of Healthy Rats but Does Not Affect Spontaneous Neural Activity. J Nutr 2019; 149:730-737. [PMID: 31006816 DOI: 10.1093/jn/nxz011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/07/2018] [Accepted: 01/17/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Although vitamin B-12 (B-12) is known to contribute to the structural and functional development of the brain, it is unclear if B-12 supplementation has any beneficial effect in healthy populations in terms of enhanced neurologic status of the brain or improved cognitive function. OBJECTIVES We investigated the effect of dietary supplementation of B-12 on the cortical neural activity of well-nourished young adult rats and tested the hypothesis that B-12 supplementation in healthy rats may reduce sensory-evoked neural activity due to enhanced inhibition. METHODS Female Lister Hooded rats weighing 190-265 g (2-4 mo old) were included in the study. The experimental group was fed with B-12 (cyanocobalamin)-enriched water at a concentration of 1 mg/L, and the control (CON) group with tap water for 3 wk. Animals were then anesthetized and cortical neural responses to whisker stimulation were recorded in vivo through the use of a multichannel microelectrode, from which local field potentials (LFPs) were extracted. RESULTS Somatosensory-evoked LFP was 25% larger in the B-12 group (4.13 ± 0.24 mV) than in the CON group (3.30 ± 0.21 mV) (P = 0.02). Spontaneous neural activity did not differ between groups; frequency spectra at each frequency bin of interest did not pass the cluster-forming threshold at the 5% significance level. CONCLUSIONS These findings do not provide evidence supporting the hypothesis of decreased neural activity due to B-12 supplementation. As the spontaneous neural activity was unaffected, the increase in somatosensory-evoked LFP may be due to enhanced afferent signal reaching the barrel cortex from the whisker pad, indicating that B-12-supplemented rats may have enhanced sensitivity to sensory stimulation compared with the CON group. We suggest that this enhancement might be the result of lowered sensory threshold, although the underlying mechanism has yet to be elucidated.
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Affiliation(s)
- Sungmin Kang
- Biomedical Engineering, School of Biological Sciences.,Centre for Integrative Neuroscience and Neurodynamics (CINN), University of Reading, Reading, United Kingdom
| | - Yurie Hayashi
- Biomedical Engineering, School of Biological Sciences
| | | | - Daniel H Baker
- Department of Psychology and York Biomedical Research Institute, University of York, York, United Kingdom
| | | | | | - Kimon-Andreas Karatzas
- Food and Nutritional Sciences.,Centre for Integrative Neuroscience and Neurodynamics (CINN), University of Reading, Reading, United Kingdom
| | - Ines Serra
- Pharmacy, School of Chemistry, Food and Pharmacy
| | | | - Claire Williams
- Psychology, School of Psychology and Clinical Language Sciences
| | - David T Field
- Centre for Integrative Neuroscience and Neurodynamics (CINN), University of Reading, Reading, United Kingdom
| | - Ying Zheng
- Biomedical Engineering, School of Biological Sciences.,Centre for Integrative Neuroscience and Neurodynamics (CINN), University of Reading, Reading, United Kingdom
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11
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Hong KS, Zafar A. Existence of Initial Dip for BCI: An Illusion or Reality. Front Neurorobot 2018; 12:69. [PMID: 30416440 PMCID: PMC6212489 DOI: 10.3389/fnbot.2018.00069] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 10/03/2018] [Indexed: 01/21/2023] Open
Abstract
A tight coupling between the neuronal activity and the cerebral blood flow (CBF) is the motivation of many hemodynamic response (HR)-based neuroimaging modalities. The increase in neuronal activity causes the increase in CBF that is indirectly measured by HR modalities. Upon functional stimulation, the HR is mainly categorized in three durations: (i) initial dip, (ii) conventional HR (i.e., positive increase in HR caused by an increase in the CBF), and (iii) undershoot. The initial dip is a change in oxygenation prior to any subsequent increase in CBF and spatially more specific to the site of neuronal activity. Despite additional evidence from various HR modalities on the presence of initial dip in human and animal species (i.e., cat, rat, and monkey); the existence/occurrence of an initial dip in HR is still under debate. This article reviews the existence and elusive nature of the initial dip duration of HR in intrinsic signal optical imaging (ISOI), functional magnetic resonance imaging (fMRI), and functional near-infrared spectroscopy (fNIRS). The advent of initial dip and its elusiveness factors in ISOI and fMRI studies are briefly discussed. Furthermore, the detection of initial dip and its role in brain-computer interface using fNIRS is examined in detail. The best possible application for the initial dip utilization and its future implications using fNIRS are provided.
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Affiliation(s)
- Keum-Shik Hong
- School of Mechanical Engineering, Pusan National University, Busan, South Korea.,Department of Cogno-Mechatronics Engineering, Pusan National University, Busan, South Korea
| | - Amad Zafar
- School of Mechanical Engineering, Pusan National University, Busan, South Korea
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12
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Ma Y, Shaik MA, Kim SH, Kozberg MG, Thibodeaux DN, Zhao HT, Yu H, Hillman EMC. Wide-field optical mapping of neural activity and brain haemodynamics: considerations and novel approaches. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0360. [PMID: 27574312 PMCID: PMC5003860 DOI: 10.1098/rstb.2015.0360] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2016] [Indexed: 12/30/2022] Open
Abstract
Although modern techniques such as two-photon microscopy can now provide cellular-level three-dimensional imaging of the intact living brain, the speed and fields of view of these techniques remain limited. Conversely, two-dimensional wide-field optical mapping (WFOM), a simpler technique that uses a camera to observe large areas of the exposed cortex under visible light, can detect changes in both neural activity and haemodynamics at very high speeds. Although WFOM may not provide single-neuron or capillary-level resolution, it is an attractive and accessible approach to imaging large areas of the brain in awake, behaving mammals at speeds fast enough to observe widespread neural firing events, as well as their dynamic coupling to haemodynamics. Although such wide-field optical imaging techniques have a long history, the advent of genetically encoded fluorophores that can report neural activity with high sensitivity, as well as modern technologies such as light emitting diodes and sensitive and high-speed digital cameras have driven renewed interest in WFOM. To facilitate the wider adoption and standardization of WFOM approaches for neuroscience and neurovascular coupling research, we provide here an overview of the basic principles of WFOM, considerations for implementation of wide-field fluorescence imaging of neural activity, spectroscopic analysis and interpretation of results. This article is part of the themed issue ‘Interpreting BOLD: a dialogue between cognitive and cellular neuroscience’.
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Affiliation(s)
- Ying Ma
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Mohammed A Shaik
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Sharon H Kim
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Mariel G Kozberg
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - David N Thibodeaux
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Hanzhi T Zhao
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Hang Yu
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
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13
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Herman MC, Cardoso MMB, Lima B, Sirotin YB, Das A. Simultaneously estimating the task-related and stimulus-evoked components of hemodynamic imaging measurements. NEUROPHOTONICS 2017; 4:031223. [PMID: 28721355 PMCID: PMC5502953 DOI: 10.1117/1.nph.4.3.031223] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 06/16/2017] [Indexed: 06/07/2023]
Abstract
Task-related hemodynamic responses contribute prominently to functional magnetic resonance imaging (fMRI) recordings. They reflect behaviorally important brain states, such as arousal and attention, and can dominate stimulus-evoked responses, yet they remain poorly understood. To help characterize these responses, we present a method for parametrically estimating both stimulus-evoked and task-related components of hemodynamic responses from subjects engaged in temporally predictable tasks. The stimulus-evoked component is modeled by convolving a hemodynamic response function (HRF) kernel with spiking. The task-related component is modeled by convolving a Fourier-series task-related function (TRF) kernel with task timing. We fit this model with simultaneous electrode recordings and intrinsic-signal optical imaging from the primary visual cortex of alert, task-engaged monkeys. With high [Formula: see text], the model returns HRFs that are consistent across experiments and recording sites for a given animal and TRFs that entrain to task timing independent of stimulation or local spiking. When the task schedule conflicts with that of stimulation, the TRF remains locked to the task emphasizing its behavioral origins. The current approach is strikingly more robust to fluctuations than earlier ones and gives consistently, if modestly, better fits. This approach could help parse the distinct components of fMRI recordings made in the context of a task.
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Affiliation(s)
- Max Charles Herman
- Columbia University, Department of Neuroscience, New York, New York, United States
| | - Mariana M. B. Cardoso
- Columbia University, Department of Neuroscience, New York, New York, United States
- University of California at San Francisco, Department of Physiology and Center for Integrative Neuroscience, San Francisco, California, United States
| | - Bruss Lima
- Columbia University, Department of Neuroscience, New York, New York, United States
- Federal University of Rio de Janeiro, Institute of Biophysics Carlos Chagas Filho, Rio de Janeiro, Brazil
| | - Yevgeniy B. Sirotin
- Columbia University, Department of Neuroscience, New York, New York, United States
| | - Aniruddha Das
- Columbia University, Department of Neuroscience, New York, New York, United States
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14
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Resting-state hemodynamics are spatiotemporally coupled to synchronized and symmetric neural activity in excitatory neurons. Proc Natl Acad Sci U S A 2016; 113:E8463-E8471. [PMID: 27974609 DOI: 10.1073/pnas.1525369113] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Brain hemodynamics serve as a proxy for neural activity in a range of noninvasive neuroimaging techniques including functional magnetic resonance imaging (fMRI). In resting-state fMRI, hemodynamic fluctuations have been found to exhibit patterns of bilateral synchrony, with correlated regions inferred to have functional connectivity. However, the relationship between resting-state hemodynamics and underlying neural activity has not been well established, making the neural underpinnings of functional connectivity networks unclear. In this study, neural activity and hemodynamics were recorded simultaneously over the bilateral cortex of awake and anesthetized Thy1-GCaMP mice using wide-field optical mapping. Neural activity was visualized via selective expression of the calcium-sensitive fluorophore GCaMP in layer 2/3 and 5 excitatory neurons. Characteristic patterns of resting-state hemodynamics were accompanied by more rapidly changing bilateral patterns of resting-state neural activity. Spatiotemporal hemodynamics could be modeled by convolving this neural activity with hemodynamic response functions derived through both deconvolution and gamma-variate fitting. Simultaneous imaging and electrophysiology confirmed that Thy1-GCaMP signals are well-predicted by multiunit activity. Neurovascular coupling between resting-state neural activity and hemodynamics was robust and fast in awake animals, whereas coupling in urethane-anesthetized animals was slower, and in some cases included lower-frequency (<0.04 Hz) hemodynamic fluctuations that were not well-predicted by local Thy1-GCaMP recordings. These results support that resting-state hemodynamics in the awake and anesthetized brain are coupled to underlying patterns of excitatory neural activity. The patterns of bilaterally-symmetric spontaneous neural activity revealed by wide-field Thy1-GCaMP imaging may depict the neural foundation of functional connectivity networks detected in resting-state fMRI.
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15
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Grinvald A, Sharon D, Omer D, Vanzetta I. Imaging the Neocortex Functional Architecture Using Multiple Intrinsic Signals: Implications for Hemodynamic-Based Functional Imaging. Cold Spring Harb Protoc 2016; 2016:pdb.top089375. [PMID: 26933255 DOI: 10.1101/pdb.top089375] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Optical imaging based on intrinsic signals has provided a new level of understanding of the principles underlying cortical development, organization, and function, providing a spatial resolution of up to 20 µm for mapping cortical columns in vivo. This introduction briefly reviews the development of this technique, the types of applications that have been pursued, and the general implications of some findings for other neuroimaging techniques based on hemodynamic responses (e.g., functional magnetic resonance imaging).
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16
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17
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Vincis R, Lagier S, Van De Ville D, Rodriguez I, Carleton A. Sensory-Evoked Intrinsic Imaging Signals in the Olfactory Bulb Are Independent of Neurovascular Coupling. Cell Rep 2015; 12:313-25. [PMID: 26146075 PMCID: PMC5066842 DOI: 10.1016/j.celrep.2015.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 05/12/2015] [Accepted: 06/03/2015] [Indexed: 11/19/2022] Open
Abstract
Functional brain-imaging techniques used in humans and animals, such as functional MRI and intrinsic optical signal (IOS) imaging, are thought to largely rely on neurovascular coupling and hemodynamic responses. Here, taking advantage of the well-described micro-architecture of the mouse olfactory bulb, we dissected the nature of odor-evoked IOSs. Using in vivo pharmacology in transgenic mouse lines reporting activity in different cell types, we show that parenchymal IOSs are largely independent of neurotransmitter release and neurovascular coupling. Furthermore, our results suggest that odor-evoked parenchymal IOSs originate from changes in light scattering of olfactory sensory neuron axons, mostly due to water movement following action potential propagation. Our study sheds light on a direct correlate of neuronal activity, which may be used for large-scale functional brain imaging.
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Affiliation(s)
- Roberto Vincis
- Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland
| | - Samuel Lagier
- Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland
| | - Dimitri Van De Ville
- Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland; Department of Radiology and Medical Informatics, University of Geneva, 1211 Geneva, Switzerland; Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Ivan Rodriguez
- Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland; Department of Genetics and Evolution, University of Geneva, 1211 Geneva, Switzerland.
| | - Alan Carleton
- Department of Basic Neurosciences, School of Medicine, University of Geneva, 1211 Geneva, Switzerland; Geneva Neuroscience Center, University of Geneva, 1211 Geneva, Switzerland.
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Tanaka H, Katura T, Sato H. Task-related oxygenation and cerebral blood volume changes estimated from NIRS signals in motor and cognitive tasks. Neuroimage 2014; 94:107-119. [DOI: 10.1016/j.neuroimage.2014.02.036] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/05/2014] [Accepted: 02/19/2014] [Indexed: 11/30/2022] Open
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19
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Bajaj S, Drake D, Butler AJ, Dhamala M. Oscillatory motor network activity during rest and movement: an fNIRS study. Front Syst Neurosci 2014; 8:13. [PMID: 24550793 PMCID: PMC3912434 DOI: 10.3389/fnsys.2014.00013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/20/2014] [Indexed: 11/29/2022] Open
Abstract
Coherent network oscillations (<0.1 Hz) linking distributed brain regions are commonly observed in the brain during both rest and task conditions. What oscillatory network exists and how network oscillations change in connectivity strength, frequency and direction when going from rest to explicit task are topics of recent inquiry. Here, we study network oscillations within the sensorimotor regions of able-bodied individuals using hemodynamic activity as measured by functional near-infrared spectroscopy (fNIRS). Using spectral interdependency methods, we examined how the supplementary motor area (SMA), the left premotor cortex (LPMC) and the left primary motor cortex (LM1) are bound as a network during extended resting state (RS) and between-tasks resting state (btRS), and how the activity of the network changes as participants execute left, right, and bilateral hand (LH, RH, and BH) finger movements. We found: (i) power, coherence and Granger causality (GC) spectra had significant peaks within the frequency band (0.01-0.04 Hz) during RS whereas the peaks shifted to a bit higher frequency range (0.04-0.08 Hz) during btRS and finger movement tasks, (ii) there was significant bidirectional connectivity between all the nodes during RS and unidirectional connectivity from the LM1 to SMA and LM1 to LPMC during btRS, and (iii) the connections from SMA to LM1 and from LPMC to LM1 were significantly modulated in LH, RH, and BH finger movements relative to btRS. The unidirectional connectivity from SMA to LM1 just before the actual task changed to the bidirectional connectivity during LH and BH finger movement. The uni-directionality could be associated with movement suppression and the bi-directionality with preparation, sensorimotor update and controlled execution. These results underscore that fNIRS is an effective tool for monitoring spectral signatures of brain activity, which may serve as an important precursor before monitoring the recovery progress following brain injury.
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Affiliation(s)
- Sahil Bajaj
- Department of Physics and Astronomy, Georgia State UniversityAtlanta, GA, USA
| | - Daniel Drake
- Department of Physical Therapy, Byrdine F. Lewis School of Nursing and Health Professions, Georgia State UniversityAtlanta, GA, USA
| | - Andrew J. Butler
- Department of Physical Therapy, Byrdine F. Lewis School of Nursing and Health Professions, Georgia State UniversityAtlanta, GA, USA
- Department of Veteran's Affairs, Atlanta Rehabilitation Research and Development Center of ExcellenceDecatur, GA, USA
- Joint Center for Advanced Brain Imaging, Center for Behavioral Neuroscience, Neuroscience Institute, Georgia State UniversityAtlanta, GA, USA
| | - Mukesh Dhamala
- Department of Physics and Astronomy, Georgia State UniversityAtlanta, GA, USA
- Joint Center for Advanced Brain Imaging, Center for Behavioral Neuroscience, Neuroscience Institute, Georgia State UniversityAtlanta, GA, USA
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20
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Stewart RS, Huang C, Arnett MT, Celikel T. Spontaneous oscillations in intrinsic signals reveal the structure of cerebral vasculature. J Neurophysiol 2013; 109:3094-104. [PMID: 23554431 DOI: 10.1152/jn.01200.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Functional imaging of intrinsic signals allows minimally invasive spatiotemporal mapping of stimulus representations in the cortex, but representations are often corrupted by stimulus-independent spatial artifacts, especially those originating from the blood vessels. In this paper, we present novel algorithms for unsupervised identification of cerebral vascularization, allowing blind separation of stimulus representations from noise. These algorithms commonly take advantage of the temporal fluctuations in global reflectance to extract anatomic information. More specifically, the phase of low-frequency oscillations relative to global fluctuations reveals local vascular identity. Arterioles can be reconstructed using their characteristically high power in those frequencies corresponding to respiration, heartbeat, and vasomotion signals. By treating the vasculature as a dynamic flow network, we finally demonstrate that direction of blood perfusion can be quantitatively visualized. Application of these methods for removal of stimulus-independent changes in reflectance permits isolation of stimulus-evoked representations even if the representation spatially overlaps with blood vessels. The algorithms can be expanded further to extract temporal information on blood flow, monitor revascularization following a focal stroke, and distinguish arterioles from venules and parenchyma.
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Affiliation(s)
- Russell S Stewart
- Undergraduate Program in Neuroscience, University of Southern California, Los Angeles, CA, USA
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Yin C, Zhou F, Wang Y, Luo W, Luo Q, Li P. Simultaneous detection of hemodynamics, mitochondrial metabolism and light scattering changes during cortical spreading depression in rats based on multi-spectral optical imaging. Neuroimage 2013; 76:70-80. [PMID: 23507389 DOI: 10.1016/j.neuroimage.2013.02.079] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/25/2013] [Accepted: 02/28/2013] [Indexed: 10/27/2022] Open
Abstract
Cortical spreading depression (CSD) is a self-propagating wave of cellular depolarization that plays an important role in the development of cerebral pathology following ischemia or trauma. Optical intrinsic signal (OIS) imaging has been widely used to investigate CSD. Sources of OIS are complex and related to the changes in brain tissue absorption and scattering. The absorbing chromophores may include oxy-hemoglobin, deoxy-hemoglobin, cytochromes, flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NADH). Considering only one or part of these elements in studies involving OIS may cause inaccurate results. Thus, we simultaneously calculated changes in HbO, HbR, FAD, cytochrome c, cytochrome aa3 and light scattering during CSD by applying multi-spectral OIS imaging at 450, 470, 500, 530, 550, 570, 600, 630, and 650 nm in the rat brain. We also showed that the hemodynamic changes during CSD may not be correctly estimated if the scattering and other chromophores such as FAD, cytochrome c and cytochrome aa3, are not included in the fitting model of multi-wavelength data analysis. As shown in our results, if considering the changes in scattering and other chromophores in data fitting model, deoxy-hemoglobin (HbR) showed a triphasic change while only a monophasic decrease in HbR will be resolved without considering changes in scattering and other chromophores as reported in previous studies. Moreover, our results showed that changes in cytochrome c was tightly related to OIS at 550 nm, cytochrome aa3 was closely related to OIS at 450, 600 and 650 nm, and FAD was closely related to OIS at 450 and 470 nm during CSD. It indicates that if the contribution by these related chromophores is not considered, using OIS at these wavelengths to determine the hemoglobin changes during CSD may lead to inaccurate results.
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Affiliation(s)
- Cui Yin
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
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Saka M, Berwick J, Jones M. Inter-trial variability in sensory-evoked cortical hemodynamic responses: the role of the magnitude of pre-stimulus fluctuations. FRONTIERS IN NEUROENERGETICS 2012; 4:10. [PMID: 23133415 PMCID: PMC3488699 DOI: 10.3389/fnene.2012.00010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/16/2012] [Indexed: 11/13/2022]
Abstract
Brain imaging techniques utilize hemodynamic changes that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. We recently investigated this issue by measuring cortical hemodynamics in response to sensory stimuli in anesthetized rodents using 2-dimensional optical imaging spectroscopy. We suggested that sensory-evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase of ongoing fluctuations at stimulus onset due to a linear superposition of evoked and ongoing hemodynamics (Saka et al., 2010). However, the previous analysis neglected to examine the possible influence of variability of the size of ongoing fluctuations. Consequently, data were further analyzed to examine whether the size of pre-stimulus hemodynamic fluctuations also influenced the magnitude of subsequent stimulus-evoked responses. Indeed, in the case of all individual trials, a moderate correlation between the size of the pre-stimulus fluctuations and the magnitudes of the subsequent sensory-evoked responses were observed. However, different correlations between the size of the pre-stimulus fluctuations and magnitudes of the subsequent sensory-evoked cortical hemodynamic responses could be observed depending on their phase at stimulus onset. These analyses suggest that both the size and phase of pre-stimulus fluctuations in cortical hemodynamics contribute to inter-trial variability in sensory-evoked responses.
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Affiliation(s)
- Mohamad Saka
- Animal Imaging Service Unit, King Fahad Centre for Medical Research, King Abdulaziz University Jeddah, Saudi Arabia
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23
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Sakata Y, Abajian M, Ripple MO, Springett R. Measurement of the oxidation state of mitochondrial cytochrome c from the neocortex of the mammalian brain. BIOMEDICAL OPTICS EXPRESS 2012; 3:1933-46. [PMID: 22876356 PMCID: PMC3409711 DOI: 10.1364/boe.3.001933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/19/2012] [Accepted: 07/21/2012] [Indexed: 05/02/2023]
Abstract
Diffuse optical remission spectra from the mammalian neocortex at visible wavelengths contain spectral features originating from the mitochondria. A new algorithm is presented, based on analytically relating the first differential of the attenuation spectrum to the first differential of the chromophore spectra, that can separate and calculate the oxidation state of cytochrome c as well as the absolute concentration and saturation of hemoglobin. The algorithm is validated in phantoms and then tested on the neocortex of the rat during an anoxic challenge. Implementation of the algorithm will provide detailed information of mitochondrial oxygenation and mitochondrial function in physiological studies of the mammalian brain.
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Kennerley AJ, Mayhew JE, Boorman L, Zheng Y, Berwick J. Is optical imaging spectroscopy a viable measurement technique for the investigation of the negative BOLD phenomenon? A concurrent optical imaging spectroscopy and fMRI study at high field (7 T). Neuroimage 2012; 61:10-20. [PMID: 22440642 PMCID: PMC3368428 DOI: 10.1016/j.neuroimage.2012.03.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 02/16/2012] [Accepted: 03/06/2012] [Indexed: 02/05/2023] Open
Abstract
Traditionally functional magnetic resonance imaging (fMRI) has been used to map activity in the human brain by measuring increases in the Blood Oxygenation Level Dependent (BOLD) signal. Often accompanying positive BOLD fMRI signal changes are sustained negative signal changes. Previous studies investigating the neurovascular coupling mechanisms of the negative BOLD phenomenon have used concurrent 2D-optical imaging spectroscopy (2D-OIS) and electrophysiology (Boorman et al., 2010). These experiments suggested that the negative BOLD signal in response to whisker stimulation was a result of an increase in deoxy-haemoglobin and reduced multi-unit activity in the deep cortical layers. However, Boorman et al. (2010) did not measure the BOLD and haemodynamic response concurrently and so could not quantitatively compare either the spatial maps or the 2D-OIS and fMRI time series directly. Furthermore their study utilised a homogeneous tissue model in which is predominantly sensitive to haemodynamic changes in more superficial layers. Here we test whether the 2D-OIS technique is appropriate for studies of negative BOLD. We used concurrent fMRI with 2D-OIS techniques for the investigation of the haemodynamics underlying the negative BOLD at 7 Tesla. We investigated whether optical methods could be used to accurately map and measure the negative BOLD phenomenon by using 2D-OIS haemodynamic data to derive predictions from a biophysical model of BOLD signal changes. We showed that despite the deep cortical origin of the negative BOLD response, if an appropriate heterogeneous tissue model is used in the spectroscopic analysis then 2D-OIS can be used to investigate the negative BOLD phenomenon.
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Affiliation(s)
- Aneurin J Kennerley
- Centre for Signal Processing in Neuroimaging and Systems Neuroscience (SPiNSN), Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Nicoletti C, Offenhauser N, Jorks D, Major S, Dreier JP. Assessment of Neurovascular Coupling. SPRINGER PROTOCOLS HANDBOOKS 2012. [DOI: 10.1007/978-1-61779-576-3_24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Renaud R, Martin C, Gurden H, Pain F. Multispectral reflectance imaging of brain activation in rodents: methodological study of the differential path length estimations and first in vivo recordings in the rat olfactory bulb. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:016012. [PMID: 22352662 DOI: 10.1117/1.jbo.17.1.016012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Dynamic maps of relative changes in blood volume and oxygenation following brain activation are obtained using multispectral reflectance imaging. The technique relies on optical absorption modifications linked to hemodynamic changes. The relative variation of hemodynamic parameters can be quantified using the modified Beer-Lambert Law if changes in reflected light intensities are recorded at two wavelengths or more and the differential path length (DP) is known. The DP is the mean path length in tissues of backscattered photons and varies with wavelength. It is usually estimated using Monte Carlo simulations in simplified semi-infinite homogeneous geometries. Here we consider the use of multilayered models of the somatosensory cortex (SsC) and olfactory bulb (OB), which are common physiological models of brain activation. Simulations demonstrate that specific DP estimation is required for SsC and OB, specifically for wavelengths above 600 nm. They validate the hypothesis of a constant path length during activation and show the need for specific DP if imaging is performed in a thinned-skull preparation. The first multispectral reflectance imaging data recorded in vivo during OB activation are presented, and the influence of DP on the hemodynamic parameters and the pattern of oxymetric changes in the activated OB are discussed.
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Affiliation(s)
- Rémi Renaud
- Université Paris-Sud, CNRS UMR8165, Orsay F-91405, France
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27
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Al abdi R, Graber HL, Xu Y, Barbour RL. Optomechanical imaging system for breast cancer detection. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2011; 28:2473-93. [PMID: 22193261 DOI: 10.1364/josaa.28.002473] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Imaging studies of the breast comprise three principal sensing domains: structural, mechanical, and functional. Combinations of these domains can yield either additive or wholly new information, depending on whether one domain interacts with the other. In this report, we describe a new approach to breast imaging based on the interaction between controlled applied mechanical force and tissue hemodynamics. Presented is a description of the system design, performance characteristics, and representative clinical findings for a second-generation dynamic near-infrared optical tomographic breast imager that examines both breasts simultaneously, under conditions of rest and controlled mechanical provocation. The expected capabilities and limitations of the developed system are described in relation to the various sensing domains for breast imaging.
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Affiliation(s)
- Rabah Al abdi
- Department of Pathology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
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28
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Denniss J, Schiessl I, Nourrit V, Fenerty CH, Gautam R, Henson DB. Relationships between visual field sensitivity and spectral absorption properties of the neuroretinal rim in glaucoma by multispectral imaging. Invest Ophthalmol Vis Sci 2011; 52:8732-8. [PMID: 21980002 DOI: 10.1167/iovs.11-8302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To investigate the relationship between neuroretinal rim (NRR) differential light absorption (DLA, a measure of spectral absorption properties) and visual field (VF) sensitivity in primary open-angle glaucoma (POAG). METHODS Patients diagnosed with (n = 22) or suspected of having (n = 7) POAG were imaged with a multispectral system incorporating a modified digital fundus camera, 250-W tungsten-halogen lamp, and fast-tuneable liquid crystal filter. Five images were captured sequentially within 1.0 second at wavelengths selected according to absorption properties of hemoglobin (range, 570-610 nm), and a Beer-Lambert law model was used to produce DLA maps of residual NRR from the images. Patients also underwent VF testing. Differences in NRR DLA in vertically opposing 180° and 45° sectors either side of the horizontal midline were compared with corresponding differences in VF sensitivity on both decibel and linear scales by Spearman's rank correlation. RESULTS The decibel VF sensitivity scale showed significant relationships between superior-inferior NRR DLA difference and sensitivity differences between corresponding VF areas in 180° NRR sectors (Spearman ρ = 0.68; P < 0.0001), superior-/inferior-temporal 45° NRR sectors (ρ = 0.57; P < 0.002), and superior-/inferior-nasal 45° NRR sectors (ρ = 0.59; P < 0.001). Using the linear VF sensitivity scale significant relationships were found for 180° NRR sectors (ρ = 0.62; P < 0.0002) and superior-inferior-nasal 45° NRR sectors (ρ = 0.53; P < 0.002). No significant difference was found between correlations using the linear or decibel VF sensitivity scales. CONCLUSIONS Residual NRR DLA is related to VF sensitivity in POAG. Multispectral imaging may provide clinically important information for the assessment and management of POAG.
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Affiliation(s)
- Jonathan Denniss
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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29
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Sirotin YB, Cardoso M, Lima B, Das A. Spatial homogeneity and task-synchrony of the trial-related hemodynamic signal. Neuroimage 2011; 59:2783-97. [PMID: 22036678 DOI: 10.1016/j.neuroimage.2011.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 10/16/2022] Open
Abstract
There is growing evidence that functional brain images in alert task-engaged subjects contain task-related but stimulus-independent signals in addition to stimulus-evoked responses. It is important to separate these different components when analyzing the neuroimaging signal. Using intrinsic-signal optical imaging combined with electrophysiology we had earlier reported a particular 'trial-related signal' in the primary visual cortex (V1) of alert monkeys performing periodic fixation tasks. This signal periodically modulated V1 tissue blood volume, in time with anticipated trial onsets. Unlike visually evoked blood volume changes, however, this signal was present even in total darkness. Further, it could not be predicted by concurrently recorded spiking or local field potentials. Here we use our earlier recording techniques to analyze the spatial distribution of this trial-related signal over our imaged area (10mm square, subdivided into a 16×16 grid, i.e. at 625 μm resolution). We show that the signal is spatially coherent and essentially homogeneous over the imaged region and fails to be predicted by concurrent electrode recordings even at the resolution of a single grid square at the electrode tip. As a corollary we show that the signal is critically linked to the animals' engagement in a task. Not only does the trial-related signal entrain accurately and precisely to any task timing at which the animal was willing to perform; the signal also loses the entrained trial-locked pattern dramatically, within a single trial, when the animal stops performing correctly. Thus the signal is very unlikely to be an ongoing task-independent vascular oscillation. These findings will help categorize the likely distinct varieties of non-stimulus-related signals evoked during behavioral tasks, and lead to a further understanding of the elements comprising the net neuroimaging response.
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Cheng RWF, Borrett DS, Cheng W, Kwan HC, Cheng RSS. Human prefrontal cortical response to the meditative state: a spectroscopy study. Int J Neurosci 2011; 120:483-8. [PMID: 20583900 DOI: 10.3109/00207454.2010.483650] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The effect of Qigong meditation on the hemodynamics of the prefrontal cortex was investigated by spectroscopy with a single-wavelength probe (650 nm) and confirmed by standard near-infrared spectroscopy with a dual-wavelength probe. Deoxyhemoglobin changes were recorded with the single-wavelength probe over the left prefrontal cortex during meditation by Qigong practitioners, and non-practitioners instructed in the technique. Practitioners showed a significant decrease in deoxyhemoglobin levels suggesting an increase in prefrontal activation during meditation. The results were confirmed in a second set of experiments with the standard dual-wavelength probe, in which significant differences in the decrease in deoxyhemoglobin and increase in oxyhemoglobin concentrations were observed in practitioners as compared with non-practitioners. The study thus provides evidence that Qigong meditation has a significant effect on prefrontal activation.
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Affiliation(s)
- Richard W F Cheng
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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31
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Brown TM, Gias C, Hatori M, Keding SR, Semo M, Coffey PJ, Gigg J, Piggins HD, Panda S, Lucas RJ. Melanopsin contributions to irradiance coding in the thalamo-cortical visual system. PLoS Biol 2010; 8:e1000558. [PMID: 21151887 PMCID: PMC2998442 DOI: 10.1371/journal.pbio.1000558] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 10/27/2010] [Indexed: 11/18/2022] Open
Abstract
Photoreception in the mammalian retina is not restricted to rods and cones but extends to a subset of retinal ganglion cells expressing the photopigment melanopsin (mRGCs). These mRGCs are known to drive such reflex light responses as circadian photoentrainment and pupillomotor movements. By contrast, until now there has been no direct assessment of their contribution to conventional visual pathways. Here, we address this deficit. Using new reporter lines, we show that mRGC projections are much more extensive than previously thought and extend across the dorsal lateral geniculate nucleus (dLGN), origin of thalamo-cortical projection neurons. We continue to show that this input supports extensive physiological light responses in the dLGN and visual cortex in mice lacking rods+cones (a model of advanced retinal degeneration). Moreover, using chromatic stimuli to isolate melanopsin-derived responses in mice with an intact visual system, we reveal strong melanopsin input to the ∼40% of neurons in the LGN that show sustained activation to a light step. We demonstrate that this melanopsin input supports irradiance-dependent increases in the firing rate of these neurons. The implication that melanopsin is required to accurately encode stimulus irradiance is confirmed using melanopsin knockout mice. Our data establish melanopsin-based photoreception as a significant source of sensory input to the thalamo-cortical visual system, providing unique irradiance information and allowing visual responses to be retained even in the absence of rods+cones. These findings identify mRGCs as a potential origin for aspects of visual perception and indicate that they may support vision in people suffering retinal degeneration.
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Affiliation(s)
- Timothy M. Brown
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Carlos Gias
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Megumi Hatori
- The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Sheena R. Keding
- The Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Ma'ayan Semo
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Peter J. Coffey
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - John Gigg
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Hugh D. Piggins
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Satchidananda Panda
- The Salk Institute for Biological Studies, La Jolla, California, United States of America
- * E-mail: (SP); (RJL)
| | - Robert J. Lucas
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail: (SP); (RJL)
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32
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Saka M, Berwick J, Jones M. Linear superposition of sensory-evoked and ongoing cortical hemodynamics. FRONTIERS IN NEUROENERGETICS 2010; 2. [PMID: 20844602 PMCID: PMC2938927 DOI: 10.3389/fnene.2010.00023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 07/14/2010] [Indexed: 11/13/2022]
Abstract
Modern non-invasive brain imaging techniques utilize changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. To investigate this issue, 2-dimensional optical imaging spectroscopy was used to measure cortical hemodynamics in response to sensory stimuli in anesthetized rodents. Pre-stimulus cortical hemodynamics displayed spontaneous periodic fluctuations and as such, data from individual stimulus presentation trials were assigned to one of four groups depending on the phase angle of pre-stimulus hemodynamic fluctuations and averaged. This analysis revealed that sensory evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase angle of ongoing fluctuations at stimulus onset. To investigate the origin of this phenomenon, "null-trials" were collected without stimulus presentation. Subtraction of phase averaged "null trials" from their phase averaged stimulus-evoked counterparts resulted in four similar time series that resembled the mean stimulus-evoked response. These analyses suggest that linear superposition of evoked and ongoing cortical hemodynamic changes may be a property of the structure of inter-trial variability.
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Affiliation(s)
- Mohamad Saka
- The Centre for Signal Processing in NeuroImaging and Systems Neuroscience, Department of Psychology, University of Sheffield Sheffield, South Yorkshire, UK
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33
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Schwartz TH. Neurovascular coupling and epilepsy: hemodynamic markers for localizing and predicting seizure onset. Epilepsy Curr 2010; 7:91-4. [PMID: 17694162 PMCID: PMC1941907 DOI: 10.1111/j.1535-7511.2007.00183.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Hemodynamic surrogates of epileptic activity are being used to map epileptic foci with PET, SPECT, and fMRI. However, there are few studies of neurovascular coupling in epilepsy. Recent data indicate that cerebral blood flow, although focally increased at the onset of a seizure, may be temporarily inadequate to meet the metabolic demands of both interictal and ictal epileptic events. Transient focal tissue hypoxia and hyperperfusion may be excellent markers for the epileptic focus and may even precede the onset of the ictal event.
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Affiliation(s)
- Theodore H Schwartz
- Department of Neurological Surgery, Weill Medical College of Cornell University, New York, NY, USA.
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Vanzetta I, Flynn C, Ivanov AI, Bernard C, Bénar CG. Investigation of Linear Coupling Between Single-Event Blood Flow Responses and Interictal Discharges in a Model of Experimental Epilepsy. J Neurophysiol 2010; 103:3139-52. [DOI: 10.1152/jn.01048.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A successful outcome of epilepsy neurosurgery relies on an accurate delineation of the epileptogenic region to be resected. Functional magnetic resonance imaging (fMRI) would allow doing this noninvasively at high spatial resolution. However, a clear, quantitative description of the relationship between hemodynamic changes and the underlying epileptiform neuronal activity is still missing, thereby preventing the systematic use of fMRI for routine epilepsy surgery planning. To this aim, we used a local epilepsy model to record simultaneously cerebral blood flow (CBF) with laser Doppler (LD) and local field potentials (LFP) in rat frontal cortex. CBF responses to individual interictal-like spikes were large and robust. Their amplitude correlated linearly with spike amplitude. Moreover, the CBF response added linearly in time over a large range of spiking rates. CBF responses could thus be predicted by a linear model of the kind currently used for the interpretation of fMRI data, but including also the spikes’ amplitudes as additional information. Predicted and measured CBF responses matched accurately. For high spiking frequencies (above ∼0.2 Hz), the responses saturated but could eventually recover, indicating the presence of multiple neurovascular coupling mechanisms, which might act at different spatiotemporal scales. Spatially, CBF responses peaked at the center of epileptic activity and displayed a spatial specificity at least as good as the millimeter. These results suggest that simultaneous electroencephalographic and blood flow-based fMRI recordings should be suitable for the noninvasive precise localization of hyperexcitable regions in epileptic patients candidate for neurosurgery.
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Affiliation(s)
- Ivo Vanzetta
- Centre National de la Recherche Scientifique, Unité Mixte de Rechereche 6193, Institut de Neurosciences Cognitives de la Méditerranée
- Université Aix-Marseille, Marseille, France
| | - Corey Flynn
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 751, Laboratoire Epilepsie et Cognition; and
- Université Aix-Marseille, Marseille, France
| | - Anton I. Ivanov
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 751, Laboratoire Epilepsie et Cognition; and
- Université Aix-Marseille, Marseille, France
| | - Christophe Bernard
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 751, Laboratoire Epilepsie et Cognition; and
- Université Aix-Marseille, Marseille, France
| | - Christian G. Bénar
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 751, Laboratoire Epilepsie et Cognition; and
- Université Aix-Marseille, Marseille, France
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Bruyns-Haylett M, Zheng Y, Berwick J, Jones M. Temporal coupling between stimulus-evoked neural activity and hemodynamic responses from individual cortical columns. Phys Med Biol 2010; 55:2203-19. [DOI: 10.1088/0031-9155/55/8/006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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36
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Cui X, Bray S, Reiss AL. Functional near infrared spectroscopy (NIRS) signal improvement based on negative correlation between oxygenated and deoxygenated hemoglobin dynamics. Neuroimage 2009; 49:3039-46. [PMID: 19945536 DOI: 10.1016/j.neuroimage.2009.11.050] [Citation(s) in RCA: 440] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/17/2009] [Accepted: 11/19/2009] [Indexed: 10/20/2022] Open
Abstract
Near infrared spectroscopy (NIRS) is a promising technology for functional brain imaging which measures hemodynamic signals from the cortex, similar to functional magnetic resonance imaging (fMRI), but does not require the participant to lie motionless in a confined space. NIRS can therefore be used for more naturalistic experiments, including face to face communication, or natural body movements, and is well suited for real-time applications that may require lengthy training. However, improving signal quality and reducing noise, especially noise induced by head motion, is challenging, particularly for real time applications. Here we study the properties of head motion induced noise, and find that motion noise causes the measured oxygenated and deoxygenated hemoglobin signals, which are typically strongly negatively correlated, to become more positively correlated. Next, we develop a method to reduce noise based on the principle that the concentration changes of oxygenated and deoxygenated hemoglobin should be negatively correlated. We show that despite its simplicity, this method is effective in reducing noise and improving signal quality, for both online and offline noise reduction.
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Affiliation(s)
- Xu Cui
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA 94305, USA.
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37
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L'Heureux B, Gurden H, Pain F. Autofluorescence imaging of NADH and flavoproteins in the rat brain: insights from Monte Carlo simulations. OPTICS EXPRESS 2009; 17:9477-9490. [PMID: 19506595 DOI: 10.1364/oe.17.009477] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
There has been recently a renewed interest in using Autofluorescence imaging (AF) of NADH and flavoproteins (Fp) to map brain activity in cortical areas. The recording of these cellular signals provides complementary information to intrinsic optical imaging based on hemodynamic changes. However, which of NADH or Fp is the best candidate for AF functional imaging is not established, and the temporal profile of AF signals is not fully understood. To bring new theoretical insights into these questions, Monte Carlo simulations of AF signals were carried out in realistic models of the rat somatosensory cortex and olfactory bulb. We show that AF signals depend on the structural and physiological features of the brain area considered and are sensitive to changes in blood flow and volume induced by sensory activation. In addition, we demonstrate the feasibility of both NADHAF and Fp-AF in the olfactory bulb.
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Affiliation(s)
- Barbara L'Heureux
- UMR8165 Imagerie et Modélisation en Neurobiologie et Cancérologie, CNRS/Université Paris XI/Paris VII, Bat 440, Campus d'Orsay, Orsay, France.
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Zheng Y, Mayhew J. A time-invariant visco-elastic windkessel model relating blood flow and blood volume. Neuroimage 2009; 47:1371-80. [PMID: 19371789 DOI: 10.1016/j.neuroimage.2009.04.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 03/02/2009] [Accepted: 04/04/2009] [Indexed: 11/30/2022] Open
Abstract
The difference between the rate of change of cerebral blood volume (CBV) and cerebral blood flow (CBF) following stimulation is thought to be due to circumferential stress relaxation in veins (Mandeville, J.B., Marota, J.J.A., Ayata, C., Zaharchuk, G., Moskowitz, M.A., Rosen, B.R., Weisskoff, R.M., 1999. Evidence of a cerebrovascular postarteriole windkessel with delayed compliance. J. Cereb. Blood Flow Metab. 19, 679-689). In this paper we explore the visco-elastic properties of blood vessels, and present a dynamic model relating changes in CBF to changes in CBV. We refer to this model as the visco-elastic windkessel (VW) model. A novel feature of this model is that the parameter characterising the pressure-volume relationship of blood vessels is treated as a state variable dependent on the rate of change of CBV, producing hysteresis in the pressure-volume space during vessel dilation and contraction. The VW model is nonlinear time-invariant, and is able to predict the observed differences between the time series of CBV and that of CBF measurements following changes in neural activity. Like the windkessel model derived by Mandeville, J.B., Marota, J.J.A., Ayata, C., Zaharchuk, G., Moskowitz, M.A., Rosen, B.R., Weisskoff, R.M., 1999. Evidence of a cerebrovascular postarteriole windkessel with delayed compliance. J. Cereb. Blood Flow Metab. 19, 679-689, the VW model is primarily a model of haemodynamic changes in the venous compartment. The VW model is demonstrated to have the following characteristics typical of visco-elastic materials: (1) hysteresis, (2) creep, and (3) stress relaxation, hence it provides a unified model of the visco-elastic properties of the vasculature. The model will not only contribute to the interpretation of the Blood Oxygen Level Dependent (BOLD) signals from functional Magnetic Resonance Imaging (fMRI) experiments, but also find applications in the study and modelling of the brain vasculature and the haemodynamics of circulatory and cardiovascular systems.
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Affiliation(s)
- Ying Zheng
- Centre for Signal Processing in Neuro-imaging and Systems Neuroscience, Department of Psychology, University of Sheffield, Sheffield, UK.
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39
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Schei JL, Foust AJ, Rojas MJ, Navas JA, Rector DM. State-dependent auditory evoked hemodynamic responses recorded optically with indwelling photodiodes. APPLIED OPTICS 2009; 48:D121-9. [PMID: 19340099 PMCID: PMC2707279 DOI: 10.1364/ao.48.00d121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Implantable optical technologies provide measurements of cerebral hemodynamic activity from freely behaving animals without movement constraint or anesthesia. In order to study state-dependent neural evoked responses and the consequential hemodynamic response, we simultaneously measured EEG and scattered light changes in chronically implanted rats. Recordings took place under freely behaving conditions, allowing us to compare the evoked responses across wake, sleep, and anesthetized states. The largest evoked electrical and optical responses occurred during quiet sleep compared to wake and REM sleep, while isoflurane anesthesia showed a large, late burst of electrical activity synchronized to the stimulus but an earlier optical response.
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Affiliation(s)
- Jennifer L Schei
- Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164, USA
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40
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Wei HL, Zheng Y, Pan Y, Coca D, Li LM, Mayhew JEW, Billings SA. Model estimation of cerebral hemodynamics between blood flow and volume changes: a data-based modeling approach. IEEE Trans Biomed Eng 2009; 56:1606-16. [PMID: 19174333 DOI: 10.1109/tbme.2009.2012722] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is well known that there is a dynamic relationship between cerebral blood flow (CBF) and cerebral blood volume (CBV). With increasing applications of functional MRI, where the blood oxygen-level-dependent signals are recorded, the understanding and accurate modeling of the hemodynamic relationship between CBF and CBV becomes increasingly important. This study presents an empirical and data-based modeling framework for model identification from CBF and CBV experimental data. It is shown that the relationship between the changes in CBF and CBV can be described using a parsimonious autoregressive with exogenous input model structure. It is observed that neither the ordinary least-squares (LS) method nor the classical total least-squares (TLS) method can produce accurate estimates from the original noisy CBF and CBV data. A regularized total least-squares (RTLS) method is thus introduced and extended to solve such an error-in-the-variables problem. Quantitative results show that the RTLS method works very well on the noisy CBF and CBV data. Finally, a combination of RTLS with a filtering method can lead to a parsimonious but very effective model that can characterize the relationship between the changes in CBF and CBV.
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Affiliation(s)
- Hua-Liang Wei
- Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield S1 3JD, UK.
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41
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Sayli O, Aksel EB, Akin A. Crosstalk and error analysis of fat layer on continuous wave near-infrared spectroscopy measurements. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:064019. [PMID: 19123665 DOI: 10.1117/1.3028008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Accurate estimation of concentration changes in muscles by continuous wave near-IR spectroscopy for muscle measurements suffers from underestimation and crosstalk problems due to the presence of superficial skin and fat layers. Underestimation error is basically caused by a homogeneous medium assumption in the calculations leading to the partial volume effect. The homogeneous medium assumption and wavelength dependence of mean partial path length in the muscle layer cause the crosstalk. We investigate underestimation errors and crosstalk by Monte Carlo simulations with a three layered (skin-fat-muscle) tissue model for a two-wavelength system where the choice of first wavelength is in the 675- to 775-nm range and the second wavelength is in the 825- to 900-nm range. Means of absolute underestimation errors and crosstalk over the considered wavelength pairs are found to be higher for greater fat thicknesses. Estimation errors of concentration changes for Hb and HbO(2) are calculated to be close for an ischemia type protocol where both Hb and HbO(2) are assumed to have equal magnitude but opposite concentration changes. The minimum estimation errors are found for the 700825- and 725825-nm pairs for this protocol.
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Affiliation(s)
- Omer Sayli
- Bogazici University, Institute of Biomedical Engineering, Bebek, Istanbul, 34342, Turkey
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42
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Morris DE, Stockford IM, Crowe JA. Determination of the validity of spectrophotometric measurements based upon cumulants of the temporal point-spread function. OPTICS LETTERS 2008; 33:1339-1341. [PMID: 18552951 DOI: 10.1364/ol.33.001339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Spectrophotometric measurements of scattering media are nontrivial owing to the nonlinear relationship between the observed attenuation A and the level of absorption coefficient micro(a). Presented is a method, utilizing frequency-domain measurements, capable of determining the validity of a measured change in micro(a) based purely on the characteristics of a baseline temporal point-spread function. The order of cumulant used is shown to provide variation of the sensitivity of the method, and its use is demonstrated through Monte Carlo simulations of transmission measurements taken from a scattering slab.
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Affiliation(s)
- David E Morris
- Applied Optics Group, School of Electrical and Electronic Engineering, University of Nottingham, Nottingham, UK
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43
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Vanzetta I, Grinvald A. Coupling between neuronal activity and microcirculation: implications for functional brain imaging. HFSP JOURNAL 2008; 2:79-98. [PMID: 19404475 PMCID: PMC2645573 DOI: 10.2976/1.2889618] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 02/11/2008] [Indexed: 01/12/2023]
Abstract
In the neocortex, neurons with similar response properties are often clustered together in column-like structures, giving rise to what has become known as functional architecture-the mapping of various stimulus feature dimensions onto the cortical sheet. At least partially, we owe this finding to the availability of several functional brain imaging techniques, both post-mortem and in-vivo, which have become available over the last two generations, revolutionizing neuroscience by yielding information about the spatial organization of active neurons in the brain. Here, we focus on how our understanding of such functional architecture is linked to the development of those functional imaging methodologies, especially to those that image neuronal activity indirectly, through metabolic or haemodynamic signals, rather than directly through measurement of electrical activity. Some of those approaches allow exploring functional architecture at higher spatial resolution than others. In particular, optical imaging of intrinsic signals reaches the striking detail of approximately 50 mum, and, together with other methodologies, it has allowed characterizing the metabolic and haemodynamic responses induced by sensory-evoked neuronal activity. Here, we review those findings about the spatio-temporal characteristics of neurovascular coupling and discuss their implications for functional brain imaging, including position emission tomography, and non-invasive neuroimaging techniques, such as funtional magnetic resonance imaging, applicable also to the human brain.
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Affiliation(s)
- Ivo Vanzetta
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
- Institut de Neurosciences Cognitives de la Méditerranée, CNRS UMR 6193, Aix-Marseille Université, 13402 Marseille Cedex 20, France
| | - Amiram Grinvald
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Berwick J, Johnston D, Jones M, Martindale J, Martin C, Kennerley AJ, Redgrave P, Mayhew JEW. Fine detail of neurovascular coupling revealed by spatiotemporal analysis of the hemodynamic response to single whisker stimulation in rat barrel cortex. J Neurophysiol 2007; 99:787-98. [PMID: 18046008 DOI: 10.1152/jn.00658.2007] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The spatial resolution of hemodynamic-based neuroimaging techniques, including functional magnetic resonance imaging, is limited by the degree to which neurons regulate their blood supply on a fine scale. Here we investigated the spatial detail of neurovascular events with a combination of high spatiotemporal resolution two-dimensional spectroscopic optical imaging, multichannel electrode recordings and cytochrome oxidase histology in the rodent whisker barrel field. After mechanical stimulation of a single whisker, we found two spatially distinct cortical hemodynamic responses: a transient response in the "upstream" branches of surface arteries and a later highly localized increase in blood volume centered on the activated cortical column. Although the spatial representation of this localized response exceeded that of a single "barrel," the spread of hemodynamic activity accurately reflected the neural response in neighboring columns rather than being due to a passive "overspill." These data confirm hemodynamics are capable of providing accurate "single-condition" maps of neural activity.
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Affiliation(s)
- J Berwick
- Department of Psychology, University of Sheffield, Sheffield S10 2TN, UK.
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45
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Springett R, Swartz HM. Measurements of oxygen in vivo: overview and perspectives on methods to measure oxygen within cells and tissues. Antioxid Redox Signal 2007; 9:1295-301. [PMID: 17576162 DOI: 10.1089/ars.2007.1620] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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46
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Moon CH, Fukuda M, Park SH, Kim SG. Neural interpretation of blood oxygenation level-dependent fMRI maps at submillimeter columnar resolution. J Neurosci 2007; 27:6892-902. [PMID: 17596437 PMCID: PMC6672231 DOI: 10.1523/jneurosci.0445-07.2007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Whether conventional gradient-echo (GE) blood oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is able to map submillimeter-scale functional columns remains debatable mainly because of the spatially nonspecific large vessel contribution, poor sensitivity and reproducibility, and lack of independent evaluation. Furthermore, if the results from optical imaging of intrinsic signals are directly applicable, regions with the highest BOLD signals may indicate neurally inactive domains rather than active columns when multiple columns are activated. To examine these issues, we performed BOLD fMRI at a magnetic field of 9.4 tesla to map orientation-selective columns of isoflurane-anesthetized cats. We could not convincingly map orientation columns using conventional block-design stimulation and differential analysis method because of large fluctuations of signals. However, we successfully obtained GE BOLD iso-orientation maps with high reproducibility (r = 0.74) using temporally encoded continuous cyclic orientation stimulation with Fourier data analysis, which reduces orientation-nonselective signals such as draining artifacts and is less sensitive to signal fluctuations. We further reduced large vessel contribution using the improved spin-echo (SE) BOLD method but with overall decreased sensitivity. Both GE and SE BOLD iso-orientation maps excluding large pial vascular regions were significantly correlated to maps with a known neural interpretation, which were obtained in contrast agent-aided cerebral blood volume fMRI and total hemoglobin-based optical imaging of intrinsic signals at a hemoglobin iso-sbestic point (570 nm). These results suggest that, unlike the expectation from deoxyhemoglobin-based optical imaging studies, the highest BOLD signals are localized to the sites of increased neural activity when column-nonselective signals are suppressed.
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Affiliation(s)
| | | | | | - Seong-Gi Kim
- Departments of Radiology and
- Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15203
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47
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Crowe J, Morris D, Woolfson M, Rodmell P, Walker J. Quantitative spectrophotometry of scattering media via frequency-domain and constant-intensity measurements. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2007; 24:1969-74. [PMID: 17728821 DOI: 10.1364/josaa.24.001969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The attenuation of light by scattering and absorbing media is nonlinearly dependent upon the absorption coefficient, since detected light has experienced many different flight times. The frequency response of such a sample to modulated light is also nonlinear. We derive an expression for the attenuation that includes both the absorption coefficient and the modulation frequency. Its form is a power series whose coefficients are the cumulants of the temporal point-spread function (TPSF). Recasting this expression in terms of intensity leads to a similar expression with the cumulants replaced by the moments of the TPSF. A means of exploiting this relationship to produce estimates of the absolute concentration of the absorbing species is suggested.
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Affiliation(s)
- John Crowe
- Applied Optics Group, School of Electrical and Electronic Engineering, University of Nottingham, UK.
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48
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Gias C, Jones M, Keegan D, Adamson P, Greenwood J, Lund R, Martindale J, Johnston D, Berwick J, Mayhew J, Coffey P. Preservation of visual cortical function following retinal pigment epithelium transplantation in the RCS rat using optical imaging techniques. Eur J Neurosci 2007; 25:1940-8. [PMID: 17439483 DOI: 10.1111/j.1460-9568.2007.05459.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aim of this study was to determine the extent of cortical functional preservation following retinal pigment epithelium (RPE) transplantation in the Royal College of Surgeons (RCS) rat using single-wavelength optical imaging and spectroscopy. The cortical responses to visual stimulation in transplanted rats at 6 months post-transplantation were compared with those from age-matched untreated dystrophic and non-dystrophic rats. Our results show that cortical responses were evoked in non-dystrophic rats to both luminance changes and pattern stimulation, whereas no response was found in untreated dystrophic animals to any of the visual stimuli tested. In contrast, a cortical response was elicited in most of the transplanted rats to luminance changes and in many of those a response was also evoked to pattern stimulation. Although the transplanted rats did not respond to high spatial frequency information we found evidence of preservation in the cortical processing of luminance changes and low spatial frequency stimulation. Anatomical sections of transplanted rat retinas confirmed the capacity of RPE transplantation to rescue photoreceptors. Good correlation was found between photoreceptor survival and the extent of cortical function preservation determined with optical imaging techniques. This study determined the efficacy of RPE transplantation to preserve visual cortical processing and established optical imaging as a powerful technique for its assessment.
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Affiliation(s)
- Carlos Gias
- Institute of Ophthalmology, University College London, London, UK.
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49
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Prakash N, Biag JD, Sheth SA, Mitsuyama S, Theriot J, Ramachandra C, Toga AW. Temporal profiles and 2-dimensional oxy-, deoxy-, and total-hemoglobin somatosensory maps in rat versus mouse cortex. Neuroimage 2007; 37 Suppl 1:S27-36. [PMID: 17574868 PMCID: PMC2227950 DOI: 10.1016/j.neuroimage.2007.04.063] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 04/20/2007] [Accepted: 04/25/2007] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Mechanisms of neurovascular coupling-the relationship between neuronal chemoelectrical activity and compensatory metabolic and hemodynamic changes-appear to be preserved across species from rats to humans despite differences in scale. However, previous work suggests that the highly cellular dense mouse somatosensory cortex has different functional hemodynamic changes compared to other species. METHODS We developed novel hardware and software for 2-dimensional optical spectroscopy (2DOS). Optical changes at four simultaneously recorded wavelengths were measured in both rat and mouse primary somatosensory cortex (S1) evoked by forepaw stimulation to create four spectral maps. The spectral maps were converted to maps of deoxy-, oxy-, and total-hemoglobin (HbR, HbO, and HbT) concentration changes using the modified Beer-Lambert law and phantom HbR and HbO absorption spectra. RESULTS : Functional hemodynamics were different in mouse versus rat neocortex. On average, hemodynamics were as expected in rat primary somatosensory cortex (S1): the fractional change in the log of HbT concentration increased monophasically 2 s after stimulus, whereas HbO changes mirrored HbR changes, with HbO showing a small initial dip at 0.5 s followed by a large increase 3.0 s post stimulus. In contrast, mouse S1 showed a novel type of stimulus-evoked hemodynamic response, with prolonged, concurrent, monophasic increases in HbR and HbT and a parallel decrease in HbO that all peaked 3.5-4.5 s post stimulus onset. For rats, at any given time point, the average size and shape of HbO and HbR forepaw maps were the same, whereas surface veins distorted the shape of the HbT map. For mice, HbO, HbR, and HbT forepaw maps were generally the same size and shape at any post-stimulus time point. CONCLUSIONS 2DOS using image splitting optics is feasible across species for brain mapping and quantifying the map topography of cortical hemodynamics. These results suggest that during physiologic stimulation, different species and/or cortical architecture may give rise to different hemodynamic changes during neurovascular coupling.
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Affiliation(s)
- Neal Prakash
- University of California, Los Angeles, David Geffen School of Medicine, Department of Neurology, Laboratory of Neuro Imaging, Los Angeles, CA 90095, USA.
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50
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Chen-Bee CH, Agoncillo T, Xiong Y, Frostig RD. The triphasic intrinsic signal: implications for functional imaging. J Neurosci 2007; 27:4572-86. [PMID: 17460070 PMCID: PMC6673004 DOI: 10.1523/jneurosci.0326-07.2007] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Intrinsic signal optical imaging with red illumination (ISOI) is used extensively to provide high spatial resolution maps of stimulus-evoked hemodynamic-related signals as an indirect means to map evoked neuronal activity. This evoked signal is generally described as beginning with an undershoot or "dip" in signal that is faster, more transient, and weaker compared with the subsequent signal overshoot. In contrast, the evoked signal detected with blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is generally described as containing an undershoot after the initial dip and overshoot, even though it, too, detects hemodynamic-related signals and its first two phases appear complementary to those of ISOI. Here, we used ISOI with 635 nm illumination to image over 13.5 s after a 1 s stimulus delivery to detect and successfully use the ISOI undershoot phase for functional mapping. Eight spatiotemporal attributes were assessed per signal phase including maximum areal extent and peak magnitude, both of which were largest for the ISOI overshoot, followed by the undershoot and then the initial dip. Peak activity location did not colocalize well between the three phases; furthermore, we found mostly modest correlations between attributes within each phase and sparse correlations between phases. Extended (13.5 s) electrophysiology recordings did not exhibit a reoccurrence of evoked suprathreshold or subthreshold neuronal responses that could be associated with the undershoot. Beyond the undershoot, additional overshoot/undershoot fluctuations were also mapped, but were typically less spatiotemporally specific to stimulus delivery. Implications for ISOI and BOLD fMRI are discussed.
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Affiliation(s)
- Cynthia H Chen-Bee
- Department of Neurobiology and Behavior, and the Center for the Neurobiology of Learning and Memory, University of California, Irvine, California 92697-4550, USA.
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