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Vasilkovska T, Salajeghe S, Vanreusel V, Van Audekerke J, Verschuuren M, Hirschler L, Warnking J, Pintelon I, Pustina D, Cachope R, Mrzljak L, Muñoz-Sanjuan I, Barbier EL, De Vos WH, Van der Linden A, Verhoye M. Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington's disease. J Biomed Sci 2024; 31:37. [PMID: 38627751 PMCID: PMC11022401 DOI: 10.1186/s12929-024-01028-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Huntington's disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have been shown to lead to dysregulated energy supply to brain regions in several neurological diseases, including HD, which could potentially trigger the process of neurodegeneration. In particular, it has been observed in cross-sectional human HD studies that vascular alterations are associated to impaired cerebral blood flow (CBF). To assess whether whole-brain changes in CBF are present and follow a pattern of progression, we investigated both resting-state brain perfusion and vascular reactivity longitudinally in the zQ175DN mouse model of HD. METHODS Using pseudo-continuous arterial spin labelling (pCASL) MRI in the zQ175DN model of HD and age-matched wild-type (WT) mice, we assessed whole-brain, resting-state perfusion at 3, 6 and 9 and 13 months of age, and assessed hypercapnia-induced cerebrovascular reactivity (CVR), at 4.5, 6, 9 and 15 months of age. RESULTS We found increased perfusion in cortical regions of zQ175DN HET mice at 3 months of age, and a reduction of this anomaly at 6 and 9 months, ages at which behavioural deficits have been reported. On the other hand, under hypercapnia, CBF was reduced in zQ175DN HET mice as compared to the WT: for multiple brain regions at 6 months of age, for only somatosensory and retrosplenial cortices at 9 months of age, and brain-wide by 15 months. CVR impairments in cortical regions, the thalamus and globus pallidus were observed in zQ175DN HET mice at 9 months, with whole brain reactivity diminished at 15 months of age. Interestingly, blood vessel density was increased in the motor cortex at 3 months, while average vessel length was reduced in the lateral portion of the caudate putamen at 6 months of age. CONCLUSION Our findings reveal early cortical resting-state hyperperfusion and impaired CVR at ages that present motor anomalies in this HD model, suggesting that further characterization of brain perfusion alterations in animal models is warranted as a potential therapeutic target in HD.
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Affiliation(s)
- Tamara Vasilkovska
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium.
| | - Somaie Salajeghe
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Verdi Vanreusel
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Johan Van Audekerke
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marlies Verschuuren
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Lydiane Hirschler
- C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Warnking
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Isabel Pintelon
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Dorian Pustina
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Roger Cachope
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Ladislav Mrzljak
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Takeda Pharmaceuticals, Cambridge, MA, USA
| | - Ignacio Muñoz-Sanjuan
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Cajal Neuroscience Inc, Seattle, WA, USA
| | - Emmanuel L Barbier
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Winnok H De Vos
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
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Le TT, Im GH, Lee CH, Choi SH, Kim SG. Mapping cerebral perfusion in mice under various anesthesia levels using highly sensitive BOLD MRI with transient hypoxia. SCIENCE ADVANCES 2024; 10:eadm7605. [PMID: 38416820 PMCID: PMC10901365 DOI: 10.1126/sciadv.adm7605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/24/2024] [Indexed: 03/01/2024]
Abstract
Cerebral perfusion is critical for the early detection of neurological diseases and for effectively monitoring disease progression and treatment responses. Mouse models are widely used in brain research, often under anesthesia, which can affect vascular physiology. However, the impact of anesthesia on regional cerebral blood volume and flow in mice has not been thoroughly investigated. In this study, we have developed a whole-brain perfusion MRI approach by using a 5-second nitrogen gas stimulus under inhalational anesthetics to induce transient BOLD dynamic susceptibility contrast (DSC). This method proved to be highly sensitive, repeatable within each imaging session, and across four weekly sessions. Relative cerebral blood volumes measured by BOLD DSC agree well with those by contrast agents. Quantitative cerebral blood volume and flow metrics were successfully measured in mice under dexmedetomidine and various isoflurane doses using both total vasculature-sensitive gradient-echo and microvasculature-sensitive spin-echo BOLD MRI. Dexmedetomidine reduces cerebral perfusion, while isoflurane increases cerebral perfusion in a dose-dependent manner.
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Affiliation(s)
- Thuy Thi Le
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
| | - Geun Ho Im
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Chan Hee Lee
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Sang Han Choi
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, Republic of Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea
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3
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Chen HF, Lambers H, Nagelmann N, Sandbrink M, Segelcke D, Pogatzki-Zahn E, Faber C, Pradier B. Generation of a whole-brain hemodynamic response function and sex-specific differences in cerebral processing of mechano-sensation in mice detected by BOLD fMRI. Front Neurosci 2023; 17:1187328. [PMID: 37700753 PMCID: PMC10493293 DOI: 10.3389/fnins.2023.1187328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/05/2023] [Indexed: 09/14/2023] Open
Abstract
BOLD fMRI has become a prevalent method to study cerebral sensory processing in rodent disease models, including pain and mechanical hypersensitivity. fMRI data analysis is frequently combined with a general-linear-model (GLM) -based analysis, which uses the convolution of a hemodynamic response function (HRF) with the stimulus paradigm. However, several studies indicated that the HRF differs across species, sexes, brain structures, and experimental factors, including stimulation modalities or anesthesia, and hence might strongly affect the outcome of BOLD analyzes. While considerable work has been done in humans and rats to understand the HRF, much less is known in mice. As a prerequisite to investigate mechano-sensory processing and BOLD fMRI data in male and female mice, we (1) designed a rotating stimulator that allows application of two different mechanical modalities, including innocuous von Frey and noxious pinprick stimuli and (2) determined and statistically compared HRFs across 30 brain structures and experimental conditions, including sex and, stimulus modalities. We found that mechanical stimulation lead to brain-wide BOLD signal changes thereby allowing extraction of HRFs from multiple brain structures. However, we did not find differences in HRFs across all brain structures and experimental conditions. Hence, we computed a whole-brain mouse HRF, which is based on 88 functional scans from 30 mice. A comparison of this mouse-specific HRF with our previously reported rat-derived HRF showed significantly slower kinetics in mice. Finally, we detected pronounced differences in cerebral BOLD activation between male and female mice with mechanical stimulation, thereby exposing divergent processing of noxious and innocuous stimuli in both sexes.
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Affiliation(s)
- Hui-Fen Chen
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Henriette Lambers
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Nina Nagelmann
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Martin Sandbrink
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Daniel Segelcke
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
| | - Esther Pogatzki-Zahn
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
| | - Cornelius Faber
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Bruno Pradier
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
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4
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Kim S, Jo Y, Im GH, Lee C, Oh C, Kook G, Kim SG, Lee HJ. Miniaturized MR-compatible ultrasound system for real-time monitoring of acoustic effects in mice using high-resolution MRI. Neuroimage 2023; 276:120201. [PMID: 37269955 DOI: 10.1016/j.neuroimage.2023.120201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/05/2023] Open
Abstract
Visualization of focused ultrasound in high spatial and temporal resolution is crucial for accurately and precisely targeting brain regions noninvasively. Magnetic resonance imaging (MRI) is the most widely used noninvasive tool for whole-brain imaging. However, focused ultrasound studies employing high-resolution (> 9.4 T) MRI in small animals are limited by the small size of the radiofrequency (RF) volume coil and the noise sensitivity of the image to external systems such as bulky ultrasound transducers. This technical note reports a miniaturized ultrasound transducer system packaged directly above a mouse brain for monitoring ultrasound-induced effects using high-resolution 9.4 T MRI. Our miniaturized system integrates MR-compatible materials with electromagnetic (EM) noise reduction techniques to demonstrate echo-planar imaging (EPI) signal changes in the mouse brain at various ultrasound acoustic intensities. The proposed ultrasound-MRI system will enable extensive research in the expanding field of ultrasound therapeutics.
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Affiliation(s)
- Subeen Kim
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Yehhyun Jo
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Geun Ho Im
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon 16419, South Korea
| | - Chanhee Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon 16419, South Korea
| | - Chaerin Oh
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Geon Kook
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon 16419, South Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea; Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon 16419, South Korea.
| | - Hyunjoo J Lee
- School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea; KAIST Institute for Nano Century (KINC), Daejeon 34141, South Korea.
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Fernandes FF, Olesen JL, Jespersen SN, Shemesh N. MP-PCA denoising of fMRI time-series data can lead to artificial activation "spreading". Neuroimage 2023; 273:120118. [PMID: 37062372 DOI: 10.1016/j.neuroimage.2023.120118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 04/18/2023] Open
Abstract
MP-PCA denoising has become the method of choice for denoising MRI data since it provides an objective threshold to separate the signal components from unwanted thermal noise components. In rodents, thermal noise in the coils is an important source of noise that can reduce the accuracy of activation mapping in fMRI. Further confounding this problem, vendor data often contains zero-filling and other post-processing steps that may violate MP-PCA assumptions. Here, we develop an approach to denoise vendor data and assess activation "spreading" caused by MP-PCA denoising in rodent task-based fMRI data. Data was obtained from N = 3 mice using conventional multislice and ultrafast acquisitions (1 s and 50 ms temporal resolution, respectively), during visual stimulation. MP-PCA denoising produced SNR gains of 64% and 39% and Fourier Spectral Amplitude (FSA) increases in BOLD maps of 9% and 7% for multislice and ultrafast data, respectively, when using a small [2 2] denoising window. Larger windows provided higher SNR and FSA gains with increased spatial extent of activation that may or may not represent real activation. Simulations showed that MP-PCA denoising can incur activation "spreading" with increased false positive rate and smoother functional maps due to local "bleeding" of principal components, and that the optimal denoising window for improved specificity of functional mapping, based on Dice score calculations, depends on the data's tSNR and functional CNR. This "spreading" effect applies also to another recently proposed low-rank denoising method (NORDIC), although to a lesser degree. Our results bode well for enhancing spatial and/or temporal resolution in future fMRI work, while taking into account the sensitivity/specificity trade-offs of low-rank denoising methods.
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Affiliation(s)
| | - Jonas L Olesen
- Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Sune N Jespersen
- Center of Functionally Integrative Neuroscience (CFIN) and MINDLab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Noam Shemesh
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal.
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6
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Huang J, Zhang Y, Zhang Q, Wei L, Zhang X, Jin C, Yang J, Li Z, Liang S. The current status and trend of the functional magnetic resonance combined with stimulation in animals. Front Neurosci 2022; 16:963175. [PMID: 36213733 PMCID: PMC9540855 DOI: 10.3389/fnins.2022.963175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
As a non-radiative, non-invasive imaging technique, functional magnetic resonance imaging (fMRI) has excellent effects on studying the activation of blood oxygen levels and functional connectivity of the brain in human and animal models. Compared with resting-state fMRI, fMRI combined with stimulation could be used to assess the activation of specific brain regions and the connectivity of specific pathways and achieve better signal capture with a clear purpose and more significant results. Various fMRI methods and specific stimulation paradigms have been proposed to investigate brain activation in a specific state, such as electrical, mechanical, visual, olfactory, and direct brain stimulation. In this review, the studies on animal brain activation using fMRI combined with different stimulation methods were retrieved. The instruments, experimental parameters, anesthesia, and animal models in different stimulation conditions were summarized. The findings would provide a reference for studies on estimating specific brain activation using fMRI combined with stimulation.
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7
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Choe KY, Bethlehem RAI, Safrin M, Dong H, Salman E, Li Y, Grinevich V, Golshani P, DeNardo LA, Peñagarikano O, Harris NG, Geschwind DH. Oxytocin normalizes altered circuit connectivity for social rescue of the Cntnap2 knockout mouse. Neuron 2022; 110:795-808.e6. [PMID: 34932941 PMCID: PMC8944915 DOI: 10.1016/j.neuron.2021.11.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 09/03/2021] [Accepted: 11/24/2021] [Indexed: 12/12/2022]
Abstract
The neural basis of abnormal social behavior in autism spectrum disorders (ASDs) remains incompletely understood. Here we used two complementary but independent brain-wide mapping approaches, mouse resting-state fMRI and c-Fos-iDISCO+ imaging, to construct brain-wide activity and connectivity maps of the Cntnap2 knockout (KO) mouse model of ASD. At the macroscale level, we detected reduced functional coupling across social brain regions despite general patterns of hyperconnectivity across major brain structures. Oxytocin administration, which rescues social deficits in KO mice, strongly stimulated many brain areas and normalized connectivity patterns. Notably, chemogenetically triggered release of endogenous oxytocin strongly stimulated the nucleus accumbens (NAc), a forebrain nucleus implicated in social reward. Furthermore, NAc-targeted approaches to activate local oxytocin receptors sufficiently rescued their social deficits. Our findings establish circuit- and systems-level mechanisms of social deficits in Cntnap2 KO mice and reveal the NAc as a region that can be modulated by oxytocin to promote social interactions.
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Affiliation(s)
- Katrina Y Choe
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Center for Autism Research and Treatment, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON L8S 4K1, Canada.
| | - Richard A I Bethlehem
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Martin Safrin
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Hongmei Dong
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Elena Salman
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Ying Li
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Valery Grinevich
- Department of Neuropeptide Research for Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim 68159, Germany
| | - Peyman Golshani
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Center for Autism Research and Treatment, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Laura A DeNardo
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Olga Peñagarikano
- Department of Pharmacology, School of Medicine, University of the Basque Country (UPV/EHU), Vizcaya 48940, Spain
| | - Neil G Harris
- Department of Neurosurgery, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Daniel H Geschwind
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Center for Autism Research and Treatment, Semel Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA.
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Characterization of brain-wide somatosensory BOLD fMRI in mice under dexmedetomidine/isoflurane and ketamine/xylazine. Sci Rep 2021; 11:13110. [PMID: 34162952 PMCID: PMC8222234 DOI: 10.1038/s41598-021-92582-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/10/2021] [Indexed: 02/05/2023] Open
Abstract
Mouse fMRI under anesthesia has become increasingly popular due to improvement in obtaining brain-wide BOLD response. Medetomidine with isoflurane has become well-accepted for resting-state fMRI, but whether this combination allows for stable, expected, and robust brain-wide evoked response in mice has yet to be validated. We thus utilized intravenous infusion of dexmedetomidine with inhaled isoflurane and intravenous infusion of ketamine/xylazine to elucidate whether stable mouse physiology and BOLD response are obtainable in response to simultaneous forepaw and whisker-pad stimulation throughout 8 h. We found both anesthetics result in hypercapnia with depressed heart rate and respiration due to self-breathing, but these values were stable throughout 8 h. Regardless of the mouse condition, brain-wide, robust, and stable BOLD response throughout the somatosensory axis was observed with differences in sensitivity and dynamics. Dexmedetomidine/isoflurane resulted in fast, boxcar-like, BOLD response with consistent hemodynamic shapes throughout the brain. Ketamine/xylazine response showed higher sensitivity, prolonged BOLD response, and evidence for cortical disinhibition as significant bilateral cortical response was observed. In addition, differing hemodynamic shapes were observed between cortical and subcortical areas. Overall, we found both anesthetics are applicable for evoked mouse fMRI studies.
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Tokunaga R, Paquette T, Tsurugizawa T, Leblond H, Piché M. Fasting prevents medetomidine-induced hyperglycaemia and alterations of neurovascular coupling in the somatosensory cortex of the rat during noxious stimulation. Eur J Neurosci 2021; 54:4906-4919. [PMID: 34137097 DOI: 10.1111/ejn.15350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/30/2021] [Accepted: 06/10/2021] [Indexed: 11/28/2022]
Abstract
Medetomidine and isoflurane are commonly used for general anaesthesia in fMRI studies, but they alter cerebral blood flow (CBF) regulation and neurovascular coupling (NVC). In addition, medetomidine induces hypoinsulinemia and hyperglycaemia, which also alter CBF regulation and NVC. Furthermore, sudden changes in arterial pressure induced by noxious stimulation may affect NVC differently under medetomidine and isoflurane anaesthesia, considering their different effects on vascular functions. The first objective of this study was to compare NVC under medetomidine and isoflurane anaesthesia during noxious stimulation. The second objective was to examine whether fasting may improve NVC by reducing medetomidine-induced hyperglycaemia. In male Wister rats, noxious electrical stimulation was applied to the sciatic nerve in fasted or non-fasted animals. CBF and local field potentials (LFP) were recorded in the somatosensory cortex to assess NVC (CBF/LFP ratio). The CBF/LFP ratio was increased by medetomidine compared with isoflurane (p = 0.004), but this effect was abolished by fasting (p = 0.8). Accordingly, medetomidine produced a threefold increase in blood glucose (p < 0.001), but this effect was also abolished by fasting (p = 0.3). This indicates that isoflurane and medetomidine anaesthesia alter NVC differently, but the undesirable glucose dependent effects of medetomidine on NVC can be prevented by fasting.
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Affiliation(s)
- Ryota Tokunaga
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Thierry Paquette
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Tomokazu Tsurugizawa
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Hugues Leblond
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Mathieu Piché
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
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Steiner AR, Rousseau-Blass F, Schroeter A, Hartnack S, Bettschart-Wolfensberger R. Systematic Review: Anesthetic Protocols and Management as Confounders in Rodent Blood Oxygen Level Dependent Functional Magnetic Resonance Imaging (BOLD fMRI)-Part B: Effects of Anesthetic Agents, Doses and Timing. Animals (Basel) 2021; 11:ani11010199. [PMID: 33467584 PMCID: PMC7830239 DOI: 10.3390/ani11010199] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary To understand brain function in rats and mice functional magnetic resonance imaging of the brain is used. With this type of “brain scan” regional changes in blood flow and oxygen consumption are measured as an indirect surrogate for activity of brain regions. Animals are often anesthetized for the experiments to prevent stress and blurred images due to movement. However, anesthesia may alter the measurements, as blood flow within the brain is differently affected by different anesthetics, and anesthetics also directly affect brain function. Consequently, results obtained under one anesthetic protocol may not be comparable with those obtained under another, and/or not representative for awake animals and humans. We have systematically searched the existing literature for studies analyzing the effects of different anesthesia methods or studies that compared anesthetized and awake animals. Most studies reported that anesthetic agents, doses and timing had an effect on functional magnetic resonance imaging results. To obtain results which promote our understanding of brain function, it is therefore essential that a standard for anesthetic protocols for functional magnetic resonance is defined and their impact is well characterized. Abstract In rodent models the use of functional magnetic resonance imaging (fMRI) under anesthesia is common. The anesthetic protocol might influence fMRI readouts either directly or via changes in physiological parameters. As long as those factors cannot be objectively quantified, the scientific validity of fMRI in rodents is impaired. In the present systematic review, literature analyzing in rats and mice the influence of anesthesia regimes and concurrent physiological functions on blood oxygen level dependent (BOLD) fMRI results was investigated. Studies from four databases that were searched were selected following pre-defined criteria. Two separate articles publish the results; the herewith presented article includes the analyses of 83 studies. Most studies found differences in BOLD fMRI readouts with different anesthesia drugs and dose rates, time points of imaging or when awake status was compared to anesthetized animals. To obtain scientifically valid, reproducible results from rodent fMRI studies, stable levels of anesthesia with agents suitable for the model under investigation as well as known and objectively quantifiable effects on readouts are, thus, mandatory. Further studies should establish dose ranges for standardized anesthetic protocols and determine time windows for imaging during which influence of anesthesia on readout is objectively quantifiable.
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Affiliation(s)
- Aline R. Steiner
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
- Correspondence:
| | - Frédérik Rousseau-Blass
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada;
| | - Aileen Schroeter
- Institute for Biomedical Engineering, University and ETH Zurich, 8093 Zurich, Switzerland;
| | - Sonja Hartnack
- Section of Epidemiology, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
| | - Regula Bettschart-Wolfensberger
- Section of Anaesthesiology, Department of Clinical and Diagnostic Services, Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland;
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11
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López-Gutiérrez MF, Gracia-Tabuenca Z, Ortiz JJ, Camacho FJ, Young LJ, Paredes RG, Díaz NF, Portillo W, Alcauter S. Brain functional networks associated with social bonding in monogamous voles. eLife 2021; 10:e55081. [PMID: 33443015 PMCID: PMC7847304 DOI: 10.7554/elife.55081] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 01/11/2021] [Indexed: 12/30/2022] Open
Abstract
Previous studies have related pair-bonding in Microtus ochrogaster, the prairie vole, with plastic changes in several brain regions. However, the interactions between these socially relevant regions have yet to be described. In this study, we used resting-state magnetic resonance imaging to explore bonding behaviors and functional connectivity of brain regions previously associated with pair-bonding. Thirty-two male and female prairie voles were scanned at baseline, 24 hr, and 2 weeks after the onset of cohabitation. By using network-based statistics, we identified that the functional connectivity of a corticostriatal network predicted the onset of affiliative behavior, while another predicted the amount of social interaction during a partner preference test. Furthermore, a network with significant changes in time was revealed, also showing associations with the level of partner preference. Overall, our findings revealed the association between network-level functional connectivity changes and social bonding.
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Affiliation(s)
| | - Zeus Gracia-Tabuenca
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
| | - Juan J Ortiz
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
| | - Francisco J Camacho
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
| | - Larry J Young
- Silvio O Conte Center for Oxytocin and Social Cognition, Center for Translational Social Neuroscience, Yerkes National Primate Research Center, Department of Psychiatry and Behavioral Sciences, Emory UniversityAtlantaUnited States
| | - Raúl G Paredes
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
- Escuela Nacional de Estudios Superiores, Unidad Juriquilla, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
| | - Néstor F Díaz
- Instituto Nacional de Perinatología Isidro Espinosa de los ReyesCiudad de MéxicoMexico
| | - Wendy Portillo
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
| | - Sarael Alcauter
- Instituto de Neurobiología, Universidad Nacional Autónoma de MéxicoQuerétaroMexico
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12
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Li Y, Han H, Shi K, Cui D, Yang J, Alberts IL, Yuan L, Zhao G, Wang R, Cai X, Teng Z. The Mechanism of Downregulated Interstitial Fluid Drainage Following Neuronal Excitation. Aging Dis 2020; 11:1407-1422. [PMID: 33269097 PMCID: PMC7673848 DOI: 10.14336/ad.2020.0224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
The drainage of brain interstitial fluid (ISF) has been observed to slow down following neuronal excitation, although the mechanism underlying this phenomenon is yet to be elucidated. In searching for the changes in the brain extracellular space (ECS) induced by electrical pain stimuli in the rat thalamus, significantly decreased effective diffusion coefficient (DECS) and volume fraction (α) of the brain ECS were shown, accompanied by the slowdown of ISF drainage. The morphological basis for structural changes in the brain ECS was local spatial deformation of astrocyte foot processes following neuronal excitation. We further studied aquaporin-4 gene (APQ4) knockout rats in which the changes of the brain ECS structure were reversed and found that the slowed DECS and ISF drainage persisted, confirming that the down-regulation of ISF drainage following neuronal excitation was mainly attributable to the release of neurotransmitters rather than to structural changes of the brain ECS. Meanwhile, the dynamic changes in the DECS were synchronized with the release and elimination processes of neurotransmitters following neuronal excitation. In conclusion, the downregulation of ISF drainage following neuronal excitation was found to be caused by the restricted diffusion in the brain ECS, and DECS mapping may be used to track the neuronal activity in the deep brain.
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Affiliation(s)
- Yuanyuan Li
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Hongbin Han
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China.
| | - Kuangyu Shi
- Department of Nuclear Medicine, University of Bern, 3010 Bern, Switzerland.
- Department of Informatics, Technical University of Munich, Garching 85748, Germany.
| | - Dehua Cui
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Jun Yang
- Department of Radiology, Peking University Third Hospital, Beijing, China.
| | - Ian Leigh Alberts
- Department of Nuclear Medicine, University of Bern, 3010 Bern, Switzerland.
| | - Lan Yuan
- Peking University Medical and Health Analysis Center, Peking University Health Science Center, Beijing, China.
| | - Guomei Zhao
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Rui Wang
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Xianjie Cai
- Department of Radiology, Peking University Third Hospital, Beijing, China.
- Beijing Key Laboratory of Magnetic Resonance Imaging Equipment and Technique, Beijing, China.
| | - Ze Teng
- Department of Radiology, Cancer Hospital Chinese Academy of Medical Sciences, Beijing, China.
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13
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Bortel A, Pilgram R, Yao ZS, Shmuel A. Dexmedetomidine - Commonly Used in Functional Imaging Studies - Increases Susceptibility to Seizures in Rats But Not in Wild Type Mice. Front Neurosci 2020; 14:832. [PMID: 33192234 PMCID: PMC7658317 DOI: 10.3389/fnins.2020.00832] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 07/16/2020] [Indexed: 12/28/2022] Open
Abstract
Functional MRI (fMRI) utilizes changes in metabolic and hemodynamic signals to indirectly infer the underlying local changes in neuronal activity. To investigate the mechanisms of fMRI responses, spontaneous fluctuations, and functional connectivity in the resting-state, it is important to pursue fMRI in animal models. Animal studies commonly use dexmedetomidine sedation. It has been demonstrated that potent sensory stimuli administered under dexmedetomidine are prone to inducing seizures in Sprague-Dawley (SD) rats. Here we combined optical imaging of intrinsic signals and cerebral blood flow with neurophysiological recordings to measure responses in rat area S1FL to electrical forepaw stimulation administered at 8 Hz. We show that the increased susceptibility to seizures starts no later than 1 h and ends no sooner than 3 h after initiating a continuous administration of dexmedetomidine. By administering different combinations of anesthetic and sedative agents, we demonstrate that dexmedetomidine is the sole agent necessary for the increased susceptibility to seizures. The increased susceptibility to seizures prevails under a combination of 0.3–0.5% isoflurane and dexmedetomidine anesthesia. The blood-oxygenation and cerebral blood flow responses to seizures induced by forepaw stimulation have a higher amplitude and a larger spatial extent relative to physiological responses to the same stimuli. The epileptic activity and the associated blood oxygenation and cerebral blood flow responses stretched beyond the stimulation period. We observed seizures in response to forepaw stimulation with 1–2 mA pulses administered at 8 Hz. In contrast, responses to stimuli administered at 4 Hz were seizure-free. We demonstrate that such seizures are generated not only in SD rats but also in Long-Evans rats, but not in C57BL6 mice stimulated with similar potent stimuli under dexmedetomidine sedation. We conclude that high-amplitude hemodynamic functional imaging responses evoked by peripheral stimulation in rats sedated with dexmedetomidine are possibly due to the induction of epileptic activity. Therefore, caution should be practiced in experiments that combine the administration of potent stimuli with dexmedetomidine sedation. We propose stimulation paradigms that elicit seizure-free, well detectable neurophysiological and hemodynamic responses in rats. We further conclude that the increased susceptibility to seizures under dexmedetomidine sedation is species dependent.
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Affiliation(s)
- Aleksandra Bortel
- Montreal Neurological Institute, McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Roland Pilgram
- Montreal Neurological Institute, McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Ze Shan Yao
- Montreal Neurological Institute, McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada.,Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Amir Shmuel
- Montreal Neurological Institute, McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
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14
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Shim H, Lee J, Kim S. BOLD fMRI and hemodynamic responses to somatosensory stimulation in anesthetized mice: spontaneous breathing vs. mechanical ventilation. NMR IN BIOMEDICINE 2020; 33:e4311. [PMID: 32297409 PMCID: PMC7317444 DOI: 10.1002/nbm.4311] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/26/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Mouse functional MRI (fMRI) has been of great interest due to the abundance of transgenic models. Due to a mouse's small size, spontaneous breathing has often been used. Because the vascular physiology affecting fMRI might not be controlled normally, its effects on functional responses were investigated with optical intrinsic signal (OIS) imaging and 9.4 T BOLD fMRI. Three conditions were tested in C57BL/6 mice: spontaneous breathing under ketamine and xylazine anesthesia (KX), mechanical ventilation under KX, and mechanical ventilation under isoflurane. Spontaneous breathing under KX induced an average pCO2 of 83 mmHg, whereas a mechanical ventilation condition achieved a pCO2 of 37-41 mmHg within a physiological range. The baseline diameter of arterial and venous vessels was only 7%-9% larger with spontaneous breathing than with mechanical ventilation under KX, but it was much smaller than that in normocapnic isoflurane-anesthetized mice. Three major functional studies were performed. First, CBV-weighted OIS and arterial dilations to 4-second forepaw stimulation were rapid and larger at normocapnia than hypercapnia under KX, but very small under isoflurane. Second, CBV-weighted OIS and arterial dilations by vasodilator acetazolamide were measured for investigating vascular reactivity and were larger in the normocapnic condition than in the hypercapnic condition under KX. Third, evoked OIS and BOLD fMRI responses in the contralateral mouse somatosensory cortex to 20-second forepaw stimulation were faster and larger in the mechanical ventilation than spontaneous breathing. BOLD fMRI peaked at the end of the 20-second stimulation under hypercapnic spontaneous breathing, and at ~9 seconds under mechanical ventilation. The peak amplitude of BOLD fMRI was 2.2% at hypercapnia and ~3.4% at normocapnia. Overall, spontaneous breathing induces sluggish reduced hemodynamic and fMRI responses, but it is still viable for KX anesthesia due to its simplicity, noninvasiveness, and well-localized BOLD activity in the somatosensory cortex.
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Affiliation(s)
- Hyun‐Ji Shim
- Center for Neuroscience Imaging Research (CNIR)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Health Sciences and Technology, SAIHSTSungkyunkwan UniversitySeoul06355Republic of Korea
| | - Joonyeol Lee
- Center for Neuroscience Imaging Research (CNIR)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Biomedical EngineeringSungkyunkwan UniversitySuwon16419Republic of Korea
| | - Seong‐Gi Kim
- Center for Neuroscience Imaging Research (CNIR)Institute for Basic Science (IBS)Suwon16419Republic of Korea
- Department of Health Sciences and Technology, SAIHSTSungkyunkwan UniversitySeoul06355Republic of Korea
- Department of Biomedical EngineeringSungkyunkwan UniversitySuwon16419Republic of Korea
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15
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Mc Larney B, Hutter MA, Degtyaruk O, Deán-Ben XL, Razansky D. Monitoring of Stimulus Evoked Murine Somatosensory Cortex Hemodynamic Activity With Volumetric Multi-Spectral Optoacoustic Tomography. Front Neurosci 2020; 14:536. [PMID: 32581686 PMCID: PMC7283916 DOI: 10.3389/fnins.2020.00536] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 05/01/2020] [Indexed: 01/17/2023] Open
Abstract
Sensory stimulation is an attractive paradigm for studying brain activity using various optical-, ultrasound- and MRI-based functional neuroimaging methods. Optoacoustics has been recently suggested as a powerful new tool for scalable mapping of multiple hemodynamic parameters with rich contrast and previously unachievable spatio-temporal resolution. Yet, its utility for studying the processing of peripheral inputs at the whole brain level has so far not been quantified. We employed volumetric multi-spectral optoacoustic tomography (vMSOT) to non-invasively monitor the HbO, HbR, and HbT dynamics across the mouse somatosensory cortex evoked by electrical paw stimuli. We show that elevated contralateral activation is preserved in the HbO map (invisible to MRI) under isoflurane anesthesia. Brain activation is shown to be predominantly confined to the somatosensory cortex, with strongest activation in the hindpaw region of the contralateral sensorimotor cortex. Furthermore, vMSOT detected the presence of an initial dip in the contralateral hindpaw region in the delta HbO channel. Sensorimotor cortical activity was identified over all other regions in HbT and HbO but not in HbR. Pearson’s correlation mapping enabled localizing the response to the sensorimotor cortex further highlighting the ability of vMSOT to bridge over imaging performance deficiencies of other functional neuroimaging modalities.
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Affiliation(s)
- Benedict Mc Larney
- Faculty of Medicine, Technical University of Munich, Munich, Germany.,Institute for Biological and Medical Imaging, Helmholtz Center Munich, Munich, Germany
| | | | - Oleksiy Degtyaruk
- Institute for Biological and Medical Imaging, Helmholtz Center Munich, Munich, Germany.,Faculty of Medicine and Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Xosé Luís Deán-Ben
- Faculty of Medicine and Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
| | - Daniel Razansky
- Faculty of Medicine, Technical University of Munich, Munich, Germany.,Institute for Biological and Medical Imaging, Helmholtz Center Munich, Munich, Germany.,Faculty of Medicine and Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.,Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, Switzerland
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16
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Reimann HM, Niendorf T. The (Un)Conscious Mouse as a Model for Human Brain Functions: Key Principles of Anesthesia and Their Impact on Translational Neuroimaging. Front Syst Neurosci 2020; 14:8. [PMID: 32508601 PMCID: PMC7248373 DOI: 10.3389/fnsys.2020.00008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
In recent years, technical and procedural advances have brought functional magnetic resonance imaging (fMRI) to the field of murine neuroscience. Due to its unique capacity to measure functional activity non-invasively, across the entire brain, fMRI allows for the direct comparison of large-scale murine and human brain functions. This opens an avenue for bidirectional translational strategies to address fundamental questions ranging from neurological disorders to the nature of consciousness. The key challenges of murine fMRI are: (1) to generate and maintain functional brain states that approximate those of calm and relaxed human volunteers, while (2) preserving neurovascular coupling and physiological baseline conditions. Low-dose anesthetic protocols are commonly applied in murine functional brain studies to prevent stress and facilitate a calm and relaxed condition among animals. Yet, current mono-anesthesia has been shown to impair neural transmission and hemodynamic integrity. By linking the current state of murine electrophysiology, Ca2+ imaging and fMRI of anesthetic effects to findings from human studies, this systematic review proposes general principles to design, apply and monitor anesthetic protocols in a more sophisticated way. The further development of balanced multimodal anesthesia, combining two or more drugs with complementary modes of action helps to shape and maintain specific brain states and relevant aspects of murine physiology. Functional connectivity and its dynamic repertoire as assessed by fMRI can be used to make inferences about cortical states and provide additional information about whole-brain functional dynamics. Based on this, a simple and comprehensive functional neurosignature pattern can be determined for use in defining brain states and anesthetic depth in rest and in response to stimuli. Such a signature can be evaluated and shared between labs to indicate the brain state of a mouse during experiments, an important step toward translating findings across species.
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Affiliation(s)
- Henning M. Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück Center for Molecular Medicine, Helmholtz Association of German Research Centers (HZ), Berlin, Germany
- Experimental and Clinical Research Center, A Joint Cooperation Between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
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17
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Zhao F, Meng X, Lu S, Hyde LA, Kennedy ME, Houghton AK, Evelhoch JL, Hines CDG. fMRI study of olfactory processing in mice under three anesthesia protocols: Insight into the effect of ketamine on olfactory processing. Neuroimage 2020; 213:116725. [PMID: 32173412 DOI: 10.1016/j.neuroimage.2020.116725] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/01/2020] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) is a valuable tool for studying neural activations in the central nervous system of animals due to its wide spatial coverage and non-invasive nature. However, the advantages of fMRI have not been fully realized in functional studies in mice, especially in the olfactory system, possibly due to the lack of suitable anesthesia protocols with spontaneous breathing. Since mice are widely used in biomedical research, it is desirable to evaluate different anesthesia protocols for olfactory fMRI studies in mice. Dexmedetomidine (DEX) as a sedative/anesthetic has been introduced to fMRI studies in mice, but it has a limited anesthesia duration. To extend the anesthesia duration, DEX has been combined with a low dose of isoflurane (ISO) or ketamine (KET) in previous functional studies in mice. In this report, olfactory fMRI studies were performed under three anesthesia protocols (DEX alone, DEX/ISO, and DEX/KET) in three different groups of mice. Isoamyl-acetate was used as an odorant, and the odorant-induced neural activations were measured by blood oxygenation-level dependent (BOLD) fMRI. BOLD fMRI responses were observed in the olfactory bulb (OB), anterior olfactory nuclei (AON), and piriform cortex (Pir). Interestingly, BOLD fMRI activations were also observed in the prefrontal cortical region (PFC), which are most likely caused by the draining vein effect. The response in the OB showed no adaptation to either repeated odor stimulations or continuous odor exposure, but the response in the Pir showed adaptation during the continuous odor exposure. The data also shows that ISO suppresses the olfactory response in the OB and AON, while KET enhances the olfactory response in the Pir. Thus, DEX/KET should be an attractive anesthesia for olfactory fMRI in mice.
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Affiliation(s)
| | | | - Sherry Lu
- Merck & Co. Inc, West Point, PA, 19486, USA
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18
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Chen X, Tong C, Han Z, Zhang K, Bo B, Feng Y, Liang Z. Sensory evoked fMRI paradigms in awake mice. Neuroimage 2020; 204:116242. [DOI: 10.1016/j.neuroimage.2019.116242] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/08/2019] [Accepted: 10/02/2019] [Indexed: 01/25/2023] Open
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19
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Argibay B, Campos F, Perez-Mato M, Vieites-Prado A, Correa-Paz C, López-Arias E, Da Silva-Candal A, Moreno V, Montero C, Sobrino T, Castillo J, Iglesias-Rey R. Light-Emitting Diode Photobiomodulation After Cerebral Ischemia. Front Neurol 2019; 10:911. [PMID: 31507516 PMCID: PMC6713875 DOI: 10.3389/fneur.2019.00911] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/06/2019] [Indexed: 11/14/2022] Open
Abstract
Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm2) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm2 at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.
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Affiliation(s)
- Bárbara Argibay
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Francisco Campos
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - María Perez-Mato
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Alba Vieites-Prado
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Clara Correa-Paz
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Esteban López-Arias
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Andrés Da Silva-Candal
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Vicente Moreno
- Optics Area, Department of Applied Physics, Faculty of Physics, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain.,Faculty of Optics and Optometry, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Carlos Montero
- Optics Area, Department of Applied Physics, Faculty of Physics, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain.,Faculty of Optics and Optometry, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Tomás Sobrino
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - José Castillo
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ramón Iglesias-Rey
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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20
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Munting LP, Derieppe MP, Suidgeest E, Denis de Senneville B, Wells JA, van der Weerd L. Influence of different isoflurane anesthesia protocols on murine cerebral hemodynamics measured with pseudo-continuous arterial spin labeling. NMR IN BIOMEDICINE 2019; 32:e4105. [PMID: 31172591 PMCID: PMC6772066 DOI: 10.1002/nbm.4105] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/22/2019] [Accepted: 03/14/2019] [Indexed: 05/15/2023]
Abstract
Arterial spin labeling (ASL)-MRI can noninvasively map cerebral blood flow (CBF) and cerebrovascular reactivity (CVR), potential biomarkers of cognitive impairment and dementia. Mouse models of disease are frequently used in translational MRI studies, which are commonly performed under anesthesia. Understanding the influence of the specific anesthesia protocol used on the measured parameters is important for accurate interpretation of hemodynamic studies with mice. Isoflurane is a frequently used anesthetic with vasodilative properties. Here, the influence of three distinct isoflurane protocols was studied with pseudo-continuous ASL in two different mouse strains. The first protocol was a free-breathing set-up with medium concentrations, the second a free-breathing set-up with low induction and maintenance concentrations, and the third a set-up with medium concentrations and mechanical ventilation. A protocol with the vasoconstrictive anesthetic medetomidine was used as a comparison. As expected, medium isoflurane anesthesia resulted in significantly higher CBF and lower CVR values than medetomidine (median whole-brain CBF of 157.7 vs 84.4 mL/100 g/min and CVR of 0.54 vs 51.7% in C57BL/6 J mice). The other two isoflurane protocols lowered the CBF and increased the CVR values compared with medium isoflurane anesthesia, without obvious differences between them (median whole-brain CBF of 138.9 vs 131.7 mL/100 g/min and CVR of 10.0 vs 9.6%, in C57BL/6 J mice). Furthermore, CVR was shown to be dependent on baseline CBF, regardless of the anesthesia protocol used.
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Affiliation(s)
- Leon P. Munting
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
- Department of Human GeneticsLeiden University Medical CenterLeidenthe Netherlands
| | - Marc P.P. Derieppe
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
- Prinses Máxima Center for Pediatric OncologyUniversity Medical Center UtrechtUtrechtthe Netherlands
| | - Ernst Suidgeest
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Baudouin Denis de Senneville
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtthe Netherlands
- Institut de Mathématiques de BordeauxUniversité Bordeaux/CNRS UMR 5251/INRIABordeaux‐Sud‐OuestFrance
| | - Jack A. Wells
- Division of Medicine, UCL Centre for Advanced Biomedical ImagingUniversity College LondonLondonUK
| | - Louise van der Weerd
- Department of RadiologyLeiden University Medical CenterLeidenthe Netherlands
- Department of Human GeneticsLeiden University Medical CenterLeidenthe Netherlands
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21
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Functional spectroscopic imaging reveals specificity of glutamate response in mouse brain to peripheral sensory stimulation. Sci Rep 2019; 9:10563. [PMID: 31332260 PMCID: PMC6646328 DOI: 10.1038/s41598-019-46477-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/28/2019] [Indexed: 12/18/2022] Open
Abstract
Non-invasive investigation of physiological changes and metabolic events associated with brain activity in mice constitutes a major challenge. Conventionally, fMRI assesses neuronal activity by evaluating activity-evoked local changes in blood oxygenation levels (BOLD). In isoflurane-anaethetized mice, however, we found that BOLD signal changes during paw stimulation appear to be dominated by arousal responses even when using innocuous stimuli. Widespread responses involving both hemispheres have been observed in response to unilateral stimulation. MRS allows probing metabolic changes associated with neuronal activation and provides a complementary readout to BOLD fMRI for investigating brain activity. In this study we evaluated the sensitivity of a free induction decay (FID) based spectroscopic imaging (MRSI) protocol for the measurement of alterations in glutamate levels elicited by unilateral electrical paw stimulation at different current amplitudes. Coronal MRSI maps of glutamate distribution with 17 × 17 voxels of 1 µl volume have been recorded with a temporal resolution of 12 min. Significant region-specific increases in glutamate levels have been observed in the contralateral but not in the ispiateral S1 somatosensory cortex upon stimulation. The amplitude of glutamate changes increased in a dose-dependent manner with the stimulus amplitude. The study demonstrates feasibility of functional MRSI in mice for studying activity-evoked glutamate changes in a temporo-spatially resolved manner.
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22
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Todd N, Zhang Y, Livingstone M, Borsook D, McDannold N. The neurovascular response is attenuated by focused ultrasound-mediated disruption of the blood-brain barrier. Neuroimage 2019; 201:116010. [PMID: 31302253 DOI: 10.1016/j.neuroimage.2019.116010] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 12/21/2022] Open
Abstract
Focused ultrasound (FUS)-induced disruption of the blood-brain barrier (BBB) is a non-invasive method to target drug delivery to specific brain areas that is now entering into the clinic. Recent studies have shown that the method has several secondary effects on local physiology and brain function beyond making the vasculature permeable to normally non-BBB penetrant molecules. This study uses functional MRI methods to investigate how FUS BBB opening alters the neurovascular response in the rat brain. Nine rats underwent actual and sham FUS induced BBB opening targeted to the right somatosensory cortex (SI) followed by four runs of bilateral electrical hind paw stimulus-evoked fMRI. The neurovascular response was quantified using measurements of the blood oxygen level dependent (BOLD) signal and cerebral blood flow (CBF). An additional three rats underwent the same FUS-BBB opening followed by stimulus-evoked fMRI with high resolution BOLD imaging and BOLD imaging of a carbogen-breathing gas challenge. BOLD and CBF measurements at two different stimulus durations demonstrate that the neurovascular response to the stimulus is attenuated in both amplitude and duration in the region targeted for FUS-BBB opening. The carbogen results show that the attenuation in response amplitude, but not duration, is still present when the signaling mechanism originates from changes in blood oxygenation instead of stimulus-induced neuronal activity. There is some evidence of non-local effects, including a possible global decrease in baseline CBF. All effects are resolved by 24 h after FUS-BBB opening. Taken together, these results suggest that FUS-BBB opening alters that state of local brain neurovascular physiology in such a way that hinders its ability to respond to demands for increased blood flow to the region. The mechanisms for this effect need to be elucidated.
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Affiliation(s)
- Nick Todd
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States.
| | - Yongzhi Zhang
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States; Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | - Nathan McDannold
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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23
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Jung WB, Shim HJ, Kim SG. Mouse BOLD fMRI at ultrahigh field detects somatosensory networks including thalamic nuclei. Neuroimage 2019; 195:203-214. [DOI: 10.1016/j.neuroimage.2019.03.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/14/2019] [Accepted: 03/27/2019] [Indexed: 01/16/2023] Open
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24
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Schaeffer DJ, Gilbert KM, Hori Y, Gati JS, Menon RS, Everling S. Integrated radiofrequency array and animal holder design for minimizing head motion during awake marmoset functional magnetic resonance imaging. Neuroimage 2019; 193:126-138. [PMID: 30879997 DOI: 10.1016/j.neuroimage.2019.03.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/01/2019] [Accepted: 03/11/2019] [Indexed: 11/30/2022] Open
Abstract
Marmosets are small New World primates that are posited to become an important preclinical animal model for studying intractable human brain diseases. A critical step in the development of marmosets as a viable model for human brain dysfunction is to characterize brain networks that are homologous with human network topologies. In this regard, the use of functional magnetic resonance imaging (fMRI) holds tremendous potential for functional brain mapping in marmosets. Although possible, implementation of hardware for fMRI in awake marmosets (free of the confounding effects of anesthesia) is not trivial due to the technical challenges associated with developing specialized imaging hardware. Here, we describe the design and implementation of a marmoset holder and head-fixation system with an integrated receive coil for awake marmoset fMRI. This design minimized head motion, with less than 100 μm of translation and 0.5 degrees of rotation over 15 consecutive resting state fMRI runs (at 15 min each) across 3 different marmosets. The fMRI data was of sufficient quality to reliably extract 8 resting state networks from each animal with only 60-90 min of resting state fMRI acquisition per animal. The restraint system proved to be an efficient and practical solution for securing an awake marmoset and positioning a receive array within minutes, limiting stress to the animal. This design is also amenable for multimodal imaging, allowing for electrode or lens placement above the skull via the open chamber design. All computer-aided-design (CAD) files and engineering drawings are provided as an open resource, with the majority of the parts designed to be 3D printed.
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Affiliation(s)
- David J Schaeffer
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Kyle M Gilbert
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Yuki Hori
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Joseph S Gati
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Ravi S Menon
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Stefan Everling
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
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25
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Yanez Lopez M, Pardon MC, Baiker K, Prior M, Yuchun D, Agostini A, Bai L, Auer DP, Faas HM. Myoinositol CEST signal in animals with increased Iba-1 levels in response to an inflammatory challenge-Preliminary findings. PLoS One 2019; 14:e0212002. [PMID: 30789943 PMCID: PMC6383890 DOI: 10.1371/journal.pone.0212002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/08/2018] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation plays an important role in the pathogenesis of a range of brain disorders. Non-invasive imaging of neuroinflammation is critical to help improve our understanding of the underlying disease mechanisms, monitor therapies and guide drug development. Generally, MRI lacks specificity to molecular imaging biomarkers, but molecular MR imaging based on chemical exchange saturation transfer (CEST) can potentially detect changes of myoinositol, a putative glial marker that may index neuroinflammation. In this pilot study we aimed to investigate, through validation with immunohistochemistry and in vivo magnetic resonance spectroscopy (MRS), whether CEST imaging can reflect the microglial response to a mild inflammatory challenge with lipopolysaccharide (LPS), in the APPSwe/ PS1 mouse model of Alzheimer’s disease and wild type controls. The response to the immune challenge was variable and did not align with genotype. Animals with a strong response to LPS (Iba1+, n = 6) showed an increase in CEST contrast compared with those who did not (Iba1-, n = 6). Changes of myoinositol levels after LPS were not significant. We discuss the difficulties of this mild inflammatory model, the role of myoinositol as a glial biomarker, and the technical challenges of CEST imaging at 0.6ppm.
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Affiliation(s)
- Maria Yanez Lopez
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | | | - Kerstin Baiker
- School of Veterinary Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Malcolm Prior
- Medical Imaging Unit, University of Nottingham, Nottingham, United Kingdom
| | - Ding Yuchun
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alessandra Agostini
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Li Bai
- School of Computer Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Dorothee P. Auer
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
| | - Henryk M. Faas
- Sir Peter Mansfield Imaging Centre, School of Medicine, The University of Nottingham, Nottingham, United Kingdom
- * E-mail:
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26
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Todd N, Zhang Y, Power C, Becerra L, Borsook D, Livingstone M, McDannold N. Modulation of brain function by targeted delivery of GABA through the disrupted blood-brain barrier. Neuroimage 2019; 189:267-275. [PMID: 30659957 DOI: 10.1016/j.neuroimage.2019.01.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/29/2018] [Accepted: 01/14/2019] [Indexed: 12/11/2022] Open
Abstract
The technology of transcranial focused ultrasound (FUS) enables a novel approach to neuromodulation, a tool for selective manipulation of brain function to be used in neurobiology research and with potential applications in clinical treatment. The method uses transcranial focused ultrasound to non-invasively open the blood-brain barrier (BBB) in a localized region such that a systemically injected neurotransmitter chemical can be delivered to the targeted brain site. The approach modulates the chemical signaling that occurs in and between neurons, making it complimentary to most other neuromodulation techniques that affect the electrical properties of neuronal activity. Here, we report delivering the inhibitory neurotransmitter GABA to the right somatosensory cortex of the rat brain during bilateral hind paw electrical stimulation and measure the inhibition of activation using functional MRI (fMRI). In a 2 × 2 factorial design, we evaluated conditions of BBB Closed vs BBB Open and No GABA vs GABA. Results from fMRI measurements of the blood oxygen level-dependent (BOLD) signal show: 1) intravenous GABA injection without FUS-mediated BBB opening does not have an effect on the BOLD response; 2) FUS-mediated BBB opening alone significantly alters the BOLD signal response to the stimulus, both in amplitude and shape of the time course; 3) the combination of FUS-mediated BBB opening and GABA injection further reduces the peak amplitude and spatial extent of the BOLD signal response to the stimulus. The data support the thesis that FUS-mediated opening of the BBB can be used to achieve non-invasive delivery of neuroactive substances for targeted manipulation of brain function.
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Affiliation(s)
- Nick Todd
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Yongzhi Zhang
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chanikarn Power
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lino Becerra
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA; Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | | | - Nathan McDannold
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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27
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Mouse fMRI under ketamine and xylazine anesthesia: Robust contralateral somatosensory cortex activation in response to forepaw stimulation. Neuroimage 2018; 177:30-44. [DOI: 10.1016/j.neuroimage.2018.04.062] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 04/24/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
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28
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Choe KY, Sanchez CF, Harris NG, Otis TS, Mathews PJ. Optogenetic fMRI and electrophysiological identification of region-specific connectivity between the cerebellar cortex and forebrain. Neuroimage 2018; 173:370-383. [PMID: 29496611 PMCID: PMC5911204 DOI: 10.1016/j.neuroimage.2018.02.047] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 02/10/2018] [Accepted: 02/22/2018] [Indexed: 12/12/2022] Open
Abstract
Complex animal behavior is produced by dynamic interactions between discrete regions of the brain. As such, defining functional connections between brain regions is critical in gaining a full understanding of how the brain generates behavior. Evidence suggests that discrete regions of the cerebellar cortex functionally project to the forebrain, mediating long-range communication potentially important in motor and non-motor behaviors. However, the connectivity map remains largely incomplete owing to the challenge of driving both reliable and selective output from the cerebellar cortex, as well as the need for methods to detect region specific activation across the entire forebrain. Here we utilize a paired optogenetic and fMRI (ofMRI) approach to elucidate the downstream forebrain regions modulated by activating a region of the cerebellum that induces stereotypical, ipsilateral forelimb movements. We demonstrate with ofMRI, that activating this forelimb motor region of the cerebellar cortex results in functional activation of a variety of forebrain and midbrain areas of the brain, including the hippocampus and primary motor, retrosplenial and anterior cingulate cortices. We further validate these findings using optogenetic stimulation paired with multi-electrode array recordings and post-hoc staining for molecular markers of activated neurons (i.e. c-Fos). Together, these findings demonstrate that a single discrete region of the cerebellar cortex is capable of influencing motor output and the activity of a number of downstream forebrain as well as midbrain regions thought to be involved in different aspects of behavior.
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Affiliation(s)
- Katrina Y Choe
- Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles, CA 90095, USA; Integrative Center for Learning and Memory, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Carlos F Sanchez
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, 90502 USA
| | - Neil G Harris
- The UCLA Brain Injury Research Center, Department of Neurosurgery, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, CA, 90095, USA
| | - Thomas S Otis
- Department of Neurobiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Paul J Mathews
- Integrative Center for Learning and Memory, University of California at Los Angeles, Los Angeles, CA 90095, USA; Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, 90502 USA; Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA.
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29
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Todd N, Zhang Y, Arcaro M, Becerra L, Borsook D, Livingstone M, McDannold N. Focused ultrasound induced opening of the blood-brain barrier disrupts inter-hemispheric resting state functional connectivity in the rat brain. Neuroimage 2018; 178:414-422. [PMID: 29852281 DOI: 10.1016/j.neuroimage.2018.05.063] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/10/2018] [Accepted: 05/25/2018] [Indexed: 12/18/2022] Open
Abstract
Focused ultrasound (FUS) is a technology capable of delivering therapeutic levels of energy through the intact skull to a tightly localized brain region. Combining the FUS pressure wave with intravenously injected microbubbles creates forces on blood vessel walls that open the blood-brain barrier (BBB). This noninvasive and localized opening of the BBB allows for targeted delivery of pharmacological agents into the brain for use in therapeutic development. It is possible to use FUS power levels such that the BBB is opened without damaging local tissues. However, open questions remain related to the effects that FUS-induced BBB opening has on brain function including local physiology and vascular hemodynamics. We evaluated the effects that FUS-induced BBB opening has on resting state functional magnetic resonance imaging (rs-fMRI) metrics. Data from rs-fMRI was acquired in rats that underwent sham FUS BBB vs. FUS BBB opening targeted to the right primary somatosensory cortex hindlimb region (S1HL). FUS BBB opening reduced the functional connectivity between the right S1HL and other sensorimotor regions, including statistically significant reduction of connectivity to the homologous region in the left hemisphere (left S1HL). The effect was observed in all three metrics analyzed: functional connectivity between anatomically defined regions, whole brain voxel-wise correlation maps based on anatomical seeds, and spatial patterns from independent component analysis. Connectivity metrics for other regions where the BBB was not perturbed were not affected. While it is not clear whether the effect is vascular or neuronal in origin, these results suggest that even safe levels of FUS BBB opening have an effect on the physiological processes that drive the signals measured by BOLD fMRI. As such these effects must be accounted for when carrying out studies using fMRI to evaluate the effects of pharmacological agents delivered via FUS-induced BBB opening.
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Affiliation(s)
- Nick Todd
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States; Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States.
| | - Yongzhi Zhang
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | - Michael Arcaro
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Lino Becerra
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States; Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, United States
| | | | - Nathan McDannold
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, United States
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30
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Asaad M, Lee JH. A guide to using functional magnetic resonance imaging to study Alzheimer's disease in animal models. Dis Model Mech 2018; 11:dmm031724. [PMID: 29784664 PMCID: PMC5992611 DOI: 10.1242/dmm.031724] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease is a leading healthcare challenge facing our society today. Functional magnetic resonance imaging (fMRI) of the brain has played an important role in our efforts to understand how Alzheimer's disease alters brain function. Using fMRI in animal models of Alzheimer's disease has the potential to provide us with a more comprehensive understanding of the observations made in human clinical fMRI studies. However, using fMRI in animal models of Alzheimer's disease presents some unique challenges. Here, we highlight some of these challenges and discuss potential solutions for researchers interested in performing fMRI in animal models. First, we briefly summarize our current understanding of Alzheimer's disease from a mechanistic standpoint. We then overview the wide array of animal models available for studying this disease and how to choose the most appropriate model to study, depending on which aspects of the condition researchers seek to investigate. Finally, we discuss the contributions of fMRI to our understanding of Alzheimer's disease and the issues to consider when designing fMRI studies for animal models, such as differences in brain activity based on anesthetic choice and ways to interrogate more specific questions in rodents beyond those that can be addressed in humans. The goal of this article is to provide information on the utility of fMRI, and approaches to consider when using fMRI, for studies of Alzheimer's disease in animal models.
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Affiliation(s)
- Mazen Asaad
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
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31
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Schlegel F, Sych Y, Schroeter A, Stobart J, Weber B, Helmchen F, Rudin M. Fiber-optic implant for simultaneous fluorescence-based calcium recordings and BOLD fMRI in mice. Nat Protoc 2018; 13:840-855. [PMID: 29599439 DOI: 10.1038/nprot.2018.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Despite the growing popularity of blood oxygen level-dependent (BOLD) functional MRI (fMRI), understanding of its underlying principles is still limited. This protocol describes a technique for simultaneous measurement of neural activity using fluorescent calcium indicators together with the corresponding hemodynamic BOLD fMRI response in the mouse brain. Our early work using small-molecule fluorophores in rats gave encouraging results but was limited to acute measurements using synthetic dyes. Our latest procedure combines fMRI with optical detection of cell-type-specific virally delivered GCaMP6, a genetically encoded calcium indicator (GECI). GCaMP6 fluorescence, which increases upon calcium binding, is collected by a chronically implanted optical fiber, allowing longitudinal studies in mice. The chronic implant, placed horizontally on the skull, has an angulated tip that reflects light into the brain and is connected via fiber optics to a remote optical setup. The technique allows access to the neocortex and does not require adaptations of commercial MRI hardware. The hybrid approach permits fiber-optic calcium recordings with simultaneous artifact-free BOLD fMRI with full brain coverage and 1-s temporal resolution using standard gradient-echo echo-planar imaging (GE-EPI) sequences. The method provides robust, cell-type-specific readouts to link neural activity to BOLD signals, as emonstrated for task-free ('resting-state') conditions and in response to hind-paw stimulation. These results highlight the power of fiber photometry combined with fMRI, which we aim to further advance in this protocol. The approach can be easily adapted to study other molecular processes using suitable fluorescent indicators.
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Affiliation(s)
- Felix Schlegel
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Yaroslav Sych
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Aileen Schroeter
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Jillian Stobart
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Bruno Weber
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Fritjof Helmchen
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.,Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
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32
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Blazquez Freches G, Chavarrias C, Shemesh N. BOLD-fMRI in the mouse auditory pathway. Neuroimage 2018; 165:265-277. [DOI: 10.1016/j.neuroimage.2017.10.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 10/09/2017] [Accepted: 10/13/2017] [Indexed: 01/31/2023] Open
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33
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Wei Z, Xu J, Liu P, Chen L, Li W, van Zijl P, Lu H. Quantitative assessment of cerebral venous blood T 2 in mouse at 11.7T: Implementation, optimization, and age effect. Magn Reson Med 2017; 80:521-528. [PMID: 29271045 DOI: 10.1002/mrm.27046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/30/2017] [Accepted: 11/20/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE To develop a non-contrast-agent MRI technique to quantify cerebral venous T2 in mice. METHODS We implemented and optimized a T2 -relaxation-under-spin-tagging (TRUST) sequence on an 11.7 Tesla animal imaging system. A flow-sensitive-alternating-inversion-recovery (FAIR) module was used to generate control and label images, pair-wise subtraction of which yielded blood signals. Then, a T2 -preparation module was applied to produce T2 -weighted images, from which blood T2 was quantified. We conducted a series of technical studies to optimize the imaging slice position, inversion slab thickness, post-labeling delay (PLD), and repetition time. We also performed three physiological studies to examine the venous T2 dependence on hyperoxia (N = 4), anesthesia (N = 3), and brain aging (N = 5). RESULTS Our technical studies suggested that, for efficient data acquisition with minimal bias in estimated T2 , a preferred TRUST protocol was to place the imaging slice at the confluence of sagittal sinuses with an inversion-slab thickness of 2.5-mm, a PLD of 1000 ms and a repetition time of 3.5 s. Venous T2 values under normoxia and hyperoxia (inhaling pure oxygen) were 26.9 ± 1.7 and 32.3 ± 2.2 ms, respectively. Moreover, standard isoflurane anesthesia resulted in a higher venous T2 compared with dexmedetomidine anesthesia (N = 3; P = 0.01) which is more commonly used in animal functional MRI studies to preserve brain function. Venous T2 exhibited a decrease with age (N = 5; P < 0.001). CONCLUSION We have developed and optimized a noninvasive method to quantify cerebral venous blood T2 in mouse at 11.7 T. This method may prove useful in studies of brain physiology and pathophysiology in animal models. Magn Reson Med 80:521-528, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zhiliang Wei
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Jiadi Xu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Peiying Liu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Lin Chen
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Wenbo Li
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Peter van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Hanzhang Lu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Hakon J, Quattromani MJ, Sjölund C, Tomasevic G, Carey L, Lee JM, Ruscher K, Wieloch T, Bauer AQ. Multisensory stimulation improves functional recovery and resting-state functional connectivity in the mouse brain after stroke. NEUROIMAGE-CLINICAL 2017; 17:717-730. [PMID: 29264113 PMCID: PMC5726755 DOI: 10.1016/j.nicl.2017.11.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/27/2017] [Accepted: 11/23/2017] [Indexed: 10/25/2022]
Abstract
Stroke causes direct structural damage to local brain networks and indirect functional damage to distant brain regions. Neuroplasticity after stroke involves molecular changes within perilesional tissue that can be influenced by regions functionally connected to the site of injury. Spontaneous functional recovery can be enhanced by rehabilitative strategies, which provides experience-driven cell signaling in the brain that enhances plasticity. Functional neuroimaging in humans and rodents has shown that spontaneous recovery of sensorimotor function after stroke is associated with changes in resting-state functional connectivity (RS-FC) within and across brain networks. At the molecular level, GABAergic inhibitory interneurons can modulate brain plasticity in peri-infarct and remote brain regions. Among this cell-type, a decrease in parvalbumin (PV)-immunoreactivity has been associated with improved behavioral outcome. Subjecting rodents to multisensory stimulation through exposure to an enriched environment (EE) enhances brain plasticity and recovery of function after stroke. Yet, how multisensory stimulation relates to RS-FC has not been determined. In this study, we investigated the effect of EE on recovery of RS-FC and behavior in mice after stroke, and if EE-related changes in RS-FC were associated with levels of PV-expressing neurons. Photothrombotic stroke was induced in the sensorimotor cortex. Beginning 2 days after stroke, mice were housed in either standard environment (STD) or EE for 12 days. Housing in EE significantly improved lost tactile-proprioceptive function compared to mice housed in STD environment. RS-FC in the mouse was measured by optical intrinsic signal imaging 14 days after stroke or sham surgery. Stroke induced a marked reduction in RS-FC within several perilesional and remote brain regions. EE partially restored interhemispheric homotopic RS-FC between spared motor regions, particularly posterior secondary motor. Compared to mice housed in STD cages, EE exposure lead to increased RS-FC between posterior secondary motor regions and contralesional posterior parietal and retrosplenial regions. The increased regional RS-FC observed in EE mice after stroke was significantly correlated with decreased PV-immunoreactivity in the contralesional posterior motor region. In conclusion, experimental stroke and subsequent housing in EE induces dynamic changes in RS-FC in the mouse brain. Multisensory stimulation associated with EE enhances RS-FC among distinct brain regions relevant for recovery of sensorimotor function and controlled movements that may involve PV/GABA interneurons. Our results indicate that targeting neural circuitry involving spared motor regions across hemispheres by neuromodulation and multimodal sensory stimulation could improve rehabilitation after stroke.
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Key Words
- EE, enriched environment
- Enriched environment
- GSR, global signal regression
- M1, primary motor cortex
- M2, secondary motor cortex
- M2p, posterior secondary motor cortex
- MSR, multiple signal regression
- NDc, interhemispheric (contralateral) node degree
- NDi, intrahemispheric node degree
- Optical imaging
- PP, posterior parietal cortex
- PV, parvalbumin
- Parvalbumin
- ROI, region of interest
- RS, retrosplenial cortex
- RS-FC, resting-state functional connectivity
- Recovery
- Resting-state functional connectivity
- SFL, somatosensory forelimb cortex
- STD, standard environment
- Stroke
- VIS, visual cortex
- fcOIS, functional connectivity optical intrinsic signal imaging
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Affiliation(s)
- Jakob Hakon
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden.
| | - Miriana Jlenia Quattromani
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden
| | - Carin Sjölund
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden
| | - Gregor Tomasevic
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden; Department of Neurosurgery, University Hospital of Lund, Lund, Sweden
| | - Leeanne Carey
- School of Allied Health, La Trobe University, Melbourne, Vic., Australia; Neurorehabilitation and Recovery Laboratory, Florey Institute of Neuroscience and Mental Health, Melbourne, Vic., Australia
| | - Jin-Moo Lee
- Department of Radiology, Washington University, Saint Louis, MO 63110, USA; Department of Neurology, Washington University, Saint Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University, Saint Louis, MO 63110, USA
| | - Karsten Ruscher
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden
| | - Tadeusz Wieloch
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden
| | - Adam Q Bauer
- Department of Radiology, Washington University, Saint Louis, MO 63110, USA
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Functional networks and network perturbations in rodents. Neuroimage 2017; 163:419-436. [DOI: 10.1016/j.neuroimage.2017.09.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 11/16/2022] Open
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Noristani HN, Boukhaddaoui H, Saint-Martin G, Auzer P, Sidiboulenouar R, Lonjon N, Alibert E, Tricaud N, Goze-Bac C, Coillot C, Perrin FE. A Combination of Ex vivo Diffusion MRI and Multiphoton to Study Microglia/Monocytes Alterations after Spinal Cord Injury. Front Aging Neurosci 2017; 9:230. [PMID: 28769787 PMCID: PMC5515855 DOI: 10.3389/fnagi.2017.00230] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Central nervous system (CNS) injury has been observed to lead to microglia activation and monocytes infiltration at the lesion site. Ex vivo diffusion magnetic resonance imaging (diffusion MRI or DWI) allows detailed examination of CNS tissues, and recent advances in clearing procedures allow detailed imaging of fluorescent-labeled cells at high resolution. No study has yet combined ex vivo diffusion MRI and clearing procedures to establish a possible link between microglia/monocytes response and diffusion coefficient in the context of spinal cord injury (SCI). We carried out ex vivo MRI of the spinal cord at different time-points after spinal cord transection followed by tetrahydrofuran based clearing and examined the density and morphology of microglia/monocytes using two-photon microscopy. Quantitative analysis revealed an early marked increase in microglial/monocytes density that is associated with an increase in the extension of the lesion measured using diffusion MRI. Morphological examination of microglia/monocytes somata at the lesion site revealed a significant increase in their surface area and volume as early as 72 hours post-injury. Time-course analysis showed differential microglial/monocytes response rostral and caudal to the lesion site. Microglia/monocytes showed a decrease in reactivity over time caudal to the lesion site, but an increase was observed rostrally. Direct comparison of microglia/monocytes morphology, obtained through multiphoton, and the longitudinal apparent diffusion coefficient (ADC), measured with diffusion MRI, highlighted that axonal integrity does not correlate with the density of microglia/monocytes or their somata morphology. We emphasize that differential microglial/monocytes reactivity rostral and caudal to the lesion site may thus coincide, at least partially, with reported temporal differences in debris clearance. Our study demonstrates that the combination of ex vivo diffusion MRI and two-photon microscopy may be used to follow structural tissue alteration. Lesion extension coincides with microglia/monocytes density; however, a direct relationship between ADC and microglia/monocytes density and morphology was not observed. We highlighted a differential rostro-caudal microglia/monocytes reactivity that may correspond to a temporal difference in debris clearance and axonal integrity. Thus, potential therapeutic strategies targeting microglia/monocytes after SCI may need to be adjusted not only with the time after injury but also relative to the location to the lesion site.
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Affiliation(s)
- Harun N Noristani
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France.,University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France
| | - Hassan Boukhaddaoui
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Guillaume Saint-Martin
- University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France.,Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Pauline Auzer
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Rahima Sidiboulenouar
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Nicolas Lonjon
- University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France.,Centre Hospitalier Universitaire de Montpellier (CHRU), Gui de Chauliac HospitalMontpellier, France
| | - Eric Alibert
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Nicolas Tricaud
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France
| | - Christophe Goze-Bac
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Christophe Coillot
- Charles Coulomb Laboratory, UMR 5221 Centre National de la Recherche ScientifiqueMontpellier, France
| | - Florence E Perrin
- Institut National de la Santé et de la Recherche Médicale, U1051Montpellier, France.,University of Montpellier, Montpellier; Institut National de la Santé et de la Recherche Médicale, U1198, Montpellier; École Pratique des Hautes ÉtudesParis, France
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Schroeter A, Grandjean J, Schlegel F, Saab BJ, Rudin M. Contributions of structural connectivity and cerebrovascular parameters to functional magnetic resonance imaging signals in mice at rest and during sensory paw stimulation. J Cereb Blood Flow Metab 2017; 37:2368-2382. [PMID: 27596833 PMCID: PMC5531337 DOI: 10.1177/0271678x16666292] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Previously, we reported widespread bilateral increases in stimulus-evoked functional magnetic resonance imaging signals in mouse brain to unilateral sensory paw stimulation. We attributed the pattern to arousal-related cardiovascular changes overruling cerebral autoregulation thereby masking specific signal changes elicited by local neuronal activity. To rule out the possibility that interhemispheric neuronal communication might contribute to bilateral functional magnetic resonance imaging responses, we compared stimulus-evoked functional magnetic resonance imaging responses to unilateral hindpaw stimulation in acallosal I/LnJ, C57BL/6, and BALB/c mice. We found bilateral blood-oxygenation-level dependent signal changes in all three strains, ruling out a dominant contribution of transcallosal communication as reason for bilaterality. Analysis of functional connectivity derived from resting-state functional magnetic resonance imaging, revealed that bilateral cortical functional connectivity is largely abolished in I/LnJ animals. Cortical functional connectivity in all strains correlated with structural connectivity in corpus callosum as revealed by diffusion tensor imaging. Given the profound influence of systemic hemodynamics on stimulus-evoked functional magnetic resonance imaging outcomes, we evaluated whether functional connectivity data might be affected by cerebrovascular parameters, i.e. baseline cerebral blood volume, vascular reactivity, and reserve. We found that effects of cerebral hemodynamics on functional connectivity are largely outweighed by dominating contributions of structural connectivity. In contrast, contributions of transcallosal interhemispheric communication to the occurrence of ipsilateral functional magnetic resonance imaging response of equal amplitude to unilateral stimuli seem negligible.
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Affiliation(s)
- Aileen Schroeter
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Joanes Grandjean
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Felix Schlegel
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
| | - Bechara J Saab
- 2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.,3 Preclinical Laboratory for Translational Research into Affective Disorders, University of Zurich Hospital for Psychiatry, Zurich, Switzerland
| | - Markus Rudin
- 1 Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.,2 Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland.,4 Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
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Lin YT, Liu HL, Day YJ, Chang CC, Hsu PH, Chen JC. Activation of NPFFR2 leads to hyperalgesia through the spinal inflammatory mediator CGRP in mice. Exp Neurol 2017; 291:62-73. [DOI: 10.1016/j.expneurol.2017.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/25/2017] [Accepted: 02/01/2017] [Indexed: 01/22/2023]
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Mazuel L, Blanc J, Repond C, Bouchaud V, Raffard G, Déglon N, Bonvento G, Pellerin L, Bouzier-Sore AK. A neuronal MCT2 knockdown in the rat somatosensory cortex reduces both the NMR lactate signal and the BOLD response during whisker stimulation. PLoS One 2017; 12:e0174990. [PMID: 28388627 PMCID: PMC5384673 DOI: 10.1371/journal.pone.0174990] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/17/2017] [Indexed: 12/20/2022] Open
Abstract
Although several in vitro and ex vivo evidence support the existence of lactate exchange between astrocytes and neurons, a direct demonstration in vivo is still lacking. In the present study, a lentiviral vector carrying a short hairpin RNA (shRNA) was used to downregulate the expression of the monocarboxylate transporter type 2 (MCT2) in neurons of the rat somatosensory cortex (called S1BF) by ~ 25%. After one hour of whisker stimulation, HRMAS 1H-NMR spectroscopy analysis of S1BF perchloric acid extracts showed that while an increase in lactate content is observed in both uninjected and shRNA-control injected extracts, such an effect was abrogated in shMCT2 injected rats. A 13C-incorporation analysis following [1-13C]glucose infusion during the stimulation confirmed that the elevated lactate observed during activation originates from newly synthesized [3-13C]lactate, with blood-derived [1-13C]glucose being the precursor. Moreover, the analysis of the 13C-labeling of glutamate in position C3 and C4 indicates that upon activation, there is an increase in TCA cycle velocity for control rats while a decrease is observed for MCT2 knockdown animals. Using in vivo localized 1H-NMR spectroscopy, an increase in lactate levels is observed in the S1BF area upon whisker stimulation for shRNA-control injected rats but not for MCT2 knockdown animals. Finally, while a robust BOLD fMRI response was evidenced in control rats, it was absent in MCT2 knockdown rats. These data not only demonstrate that glucose-derived lactate is locally produced following neuronal activation but also suggest that its use by neurons via MCT2 is probably essential to maintain synaptic activity within the barrel cortex.
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Affiliation(s)
- Leslie Mazuel
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Jordy Blanc
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Cendrine Repond
- Département de Physiologie, 7 rue du Bugnon, CH Lausanne, Switzerland
| | - Véronique Bouchaud
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Gérard Raffard
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
| | - Nicole Déglon
- Department of Clinical Neurosciences, Laboratory of Cellular and Molecular Neurotherapies (LCMN), Lausanne University Hospital, Lausanne, Switzerland
- Neurosciences Research Center (CRN), LCMN, Lausanne University Hospital, Lausanne, Switzerland
| | - Gilles Bonvento
- Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Département de la Recherche Fondamentale (DRF), Institut d’Imagerie Biomédicale (I2BM), Molecular Imaging Center (MIRCen), CNRS UMR 9199, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Luc Pellerin
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
- Département de Physiologie, 7 rue du Bugnon, CH Lausanne, Switzerland
| | - Anne-Karine Bouzier-Sore
- Centre de Résonance Magnétique des Systèmes Biologiques UMR 5536, CNRS—Université Bordeaux 146 rue Léo-Saignat, Bordeaux, France
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Activity and connectivity changes of central projection areas revealed by functional magnetic resonance imaging in Na V1.8-deficient mice upon cold signaling. Sci Rep 2017; 7:543. [PMID: 28373680 PMCID: PMC5428718 DOI: 10.1038/s41598-017-00524-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 03/03/2017] [Indexed: 12/19/2022] Open
Abstract
The voltage-gated sodium channel subtype NaV1.8 is expressed in the peripheral nervous system in primary afferent nociceptive C-fibers and is essential for noxious cold signaling. We utilized functional magnetic resonance imaging on NaV1.8-deficient (NaV1.8−/−) compared with wildtype (WT) mice to identify brain structures decoding noxious cold and/or heat signals. In NaV1.8−/− mice functional activity patterns, activated volumes and BOLD signal amplitudes are significantly reduced upon noxious cold stimulation whereas differences of noxious heat processing are less pronounced. Graph-theoretical analysis of the functional connectivity also shows dramatic alterations in noxious cold sensation in NaV1.8−/− mice and clearly reduced interactions between certain brain structures. In contrast, upon heat stimulation qualitatively quite the same functional connectivity pattern and consequently less prominent connectivity differences were observed between NaV1.8−/− and WT mice. Thus, the fact that NaV1.8−/− mice do not perceive nociceptive aspects of strong cooling in contrast to their WT littermates seems not only to be a pure peripheral phenomenon with diminished peripheral transmission, but also consists of upstream effects leading to altered subsequent nociceptive processing in the central nervous system and consequently altered connectivity between pain-relevant brain structures.
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Reisman MD, Markow ZE, Bauer AQ, Culver JP. Structured illumination diffuse optical tomography for noninvasive functional neuroimaging in mice. NEUROPHOTONICS 2017; 4:021102. [PMID: 28439519 PMCID: PMC5391480 DOI: 10.1117/1.nph.4.2.021102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/01/2017] [Indexed: 05/15/2023]
Abstract
Optical intrinsic signal (OIS) imaging has been a powerful tool for capturing functional brain hemodynamics in rodents. Recent wide field-of-view implementations of OIS have provided efficient maps of functional connectivity from spontaneous brain activity in mice. However, OIS requires scalp retraction and is limited to superficial cortical tissues. Diffuse optical tomography (DOT) techniques provide noninvasive imaging, but previous DOT systems for rodent neuroimaging have been limited either by sparse spatial sampling or by slow speed. Here, we develop a DOT system with asymmetric source-detector sampling that combines the high-density spatial sampling (0.4 mm) detection of a scientific complementary metal-oxide-semiconductor camera with the rapid (2 Hz) imaging of a few ([Formula: see text]) structured illumination (SI) patterns. Analysis techniques are developed to take advantage of the system's flexibility and optimize trade-offs among spatial sampling, imaging speed, and signal-to-noise ratio. An effective source-detector separation for the SI patterns was developed and compared with light intensity for a quantitative assessment of data quality. The light fall-off versus effective distance was also used for in situ empirical optimization of our light model. We demonstrated the feasibility of this technique by noninvasively mapping the functional response in the somatosensory cortex of the mouse following electrical stimulation of the forepaw.
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Affiliation(s)
- Matthew D. Reisman
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
| | - Zachary E. Markow
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Adam Q. Bauer
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Joseph P. Culver
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Address all correspondence to: Joseph P. Culver, E-mail:
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Kao YCJ, Oyarzabal EA, Zhang H, Faber JE, Shih YYI. Role of Genetic Variation in Collateral Circulation in the Evolution of Acute Stroke: A Multimodal Magnetic Resonance Imaging Study. Stroke 2017; 48:754-761. [PMID: 28188261 DOI: 10.1161/strokeaha.116.015878] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND PURPOSE No studies have determined the effect of differences in pial collateral extent (number and diameter), independent of differences in environmental factors and unknown genetic factors, on severity of stroke. We examined ischemic tissue evolution during acute stroke, as measured by magnetic resonance imaging and histology, by comparing 2 congenic mouse strains with otherwise identical genetic backgrounds but with different alleles of the Determinant of collateral extent-1 (Dce1) genetic locus. We also optimized magnetic resonance perfusion and diffusion-deficit thresholds by using histological measures of ischemic tissue. METHODS Perfusion, diffusion, and T2-weighted magnetic resonance imaging were performed on collateral-poor (congenic-Bc) and collateral-rich (congenic-B6) mice at 1, 5, and 24 hours after permanent middle cerebral artery occlusion. Magnetic resonance imaging-derived penumbra and ischemic core volumes were confirmed by histology in a subset of mice at 5 and 24 hours after permanent middle cerebral artery occlusion. RESULTS Although perfusion-deficit volumes were similar between strains 1 hour after permanent middle cerebral artery occlusion, diffusion-deficit volumes were 32% smaller in collateral-rich mice. At 5 hours, collateral-rich mice had markedly restored perfusion patterns showing reduced perfusion-deficit volumes, smaller infarct volumes, and smaller perfusion-diffusion mismatch volumes compared with the collateral-poor mice (P<0.05). At 24 hours, collateral-rich mice had 45% smaller T2-weighted lesion volumes (P<0.005) than collateral-poor mice, with no difference in perfusion-diffusion mismatch volumes because of penumbral death occurring 5 to 24 hours after permanent middle cerebral artery occlusion in collateral-poor mice. CONCLUSIONS Variation in collateral extent significantly alters infarct volume expansion, transiently affects perfusion and diffusion magnetic resonance imaging signatures, and impacts salvage of ischemic penumbra after stroke onset.
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Affiliation(s)
- Yu-Chieh Jill Kao
- From the Department of Neurology (Y.-C.J.K., E.A.O.), Biomedical Research Imaging Center (Y.-C.J.K., E.A.O., Y.-Y.I.S.), Neurobiology Curriculum (E.A.O., J.E.F.), Department of Cell Biology and Physiology (H.Z., J.E.F.), McAllister Heart Institute (H.Z., J.E.F., Y.-Y.I.S.), and Department of Biomedical Engineering (Y.-Y.I.S.), University of North Carolina, Chapel Hill; and Translational Imaging Research Center (Y.-C.J.K.) and Department of Radiology, School of Medicine (Y.-C.J.K.), College of Medicine, Taipei Medical University, Taiwan
| | - Esteban A Oyarzabal
- From the Department of Neurology (Y.-C.J.K., E.A.O.), Biomedical Research Imaging Center (Y.-C.J.K., E.A.O., Y.-Y.I.S.), Neurobiology Curriculum (E.A.O., J.E.F.), Department of Cell Biology and Physiology (H.Z., J.E.F.), McAllister Heart Institute (H.Z., J.E.F., Y.-Y.I.S.), and Department of Biomedical Engineering (Y.-Y.I.S.), University of North Carolina, Chapel Hill; and Translational Imaging Research Center (Y.-C.J.K.) and Department of Radiology, School of Medicine (Y.-C.J.K.), College of Medicine, Taipei Medical University, Taiwan
| | - Hua Zhang
- From the Department of Neurology (Y.-C.J.K., E.A.O.), Biomedical Research Imaging Center (Y.-C.J.K., E.A.O., Y.-Y.I.S.), Neurobiology Curriculum (E.A.O., J.E.F.), Department of Cell Biology and Physiology (H.Z., J.E.F.), McAllister Heart Institute (H.Z., J.E.F., Y.-Y.I.S.), and Department of Biomedical Engineering (Y.-Y.I.S.), University of North Carolina, Chapel Hill; and Translational Imaging Research Center (Y.-C.J.K.) and Department of Radiology, School of Medicine (Y.-C.J.K.), College of Medicine, Taipei Medical University, Taiwan
| | - James E Faber
- From the Department of Neurology (Y.-C.J.K., E.A.O.), Biomedical Research Imaging Center (Y.-C.J.K., E.A.O., Y.-Y.I.S.), Neurobiology Curriculum (E.A.O., J.E.F.), Department of Cell Biology and Physiology (H.Z., J.E.F.), McAllister Heart Institute (H.Z., J.E.F., Y.-Y.I.S.), and Department of Biomedical Engineering (Y.-Y.I.S.), University of North Carolina, Chapel Hill; and Translational Imaging Research Center (Y.-C.J.K.) and Department of Radiology, School of Medicine (Y.-C.J.K.), College of Medicine, Taipei Medical University, Taiwan
| | - Yen-Yu Ian Shih
- From the Department of Neurology (Y.-C.J.K., E.A.O.), Biomedical Research Imaging Center (Y.-C.J.K., E.A.O., Y.-Y.I.S.), Neurobiology Curriculum (E.A.O., J.E.F.), Department of Cell Biology and Physiology (H.Z., J.E.F.), McAllister Heart Institute (H.Z., J.E.F., Y.-Y.I.S.), and Department of Biomedical Engineering (Y.-Y.I.S.), University of North Carolina, Chapel Hill; and Translational Imaging Research Center (Y.-C.J.K.) and Department of Radiology, School of Medicine (Y.-C.J.K.), College of Medicine, Taipei Medical University, Taiwan.
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43
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Bukhari Q, Schroeter A, Cole DM, Rudin M. Resting State fMRI in Mice Reveals Anesthesia Specific Signatures of Brain Functional Networks and Their Interactions. Front Neural Circuits 2017; 11:5. [PMID: 28217085 PMCID: PMC5289996 DOI: 10.3389/fncir.2017.00005] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/16/2017] [Indexed: 01/29/2023] Open
Abstract
fMRI studies in mice typically require the use of anesthetics. Yet, it is known that anesthesia alters responses to stimuli or functional networks at rest. In this work, we have used Dual Regression analysis Network Modeling to investigate the effects of two commonly used anesthetics, isoflurane and medetomidine, on rs-fMRI derived functional networks, and in particular to what extent anesthesia affected the interaction within and between these networks. Experimental data have been used from a previous study (Grandjean et al., 2014). We applied multivariate ICA analysis and Dual Regression to infer the differences in functional connectivity between isoflurane- and medetomidine-anesthetized mice. Further network analysis was performed to investigate within- and between-network connectivity differences between these anesthetic regimens. The results revealed five major networks in the mouse brain: lateral cortical, associative cortical, default mode, subcortical, and thalamic network. The anesthesia regime had a profound effect both on within- and between-network interactions. Under isoflurane anesthesia predominantly intra- and inter-cortical interactions have been observed, with only minor interactions involving subcortical structures and in particular attenuated cortico-thalamic connectivity. In contrast, medetomidine-anesthetized mice displayed subcortical functional connectivity including interactions between cortical and thalamic ICA components. Combining the two anesthetics at low dose resulted in network interaction that constituted the superposition of the interaction observed for each anesthetic alone. The study demonstrated that network modeling is a promising tool for analyzing the brain functional architecture in mice and comparing alterations therein caused by different physiological or pathological states. Understanding the differential effects of anesthetics on brain networks and their interaction is essential when interpreting fMRI data recorded under specific physiological and pathological conditions.
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Affiliation(s)
- Qasim Bukhari
- Institute of Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland
| | - Aileen Schroeter
- Institute of Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland
| | - David M Cole
- Institute of Biomedical Engineering, University of Zurich and ETH ZurichZurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of PsychiatryZurich, Switzerland
| | - Markus Rudin
- Institute of Biomedical Engineering, University of Zurich and ETH ZurichZurich, Switzerland; Institute of Pharmacology and Toxicology, University of ZurichZurich, Switzerland
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Keilholz SD, Pan WJ, Billings J, Nezafati M, Shakil S. Noise and non-neuronal contributions to the BOLD signal: applications to and insights from animal studies. Neuroimage 2016; 154:267-281. [PMID: 28017922 DOI: 10.1016/j.neuroimage.2016.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/21/2016] [Accepted: 12/08/2016] [Indexed: 01/08/2023] Open
Abstract
The BOLD signal reflects hemodynamic events within the brain, which in turn are driven by metabolic changes and neural activity. However, the link between BOLD changes and neural activity is indirect and can be influenced by a number of non-neuronal processes. Motion and physiological cycles have long been known to affect the BOLD signal and are present in both humans and animal models. Differences in physiological baseline can also contribute to intra- and inter-subject variability. The use of anesthesia, common in animal studies, alters neural activity, vascular tone, and neurovascular coupling. Most intriguing, perhaps, are the contributions from other processes that do not appear to be neural in origin but which may provide information about other aspects of neurophysiology. This review discusses different types of noise and non-neuronal contributors to the BOLD signal, sources of variability for animal studies, and insights to be gained from animal models.
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Affiliation(s)
- Shella D Keilholz
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States; Neuroscience Program, Emory University, Atlanta, GA, United States.
| | - Wen-Ju Pan
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States
| | - Jacob Billings
- Neuroscience Program, Emory University, Atlanta, GA, United States
| | - Maysam Nezafati
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States
| | - Sadia Shakil
- Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States
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45
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Functional brain mapping using specific sensory-circuit stimulation and a theoretical graph network analysis in mice with neuropathic allodynia. Sci Rep 2016; 6:37802. [PMID: 27898057 PMCID: PMC5127182 DOI: 10.1038/srep37802] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 11/02/2016] [Indexed: 11/08/2022] Open
Abstract
Allodynia, a form of neuropathic pain, is defined as pain in response to a non-nociceptive stimulus. The brain regions responsible for pain, which are not normally activated, can be activated in allodynic mice by providing a suitable stimulus to Aβ-fibers, which transmit signals from tactile sensory fibers. Functional MRI (fMRI) can be used to objectively observe abnormal brain activation. In the present study, fMRI was conducted to investigate allodynia in mice; allodynia was generated by surgical injury at the L4 spinal nerve root, thus selectively stimulating sensory nerve fibers. In intact mice, only the primary somatosensory cortex (S1) was activated by stimulation of Aβ-fibers. Meanwhile, allodynic mice showed significantly higher BOLD signals in the anterior cingulate area (ACA) and thalamus. Using resting state fMRI, both degree and eigenvector centrality were significantly decreased in the contralateral S1, clustering coefficient and local efficiency were significantly increased in the ACA, and betweenness centrality was significantly higher in the ventral posterolateral nucleus of the thalamus. These results suggest that the observed abnormal BOLD activation is associated with defects in Aβ-fibers when Aβ-fibers in allodynic mice are selectively stimulated. The objective approach enabled by fMRI can improve our understanding of pathophysiological mechanisms and therapeutic efficacy.
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Niranjan A, Christie IN, Solomon SG, Wells JA, Lythgoe MF. fMRI mapping of the visual system in the mouse brain with interleaved snapshot GE-EPI. Neuroimage 2016; 139:337-345. [PMID: 27296012 PMCID: PMC4988789 DOI: 10.1016/j.neuroimage.2016.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/01/2016] [Accepted: 06/09/2016] [Indexed: 12/01/2022] Open
Abstract
The use of functional magnetic resonance imaging (fMRI) in mice is increasingly prevalent, providing a means to non-invasively characterise functional abnormalities associated with genetic models of human diseases. The predominant stimulus used in task-based fMRI in the mouse is electrical stimulation of the paw. Task-based fMRI in mice using visual stimuli remains underexplored, despite visual stimuli being common in human fMRI studies. In this study, we map the mouse brain visual system with BOLD measurements at 9.4T using flashing light stimuli with medetomidine anaesthesia. BOLD responses were observed in the lateral geniculate nucleus, the superior colliculus and the primary visual area of the cortex, and were modulated by the flashing frequency, diffuse vs focussed light and stimulus context. Negative BOLD responses were measured in the visual cortex at 10Hz flashing frequency; but turned positive below 5Hz. In addition, the use of interleaved snapshot GE-EPI improved fMRI image quality without diminishing the temporal contrast-noise-ratio. Taken together, this work demonstrates a novel methodological protocol in which the mouse brain visual system can be non-invasively investigated using BOLD fMRI.
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Affiliation(s)
- Arun Niranjan
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK
| | - Isabel N Christie
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK; Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Samuel G Solomon
- Department of Experimental Psychology, University College London, London, UK
| | - Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, UK
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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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Low LA, Bauer LC, Klaunberg BA. Comparing the Effects of Isoflurane and Alpha Chloralose upon Mouse Physiology. PLoS One 2016; 11:e0154936. [PMID: 27148970 PMCID: PMC4858227 DOI: 10.1371/journal.pone.0154936] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 04/21/2016] [Indexed: 11/30/2022] Open
Abstract
Functional magnetic resonance imaging of mice requires that the physiology of the mouse (body temperature, respiration and heart rates, blood pH level) be maintained in order to prevent changes affecting the outcomes of functional scanning, namely blood oxygenation level dependent (BOLD) measures and cerebral blood flow (CBF). The anesthetic used to sedate mice for scanning can have major effects on physiology. While alpha chloralose has been commonly used for functional imaging of rats, its effects on physiology are not well characterized in the literature for any species. In this study, we anesthetized or sedated mice with isoflurane or alpha chloralose for up to two hours, and monitored physiological parameters and arterial blood gasses. We found that, when normal body temperature is maintained, breathing rates for both drugs decrease over the course of two hours. In addition, alpha chloralose causes a substantial drop in heart rate and blood pH with severe hypercapnia (elevated blood CO2) that is not seen in isoflurane-treated animals. We suggest that alpha chloralose does not maintain normal mouse physiology adequately for functional brain imaging outcome measures.
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Affiliation(s)
- Lucie A. Low
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, Maryland, United States
| | - Lucy C. Bauer
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, Maryland, United States
| | - Brenda A. Klaunberg
- NIH Mouse Imaging Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States
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49
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A novel anesthesia regime enables neurofunctional studies and imaging genetics across mouse strains. Sci Rep 2016; 6:24523. [PMID: 27080031 PMCID: PMC4832200 DOI: 10.1038/srep24523] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 03/30/2016] [Indexed: 12/18/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) has revolutionized neuroscience by opening a unique window that allows neurocircuitry function and pathological alterations to be probed non-invasively across brain disorders. Here we report a novel sustainable anesthesia procedure for small animal neuroimaging that overcomes shortcomings of anesthetics commonly used in rodent fMRI. The significantly improved preservation of cerebrovascular dynamics enhances sensitivity to neural activity changes for which it serves as a proxy in fMRI readouts. Excellent cross-species/strain applicability provides coherence among preclinical findings and is expected to improve translation to clinical fMRI investigations. The novel anesthesia procedure based on the GABAergic anesthetic etomidate was extensively validated in fMRI studies conducted in a range of genetically engineered rodent models of autism and strains commonly used for transgenic manipulations. Etomidate proved effective, yielded long-term stable physiology with basal cerebral blood flow of ~0.5 ml/g/min and full recovery. Cerebrovascular responsiveness of up to 180% was maintained as demonstrated with perfusion- and BOLD-based fMRI upon hypercapnic, pharmacological and sensory stimulation. Hence, etomidate lends itself as an anesthetic-of-choice for translational neuroimaging studies across rodent models of brain disorders.
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50
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Reimann HM, Hentschel J, Marek J, Huelnhagen T, Todiras M, Kox S, Waiczies S, Hodge R, Bader M, Pohlmann A, Niendorf T. Normothermic Mouse Functional MRI of Acute Focal Thermostimulation for Probing Nociception. Sci Rep 2016; 6:17230. [PMID: 26821826 PMCID: PMC4731789 DOI: 10.1038/srep17230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 10/27/2015] [Indexed: 11/30/2022] Open
Abstract
Combining mouse genomics and functional magnetic resonance imaging (fMRI) provides a promising tool to unravel the molecular mechanisms of chronic pain. Probing murine nociception via the blood oxygenation level-dependent (BOLD) effect is still challenging due to methodological constraints. Here we report on the reproducible application of acute noxious heat stimuli to examine the feasibility and limitations of functional brain mapping for central pain processing in mice. Recent technical and procedural advances were applied for enhanced BOLD signal detection and a tight control of physiological parameters. The latter includes the development of a novel mouse cradle designed to maintain whole-body normothermia in anesthetized mice during fMRI in a way that reflects the thermal status of awake, resting mice. Applying mild noxious heat stimuli to wildtype mice resulted in highly significant BOLD patterns in anatomical brain structures forming the pain matrix, which comprise temporal signal intensity changes of up to 6% magnitude. We also observed sub-threshold correlation patterns in large areas of the brain, as well as alterations in mean arterial blood pressure (MABP) in response to the applied stimulus.
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Affiliation(s)
- Henning Matthias Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jan Hentschel
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Jaroslav Marek
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Mihail Todiras
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Stefanie Kox
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Russ Hodge
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Michael Bader
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine, Berlin, Germany.,Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrueck Center for Molecular Medicine, Berlin, Germany
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