1
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Pradier B, Wachsmuth L, Nagelmann N, Segelcke D, Kreitz S, Hess A, Pogatzki-Zahn EM, Faber C. Combined resting state-fMRI and calcium recordings show stable brain states for task-induced fMRI in mice under combined ISO/MED anesthesia. Neuroimage 2021; 245:118626. [PMID: 34637903 DOI: 10.1016/j.neuroimage.2021.118626] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 09/27/2021] [Indexed: 11/28/2022] Open
Abstract
For fMRI in animal models, the combination of low-dose anesthetic, isoflurane (ISO), and the sedative medetomidine (MED) has recently become an advocated regimen to achieve stable neuronal states and brain networks in rats that are required for reliable task-induced BOLD fMRI. However, in mice the temporal stability of neuronal states and networks in resting-state (rs)-fMRI experiments during the combined ISO/MED regimen has not been systematically investigated. Using a multimodal approach with optical calcium (Ca2+) recordings and rs-fMRI, we investigated cortical neuronal/astrocytic Ca2+activity states and brain networks at multiple time points while switching from anesthesia with 1% ISO to a combined ISO/MED regimen. We found that cortical activity states reached a steady-state 45 min following start of MED infusion as indicated by stable Ca2+ transients. Similarly, rs-networks were not statistically different between anesthesia with ISO and the combined ISO/MED regimen 45 and 100 min after start of MED. Importantly, during the transition time we identified changed rs-network signatures that likely reflect the different mode of action of the respective anesthetic; these included a dose-dependent increase in cortico-cortical functional connectivity (FC) presumably caused by reduction of ISO concentration and decreased FC in subcortical arousal nuclei due to MED infusion. Furthermore, we report detection of visual stimulation-induced BOLD fMRI during the stable ISO/MED neuronal state 45 min after induction. Based on our findings, we recommend a 45-minute waiting period after switching from ISO anesthesia to the combined ISO/MED regimen before performing rs- or task-induced fMRI experiments.
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Affiliation(s)
- Bruno Pradier
- Department of Clinical Radiology, Translational Research Imaging Center, University Hospital Münster, Münster 48149, Germany; Department of Anesthesiology Intensive Care and Pain Medicine, University Hospital Münster, Germany
| | - Lydia Wachsmuth
- Department of Clinical Radiology, Translational Research Imaging Center, University Hospital Münster, Münster 48149, Germany
| | - Nina Nagelmann
- Department of Clinical Radiology, Translational Research Imaging Center, University Hospital Münster, Münster 48149, Germany
| | - Daniel Segelcke
- Department of Anesthesiology Intensive Care and Pain Medicine, University Hospital Münster, Germany
| | - Silke Kreitz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Emil Fischer Center, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Andreas Hess
- Institute of Experimental and Clinical Pharmacology and Toxicology, Emil Fischer Center, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Esther M Pogatzki-Zahn
- Department of Anesthesiology Intensive Care and Pain Medicine, University Hospital Münster, Germany
| | - Cornelius Faber
- Department of Clinical Radiology, Translational Research Imaging Center, University Hospital Münster, Münster 48149, Germany.
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2
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Liu Y, Perez PD, Ma Z, Ma Z, Dopfel D, Cramer S, Tu W, Zhang N. An open database of resting-state fMRI in awake rats. Neuroimage 2020; 220:117094. [PMID: 32610063 PMCID: PMC7605641 DOI: 10.1016/j.neuroimage.2020.117094] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 06/10/2020] [Accepted: 06/18/2020] [Indexed: 12/15/2022] Open
Abstract
Rodent models are essential to translational research in health and disease. Investigation in rodent brain function and organization at the systems level using resting-state functional magnetic resonance imaging (rsfMRI) has become increasingly popular. Due to this rapid progress, publicly shared rodent rsfMRI databases can be of particular interest and importance to the scientific community, as inspired by human neuroscience and psychiatric research that are substantially facilitated by open human neuroimaging datasets. However, such databases in rats are still rare. In this paper, we share an open rsfMRI database acquired in 90 rats with a well-established awake imaging paradigm that avoids anesthesia interference. Both raw and preprocessed data are made publicly available. Procedures in data preprocessing to remove artefacts induced by the scanner, head motion and non-neural physiological noise are described in details. We also showcase inter-regional functional connectivity and functional networks obtained from the database.
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Affiliation(s)
- Yikang Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Pablo D Perez
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zilu Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zhiwei Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - David Dopfel
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Samuel Cramer
- Neuroscience Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wenyu Tu
- Neuroscience Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA; Neuroscience Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
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3
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Zhou W, Cai A, Nie B, Zhang W, Yang T, Zheng N, Manyande A, Wang X, Xu F, Tian X, Wang J. Investigation of robust visual reaction and functional connectivity in the rat brain induced by rocuronium bromide with functional MRI. Am J Transl Res 2020; 12:2396-2408. [PMID: 32655779 PMCID: PMC7344061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has been used extensively to understand the brain function of a wide range of neurological and psychiatric disorders. When applied to animal studies, anesthesia is always used to reduce the movement of the animal and also reduce the impacts on the results of fMRI. Several awake models have been proposed by applying physical animal movement restrictions. However, restraining devices were designed for individual subject which limits the promotion of fMRI in awake animals. Here, a clinical muscle relaxant rocuronium bromide (RB) was introduced to restrain the animal in fMRI scanning time. The fMRI reactions of the animal induced with RB and the other two commonly used anesthesia protocols were investigated. The results of the fMRI showed that there were increased functional connectivity and well-round visual responses in the RB induced state. Furthermore, significant BOLD signal changes were found in the cortex and thalamus regions when the animal revived from isoflurane, which should be essential to further understand the effects of anesthesia on the brain.
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Affiliation(s)
- Wenchang Zhou
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430070, Hubei, P. R. China
| | - Aoling Cai
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and TechnologyWuhan 430074, Hubei, P. R. China
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of SciencesWuhan 430071, Hubei, P. R. China
| | - Binbin Nie
- Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of SciencesBeijing 100049, P. R. China
- University of Chinese Academy of SciencesBeijing 100049, P. R. China
| | - Wen Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430070, Hubei, P. R. China
| | - Ting Yang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430070, Hubei, P. R. China
| | - Ning Zheng
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of SciencesWuhan 430071, Hubei, P. R. China
- University of Chinese Academy of SciencesBeijing 100049, P. R. China
| | - Anne Manyande
- School of Human and Social Sciences, University of West LondonLondon, UK.
| | - Xuxia Wang
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of SciencesWuhan 430071, Hubei, P. R. China
- University of Chinese Academy of SciencesBeijing 100049, P. R. China
| | - Fuqiang Xu
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and TechnologyWuhan 430074, Hubei, P. R. China
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of SciencesWuhan 430071, Hubei, P. R. China
- University of Chinese Academy of SciencesBeijing 100049, P. R. China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of SciencesShanghai 200031, P. R. China
| | - Xuebi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhan 430070, Hubei, P. R. China
| | - Jie Wang
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of SciencesWuhan 430071, Hubei, P. R. China
- University of Chinese Academy of SciencesBeijing 100049, P. R. China
- Hebei Provincial Key Laboratory of Basic Medicine for Diabetes, 2nd Hospital of ShijiazhuangShijiazhuang 050051, Hebei, P. R. China
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4
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Landau AM, Noer O, Alstrup AKO, Audrain H, Wegener G, Gjedde A, Doudet DJ, Winterdahl M. Type of Anaesthetic Influences [ 11C]MDL100,907 Binding to 5HT 2A Receptors in Porcine Brain. Mol Imaging Biol 2020; 22:797-804. [PMID: 31993926 DOI: 10.1007/s11307-020-01476-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE Anaesthesia routinely is used in animal neuroimaging in order to reduce head motion artefacts and minimize the influence of stress. However, anaesthetics can modify radioligand binding profiles at receptor targets studied by positron emission tomography (PET). Here, we determined the effects of two routine anaesthetics on the binding of a tracer of the serotonin 5HT2A receptors. PROCEDURES Isoflurane- and propofol-anesthetised Göttingen minipigs were imaged with [11C]MDL100,907 PET and analysed using regions of interest and statistical non-parametric mapping. RESULTS The binding potentials of the tracer in striatum under isoflurane anaesthesia significantly exceeded those obtained under propofol anaesthesia, an effect we attribute to the higher blood flow in brain induced by the former. CONCLUSIONS Interactions between radioligands and anaesthesia must be carefully evaluated in the design of in vivo neuroimaging and interpretation of data.
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Affiliation(s)
- Anne M Landau
- Department of Nuclear Medicine and PET, Aarhus University, Aarhus, Denmark. .,Translational Neuropsychiatry Unit, Aarhus University, Aarhus, Denmark.
| | - Ove Noer
- Department of Nuclear Medicine and PET, Aarhus University, Aarhus, Denmark
| | | | - Hélène Audrain
- Department of Nuclear Medicine and PET, Aarhus University, Aarhus, Denmark
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Aarhus University, Aarhus, Denmark
| | - Albert Gjedde
- Department of Nuclear Medicine and PET, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine, University of Southern Denmark, Odense University Hospital, Odense, Denmark.,Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Doris J Doudet
- Department of Medicine/Neurology, University of British Columbia, Vancouver, Canada
| | - Michael Winterdahl
- Department of Nuclear Medicine and PET, Aarhus University, Aarhus, Denmark
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5
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Levine AT, Li B, Barnes P, Lomber SG, Butler BE. Assessment of anesthesia on physiological stability and BOLD signal reliability during visual or acoustic stimulation in the cat. J Neurosci Methods 2020; 334:108603. [PMID: 31982459 DOI: 10.1016/j.jneumeth.2020.108603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Neuroimaging methods including fMRI provide powerful tools to observe whole-brain functional networks. This is particularly powerful in animal models, allowing these networks to be probed using complementary methods. However, most animals must be anesthetized for neuroimaging, giving rise to complications resulting from anesthetic effects on the animal's physiological and neurological functions. For example, an established protocol for feline neuroimaging involves co-administration of ketamine and isoflurane - the latter of which is known to suppress cortical function. NEW METHOD Here, we compare this established protocol to alfaxalone, a single-agent anesthetic for functional neuroimaging. We first compare the two in a controlled environment to assess relative safety and to measure physiological stability over an extended time window. We then compare patterns of auditory and visually-evoked activity measured at 7 T to assess mean signal strength and between-subjects signal variability. RESULTS IN COMPARISON WITH EXISTING METHODS We show that alfaxalone results in more stable respiratory rates over the 120 min testing period, with evidence of smaller between-measurements variability within this time window, when compared to ketamine plus isoflurane. Moreover, we demonstrate that both agents evoke similar mean BOLD signals across animals, but that alfaxalone elicits more consistent BOLD activity in response to sound stimuli across all ROIs observed. CONCLUSIONS Alfaxalone is observed to be more physiologically stable, evoking a more consistent BOLD signal across animals than the co-administration of ketamine and isoflurane. Thus, an alfaxalone-based protocol may represent a better approach for neuroimaging in animal models requiring anesthesia.
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Affiliation(s)
- Alexandra T Levine
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, N6A 5C1, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario, N6A 3K7, Canada
| | - Benson Li
- Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada
| | - Paisley Barnes
- Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Stephen G Lomber
- Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada; Department of Physiology & Pharmacology, University of Western Ontario, London, Ontario, N6A 5C1, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario, N6A 3K7, Canada; National Centre for Audiology, University of Western Ontario, London, Ontario, N6G 1H1, Canada
| | - Blake E Butler
- Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario, N6A 3K7, Canada; National Centre for Audiology, University of Western Ontario, London, Ontario, N6G 1H1, Canada.
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6
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Mandino F, Cerri DH, Garin CM, Straathof M, van Tilborg GAF, Chakravarty MM, Dhenain M, Dijkhuizen RM, Gozzi A, Hess A, Keilholz SD, Lerch JP, Shih YYI, Grandjean J. Animal Functional Magnetic Resonance Imaging: Trends and Path Toward Standardization. Front Neuroinform 2020; 13:78. [PMID: 32038217 PMCID: PMC6987455 DOI: 10.3389/fninf.2019.00078] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/19/2019] [Indexed: 12/21/2022] Open
Abstract
Animal whole-brain functional magnetic resonance imaging (fMRI) provides a non-invasive window into brain activity. A collection of associated methods aims to replicate observations made in humans and to identify the mechanisms underlying the distributed neuronal activity in the healthy and disordered brain. Animal fMRI studies have developed rapidly over the past years, fueled by the development of resting-state fMRI connectivity and genetically encoded neuromodulatory tools. Yet, comparisons between sites remain hampered by lack of standardization. Recently, we highlighted that mouse resting-state functional connectivity converges across centers, although large discrepancies in sensitivity and specificity remained. Here, we explore past and present trends within the animal fMRI community and highlight critical aspects in study design, data acquisition, and post-processing operations, that may affect the results and influence the comparability between studies. We also suggest practices aimed to promote the adoption of standards within the community and improve between-lab reproducibility. The implementation of standardized animal neuroimaging protocols will facilitate animal population imaging efforts as well as meta-analysis and replication studies, the gold standards in evidence-based science.
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Affiliation(s)
- Francesca Mandino
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Domenic H. Cerri
- Center for Animal MRI, Department of Neurology, Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Clement M. Garin
- Direction de la Recherche Fondamentale, MIRCen, Institut de Biologie François Jacob, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Milou Straathof
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Geralda A. F. van Tilborg
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - M. Mallar Chakravarty
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
- Department of Biological and Biomedical Engineering, Douglas Mental Health University Institute, McGill University, Montreal, QC, Canada
| | - Marc Dhenain
- Direction de la Recherche Fondamentale, MIRCen, Institut de Biologie François Jacob, Commissariat à l’Énergie Atomique et aux Énergies Alternatives, Fontenay-aux-Roses, France
- Neurodegenerative Diseases Laboratory, Centre National de la Recherche Scientifique, UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Rick M. Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Alessandro Gozzi
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Centre for Neuroscience and Cognitive Systems @ UNITN, Rovereto, Italy
| | - Andreas Hess
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich–Alexander University Erlangen–Nürnberg, Erlangen, Germany
| | - Shella D. Keilholz
- Department of Biomedical Engineering, Georgia Tech, Emory University, Atlanta, GA, United States
| | - Jason P. Lerch
- Hospital for Sick Children, Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Wellcome Centre for Integrative NeuroImaging, University of Oxford, Oxford, United Kingdom
| | - Yen-Yu Ian Shih
- Center for Animal MRI, Department of Neurology, Biomedical Research Imaging Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Joanes Grandjean
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, Singapore
- Department of Radiology and Nuclear Medicine, Donders Institute for Brain, Cognition, and Behaviour, Donders Institute, Radboud University Medical Center, Nijmegen, Netherlands
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7
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Dopfel D, Zhang N. Mapping stress networks using functional magnetic resonance imaging in awake animals. Neurobiol Stress 2018; 9:251-263. [PMID: 30450389 PMCID: PMC6234259 DOI: 10.1016/j.ynstr.2018.06.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 05/27/2018] [Accepted: 06/26/2018] [Indexed: 12/15/2022] Open
Abstract
The neurobiology of stress is studied through behavioral neuroscience, endocrinology, neuronal morphology and neurophysiology. There is a shift in focus toward progressive changes throughout stress paradigms and individual susceptibility to stress that requires methods that allow for longitudinal study design and study of individual differences in stress response. Functional magnetic resonance imaging (fMRI), with the advantages of noninvasiveness and a large field of view, can be used for functionally mapping brain-wide regions and circuits critical to the stress response, making it suitable for longitudinal studies and understanding individual variability of short-term and long-term consequences of stress exposure. In addition, fMRI can be applied to both animals and humans, which is highly valuable in translating findings across species and examining whether the physiology and neural circuits involved in the stress response are conserved in mammals. However, compared to human fMRI studies, there are a number of factors that are essential for the success of fMRI studies in animals. This review discussed the use of fMRI in animal studies of stress. It reviewed advantages, challenges and technical considerations of the animal fMRI methodology as well as recent literature of stress studies using fMRI in animals. It also highlighted the development of combining fMRI with other methods and the future potential of fMRI in animal studies of stress. We conclude that animal fMRI studies, with their flexibility, low cost and short time frame compared to human studies, are crucial to advancing our understanding of the neurobiology of stress.
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Affiliation(s)
- David Dopfel
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Nanyin Zhang
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
- The Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA
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8
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Ma Z, Ma Y, Zhang N. Development of brain-wide connectivity architecture in awake rats. Neuroimage 2018; 176:380-389. [PMID: 29738909 DOI: 10.1016/j.neuroimage.2018.05.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 05/02/2018] [Indexed: 12/13/2022] Open
Abstract
Childhood and adolescence are both critical developmental periods, evidenced by complex neurophysiological changes the brain undergoes and high occurrence rates of neuropsychiatric disorders during these periods. Despite substantial progress in elucidating the developmental trajectories of individual neural circuits, our knowledge of developmental changes of whole-brain connectivity architecture in animals is sparse. To fill this gap, here we longitudinally acquired rsfMRI data in awake rats during five developmental stages from juvenile to adulthood. We found that the maturation timelines of brain circuits were heterogeneous and system specific. Functional connectivity (FC) tended to decrease in subcortical circuits, but increase in cortical circuits during development. In addition, the developing brain exhibited hemispheric functional specialization, evidenced by reduced inter-hemispheric FC between homotopic regions, and lower similarity of region-to-region FC patterns between the two hemispheres. Finally, we showed that whole-brain network development was characterized by reduced clustering (i.e. local communication) but increased integration (distant communication). Taken together, the present study has systematically characterized the development of brain-wide connectivity architecture from juvenile to adulthood in awake rats. It also serves as a critical reference point for understanding circuit- and network-level changes in animal models of brain development-related disorders. Furthermore, FC data during brain development in awake rodents contain high translational value and can shed light onto comparative neuroanatomy.
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Affiliation(s)
- Zilu Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yuncong Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
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9
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Pérez-Cervera L, Caramés JM, Fernández-Mollá LM, Moreno A, Fernández B, Pérez-Montoyo E, Moratal D, Canals S, Pacheco-Torres J. Mapping Functional Connectivity in the Rodent Brain Using Electric-Stimulation fMRI. Methods Mol Biol 2018; 1718:117-134. [PMID: 29341006 DOI: 10.1007/978-1-4939-7531-0_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Since its discovery in the early 90s, BOLD signal-based functional Magnetic Resonance Imaging (fMRI) has become a fundamental technique for the study of brain activity in basic and clinical research. Functional MRI signals provide an indirect but robust and quantitative readout of brain activity through the tight coupling between cerebral blood flow and neuronal activation, the so-called neurovascular coupling. Combined with experimental techniques only available in animal models, such as intracerebral micro-stimulation, optogenetics or pharmacogenetics, provides a powerful framework to investigate the impact of specific circuit manipulations on overall brain dynamics. The purpose of this chapter is to provide a comprehensive protocol to measure brain activity using fMRI with intracerebral electric micro-stimulation in murine models. Preclinical research (especially in rodents) opens the door to very sophisticated and informative experiments, but at the same time imposes important constrains (i.e., anesthetics, translatability), some of which will be addressed here.
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Affiliation(s)
- Laura Pérez-Cervera
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
| | - José María Caramés
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
| | | | - Andrea Moreno
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Valencia, 46022, Spain
| | - Begoña Fernández
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
| | - Elena Pérez-Montoyo
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
| | - David Moratal
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Valencia, 46022, Spain
| | - Santiago Canals
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain
| | - Jesús Pacheco-Torres
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Sant Joan d'Alacant, 03550, Spain.
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10
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Yen CCC, Papoti D, Silva AC. Investigating the spatiotemporal characteristics of the deoxyhemoglobin-related and deoxyhemoglobin-unrelated functional hemodynamic response across cortical layers in awake marmosets. Neuroimage 2018; 164:121-130. [PMID: 28274833 PMCID: PMC5587354 DOI: 10.1016/j.neuroimage.2017.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 01/05/2023] Open
Abstract
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) has become a major tool to map neural activity. However, the spatiotemporal characteristics of the BOLD functional hemodynamic response across the cortical layers remain poorly understood. While human fMRI studies suffer from low spatiotemporal resolution, the use of anesthesia in animal models introduces confounding factors. Additionally, inflow contributions to the fMRI signal become non-negligible when short repetition times (TRs) are used. In the present work, we mapped the BOLD fMRI response to somatosensory stimulation in awake marmosets. To address the above technical concerns, we used a dual-echo gradient-recalled echo planar imaging (GR-EPI) sequence to separate the deoxyhemoglobin-related response (absolute T2* differences) from the deoxyhemoglobin-unrelated response (relative S0 changes). We employed a spatial saturation pulse to saturate incoming arterial spins and reduce inflow effects. Functional GR-EPI images were obtained from a single coronal slice with two different echo times (13.5 and 40.5ms) and TR=0.2s. BOLD, T2*, and S0 images were calculated and their functional responses were detected in both hemispheres of primary somatosensory cortex, from which five laminar regions (L1+2, L3, L4, L5, and L6) were derived. The spatiotemporal distribution of the BOLD response across the cortical layers was heterogeneous, with the middle layers having the highest BOLD amplitudes and shortest onset times. ΔT2* also showed a similar trend. However, functional S0 changes were detected only in L1+2, with a fast onset time. Because inflow effects were minimized, the source of S0 functional changes in L1+2 could be attributed to a reduction of cerebrospinal fluid volume fraction due to the functional increase in cerebral blood volume and to unmodeled T2* changes in the extra- and intra-venous compartments. Caution should be exercised when interpreting laminar BOLD fMRI changes in superficial layers as surrogates of underlying neural activity.
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Affiliation(s)
- Cecil Chern-Chyi Yen
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel Papoti
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Afonso C Silva
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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Pérez PD, Ma Z, Hamilton C, Sánchez C, Mørk A, Pehrson AL, Bundgaard C, Zhang N. Acute effects of vortioxetine and duloxetine on resting-state functional connectivity in the awake rat. Neuropharmacology 2017; 128:379-387. [PMID: 29104073 DOI: 10.1016/j.neuropharm.2017.10.038] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 10/25/2017] [Accepted: 10/28/2017] [Indexed: 12/21/2022]
Abstract
The antidepressant vortioxetine exerts its effects via modulation of several serotonin (5-HT) receptors and inhibition of the 5-HT transporter (SERT). Additionally, vortioxetine has beneficial effects on aspects of cognitive dysfunction in depressed patients. However, a global examination of the drug effect on brain network connectivity is still missing. Here we compared the effects of vortioxetine and a serotonin norepinephrine reuptake inhibitor, duloxetine, on resting-state functional connectivity (RSFC) across the whole brain in awake rats using a combination of pharmacological and awake animal resting-state functional magnetic resonance imaging (rsfMRI) techniques. Our data showed that vortioxetine and duloxetine affected different inter-areal connections with limited overlap, indicating that in addition to different primary target profiles, these two antidepressants have distinct mechanisms of action at the systems level. Further, our data suggest that vortioxetine can affect specific brain areas with distinct 5-HT receptor expression profiles. Taken together, this study demonstrates that the awake animal fMRI approach provides a powerful tool to elucidate the effects of drugs on the brain with high spatial specificity and a global field of view. This capability is valuable to understand how different drugs affect the systems-level brain function, and provides important guidance to dissect specific brain regions and connections for further detailed mechanistic studies. This study also highlights the translational opportunity of the awake animal fMRI approach between preclinical results and human studies.
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Affiliation(s)
- Pablo D Pérez
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Zhiwei Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Christina Hamilton
- The Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | | | - Arne Mørk
- H. Lundbeck A/S, Copenhagen, Denmark
| | | | | | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA; The Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, USA.
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12
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Van Den Berge N, Albaugh DL, Salzwedel A, Vanhove C, Van Holen R, Gao W, Stuber GD, Shih YYI. Functional circuit mapping of striatal output nuclei using simultaneous deep brain stimulation and fMRI. Neuroimage 2017; 146:1050-1061. [PMID: 27825979 PMCID: PMC5322177 DOI: 10.1016/j.neuroimage.2016.10.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/08/2016] [Accepted: 10/31/2016] [Indexed: 01/11/2023] Open
Abstract
The substantia nigra pars reticulata (SNr) and external globus pallidus (GPe) constitute the two major output targets of the rodent striatum. Both the SNr and GPe converge upon thalamic relay nuclei (directly or indirectly, respectively), and are traditionally modeled as functionally antagonistic relay inputs. However, recent anatomical and functional studies have identified unanticipated circuit connectivity in both the SNr and GPe, demonstrating their potential as far more than relay nuclei. In the present study, we employed simultaneous deep brain stimulation and functional magnetic resonance imaging (DBS-fMRI) with cerebral blood volume (CBV) measurements to functionally and unbiasedly map the circuit- and network level connectivity of the SNr and GPe. Sprague-Dawley rats were implanted with a custom-made MR-compatible stimulating electrode in the right SNr (n=6) or GPe (n=7). SNr- and GPe-DBS, conducted across a wide range of stimulation frequencies, revealed a number of surprising evoked responses, including unexpected CBV decreases within the striatum during DBS at either target, as well as GPe-DBS-evoked positive modulation of frontal cortex. Functional connectivity MRI revealed global modulation of neural networks during DBS at either target, sensitive to stimulation frequency and readily reversed following cessation of stimulation. This work thus contributes to a growing literature demonstrating extensive and unanticipated functional connectivity among basal ganglia nuclei.
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Affiliation(s)
- Nathalie Van Den Berge
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, USA; Medical Image and Signal Processing Group, Ghent University, Ghent, Belgium
| | - Daniel L Albaugh
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, USA; Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC, USA
| | - Andrew Salzwedel
- Biomedical Imaging Research Institute, Department of Biomedical Sciences and Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Christian Vanhove
- Medical Image and Signal Processing Group, Ghent University, Ghent, Belgium
| | - Roel Van Holen
- Medical Image and Signal Processing Group, Ghent University, Ghent, Belgium
| | - Wei Gao
- Biomedical Imaging Research Institute, Department of Biomedical Sciences and Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Garret D Stuber
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC, USA; Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, USA; Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC, USA; Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA.
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13
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Tilbrook AJ, Ralph CR. Neurophysiological assessment of animal welfare. ANIMAL PRODUCTION SCIENCE 2017. [DOI: 10.1071/an17312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Livestock industries such as the pork industry are striving to continuously improve the welfare of animals. Inherent to the success of this is the ability to rigorously assess the welfare of animals in the field. While much progress has been made towards the development of methodology to assess the welfare of animals, there have been major challenges to establishing practical and definitive procedures to assess the welfare of animals. These include, but are not limited to, establishing a universally accepted definition of animal welfare and the choice of measures that are taken from the animal to assess its welfare. Measures of biological functioning and affective (emotional) state of the animal have been common, but there have been many limitations in terms of practical application. Some of the reasons for this include the choice of physiological measures, which are often restrictive in providing information about welfare, affective measures being restricted to specific behavioural measures and the biological-functioning and affective-states approaches being undertaken in isolation. Biological and affective functioning are integrated and controlled by the brain. Many of the regions of the brain involved in the regulation of biological and emotional functioning have been identified. Furthermore, there is considerable knowledge about the roles and interactions among the neurophysiological systems in these brain regions. We propose a strategy to use this knowledge to develop procedures to assess animal welfare. The initial phase is to identify the neural pathways that regulate the physiological and emotional processes that allow animals to adapt and cope. The next phase is to determine the activity of these pathways in conscious animals in the field. This requires the identification of biomarkers of specific neuronal activity that can be measured in the conscious animal in the field. Emerging technologies are offering promise in the identification of such biomarkers and some of these are already applicable to the pig. There is now the opportunity to apply this strategy within the pork industry to assess the welfare of pigs throughout the value chain.
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14
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Gao YR, Ma Y, Zhang Q, Winder AT, Liang Z, Antinori L, Drew PJ, Zhang N. Time to wake up: Studying neurovascular coupling and brain-wide circuit function in the un-anesthetized animal. Neuroimage 2016; 153:382-398. [PMID: 27908788 PMCID: PMC5526447 DOI: 10.1016/j.neuroimage.2016.11.069] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 11/18/2016] [Accepted: 11/27/2016] [Indexed: 01/08/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) has allowed the noninvasive study of task-based and resting-state brain dynamics in humans by inferring neural activity from blood-oxygenation-level dependent (BOLD) signal changes. An accurate interpretation of the hemodynamic changes that underlie fMRI signals depends on the understanding of the quantitative relationship between changes in neural activity and changes in cerebral blood flow, oxygenation and volume. While there has been extensive study of neurovascular coupling in anesthetized animal models, anesthesia causes large disruptions of brain metabolism, neural responsiveness and cardiovascular function. Here, we review work showing that neurovascular coupling and brain circuit function in the awake animal are profoundly different from those in the anesthetized state. We argue that the time is right to study neurovascular coupling and brain circuit function in the awake animal to bridge the physiological mechanisms that underlie animal and human neuroimaging signals, and to interpret them in light of underlying neural mechanisms. Lastly, we discuss recent experimental innovations that have enabled the study of neurovascular coupling and brain-wide circuit function in un-anesthetized and behaving animal models.
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Affiliation(s)
- Yu-Rong Gao
- Neuroscience Graduate Program, Pennsylvania State University, University Park, PA 16802, Unidted States; Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Yuncong Ma
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Aaron T Winder
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Zhifeng Liang
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Lilith Antinori
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, Unidted States
| | - Patrick J Drew
- Neuroscience Graduate Program, Pennsylvania State University, University Park, PA 16802, Unidted States; Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802, Unidted States; Department of Neurosurgery, Pennsylvania State University, University Park, PA 16802, Unidted States; Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, Unidted States.
| | - Nanyin Zhang
- Neuroscience Graduate Program, Pennsylvania State University, University Park, PA 16802, Unidted States; Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, Unidted States.
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15
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Yoshida K, Mimura Y, Ishihara R, Nishida H, Komaki Y, Minakuchi T, Tsurugizawa T, Mimura M, Okano H, Tanaka KF, Takata N. Physiological effects of a habituation procedure for functional MRI in awake mice using a cryogenic radiofrequency probe. J Neurosci Methods 2016; 274:38-48. [PMID: 27702586 DOI: 10.1016/j.jneumeth.2016.09.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/26/2016] [Accepted: 09/30/2016] [Indexed: 01/02/2023]
Abstract
BACKGROUND Functional magnetic resonance imaging (fMRI) in mice is typically performed under anesthesia due to difficulties in holding the head of awake mice stably with a conventional three-point fixation method that uses a tooth-bar and earplugs. Although some studies have succeeded in fMRI in awake mice by attaching a head-post on the skull, this cannot be applied to fMRI using a high signal-to-noise ratio (SNR) cryogenic MRI-detector, CryoProbe, because it covers the head of a mouse closely. NEW METHOD We developed head-fixation implements for awake mice that are applicable to fMRI using CryoProbe. RESULTS A head-bar was surgically attached to the skull of a mouse that was then habituated to a mock fMRI-environment, two hours/day for eight days with physiological examinations of body-weight, fecal weight, electromyogram (EMG), and electrocardiogram. EMG power decreased with just one day of habituation, whereas heart rate decreased after at least seven days of habituation. Estimated head motions of awake mice during fMRI were significantly smaller than a voxel size. Unexpectedly, temporal SNR of fMRI signals for awake mice was higher than that for anesthetized mice held by a conventional method. Functional connectivity in the brain of both anesthetized and awake mice showed bilateral and unilateral networks. COMPARISON WITH EXISTING METHOD(S): fMRI using CryoProbe had been performed on anesthetized mice previously. Our method does not use anesthetics during habituation or fMRI. CONCLUSION Our method would be beneficial for translational research using fMRI in mice and humans because human fMRI is typically performed without anesthetics.
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Affiliation(s)
- Keitaro Yoshida
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Yu Mimura
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Ryosuke Ishihara
- Department of Physiology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Hiroshi Nishida
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Yuji Komaki
- Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki, Kanagawa 210-0821, Japan
| | - Tomohito Minakuchi
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Tomokazu Tsurugizawa
- NeuroSpin, Commissariat à l'Energie Atomique et aux Energies Alternatives, 91191 Gif-sur-Yvette, France
| | - Masaru Mimura
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- Department of Physiology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
| | - Norio Takata
- Department of Neuropsychiatry, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan; Central Institute for Experimental Animals (CIEA), 3-25-12 Tonomachi, Kawasaki, Kanagawa 210-0821, Japan.
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16
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Low LA, Bauer LC, Pitcher MH, Bushnell MC. Restraint training for awake functional brain scanning of rodents can cause long-lasting changes in pain and stress responses. Pain 2016; 157:1761-1772. [PMID: 27058679 PMCID: PMC4949008 DOI: 10.1097/j.pain.0000000000000579] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 03/28/2016] [Accepted: 03/31/2016] [Indexed: 01/13/2023]
Abstract
With the increased interest in longitudinal brain imaging of awake rodents, it is important to understand both the short-term and long-term effects of restraint on sensory and emotional processing in the brain. To understand the effects of repeated restraint on pain behaviors and stress responses, we modeled a restraint protocol similar to those used to habituate rodents for magnetic resonance imaging scanning, and studied sensory sensitivity and stress hormone responses over 5 days. To uncover lasting effects of training, we also looked at responses to the formalin pain test 2 weeks later. We found that while restraint causes acute increases in the stress hormone corticosterone, it can also cause lasting reductions in nociceptive behavior in the formalin test, coupled with heightened corticosterone levels and increased activation of the "nociceptive" central nucleus of the amygdala, as seen by Fos protein expression. These results suggest that short-term repeated restraint, similar to that used to habituate rats for awake functional brain scanning, could potentially cause long-lasting changes in physiological and brain responses to pain stimuli that are stress-related, and therefore could potentially confound the functional activation patterns seen in awake rodents in response to pain stimuli.
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Affiliation(s)
- Lucie A. Low
- Laboratory of Pain and Integrative Neuroscience, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Lucy C. Bauer
- Laboratory of Pain and Integrative Neuroscience, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - Mark H. Pitcher
- Laboratory of Pain and Integrative Neuroscience, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
| | - M. Catherine Bushnell
- Laboratory of Pain and Integrative Neuroscience, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA
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17
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Chang PC, Procissi D, Bao Q, Centeno MV, Baria A, Apkarian AV. Novel method for functional brain imaging in awake minimally restrained rats. J Neurophysiol 2016; 116:61-80. [PMID: 27052584 DOI: 10.1152/jn.01078.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 04/05/2016] [Indexed: 11/22/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) in rodents holds great promise for advancing our knowledge about human brain function. However, the use of anesthetics to immobilize rodents during fMRI experiments has restricted the type of questions that can be addressed using this technique. Here we describe an innovative procedure to train rats to be constrained without the need of any anesthesia during the whole procedure. We show that with 8-10 days of acclimation rats can be conscious and remain still during fMRI experiments under minimal stress. In addition, we provide fMRI results of conscious rodents in a variety of commonly used fMRI experimental paradigms, and we demonstrate the improved quality of these scans by comparing results when the same rodents were scanned under anesthesia. We confirm that the awake scanning procedure permits an improved evaluation of brain networks and brain response to external stimuli with minimal movement artifact. The present study further advances the field of fMRI in awake rodents, which provide more direct, forward and reverse, translational opportunities regarding brain functional correspondences between human and rodent research.
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Affiliation(s)
- Pei-Ching Chang
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Daniel Procissi
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and
| | - Qiyuan Bao
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Maria Virginia Centeno
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Alex Baria
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - A Vania Apkarian
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois;
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18
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Harris AP, Lennen RJ, Brydges NM, Jansen MA, Pernet CR, Whalley HC, Marshall I, Baker S, Basso AM, Day M, Holmes MC, Hall J. The role of brain-derived neurotrophic factor in learned fear processing: an awake rat fMRI study. GENES BRAIN AND BEHAVIOR 2016; 15:221-30. [PMID: 26586578 PMCID: PMC4819698 DOI: 10.1111/gbb.12277] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/04/2015] [Accepted: 11/17/2015] [Indexed: 12/12/2022]
Abstract
Brain‐derived neurotrophic factor (BDNF) signaling is implicated in the etiology of many psychiatric disorders associated with altered emotional processing. Altered peripheral (plasma) BDNF levels have been proposed as a biomarker for neuropsychiatric disease risk in humans. However, the relationship between peripheral and central BDNF levels and emotional brain activation is unknown. We used heterozygous BDNF knockdown rats (BDNF+/−) to examine the effects of genetic variation in the BDNF gene on peripheral and central BDNF levels and emotional brain activation as assessed by awake functional magnetic resonance imaging (fMRI). BDNF+/− and control rats were trained to associate a flashing light (conditioned stimulus; CS) with foot‐shock, and brain activation in response to the CS was measured 24 h later in awake rats using fMRI. Central and peripheral BDNF levels were decreased in BDNF+/− rats compared with control rats. Activation of fear circuitry (amygdala, periaqueductal gray, granular insular) was seen in control animals; however, activation of this circuitry was absent in BDNF+/− animals. Behavioral experiments confirmed impaired conditioned fear responses in BDNF+/− rats, despite intact innate fear responses. These data confirm a positive correlation [r = 0.86, 95% confidence interval (0.55, 0.96); P = 0.0004] between peripheral and central BDNF levels and indicate a functional relationship between BDNF levels and emotional brain activation as assessed by fMRI. The results demonstrate the use of rodent fMRI as a sensitive tool for measuring brain function in preclinical translational studies using genetically modified rats and support the use of peripheral BDNF as a biomarker of central affective processing.
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Affiliation(s)
- A P Harris
- University/BHF Centre for Cardiovascular Sciences.,Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
| | - R J Lennen
- University/BHF Centre for Cardiovascular Sciences
| | - N M Brydges
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - M A Jansen
- University/BHF Centre for Cardiovascular Sciences
| | - C R Pernet
- Centre for Clinical Brain Sciences (CCBS) Neuroimaging Sciences
| | - H C Whalley
- Division of Psychiatry, Royal Edinburgh Hospital, University of Edinburgh, Edinbugh, UK
| | - I Marshall
- University/BHF Centre for Cardiovascular Sciences.,Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences (CCBS) Neuroimaging Sciences
| | - S Baker
- AbbVie, Translational Sciences-Imaging, North Chicago, IL, USA
| | - A M Basso
- AbbVie, Translational Sciences-Imaging, North Chicago, IL, USA
| | - M Day
- Alexion Pharmaceuticals, Cheshire, CT, USA
| | - M C Holmes
- University/BHF Centre for Cardiovascular Sciences.,Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
| | - J Hall
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
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19
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Miller B, Lim AN, Heidbreder AF, Black KJ. An Automated Motion Detection and Reward System for Animal Training. Cureus 2015; 7:e397. [PMID: 26798573 PMCID: PMC4699987 DOI: 10.7759/cureus.397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
A variety of approaches has been used to minimize head movement during functional brain imaging studies in awake laboratory animals. Many laboratories expend substantial effort and time training animals to remain essentially motionless during such studies. We could not locate an “off-the-shelf” automated training system that suited our needs. We developed a time- and labor-saving automated system to train animals to hold still for extended periods of time. The system uses a personal computer and modest external hardware to provide stimulus cues, monitor movement using commercial video surveillance components, and dispense rewards. A custom computer program automatically increases the motionless duration required for rewards based on performance during the training session but allows changes during sessions. This system was used to train cynomolgus monkeys (Macaca fascicularis) for awake neuroimaging studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). The automated system saved the trainer substantial time, presented stimuli and rewards in a highly consistent manner, and automatically documented training sessions. We have limited data to prove the training system's success, drawn from the automated records during training sessions, but we believe others may find it useful. The system can be adapted to a range of behavioral training/recording activities for research or commercial applications, and the software is freely available for non-commercial use.
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Affiliation(s)
- Brad Miller
- Psychiatry, Washington University School of Medicine
| | - Audrey N Lim
- Psychiatry, Washington University School of Medicine
| | | | - Kevin J Black
- Departments of Psychiatry, Neurology, Radiology, and Anatomy & Neurobiology, Washington University School of Medicine
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20
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Harris AP, Lennen RJ, Marshall I, Jansen MA, Pernet CR, Brydges NM, Duguid IC, Holmes MC. Imaging learned fear circuitry in awake mice using fMRI. Eur J Neurosci 2015; 42:2125-34. [PMID: 25943794 PMCID: PMC4744695 DOI: 10.1111/ejn.12939] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/20/2015] [Accepted: 04/30/2015] [Indexed: 01/04/2023]
Abstract
Functional magnetic resonance imaging (fMRI) of learned behaviour in ‘awake rodents’ provides the opportunity for translational preclinical studies into the influence of pharmacological and genetic manipulations on brain function. fMRI has recently been employed to investigate learned behaviour in awake rats. Here, this methodology is translated to mice, so that future fMRI studies may exploit the vast number of genetically modified mouse lines that are available. One group of mice was conditioned to associate a flashing light (conditioned stimulus, CS) with foot shock (PG; paired group), and another group of mice received foot shock and flashing light explicitly unpaired (UG; unpaired group). The blood oxygen level‐dependent signal (proxy for neuronal activation) in response to the CS was measured 24 h later in awake mice from the PG and UG using fMRI. The amygdala, implicated in fear processing, was activated to a greater degree in the PG than in the UG in response to the CS. Additionally, the nucleus accumbens was activated in the UG in response to the CS. Because the CS signalled an absence of foot shock in the UG, it is possible that this region is involved in processing the safety aspect of the CS. To conclude, the first use of fMRI to visualise brain activation in awake mice that are completing a learned emotional task is reported. This work paves the way for future preclinical fMRI studies to investigate genetic and environmental influences on brain function in transgenic mouse models of disease and aging.
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Affiliation(s)
- Anjanette P Harris
- BHF Centre for Cardiovascular Sciences, QMRI, University of Edinburgh, Edinburgh, EH16 4TJ, UK.,Centre for Cognitive Ageing and Cognitive Epidemiology, QMRI, University of Edinburgh, Edinburgh, UK
| | - Ross J Lennen
- BHF Centre for Cardiovascular Sciences, QMRI, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Ian Marshall
- Centre for Cognitive Ageing and Cognitive Epidemiology, QMRI, University of Edinburgh, Edinburgh, UK.,Neuroimaging Sciences, Centre for Clinical Brain Sciences, Edinburgh, UK
| | - Maurits A Jansen
- BHF Centre for Cardiovascular Sciences, QMRI, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Cyril R Pernet
- Neuroimaging Sciences, Centre for Clinical Brain Sciences, Edinburgh, UK
| | - Nichola M Brydges
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK
| | - Ian C Duguid
- Integrative Physics, University of Edinburgh, Edinburgh, UK
| | - Megan C Holmes
- BHF Centre for Cardiovascular Sciences, QMRI, University of Edinburgh, Edinburgh, EH16 4TJ, UK.,Centre for Cognitive Ageing and Cognitive Epidemiology, QMRI, University of Edinburgh, Edinburgh, UK
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21
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Bruijnzeel AW, Alexander JC, Perez PD, Bauzo-Rodriguez R, Hall G, Klausner R, Guerra V, Zeng H, Igari M, Febo M. Acute nicotine administration increases BOLD fMRI signal in brain regions involved in reward signaling and compulsive drug intake in rats. Int J Neuropsychopharmacol 2014; 18:pyu011. [PMID: 25552431 PMCID: PMC4368882 DOI: 10.1093/ijnp/pyu011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Acute nicotine administration potentiates brain reward function and enhances motor and cognitive function. These studies investigated which brain areas are being activated by a wide range of doses of nicotine, and if this is diminished by pretreatment with the nonselective nicotinic receptor antagonist mecamylamine. METHODS Drug-induced changes in brain activity were assessed by measuring changes in the blood oxygen level dependent (BOLD) signal using an 11.1-Tesla magnetic resonance scanner. In the first experiment, nicotine naïve rats were mildly anesthetized and the effect of nicotine (0.03-0.6 mg/kg) on the BOLD signal was investigated for 10 min. In the second experiment, the effect of mecamylamine on nicotine-induced brain activity was investigated. RESULTS A high dose of nicotine increased the BOLD signal in brain areas implicated in reward signaling, such as the nucleus accumbens shell and the prelimbic area. Nicotine also induced a dose-dependent increase in the BOLD signal in the striato-thalamo-orbitofrontal circuit, which plays a role in compulsive drug intake, and in the insular cortex, which contributes to nicotine craving and relapse. In addition, nicotine induced a large increase in the BOLD signal in motor and somatosensory cortices. Mecamylamine alone did not affect the BOLD signal in most brain areas, but induced a negative BOLD response in cortical areas, including insular, motor, and somatosensory cortices. Pretreatment with mecamylamine completely blocked the nicotine-induced increase in the BOLD signal. CONCLUSIONS These studies demonstrate that acute nicotine administration activates brain areas that play a role in reward signaling, compulsive behavior, and motor and cognitive function.
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Affiliation(s)
| | | | - Pablo D. Perez
- * These two authors equally contributed to the present work
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22
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Shah L, Kulkarni P, Ferris C, Amiji MM. Analgesic efficacy and safety of DALDA peptide analog delivery to the brain using oil-in-water nanoemulsion formulation. Pharm Res 2014; 31:2724-34. [PMID: 24792826 DOI: 10.1007/s11095-014-1370-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/21/2014] [Indexed: 01/15/2023]
Abstract
PURPOSE The main objective of this study was to develop and evaluate therapeutic efficacy and safety following systemic delivery of a peptide analgesic into the CNS using an oil-in-water nanoemulsion system. METHODS We have formulated a safe and effective, omega-3 rich polyunsaturated fatty acid containing oil-in-water nanoemulsion formulation, for encapsulating and delivering chemically-modified DALDA, a potent mu-opioid peptide analogue, to the CNS. One of the challenges with CNS delivery is the lack of a non-invasive bioanalytical technique to confirm CNS uptake and therapeutic efficacy. Using blood oxygen-level dependent (BOLD) functional magenetic resonance imaging (fMRI), we provide quantitative evidence of nanoemulsion-based delivery and analgesic activity of DALDA analogue in capsaicin-induced awake rat model of pain. RESULTS Nanoemulsion formulation effectively encapsulated the modified analgesic peptide and demonstrated efficacy in the capsaicin- pain induced functional magnetic resonance imaging model in rodents. Preliminary safety evaluations show that the nanoemulsion system was well tolerated and did not cause any acute negative effects. CONCLUSIONS Overall, these results show tremendous opportunity for the development of modified peptide analgesic-encapsulated nanoemulsion formulations for CNS delivery and therapeutic efficacy.
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Affiliation(s)
- Lipa Shah
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, 02115, USA
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23
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Advancing the discovery of medications for autism spectrum disorder using new technologies to reveal social brain circuitry in rodents. Psychopharmacology (Berl) 2014; 231:1147-65. [PMID: 24522332 DOI: 10.1007/s00213-014-3464-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 01/21/2014] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition characterized by core differences and impairments in social behavioral functioning. There are no approved medications for improving social cognition and behavior in ASD, and the underlying mechanisms needed to discover safer, more effective medications are unclear. DISCUSSION In this review, we diagram the basic neurocircuitry governing social behaviors in order to provide a neurobiological framework for the origins of the core social behavioral symptoms of ASD. In addition, we discuss recent technological innovations in research tools that provide unprecedented observation of cellular morphology and activity deep within the intact brain and permit the precise control of discrete brain regions and specific cell types at distinct developmental stages. CONCLUSIONS The use of new technologies to reveal the neural circuits underlying social behavioral impairments associated with ASD is advancing our understanding of the brain changes underlying ASD and enabling the discovery of novel and effective therapeutic interventions.
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Effects of anesthesia and species on the uptake or binding of radioligands in vivo in the Göttingen minipig. BIOMED RESEARCH INTERNATIONAL 2013; 2013:808713. [PMID: 24083242 PMCID: PMC3780537 DOI: 10.1155/2013/808713] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/15/2013] [Accepted: 07/15/2013] [Indexed: 01/22/2023]
Abstract
Progress in neuroscience research often involves animals, as no adequate alternatives exist to animal models of living systems. However, both the physiological characteristics of the species used and the effects of anesthesia raise questions of common concern. Here, we demonstrate the confounding influences of these effects on tracer binding in positron emission tomography (PET). We determined the effects of two routinely used anesthetics (isoflurane and propofol) on the binding of two tracers of monoamine function, [11C]SCH23390, a tracer of the dopamine D1 and D5 receptors, and the alpha2-adrenoceptor antagonist, [11C]yohimbine, in Göttingen minipigs. The kinetics of SCH23390 in the pigs differed from those of our earlier studies in primates. With two different graphical analyses of uptake of SCH23390, the initial clearance values of this tracer were higher with isoflurane than with propofol anesthesia, indicative of differences in blood flow, whereas no significant differences were observed for the volumes of distribution of yohimbine. The study underscores the importance of differences of anesthesia and species when the properties of radioligands are evaluated under different circumstances that may affect blood flow and tracer uptake. These differences must be considered in the choice of a particular animal species and mode of anesthesia for a particular application.
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25
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Becerra L, Upadhyay J, Chang PC, Bishop J, Anderson J, Baumgartner R, Schwarz AJ, Coimbra A, Wallin D, Nutile L, George E, Maier G, Sunkaraneni S, Iyengar S, Evelhoch JL, Bleakman D, Hargreaves R, Borsook D. Parallel buprenorphine phMRI responses in conscious rodents and healthy human subjects. J Pharmacol Exp Ther 2013; 345:41-51. [PMID: 23370795 DOI: 10.1124/jpet.112.201145] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pharmacological magnetic resonance imaging (phMRI) is one method by which a drug's pharmacodynamic effects in the brain can be assessed. Although phMRI has been frequently used in preclinical and clinical settings, the extent to which a phMRI signature for a compound translates between rodents and humans has not been systematically examined. In the current investigation, we aimed to build on recent clinical work in which the functional response to 0.1 and 0.2 mg/70 kg i.v. buprenorphine (partial µ-opioid receptor agonist) was measured in healthy humans. Here, we measured the phMRI response to 0.04 and 0.1 mg/kg i.v. buprenorphine in conscious, naive rats to establish the parallelism of the phMRI signature of buprenorphine across species. PhMRI of 0.04 and 0.1 mg/kg i.v. buprenorphine yielded dose-dependent activation in a brain network composed of the somatosensory cortex, cingulate, insula, striatum, thalamus, periaqueductal gray, and cerebellum. Similar dose-dependent phMRI activation was observed in the human phMRI studies. These observations indicate an overall preservation of pharmacodynamic responses to buprenorphine between conscious, naive rodents and healthy human subjects, particularly in brain regions implicated in pain and analgesia. This investigation further demonstrates the usefulness of phMRI as a translational tool in neuroscience research that can provide mechanistic insight and guide dose selection in drug development.
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Affiliation(s)
- Lino Becerra
- Imaging Consortium for Drug Development, P.A.I.N. Group, Harvard Medical School, Children’s Hospital of Boston, Waltham, Massachusetts 02453, USA.
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26
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García-García I, Narberhaus A, Marqués-Iturria I, Garolera M, Rădoi A, Segura B, Pueyo R, Ariza M, Jurado MA. Neural Responses to Visual Food Cues: Insights from Functional Magnetic Resonance Imaging. EUROPEAN EATING DISORDERS REVIEW 2013; 21:89-98. [DOI: 10.1002/erv.2216] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - A. Rădoi
- Neurotraumatology and Neurosurgery Research Unit; Vall d'Hebron Research Institute; Barcelona; Spain
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27
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Brain processing of biologically relevant odors in the awake rat, as revealed by manganese-enhanced MRI. PLoS One 2012; 7:e48491. [PMID: 23119035 PMCID: PMC3485357 DOI: 10.1371/journal.pone.0048491] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 09/26/2012] [Indexed: 11/19/2022] Open
Abstract
Background So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages. Methodology/Principal Findings Odors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex. Conclusion/Significance By providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed.
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28
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Thompson SJ, Bushnell MC. Rodent functional and anatomical imaging of pain. Neurosci Lett 2012; 520:131-9. [PMID: 22445887 DOI: 10.1016/j.neulet.2012.03.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/06/2012] [Accepted: 03/07/2012] [Indexed: 02/07/2023]
Abstract
Human brain imaging has provided much information about pain processing and pain modulation, but brain imaging in rodents can provide information not attainable in human studies. First, the short lifespan of rats and mice, as well as the ability to have homogenous genetics and environments, allows for longitudinal studies of the effects of chronic pain on the brain. Second, brain imaging in animals allows for the testing of central actions of novel pharmacological and nonpharmacological analgesics before they can be tested in humans. The two most commonly used brain imaging methods in rodents are magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI provides better spatial and temporal resolution than PET, but PET allows for the imaging of neurotransmitters and non-neuronal cells, such as astrocytes, in addition to functional imaging. One problem with rodent brain imaging involves methods for keeping the subject still in the scanner. Both anesthetic agents and restraint techniques have potential confounds. Some PET methods allow for tracer uptake before the animal is anesthetized, but imaging a moving animal also has potential confounds. Despite the challenges associated with the various techniques, the 31 studies using either functional MRI or PET to image pain processing in rodents have yielded surprisingly consistent results, with brain regions commonly activated in human pain imaging studies (somatosensory cortex, cingulate cortex, thalamus) also being activated in the majority of these studies. Pharmacological imaging in rodents shows overlapping activation patterns with pain and opiate analgesics, similar to what is found in humans. Despite the many structural imaging studies in human chronic pain patients, only one study has been performed in rodents, but that study confirmed human findings of decreased cortical thickness associated with chronic pain. Future directions in rodent pain imaging include miniaturized PET for the freely moving animal, as well as new MRI techniques that enable ongoing chronic pain imaging.
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Affiliation(s)
- Scott J Thompson
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC H3A 2T5, Canada
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Kulkarni P, Stolberg T, Sullivanjr JM, Ferris CF. Imaging evolutionarily conserved neural networks: preferential activation of the olfactory system by food-related odor. Behav Brain Res 2012; 230:201-7. [PMID: 22343130 DOI: 10.1016/j.bbr.2012.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 01/30/2012] [Accepted: 02/02/2012] [Indexed: 11/17/2022]
Abstract
Rodents routinely forge and rely on hippocampal-dependent spatial memory to guide them to sources of caloric rich food in their environment. Has evolution affected the olfactory system and its connections to the hippocampus and limbic cortex, so rodents have an innate sensitivity to energy rich food and their location? To test this notion, we used functional magnetic resonance imaging in awake rats to observe changes in brain activity in response to four odors: benzaldehyde (almond odor), isoamyl acetate (banana odor), methyl benzoate (rosy odor), and limonene (citrus odor). We chose the almond odor because nuts are high in calories and would be expected to convey greater valance as compared to the other odors. Moreover, the standard food chow is devoid of nuts, so laboratory bred rats would not have any previous exposure to this food. Activation maps derived from computational analysis using a 3D segmented rat MRI atlas were dramatically different between odors. Animals exposed to banana, rosy and citrus odors showed modest activation of the primary olfactory system, hippocampus and limbic cortex. However, animals exposed to almond showed a robust increase in brain activity in the primary olfactory system particularly the main olfactory bulb, anterior olfactory nucleus and tenia tecta. The most significant difference in brain activation between odors was observed in the hippocampus and limbic cortex. These findings show that fMRI can be used to identify neural circuits that have an innate sensitivity to environmental stimuli that may help in an animal's survival.
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Affiliation(s)
- Praveen Kulkarni
- Department of Psychology and Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115-5000, USA
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30
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Upadhyay J, Baker SJ, Chandran P, Miller L, Lee Y, Marek GJ, Sakoglu U, Chin CL, Luo F, Fox GB, Day M. Default-mode-like network activation in awake rodents. PLoS One 2011; 6:e27839. [PMID: 22125628 PMCID: PMC3220684 DOI: 10.1371/journal.pone.0027839] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/26/2011] [Indexed: 01/22/2023] Open
Abstract
During wakefulness and in absence of performing tasks or sensory processing, the default-mode network (DMN), an intrinsic central nervous system (CNS) network, is in an active state. Non-human primate and human CNS imaging studies have identified the DMN in these two species. Clinical imaging studies have shown that the pattern of activity within the DMN is often modulated in various disease states (e.g., Alzheimer's, schizophrenia or chronic pain). However, whether the DMN exists in awake rodents has not been characterized. The current data provides evidence that awake rodents also possess ‘DMN-like’ functional connectivity, but only subsequent to habituation to what is initially a novel magnetic resonance imaging (MRI) environment as well as physical restraint. Specifically, the habituation process spanned across four separate scanning sessions (Day 2, 4, 6 and 8). At Day 8, significant (p<0.05) functional connectivity was observed amongst structures such as the anterior cingulate (seed region), retrosplenial, parietal, and hippocampal cortices. Prior to habituation (Day 2), functional connectivity was only detected (p<0.05) amongst CNS structures known to mediate anxiety (i.e., anterior cingulate (seed region), posterior hypothalamic area, amygdala and parabracial nucleus). In relating functional connectivity between cingulate-default-mode and cingulate-anxiety structures across Days 2-8, a significant inverse relationship (r = −0.65, p = 0.0004) was observed between these two functional interactions such that increased cingulate-DMN connectivity corresponded to decreased cingulate anxiety network connectivity. This investigation demonstrates that the cingulate is an important component of both the rodent DMN-like and anxiety networks.
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Affiliation(s)
- Jaymin Upadhyay
- Translational Sciences, Advanced Technology, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois, United States of America.
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Abstract
Intrinsic connectional architecture of the brain is a crucial element in understanding the governing principle of brain organization. To date, enormous effort has been focused on addressing this issue in humans by combining resting-state functional magnetic resonance imaging (rsfMRI) with other techniques. However, this research area is significantly underexplored in animals, perhaps because of confounding effects of anesthetic agents used in most animal experiments on functional connectivity. To bridge this gap, we have systematically investigated the intrinsic connectional architecture in the rodent brain by using a previously established awake-animal imaging model. First, group independent component analysis was applied to the rsfMRI data to extract elementary functional clusters of the brain. The connectional relationships between these clusters, as evaluated by partial correlation analysis, were then used to construct a graph of whole-brain neural network. This network exhibited the typical features of small-worldness and strong community structures seen in the human brain. Finally, the whole-brain network was segregated into community structures using a graph-based analysis. The results of this work provided a functional atlas of intrinsic connectional architecture of the rat brain at both intraregion and interregion levels. More importantly, the current work revealed that functional networks in rats are organized in a nontrivial manner and conserve fundamental topological properties that are also seen in the human brain. Given the high psychopathological relevance of network organization of the brain, this study demonstrated the feasibility of studying mechanisms and therapies of multiple neurological and psychiatric diseases through translational research.
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Schulz D, Southekal S, Junnarkar SS, Pratte JF, Purschke ML, Stoll SP, Ravindranath B, Maramraju SH, Krishnamoorthy S, Henn FA, O'Connor P, Woody CL, Schlyer DJ, Vaska P. Simultaneous assessment of rodent behavior and neurochemistry using a miniature positron emission tomograph. Nat Methods 2011; 8:347-52. [DOI: 10.1038/nmeth.1582] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 02/02/2011] [Indexed: 12/12/2022]
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Silva AC, Liu JV, Hirano Y, Leoni RF, Merkle H, Mackel JB, Zhang XF, Nascimento GC, Stefanovic B. Longitudinal functional magnetic resonance imaging in animal models. Methods Mol Biol 2011; 711:281-302. [PMID: 21279608 PMCID: PMC4748954 DOI: 10.1007/978-1-61737-992-5_14] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has had an essential role in furthering our understanding of brain physiology and function. fMRI techniques are nowadays widely applied in neuroscience research, as well as in translational and clinical studies. The use of animal models in fMRI studies has been fundamental in helping elucidate the mechanisms of cerebral blood-flow regulation, and in the exploration of basic neuroscience questions, such as the mechanisms of perception, behavior, and cognition. Because animals are inherently non-compliant, most fMRI performed to date have required the use of anesthesia, which interferes with brain function and compromises interpretability and applicability of results to our understanding of human brain function. An alternative approach that eliminates the need for anesthesia involves training the animal to tolerate physical restraint during the data acquisition. In the present chapter, we review these two different approaches to obtaining fMRI data from animal models, with a specific focus on the acquisition of longitudinal data from the same subjects.
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Affiliation(s)
- Afonso C Silva
- Cerebral Microcirculation Unit, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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Rinaldi S, Fontani V, Castagna A. Brain activity modification produced by a single radioelectric asymmetric brain stimulation pulse: a new tool for neuropsychiatric treatments. Preliminary fMRI study. Neuropsychiatr Dis Treat 2011; 7:649-54. [PMID: 22090800 PMCID: PMC3215521 DOI: 10.2147/ndt.s26123] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Radioelectric asymmetric brain stimulation technology with its treatment protocols has shown efficacy in various psychiatric disorders. The aim of this work was to highlight the mechanisms by which these positive effects are achieved. The current study was conducted to determine whether a single 500-millisecond radioelectric asymmetric conveyor (REAC) brain stimulation pulse (BSP), applied to the ear, can effect a modification of brain activity that is detectable using functional magnetic resonance imaging (fMRI). METHODS Ten healthy volunteers, six females and four males, underwent fMRI during a simple finger-tapping motor task before and after receiving a single 500-millisecond REAC-BSP. RESULTS The fMRI results indicate that the average variation in task-induced encephalic activation patterns is lower in subjects following the single REAC pulse. CONCLUSION The current report demonstrates that a single REAC-BSP is sufficient to modulate brain activity in awake subjects, able to be measured using fMRI. These initial results open new perspectives into the understanding of the effects of weak and brief radio pulses upon brain activity, and provide the basis for further indepth studies using REAC-BSP and fMRI.
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Affiliation(s)
- Salvatore Rinaldi
- Department of Neuro-Psycho-Physio Pathology, Rinaldi Fontani Institute, Florence, Italy
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35
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CNS activation maps in awake rats exposed to thermal stimuli to the dorsum of the hindpaw. Neuroimage 2011; 54:1355-66. [DOI: 10.1016/j.neuroimage.2010.08.056] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 08/19/2010] [Accepted: 08/21/2010] [Indexed: 01/08/2023] Open
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Febo M. Technical and conceptual considerations for performing and interpreting functional MRI studies in awake rats. Front Psychiatry 2011; 2:43. [PMID: 21808625 PMCID: PMC3137945 DOI: 10.3389/fpsyt.2011.00043] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 06/29/2011] [Indexed: 01/12/2023] Open
Abstract
Functional neuroimaging studies in rodents have the potential to provide insight into neurodevelopmental and psychiatric conditions. The strength of the technique lies in its non-invasive nature that can permit longitudinal functional studies in the same animal over its adult life. The relatively good spatial and temporal resolution and the ever-growing database on the biological and biophysical basis of the blood oxygen level dependent (BOLD) signal make it a unique technique in preclinical neuroscience research. Our laboratory has used imaging to investigate brain activation in awake rats following cocaine administration and during the presentation of lactation-associated sensory stimuli. Factors that deserve attention when planning functional magnetic resonance imaging studies in rats include technical issues, animal physiology and interpretability of the resulting data. The present review discusses the pros and cons of animal imaging with a particular focus on the technical aspects of studies with awake rats. Overall, the benefits of the technique outweigh its limitations and the rapidly evolving methods will open the way for more laboratories to employ the technique in neuroscience research.
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Affiliation(s)
- Marcelo Febo
- Department of Psychiatry, The McKnight Brain Institute, University of Florida College of Medicine Gainesville, FL, USA
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Zhang N, Rane P, Huang W, Liang Z, Kennedy D, Frazier JA, King J. Mapping resting-state brain networks in conscious animals. J Neurosci Methods 2010; 189:186-96. [PMID: 20382183 DOI: 10.1016/j.jneumeth.2010.04.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 03/30/2010] [Accepted: 04/01/2010] [Indexed: 11/20/2022]
Abstract
In the present study we mapped brain functional connectivity in the conscious rat at the "resting state" based on intrinsic blood-oxygenation-level dependent (BOLD) fluctuations. The conscious condition eliminated potential confounding effects of anesthetic agents on the connectivity between brain regions. Indeed, using correlational analysis we identified multiple cortical and subcortical regions that demonstrated temporally synchronous variation with anatomically well-defined regions that are crucial to cognitive and emotional information processing including the prefrontal cortex (PFC), thalamus and retrosplenial cortex. The functional connectivity maps created were stringently validated by controlling for false positive detection of correlation, the physiologic basis of the signal source, as well as quantitatively evaluating the reproducibility of maps. Taken together, the present study has demonstrated the feasibility of assessing functional connectivity in conscious animals using fMRI and thus provided a convenient and non-invasive tool to systematically investigate the connectional architecture of selected brain networks in multiple animal models.
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Affiliation(s)
- Nanyin Zhang
- Center for Comparative Neuroimaging (CCNI), Department of Psychiatry, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, United States.
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Brain activation in response to visceral stimulation in rats with amygdala implants of corticosterone: an FMRI study. PLoS One 2010; 5:e8573. [PMID: 20052291 PMCID: PMC2797306 DOI: 10.1371/journal.pone.0008573] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 12/15/2009] [Indexed: 12/30/2022] Open
Abstract
Background Although visceral pain of gastrointestinal (GI) origin is the major complaint in patients with irritable bowel syndrome (IBS) it remains poorly understood. Brain imaging studies suggest a defect in brain-gut communication in IBS with a greater activation of central arousal circuits including the amygdala. Previously, we found that stereotaxic implantation of corticosterone (CORT) onto the amygdala in rats induced anxiety and colonic hypersensitivity. In the present study we used functional magnetic resonance imaging (fMRI) to identify specific brain sites activated in a rat model characterized by anxiety and colonic hypersensitivity. Methodology/Principal Findings Anesthetized male rats received micropellets (30 µg each) of either CORT or cholesterol (CHOL), to serve as a control, implanted stereotaxically on the dorsal margin of each amygdala. Seven days later, rats were anesthetized and placed in the fMRI magnet (7T). A series of isobaric colorectal balloon distensions (CRD - 90s ‘off’, 30s ‘on’, 8 replicates) at two pressures (40 and 60 mmHg) were performed in a standard block-design. Cross correlation statistical analysis was used to determine significant differences between distended and non-distended states in CORT and CHOL-treated animals. Analysis of the imaging data demonstrated greater overall brain activation in response to CRD in rats with CORT implants compared to CHOL controls. Additionally, CORT implants produced significant positive bilateral increases in MRI signal in response to CRD in specific nuclei known as integration sites important in anxiety and pain perception. Conclusions and Significance These data indicate that chronic exposure of the amygdala to elevated levels of CORT enhances overall brain activation in response to CRD, and identified other specific brain regions activated in response to mechanical distension of the colon. These results demonstrate the feasibility of performing fMRI imaging in a rodent model that supports clinical observations in IBS patients with enhanced amygdala activation and symptomatology of abdominal pain and anxiety.
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Abstract
Multimodality small-animal molecular imaging has become increasingly important as transgenic and knockout mice are produced to model human diseases. With the ever-increasing number and importance of human disease models, particularly in rodents (mice and rats), the ability of high-resolution multimodality molecular imaging instrumentation to contribute unique information is becoming more common and necessary. Multimodality imaging with high spatial resolution and good sensitivity, which combines modalities and records sequentially or simultaneously complementary information, offers many advantages in certain research experiments. This article discusses the current trends and new horizons in preclinical multimodality imaging in-vivo and its role in biomedical research.
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Affiliation(s)
- David B Stout
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine at UCLA, 570 Westwood Plaza, CNSI Building, Room 2151, Los Angeles, CA 90095, USA
| | - Habib Zaidi
- Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva, Switzerland.
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Revel FG, Gottowik J, Gatti S, Wettstein JG, Moreau JL. Rodent models of insomnia: A review of experimental procedures that induce sleep disturbances. Neurosci Biobehav Rev 2009; 33:874-99. [DOI: 10.1016/j.neubiorev.2009.03.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 03/04/2009] [Accepted: 03/04/2009] [Indexed: 12/21/2022]
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Ferris CF, Stolberg T, Kulkarni P, Murugavel M, Blanchard R, Blanchard DC, Febo M, Brevard M, Simon NG. Imaging the neural circuitry and chemical control of aggressive motivation. BMC Neurosci 2008; 9:111. [PMID: 19014547 PMCID: PMC2601047 DOI: 10.1186/1471-2202-9-111] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 11/13/2008] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND With the advent of functional magnetic resonance imaging (fMRI) in awake animals it is possible to resolve patterns of neuronal activity across the entire brain with high spatial and temporal resolution. Synchronized changes in neuronal activity across multiple brain areas can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviors. To this end, fMRI in conscious rats combined with 3D computational analysis was used to identifying the putative distributed neural circuit involved in aggressive motivation and how this circuit is affected by drugs that block aggressive behavior. RESULTS To trigger aggressive motivation, male rats were presented with their female cage mate plus a novel male intruder in the bore of the magnet during image acquisition. As expected, brain areas previously identified as critical in the organization and expression of aggressive behavior were activated, e.g., lateral hypothalamus, medial basal amygdala. Unexpected was the intense activation of the forebrain cortex and anterior thalamic nuclei. Oral administration of a selective vasopressin V1a receptor antagonist SRX251 or the selective serotonin reuptake inhibitor fluoxetine, drugs that block aggressive behavior, both caused a general suppression of the distributed neural circuit involved in aggressive motivation. However, the effect of SRX251, but not fluoxetine, was specific to aggression as brain activation in response to a novel sexually receptive female was unaffected. CONCLUSION The putative neural circuit of aggressive motivation identified with fMRI includes neural substrates contributing to emotional expression (i.e. cortical and medial amygdala, BNST, lateral hypothalamus), emotional experience (i.e. hippocampus, forebrain cortex, anterior cingulate, retrosplenial cortex) and the anterior thalamic nuclei that bridge the motor and cognitive components of aggressive responding. Drugs that block vasopressin neurotransmission or enhance serotonin activity suppress activity in this putative neural circuit of aggressive motivation, particularly the anterior thalamic nuclei.
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Affiliation(s)
- Craig F Ferris
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
- Department of Psychology, Northeastern University, Boston, Massachusetts 02115-5000, USA
| | - Tara Stolberg
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Praveen Kulkarni
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Murali Murugavel
- Dept Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Robert Blanchard
- Department of Psychology, University of Hawaii, Honolulu, Hawaii, USA
| | | | - Marcelo Febo
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Mathew Brevard
- Insight Neuroimaging Systems, Worcester, Massachusetts, USA
| | - Neal G Simon
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
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The advantages and disadvantages of using functional magnetic resonance imaging (fMRI). J Neuroendocrinol 2007; 19:669. [PMID: 17620109 DOI: 10.1111/j.1365-2826.2007.01582.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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