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Rivlin M, Navon G. Effect of reducing isoflurane level on glucosamine uptake in the mouse brain during magnetic resonance imaging studies. Neuroimage 2024; 297:120691. [PMID: 38901773 DOI: 10.1016/j.neuroimage.2024.120691] [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: 01/08/2024] [Revised: 06/11/2024] [Accepted: 06/14/2024] [Indexed: 06/22/2024] Open
Abstract
Anesthesia is often required during magnetic resonance imaging (MRI) examinations in animal studies. Anesthetic drugs differ in their capacity to interfere with homeostatic mechanisms responsible for glucose metabolism in the brain, which may create a constraint in the study design. Recent studies suggest that the chemical exchange saturation transfer (CEST) MRI scanning technique can detect localized metabolic changes in rodent brains induced by the uptake of glucose or its analogs; however, most of these studies do not account for the impact of anesthesia type on the brain metabolism. Herein, we aimed to evaluate the effect of reduced isoflurane levels on the preclinical imaging of glucosamine (GlcN) uptake in healthy mouse brains to establish optimal conditions for future brain imaging studies using the CEST MRI technique. The commonly used anesthesia protocol for longitudinal MRI examinations using 1.5% isoflurane level was compared to that using a mixture of low isoflurane (0.8%) level combined with midazolam (2 mg/kg, SC). Magnetization transfer ratio asymmetry (MTRasym) and area under the curve (AUC) analyses were used to characterize GlcN signals in the brain. The results indicated that mice injected with GlcN and anesthetized with 1.5% isoflurane exhibited low and insignificant changes in the MTRasym and AUC signals in the frontal cortex, whereas mice administered with 0.8% isoflurane combined with midazolam demonstrated a significant increase in these signals in the frontal cortex. This study highlights the diverse GlcN metabolic changes observed in mouse brains under variable levels of isoflurane anesthesia using the CEST MRI method. The results suggest that it is feasible to maintain anesthesia with low-dose isoflurane by integrating midazolam, which may enable the investigation of GlcN uptake in the brain. Thus, reducing isoflurane levels may support studies into mouse brain metabolism using the CEST MRI method and should be considered in future studies.
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Affiliation(s)
- Michal Rivlin
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Gil Navon
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel.
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2
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Mosneag IE, Flaherty SM, Wykes RC, Allan SM. Stroke and Translational Research - Review of Experimental Models with a Focus on Awake Ischaemic Induction and Anaesthesia. Neuroscience 2024; 550:89-101. [PMID: 38065289 DOI: 10.1016/j.neuroscience.2023.11.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
Animal models are an indispensable tool in the study of ischaemic stroke with hundreds of drugs emerging from the preclinical pipeline. However, all of these drugs have failed to translate into successful treatments in the clinic. This has brought into focus the need to enhance preclinical studies to improve translation. The confounding effects of anaesthesia on preclinical stroke modelling has been raised as an important consideration. Various volatile and injectable anaesthetics are used in preclinical models during stroke induction and for outcome measurements such as imaging or electrophysiology. However, anaesthetics modulate several pathways essential in the pathophysiology of stroke in a dose and drug dependent manner. Most notably, anaesthesia has significant modulatory effects on cerebral blood flow, metabolism, spreading depolarizations, and neurovascular coupling. To minimise anaesthetic complications and improve translational relevance, awake stroke induction has been attempted in limited models. This review outlines anaesthetic strategies employed in preclinical ischaemic rodent models and their reported cerebral effects. Stroke related complications are also addressed with a focus on infarct volume, neurological deficits, and thrombolysis efficacy. We also summarise routinely used focal ischaemic stroke rodent models and discuss the attempts to induce some of these models in awake rodents.
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Affiliation(s)
- Ioana-Emilia Mosneag
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom.
| | - Samuel M Flaherty
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom
| | - Robert C Wykes
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom; Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Stuart M Allan
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance NHS Foundation Trust, University of Manchester, Manchester, United Kingdom
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3
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Li J, Yang F, Zhan F, Estin J, Iyer A, Zhao M, Niemeyer JE, Luo P, Li D, Lin W, Liou JY, Ma H, Schwartz TH. Mesoscopic mapping of hemodynamic responses and neuronal activity during pharmacologically induced interictal spikes in awake and anesthetized mice. J Cereb Blood Flow Metab 2024; 44:911-924. [PMID: 38230631 PMCID: PMC11318398 DOI: 10.1177/0271678x241226742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 12/14/2023] [Accepted: 12/20/2023] [Indexed: 01/18/2024]
Abstract
Imaging hemodynamic responses to interictal spikes holds promise for presurgical epilepsy evaluations. Understanding the hemodynamic response function is crucial for accurate interpretation. Prior interictal neurovascular coupling data primarily come from anesthetized animals, impacting reliability. We simultaneously monitored calcium fluctuations in excitatory neurons, hemodynamics, and local field potentials (LFP) during bicuculline-induced interictal events in both isoflurane-anesthetized and awake mice. Isoflurane significantly affected LFP amplitude but had little impact on the amplitude and area of the calcium signal. Anesthesia also dramatically blunted the amplitude and latency of the hemodynamic response, although not its area of spread. Cerebral blood volume change provided the best spatial estimation of excitatory neuronal activity in both states. Targeted silencing of the thalamus in awake mice failed to recapitulate the impact of anesthesia on hemodynamic responses suggesting that isoflurane's interruption of the thalamocortical loop did not contribute either to the dissociation between the LFP and the calcium signal nor to the alterations in interictal neurovascular coupling. The blood volume increase associated with interictal spikes represents a promising mapping signal in both the awake and anesthetized states.
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Affiliation(s)
- Jing Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Fan Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Fengrui Zhan
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Joshua Estin
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Aditya Iyer
- Department of Anesthesiology, Weill Cornell Medicine, New York, USA
| | - Mingrui Zhao
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - James E Niemeyer
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Peijuan Luo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Dan Li
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Weihong Lin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jyun-you Liou
- Department of Anesthesiology, Weill Cornell Medicine, New York, USA
| | - Hongtao Ma
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, USA
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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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Lindhardt TB, Gutiérrez-Jiménez E, Liang Z, Hansen B. Male and Female C57BL/6 Mice Respond Differently to Awake Magnetic Resonance Imaging Habituation. Front Neurosci 2022; 16:853527. [PMID: 35757553 PMCID: PMC9226328 DOI: 10.3389/fnins.2022.853527] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/18/2022] [Indexed: 01/20/2023] Open
Abstract
Traditionally, preclinical magnetic resonance imaging (MRI) has been performed in anesthetized animals. However, anesthesia has been shown to perturb normal brain function and physiology. Such effects limit our ability to detect subtle physiological alterations in disease models and treatment studies, thus hampering discovery and compromising generality of findings. Therefore, methods for awake animal MRI are needed to study the rodent brain in its natural physiological state, free of anesthetics. Current setups for awake animal MRI rely on restraining systems to avoid animal movement during scanning. To reduce restraint stress, animals are habituated to the scanner environment prior to MRI data collection. To date, however, most awake MRI studies employ male rodents only. This is a fundamental limitation as results obtained may be pertinent only to half of the population. We characterized training and habituation responses of male and female mice to provide improved, sex-dependent training procedures for awake mouse MRI. We recorded heart rate, monitored behavioral responses (body weight and fecal boli weight) and fecal corticosterone levels (FCM) as indicators of wellbeing and stress during a 14-day progressive habituation protocol. In addition, we also assessed discomfort levels and anxiety using the mouse grimace scale (MGS) and light/dark test (LDT), respectively. All scores were compared between both groups. We found that heart rate was significantly decreased after 10 and 11 days of training for both males and females, respectively. However, the specific time course for this decrease was significantly different between males and females, and females exhibited higher anxiety levels during habituation and 14 days after habituation than males. Lastly, we also found that mean FCM levels for both groups were decreased after 11 days of MRI habituation. The present work shows that mice can be successfully trained for extended MRI sessions which is necessary for many (particularly non-fMRI) studies. Importantly, we find that males and females differ in their response to awake MRI habituation, which should be considered in future awake MRI studies that aim to include male and female mice.
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Affiliation(s)
- Thomas Beck Lindhardt
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Eugenio Gutiérrez-Jiménez
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Zhifeng Liang
- CAS Center for Excellence in Brain Sciences and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China
| | - Brian Hansen
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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6
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The effects of locomotion on sensory-evoked haemodynamic responses in the cortex of awake mice. Sci Rep 2022; 12:6236. [PMID: 35422473 PMCID: PMC9010417 DOI: 10.1038/s41598-022-10195-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/04/2022] [Indexed: 12/22/2022] Open
Abstract
Investigating neurovascular coupling in awake rodents is becoming ever more popular due, in part, to our increasing knowledge of the profound impacts that anaesthesia can have upon brain physiology. Although awake imaging brings with it many advantages, we still do not fully understand how voluntary locomotion during imaging affects sensory-evoked haemodynamic responses. In this study we investigated how evoked haemodynamic responses can be affected by the amount and timing of locomotion. Using an awake imaging set up, we used 2D-Optical Imaging Spectroscopy (2D-OIS) to measure changes in cerebral haemodynamics within the sensory cortex of the brain during either 2 s whisker stimulation or spontaneous (no whisker stimulation) experiments, whilst animals could walk on a spherical treadmill. We show that locomotion alters haemodynamic responses. The amount and timing of locomotion relative to whisker stimulation is important, and can significantly impact sensory-evoked haemodynamic responses. If locomotion occurred before or during whisker stimulation, the amplitude of the stimulus-evoked haemodynamic response was significantly altered. Therefore, monitoring of locomotion during awake imaging is necessary to ensure that conclusions based on comparisons of evoked haemodynamic responses (e.g., between control and disease groups) are not confounded by the effects of locomotion.
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Zhang Q, Turner KL, Gheres KW, Hossain MS, Drew PJ. Behavioral and physiological monitoring for awake neurovascular coupling experiments: a how-to guide. NEUROPHOTONICS 2022; 9:021905. [PMID: 35639834 PMCID: PMC8802326 DOI: 10.1117/1.nph.9.2.021905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/28/2021] [Indexed: 06/15/2023]
Abstract
Significance: Functional brain imaging in awake animal models is a popular and powerful technique that allows the investigation of neurovascular coupling (NVC) under physiological conditions. However, ubiquitous facial and body motions (fidgeting) are prime drivers of spontaneous fluctuations in neural and hemodynamic signals. During periods without movement, animals can rapidly transition into sleep, and the hemodynamic signals tied to arousal state changes can be several times larger than sensory-evoked responses. Given the outsized influence of facial and body motions and arousal signals in neural and hemodynamic signals, it is imperative to detect and monitor these events in experiments with un-anesthetized animals. Aim: To cover the importance of monitoring behavioral state in imaging experiments using un-anesthetized rodents, and describe how to incorporate detailed behavioral and physiological measurements in imaging experiments. Approach: We review the effects of movements and sleep-related signals (heart rate, respiration rate, electromyography, intracranial pressure, whisking, and other body movements) on brain hemodynamics and electrophysiological signals, with a focus on head-fixed experimental setup. We summarize the measurement methods currently used in animal models for detection of those behaviors and arousal changes. We then provide a guide on how to incorporate this measurements with functional brain imaging and electrophysiology measurements. Results: We provide a how-to guide on monitoring and interpreting a variety of physiological signals and their applications to NVC experiments in awake behaving mice. Conclusion: This guide facilitates the application of neuroimaging in awake animal models and provides neuroscientists with a standard approach for monitoring behavior and other associated physiological parameters in head-fixed animals.
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Affiliation(s)
- Qingguang Zhang
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
| | - Kevin L. Turner
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Kyle W. Gheres
- The Pennsylvania State University, Graduate Program in Molecular Cellular and Integrative Biosciences, University Park, Pennsylvania, United States
| | - Md Shakhawat Hossain
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
| | - Patrick J. Drew
- The Pennsylvania State University, Center for Neural Engineering, Department of Engineering Science and Mechanics, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Biomedical Engineering, University Park, Pennsylvania, United States
- The Pennsylvania State University, Department of Neurosurgery, University Park, Pennsylvania, United States
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8
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Şencan İ, Esipova T, Kılıç K, Li B, Desjardins M, Yaseen MA, Wang H, Porter JE, Kura S, Fu B, Secomb TW, Boas DA, Vinogradov SA, Devor A, Sakadžić S. Optical measurement of microvascular oxygenation and blood flow responses in awake mouse cortex during functional activation. J Cereb Blood Flow Metab 2022; 42:510-525. [PMID: 32515672 PMCID: PMC8985437 DOI: 10.1177/0271678x20928011] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The cerebral cortex has a number of conserved morphological and functional characteristics across brain regions and species. Among them, the laminar differences in microvascular density and mitochondrial cytochrome c oxidase staining suggest potential laminar variability in the baseline O2 metabolism and/or laminar variability in both O2 demand and hemodynamic response. Here, we investigate the laminar profile of stimulus-induced intravascular partial pressure of O2 (pO2) transients to stimulus-induced neuronal activation in fully awake mice using two-photon phosphorescence lifetime microscopy. Our results demonstrate that stimulus-induced changes in intravascular pO2 are conserved across cortical layers I-IV, suggesting a tightly controlled neurovascular response to provide adequate O2 supply across cortical depth. In addition, we observed a larger change in venular O2 saturation (ΔsO2) compared to arterioles, a gradual increase in venular ΔsO2 response towards the cortical surface, and absence of the intravascular "initial dip" previously reported under anesthesia. This study paves the way for quantification of layer-specific cerebral O2 metabolic responses, facilitating investigation of brain energetics in health and disease and informed interpretation of laminar blood oxygen level dependent functional magnetic resonance imaging signals.
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Affiliation(s)
- İkbal Şencan
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Tatiana Esipova
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Kıvılcım Kılıç
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Michèle Desjardins
- Department of Physics, Engineering Physics and Optics, Université Laval, QC, Canada
| | - Mohammad A Yaseen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Hui Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Jason E Porter
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Sreekanth Kura
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, AZ, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Chemistry, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.,Department of Biomedical Engineering, Boston University, Boston, MA, USA.,Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.,Department of Radiology, University of California San Diego, La Jolla, CA, USA
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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Shabir O, Pendry B, Lee L, Eyre B, Sharp PS, Rebollar MA, Drew D, Howarth C, Heath PR, Wharton SB, Francis SE, Berwick J. Assessment of neurovascular coupling and cortical spreading depression in mixed mouse models of atherosclerosis and Alzheimer's disease. eLife 2022; 11:e68242. [PMID: 35014950 PMCID: PMC8752088 DOI: 10.7554/elife.68242] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022] Open
Abstract
Neurovascular coupling is a critical brain mechanism whereby changes to blood flow accompany localised neural activity. The breakdown of neurovascular coupling is linked to the development and progression of several neurological conditions including dementia. In this study, we examined cortical haemodynamics in mouse preparations that modelled Alzheimer's disease (J20-AD) and atherosclerosis (PCSK9-ATH) between 9 and 12 m of age. We report novel findings with atherosclerosis where neurovascular decline is characterised by significantly reduced blood volume, altered levels of oxyhaemoglobin and deoxyhaemoglobin, in addition to global neuroinflammation. In the comorbid mixed model (J20-PCSK9-MIX), we report a 3 x increase in hippocampal amyloid-beta plaques. A key finding was that cortical spreading depression (CSD) due to electrode insertion into the brain was worse in the diseased animals and led to a prolonged period of hypoxia. These findings suggest that systemic atherosclerosis can be detrimental to neurovascular health and that having cardiovascular comorbidities can exacerbate pre-existing Alzheimer's-related amyloid-plaques.
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Affiliation(s)
- Osman Shabir
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
| | - Ben Pendry
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Llywelyn Lee
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Beth Eyre
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Paul S Sharp
- Medicines Discovery CatapultAlderley EdgeUnited Kingdom
| | - Monica A Rebollar
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - David Drew
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
| | - Clare Howarth
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Stephen B Wharton
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Institute for Translational Neuroscience (SITraN), University of SheffieldSheffieldUnited Kingdom
| | - Sheila E Francis
- Department of Infection, Immunity and Cardiovascular Disease (IICD), University of Sheffield Medical School, Royal Hallamshire HospitalSheffieldUnited Kingdom
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
| | - Jason Berwick
- Healthy Lifespan Institute (HELSI), University of SheffieldSheffieldUnited Kingdom
- Neuroscience Institute, University of SheffieldSheffieldUnited Kingdom
- Sheffield Neurovascular Lab, Department of Psychology, University of SheffieldSheffieldUnited Kingdom
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10
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Rakymzhan A, Li Y, Tang P, Wang RK. Differences in cerebral blood vasculature and flow in awake and anesthetized mouse cortex revealed by quantitative optical coherence tomography angiography. J Neurosci Methods 2021; 353:109094. [PMID: 33549637 DOI: 10.1016/j.jneumeth.2021.109094] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 01/27/2021] [Accepted: 01/31/2021] [Indexed: 12/25/2022]
Abstract
BACKGROUND Most of the in vivo neurovascular imaging studies are performed in anesthetized animals. However, anesthesia significantly affects cerebral hemodynamics. NEW METHOD We applied optical coherence tomography (OCT) methods such as optical microangiography (OMAG) and Doppler optical microangiography (DOMAG) to quantitatively evaluate the effect of anesthesia in cerebral vasculature and blood flow in mouse brain. RESULTS The OMAG results indicated the increase of large vessel diameter and capillary density induced by ketamine-xylazine and isoflurane, meaning that both anesthetics caused vasodilation. In addition, the preliminary results from DOMAG showed that isoflurane increased the baseline cerebral blood flow. COMPARISON WITH EXISTING METHODS In comparison with other in vivo imaging modalities, OCT can provide label-free assessment of cortical tissue including tissue morphology, cerebral blood vessel network and flow information down to capillary level, with a large field of view and high imaging speed. CONCLUSIONS OCT angiography methods demonstrated the ability to measure the differences in the baseline morphological and flow parameters of both large and capillary cerebrovascular networks between awake and anesthetized mice.
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Affiliation(s)
- Adiya Rakymzhan
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Peijun Tang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA.
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11
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Sharp PS, Ameen-Ali KE, Boorman L, Harris S, Wharton S, Howarth C, Shabir O, Redgrave P, Berwick J. Neurovascular coupling preserved in a chronic mouse model of Alzheimer's disease: Methodology is critical. J Cereb Blood Flow Metab 2020; 40:2289-2303. [PMID: 31760864 PMCID: PMC7585931 DOI: 10.1177/0271678x19890830] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Impaired neurovascular coupling has been suggested as an early pathogenic factor in Alzheimer's disease (AD), which could serve as an early biomarker of cerebral pathology. We have established an anaesthetic regime to allow repeated measurements of neurovascular function over three months in the J20 mouse model of AD (J20-AD) and wild-type (WT) controls. Animals were 9-12 months old at the start of the experiment. Mice were chronically prepared with a cranial window through which 2-Dimensional optical imaging spectroscopy (2D-OIS) was used to generate functional maps of the cerebral blood volume and saturation changes evoked by whisker stimulation and vascular reactivity challenges. Unexpectedly, the hemodynamic responses were largely preserved in the J20-AD group. This result failed to confirm previous investigations using the J20-AD model. However, a final acute electrophysiology and 2D-OIS experiment was performed to measure both neural and hemodynamic responses concurrently. In this experiment, previously reported deficits in neurovascular coupling in the J20-AD model were observed. This suggests that J20-AD mice may be more susceptible to the physiologically stressing conditions of an acute experimental procedure compared to WT animals. These results therefore highlight the importance of experimental procedure when determining the characteristics of animal models of human disease.
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Affiliation(s)
- Paul S Sharp
- Nanomedicine Lab, Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Department of Psychology, University of Sheffield, Sheffield, UK
| | - Kamar E Ameen-Ali
- Department of Psychology, University of Sheffield, Sheffield, UK.,Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Luke Boorman
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Sam Harris
- Department of Psychology, University of Sheffield, Sheffield, UK.,UK Dementia Research Institute, UCL Institute of Neurology, University College London, London, UK
| | - Stephen Wharton
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Osman Shabir
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Peter Redgrave
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Jason Berwick
- Department of Psychology, University of Sheffield, Sheffield, UK
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12
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Li Y, Rakymzhan A, Tang P, Wang RK. Procedure and protocols for optical imaging of cerebral blood flow and hemodynamics in awake mice. BIOMEDICAL OPTICS EXPRESS 2020; 11:3288-3300. [PMID: 32637255 PMCID: PMC7316002 DOI: 10.1364/boe.394649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/09/2020] [Accepted: 05/19/2020] [Indexed: 05/10/2023]
Abstract
We describe a method and procedure that allows for the optical coherence tomography angiography (OCTA) and intrinsic optical signal imaging (IOSI) of cerebral blood flow and hemodynamics in fully awake mice. We detail the procedure of chronic cranial window preparation, the use of an air-lift mobile homecage to achieve stable optical recording in the head-restrained awake mouse, and the imaging methods to achieve multiparametric hemodynamic measurements. The results show that by using a collection of OCTA algorithms, the high-resolution cerebral vasculature can be reliably mapped at a fully awake state, including flow velocity measurements in penetrating arterioles and capillary bed. Lastly, we demonstrate how the awake imaging paradigm is used to study cortical hemodynamics in the mouse barrel cortex during whisker stimulation. The method presented here will facilitate optical recording in the awake, active mice and open the door to many projects that can bridge the hemodynamics in neurovascular units to naturalistic behavior.
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13
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Crofts A, Trotman-Lucas M, Janus J, Kelly M, Gibson CL. A longitudinal, multi-parametric functional MRI study to determine age-related changes in the rodent brain. Neuroimage 2020; 218:116976. [PMID: 32464290 PMCID: PMC7422839 DOI: 10.1016/j.neuroimage.2020.116976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 04/24/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023] Open
Abstract
As the population ages, the incidence of age-related neurological diseases and cognitive decline increases. To further understand disease-related changes in brain function it is advantageous to examine brain activity changes in healthy aging rodent models to permit mechanistic investigation. Here, we examine the suitability, in rodents, of using a novel, minimally invasive anaesthesia protocol in combination with a functional MRI protocol to assess alterations in neuronal activity due to physiological aging. 11 Wistar Han female rats were studied at 7, 9, 12, 15 and 18 months of age. Under an intravenous infusion of propofol, animals underwent functional magnetic resonance imaging (fMRI) and functional magnetic resonance spectroscopy (fMRS) with forepaw stimulation to quantify neurotransmitter activity, and resting cerebral blood flow (CBF) quantification using arterial spin labelling (ASL) to study changes in neurovascular coupling over time. Animals showed a significant decrease in size of the active region with age (P < 0.05). fMRS results showed a significant decrease in glutamate change with stimulation (ΔGlu) with age (P < 0.05), and ΔGlu became negative from 12 months onwards. Global CBF remained constant for the duration of the study. This study shows age related changes in the blood oxygen level dependent (BOLD) response in rodents that correlate with those seen in humans. The results also suggest that a reduction in synaptic glutamate turnover with age may underlie the reduction in the BOLD response, while CBF is preserved. Describe a novel anaesthetic protocol to examine age-related alterations in neuronal activity in rodents. Size of the BOLD signal in the somatosensory cortex decreased with age. Reduction in glutamate turnover with age. No change in resting CBF with age.
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Affiliation(s)
- Andrew Crofts
- Department of Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, UK; Preclinical Imaging Facility, Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Melissa Trotman-Lucas
- Department of Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, UK; School of Psychology, University of Nottingham, Nottingham, UK
| | - Justyna Janus
- Preclinical Imaging Facility, Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Michael Kelly
- Preclinical Imaging Facility, Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Claire L Gibson
- Department of Neuroscience, Psychology & Behaviour, University of Leicester, Leicester, UK; School of Psychology, University of Nottingham, Nottingham, UK.
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14
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Shabir O, Sharp P, Rebollar MA, Boorman L, Howarth C, Wharton SB, Francis SE, Berwick J. Enhanced Cerebral Blood Volume under Normobaric Hyperoxia in the J20-hAPP Mouse Model of Alzheimer's Disease. Sci Rep 2020; 10:7518. [PMID: 32371859 PMCID: PMC7200762 DOI: 10.1038/s41598-020-64334-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 04/14/2020] [Indexed: 11/14/2022] Open
Abstract
Early impairments to neurovascular coupling have been proposed to be a key pathogenic factor in the onset and progression of Alzheimer's disease (AD). Studies have shown impaired neurovascular function in several mouse models of AD, including the J20-hAPP mouse. In this study, we aimed to investigate early neurovascular changes using wild-type (WT) controls and J20-hAPP mice at 6 months of age, by measuring cerebral haemodynamics and neural activity to physiological sensory stimulations. A thinned cranial window was prepared to allow access to cortical vasculature and imaged using 2D-optical imaging spectroscopy (2D-OIS). After chronic imaging sessions where the skull was intact, a terminal acute imaging session was performed where an electrode was inserted into the brain to record simultaneous neural activity. We found that cerebral haemodynamic changes were significantly enhanced in J20-hAPP mice compared with controls in response to physiological stimulations, potentially due to the significantly higher neural activity (hyperexcitability) seen in the J20-hAPP mice. Thus, neurovascular coupling remained preserved under a chronic imaging preparation. Further, under hyperoxia, the baseline blood volume and saturation of all vascular compartments in the brains of J20-hAPP mice were substantially enhanced compared to WT controls, but this effect disappeared under normoxic conditions. This study highlights novel findings not previously seen in the J20-hAPP mouse model, and may point towards a potential therapeutic strategy.
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Affiliation(s)
- Osman Shabir
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Paul Sharp
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Monica A Rebollar
- Sheffield Institute for Translational Neuroscience (SITraN), 385a Glossop Road, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Luke Boorman
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Clare Howarth
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Stephen B Wharton
- Sheffield Institute for Translational Neuroscience (SITraN), 385a Glossop Road, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Sheila E Francis
- Department of Infection, Immunity & Cardiovascular Disease (IICD), University of Sheffield, Medical School, Beech Hill Road, Sheffield, S10 2RX, UK
| | - Jason Berwick
- The Neurovascular & Neuroimaging Group (Department of Psychology), Alfred Denny Building, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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15
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Brezzo G, Simpson J, Ameen-Ali KE, Berwick J, Martin C. Acute effects of systemic inflammation upon the neuro-glial-vascular unit and cerebrovascular function. Brain Behav Immun Health 2020; 5:100074. [PMID: 32685933 PMCID: PMC7357601 DOI: 10.1016/j.bbih.2020.100074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/30/2022] Open
Abstract
Brain health relies on a tightly regulated system known as neurovascular coupling whereby the cellular constituents of the neuro-glial-vascular unit (NGVU) regulate cerebral haemodynamics in accordance with brain metabolic demand. Disruption of neurovascular coupling impairs brain health and is associated with the development of a number for neurological conditions, including Alzheimer's disease. The NGVU is also a key site of action for neuroinflammatory responses and contributes to the transition of systemic inflammation to neuroinflammatory processes. Thus, systemic inflammatory challenges may cause a shift in NGVU operation towards prioritising neuroinflammatory action and thus altering neurovascular coupling and resultant cerebrovascular changes. To investigate this, rats were injected with lipopolysaccharide (LPS) (2 mg/kg) to induce a systemic inflammatory response, or vehicle, and brain haemodynamic responses to sensory and non-sensory (hypercapnia) stimuli were assessed in vivo using optical imaging techniques. Following imaging, animals were perfused and their brains extracted to histologically characterise components of the NGVU to determine the association between underlying cellular changes and in vivo blood flow regulation. LPS-treated animals showed changes in haemodynamic function and cerebrovascular dynamics 6 hours after LPS administration. Histological assessment identified a significant increase in astrogliosis, microgliosis and endothelial activation in LPS-treated animals. Our data shows that an acutely induced systemic inflammatory response is able to rapidly alter in vivo haemodynamic function and is associated with significant changes in the cellular constituents of the NGVU. We suggest that these effects are initially mediated by endothelial cells, which are directly exposed to the circulating inflammatory stimulus and have been implicated in regulating functional hyperaemia.
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Affiliation(s)
- Gaia Brezzo
- The University of Sheffield, Department of Psychology, Cathedral Court, 1 Vicar Lane, Sheffield, S1 2LT, UK
| | - Julie Simpson
- The University of Sheffield, Sheffield Institute for Translational Neuroscience (SITraN), 385a Glossop Road, Sheffield, S10 2HQ, UK
| | - Kamar E. Ameen-Ali
- The University of Sheffield, Department of Psychology, Cathedral Court, 1 Vicar Lane, Sheffield, S1 2LT, UK
| | - Jason Berwick
- The University of Sheffield, Department of Psychology, Cathedral Court, 1 Vicar Lane, Sheffield, S1 2LT, UK
| | - Chris Martin
- The University of Sheffield, Department of Psychology, Cathedral Court, 1 Vicar Lane, Sheffield, S1 2LT, UK
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16
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Lee L, Boorman L, Glendenning E, Christmas C, Sharp P, Redgrave P, Shabir O, Bracci E, Berwick J, Howarth C. Key Aspects of Neurovascular Control Mediated by Specific Populations of Inhibitory Cortical Interneurons. Cereb Cortex 2020; 30:2452-2464. [PMID: 31746324 PMCID: PMC7174996 DOI: 10.1093/cercor/bhz251] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/20/2019] [Accepted: 10/01/2019] [Indexed: 01/21/2023] Open
Abstract
Inhibitory interneurons can evoke vasodilation and vasoconstriction, making them potential cellular drivers of neurovascular coupling. However, the specific regulatory roles played by particular interneuron subpopulations remain unclear. Our purpose was therefore to adopt a cell-specific optogenetic approach to investigate how somatostatin (SST) and neuronal nitric oxide synthase (nNOS)-expressing interneurons might influence the neurovascular relationship. In mice, specific activation of SST- or nNOS-interneurons was sufficient to evoke hemodynamic changes. In the case of nNOS-interneurons, robust hemodynamic changes occurred with minimal changes in neural activity, suggesting that the ability of blood oxygen level dependent functional magnetic resonance imaging (BOLD fMRI) to reliably reflect changes in neuronal activity may be dependent on type of neuron recruited. Conversely, activation of SST-interneurons produced robust changes in evoked neural activity with shallow cortical excitation and pronounced deep layer cortical inhibition. Prolonged activation of SST-interneurons often resulted in an increase in blood volume in the centrally activated area with an accompanying decrease in blood volume in the surrounding brain regions, analogous to the negative BOLD signal. These results demonstrate the role of specific populations of cortical interneurons in the active control of neurovascular function.
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Affiliation(s)
- L Lee
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - L Boorman
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - E Glendenning
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - C Christmas
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - P Sharp
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - P Redgrave
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - O Shabir
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - E Bracci
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - J Berwick
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - C Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
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17
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Kim E, Sanchez-Casanova J, Anguluan E, Kim H, Kim JG. Mobile Wireless Low-intensity Transcranial Ultrasound Stimulation System for Freely Behaving Small Animals. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:6282-6285. [PMID: 31947278 DOI: 10.1109/embc.2019.8857372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Transcranial ultrasound stimulation (tUS) is a promising noninvasive approach to modulate brain circuits. While low-intensity tUS is putatively safe and has already been used for human participants, pre-clinical studies that aim to determine the effects of tUS on the brain still need to be carried out. Conventional tUS stimulation, however, requires the use of the anesthetized or immobilized animal model, which can place considerable restrictions on behavior. Thus, this work presents a portable, low cost, wireless system to achieve ultrasound brain stimulation in freely behaving animals. The tUS system was developed based on a commercial 16 MHz microcontroller and amplifier circuit. The acoustic wave with a central frequency of 450 kHz was generated from a 5mm PZT with a peak pressure of 426 kPa. The wireless tUS with a total weight of 20 g was placed on the back of the rat allowing the animal a full range of unimpeded motion. The mobile ultrasound system was able to induce a robust ear movement as a response to stimulation of the motor cortex. The outcome demonstrates the ability of wireless tUS to modulate the brain circuit of a freely behaving rat. The portability of the whole system provides a more natural environment for investigating the effect of tUS on behavior and chronic studies.
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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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How reliable is cerebral blood flow to map changes in neuronal activity? Auton Neurosci 2019; 217:71-79. [PMID: 30744905 DOI: 10.1016/j.autneu.2019.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/17/2018] [Accepted: 01/27/2019] [Indexed: 02/06/2023]
Abstract
Neuroimaging techniques, such as functional MRI, map brain activity through hemodynamic-based signals, and are invaluable diagnostic tools in several neurological disorders such as stroke and dementia. Hemodynamic signals are normally precisely related to the underlying neuronal activity through neurovascular coupling mechanisms that ensure the supply of blood, glucose and oxygen to neurons at work. The knowledge of neurovascular coupling has greatly advanced over the last 30 years, it involves multifaceted interactions between excitatory and inhibitory neurons, astrocytes, and the microvessels. While the tight relationship between blood flow and neuronal activity forms a fundamental brain function, whether neurovascular coupling mechanisms are reliable across physiological and pathological conditions has been questioned. In this review, we interrogate the relationship between blood flow and neuronal activity during activation of different brain pathways: a sensory stimulation driven by glutamate, and stimulation of neuromodulatory pathways driven by acetylcholine or noradrenaline, and we compare the underlying neurovascular coupling mechanisms. We further question if neurovascular coupling mechanisms are affected by changing brain states, as seen in behavioral conditions of sleep, wakefulness, attention and in pathological conditions. Finally, we provide a short overview of how alterations of the brain vasculature could compromise the reliability of neurovascular coupling. Overall, while neurovascular coupling requires activation of common signalling pathways, alternate unique cascades exist depending on the activated pathways. Further studies are needed to fully elucidate the alterations in neurovascular coupling across brain states and pathological conditions.
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20
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de Roever I, Bale G, Mitra S, Meek J, Robertson NJ, Tachtsidis I. Investigation of the Pattern of the Hemodynamic Response as Measured by Functional Near-Infrared Spectroscopy (fNIRS) Studies in Newborns, Less Than a Month Old: A Systematic Review. Front Hum Neurosci 2018; 12:371. [PMID: 30333736 PMCID: PMC6176492 DOI: 10.3389/fnhum.2018.00371] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 08/29/2018] [Indexed: 01/03/2023] Open
Abstract
It has been 20 years since functional near-infrared spectroscopy (fNIRS) was first used to investigate the evoked hemodynamic response to a stimulus in newborns. The hemodynamic response to functional activation is well-established in adults, with an observed increase in concentration change of oxygenated hemoglobin (Δ[HbO2]) and decrease in deoxygenated hemoglobin (Δ[HHb]). However, functional studies in newborns have revealed a mixed response, particularly with Δ[HHb] where an inconsistent change in direction is observed. The reason for this heterogeneity is unknown, with potential explanations arising from differing physiology in the developing brain, or differences in instrumentation or methodology. The aim of this review is to collate the findings from studies that have employed fNIRS to monitor cerebral hemodynamics in term newborn infants aged 1 day-1 month. A total of 46 eligible studies were identified; some studies investigated more than one stimulus type, resulting in a total of 51 reported results. The NIRS parameters reported varied across studies with 50/51 cases reporting Δ[HbO2], 39/51 reporting Δ[HHb], and 13/51 reporting total hemoglobin concentration Δ[HbT] (Δ[HbO2] + Δ[HHb]). However, of the 39 cases reporting Δ[HHb] in graphs or tables, only 24 studies explicitly discussed the response (i.e., direction of change) of this variable. In the studies where the fNIRS responses were discussed, 46/51 cases observed an increase in Δ[HbO2], 7/51 observed an increase or varied Δ[HHb], and 2/51 reported a varied or negative Δ[HbT]. An increase in Δ[HbO2] and decrease or no change in Δ[HHb] was observed in 15 studies. By reviewing this body of literature, we have identified that the majority of research articles reported an increase in Δ[HbO2] across various functional tasks and did not report the response of Δ[HHb]. Confirming the normal, healthy hemodynamic response in newborns will allow identification of unhealthy patterns and their association to normal neurodevelopment.
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Affiliation(s)
- Isabel de Roever
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Gemma Bale
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Subhabrata Mitra
- Department of Neonatology, Institute for Women's Health, University College London, London, United Kingdom
| | - Judith Meek
- Department of Neonatology, Institute for Women's Health, University College London, London, United Kingdom
| | - Nicola J. Robertson
- Department of Neonatology, Institute for Women's Health, University College London, London, United Kingdom
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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21
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Rau R, Kruizinga P, Mastik F, Belau M, de Jong N, Bosch JG, Scheffer W, Maret G. 3D functional ultrasound imaging of pigeons. Neuroimage 2018; 183:469-477. [PMID: 30118869 DOI: 10.1016/j.neuroimage.2018.08.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/25/2018] [Accepted: 08/09/2018] [Indexed: 01/21/2023] Open
Abstract
Recent advances in ultrasound Doppler imaging have facilitated the technique of functional ultrasound (fUS) which enables visualization of brain-activity due to neurovascular coupling. As of yet, this technique has been applied to rodents as well as to human subjects during awake craniotomy surgery and human newborns. Here we demonstrate the first successful fUS studies on awake pigeons subjected to auditory and visual stimulation. To allow successful fUS on pigeons we improved the temporal resolution of fUS up to 20,000 frames per second with real-time visualization and continuous recording. We show that this gain in temporal resolution significantly increases the sensitivity for detecting small fluctuations in cerebral blood flow and volume which may reflect increased local neural activity. Through this increased sensitivity we were able to capture the elaborate 3D neural activity pattern evoked by a complex stimulation pattern, such as a moving light source. By pushing the limits of fUS further, we have reaffirmed the enormous potential of this technique as a new standard in functional brain imaging with the capacity to unravel unknown, stimulus related hemodynamics with excellent spatiotemporal resolution with a wide field of view.
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Affiliation(s)
- Richard Rau
- Department of Physics, University of Konstanz, Konstanz, Germany. http://cms.uni-konstanz.de/physik/maret/
| | - Pieter Kruizinga
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands; Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands
| | - Frits Mastik
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | - Markus Belau
- Department of Physics, University of Konstanz, Konstanz, Germany
| | - Nico de Jong
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands; Laboratory of Acoustical Wavefield Imaging, Delft University of Technology, Delft, the Netherlands
| | - Johannes G Bosch
- Department of Biomedical Engineering, Thoraxcenter, Erasmus MC, Rotterdam, the Netherlands
| | | | - Georg Maret
- Department of Physics, University of Konstanz, Konstanz, Germany.
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22
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Qi H, Mariager CØ, Lindhardt J, Nielsen PM, Stødkilde‐Jørgensen H, Laustsen C. Effects of anesthesia on renal function and metabolism in rats assessed by hyperpolarized
MRI. Magn Reson Med 2018. [DOI: 10.1002/mrm.27165] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Haiyun Qi
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhus Denmark
| | | | - Jakob Lindhardt
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhus Denmark
| | - Per Mose Nielsen
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhus Denmark
| | | | - Christoffer Laustsen
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhus Denmark
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23
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Kim E, Anguluan E, Kim JG. Monitoring cerebral hemodynamic change during transcranial ultrasound stimulation using optical intrinsic signal imaging. Sci Rep 2017; 7:13148. [PMID: 29030623 PMCID: PMC5640689 DOI: 10.1038/s41598-017-13572-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/25/2017] [Indexed: 12/27/2022] Open
Abstract
Transcranial ultrasound stimulation (tUS) is a promising non-invasive approach to modulate brain circuits. The application is gaining popularity, however the full effect of ultrasound stimulation is still unclear and further investigation is needed. This study aims to apply optical intrinsic signal imaging (OISI) for the first time, to simultaneously monitor the wide-field cerebral hemodynamic change during tUS on awake animal with high spatial and temporal resolution. Three stimulation paradigms were delivered using a single-element focused transducer operating at 425 kHz in pulsed mode having the same intensity (ISPPA = 1.84 W/cm2, ISPTA = 129 mW/cm2) but varying pulse repetition frequencies (PRF). The results indicate a concurrent hemodynamic change occurring with all actual tUS but not under a sham stimulation. The stimulation initiated the increase of oxygenated hemoglobin (HbO) and decrease of deoxygenated hemoglobin (RHb). A statistically significant difference (p < 0.05) was found in the amplitude change of hemodynamics evoked by varying PRF. Moreover, the acoustic stimulation was able to trigger a global as well as local cerebral hemodynamic alteration in the mouse cortex. Thus, the implementation of OISI offers the possibility of directly investigating brain response in an awake animal during tUS through cerebral hemodynamic change.
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Affiliation(s)
- Evgenii Kim
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju, 61005, Korea
| | - Eloise Anguluan
- Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Korea
| | - Jae Gwan Kim
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Gwangju, 61005, Korea. .,Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Korea.
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24
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Kyweriga M, Sun J, Wang S, Kline R, Mohajerani MH. A Large Lateral Craniotomy Procedure for Mesoscale Wide-field Optical Imaging of Brain Activity. J Vis Exp 2017. [PMID: 28518107 DOI: 10.3791/52642] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The craniotomy is a commonly performed procedure to expose the brain for in vivo experiments. In mouse research, most labs utilize a small craniotomy, typically 3 mm x 3 mm. This protocol introduces a method for creating a substantially larger 7 mm x 6 mm cranial window exposing most of a cerebral hemisphere over the mouse temporal and parietal cortices (e.g., bregma 2.5 - 4.5 mm, lateral 0 - 6 mm). To perform this surgery, the head must be tilted approximately 30° and much of the temporal muscle must be retracted. Due to the large amount of bone removal, this procedure is intended only for acute experiments with the animal anesthetized throughout the surgery and experiment. The main advantage of this innovative large lateral cranial window is to provide simultaneous access to both medial and lateral areas of the cortex. This large unilateral cranial window can be used to study the neural dynamics between cells, as well as between different cortical areas by combining multi-electrode electrophysiological recordings, imaging of neuronal activity (e.g., intrinsic or extrinsic imaging), and optogenetic stimulation. Additionally, this large craniotomy also exposes a large area of cortical blood vessels, allowing for direct manipulation of the lateral cortical vasculature.
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Affiliation(s)
- Michael Kyweriga
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Jianjun Sun
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Sunny Wang
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
| | - Richard Kline
- Canadian Center for Behavioural Neuroscience, University of Lethbridge
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25
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Lecrux C, Hamel E. Neuronal networks and mediators of cortical neurovascular coupling responses in normal and altered brain states. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150350. [PMID: 27574304 PMCID: PMC5003852 DOI: 10.1098/rstb.2015.0350] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2016] [Indexed: 12/18/2022] Open
Abstract
Brain imaging techniques that use vascular signals to map changes in neuronal activity, such as blood oxygenation level-dependent functional magnetic resonance imaging, rely on the spatial and temporal coupling between changes in neurophysiology and haemodynamics, known as 'neurovascular coupling (NVC)'. Accordingly, NVC responses, mapped by changes in brain haemodynamics, have been validated for different stimuli under physiological conditions. In the cerebral cortex, the networks of excitatory pyramidal cells and inhibitory interneurons generating the changes in neural activity and the key mediators that signal to the vascular unit have been identified for some incoming afferent pathways. The neural circuits recruited by whisker glutamatergic-, basal forebrain cholinergic- or locus coeruleus noradrenergic pathway stimulation were found to be highly specific and discriminative, particularly when comparing the two modulatory systems to the sensory response. However, it is largely unknown whether or not NVC is still reliable when brain states are altered or in disease conditions. This lack of knowledge is surprising since brain imaging is broadly used in humans and, ultimately, in conditions that deviate from baseline brain function. Using the whisker-to-barrel pathway as a model of NVC, we can interrogate the reliability of NVC under enhanced cholinergic or noradrenergic modulation of cortical circuits that alters brain states.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- C Lecrux
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Quebec, Canada H3A 2B4
| | - E Hamel
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Quebec, Canada H3A 2B4
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26
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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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27
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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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28
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Inter-Strain Differences in Default Mode Network: A Resting State fMRI Study on Spontaneously Hypertensive Rat and Wistar Kyoto Rat. Sci Rep 2016; 6:21697. [PMID: 26898170 PMCID: PMC4761976 DOI: 10.1038/srep21697] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/28/2016] [Indexed: 01/24/2023] Open
Abstract
Genetic divergences among mammalian strains are presented phenotypically in various aspects of physical appearance such as body shape and facial features. Yet how genetic diversity is expressed in brain function still remains unclear. Functional connectivity has been shown to be a valuable approach in characterizing the relationship between brain functions and behaviors. Alterations in the brain default mode network (DMN) have been found in human neuropsychological disorders. In this study we selected the spontaneously hypertensive rat (SHR) and the Wistar Kyoto rat (WKY), two inbred rat strains with close genetic origins, to investigate variations in the DMN. Our results showed that the major DMN differences are the activities in hippocampal area and caudate putamen region. This may be correlated to the hyperactive behavior of the SHR strain. Advanced animal model studies on variations in the DMN may have potential to shed new light on translational medicine, especially with regard to neuropsychological disorders.
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