51
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Seewoo BJ, Etherington SJ, Feindel KW, Rodger J. Combined rTMS/fMRI Studies: An Overlooked Resource in Animal Models. Front Neurosci 2018; 12:180. [PMID: 29628873 PMCID: PMC5876299 DOI: 10.3389/fnins.2018.00180] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 03/06/2018] [Indexed: 12/11/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique, which has brain network-level effects in healthy individuals and is also used to treat many neurological and psychiatric conditions in which brain connectivity is believed to be abnormal. Despite the fact that rTMS is being used in a clinical setting and animal studies are increasingly identifying potential cellular and molecular mechanisms, little is known about how these mechanisms relate to clinical changes. This knowledge gap is amplified by non-overlapping approaches used in preclinical and clinical rTMS studies: preclinical studies are mostly invasive, using cellular and molecular approaches, while clinical studies are non-invasive, including functional magnetic resonance imaging (fMRI), TMS electroencephalography (EEG), positron emission tomography (PET), and behavioral measures. A non-invasive method is therefore needed in rodents to link our understanding of cellular and molecular changes to functional connectivity changes that are clinically relevant. fMRI is the technique of choice for examining both short and long term functional connectivity changes in large-scale networks and is becoming increasingly popular in animal research because of its high translatability, but, to date, there have been no reports of animal rTMS studies using this technique. This review summarizes the main studies combining different rTMS protocols with fMRI in humans, in both healthy and patient populations, providing a foundation for the design of equivalent studies in animals. We discuss the challenges of combining these two methods in animals and highlight considerations important for acquiring clinically-relevant information from combined rTMS/fMRI studies in animals. We believe that combining rTMS and fMRI in animal models will generate new knowledge in the following ways: functional connectivity changes can be explored in greater detail through complementary invasive procedures, clarifying mechanism and improving the therapeutic application of rTMS, as well as improving interpretation of fMRI data. And, in a more general context, a robust comparative approach will refine the use of animal models of specific neuropsychiatric conditions.
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Affiliation(s)
- Bhedita J Seewoo
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,Centre for Microscopy, Characterization and Analysis, Research Infrastructure Centers, The University of Western Australia, Perth, WA, Australia
| | - Sarah J Etherington
- School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - Kirk W Feindel
- Centre for Microscopy, Characterization and Analysis, Research Infrastructure Centers, The University of Western Australia, Perth, WA, Australia.,School of Biomedical Sciences, University of Western Australia, Perth, WA, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neurosciences, School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,Brain Plasticity Group, Perron Institute for Neurological and Translational Research, Perth, WA, Australia
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52
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Broadwater MA, Lee SH, Yu Y, Zhu H, Crews FT, Robinson DL, Shih YYI. Adolescent alcohol exposure decreases frontostriatal resting-state functional connectivity in adulthood. Addict Biol 2018; 23:810-823. [PMID: 28691248 PMCID: PMC5760482 DOI: 10.1111/adb.12530] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/18/2017] [Accepted: 05/23/2017] [Indexed: 12/11/2022]
Abstract
Connectivity of the prefrontal cortex (PFC) matures through adolescence, coinciding with emergence of adult executive function and top-down inhibitory control over behavior. Alcohol exposure during this critical period of brain maturation may affect development of PFC and frontolimbic connectivity. Adult rats exposed to adolescent intermittent ethanol (AIE; 5 g/kg ethanol, 25 percent v/v in water, intragastrically, 2-day-on, 2-day-off, postnatal day 25-54) or water control underwent resting-state functional MRI to test the hypothesis that AIE induces persistent changes in frontolimbic functional connectivity under baseline and acute alcohol conditions (2 g/kg ethanol or saline, intraperitoneally administered during scanning). Data were acquired on a Bruker 9.4-T MR scanner with rats under dexmedetomidine sedation in combination with isoflurane. Frontolimbic network regions-of-interest for data analysis included PFC [prelimbic (PrL), infralimbic (IL), and orbitofrontal cortex (OFC) portions], nucleus accumbens (NAc), caudate putamen (CPu), dorsal hippocampus, ventral tegmental area, amygdala, and somatosensory forelimb used as a control region. AIE decreased baseline resting-state connectivity between PFC subregions (PrL-IL and IL-OFC) and between PFC-striatal regions (PrL-NAc, IL-CPu, IL-NAc, OFC-CPu, and OFC-NAc). Acute ethanol induced negative blood-oxygen-level-dependent changes within all regions of interest examined, along with significant increases in functional connectivity in control, but not AIE animals. Together, these data support the hypothesis that binge-like adolescent alcohol exposure causes persistent decreases in baseline frontolimbic (particularly frontostriatal) connectivity and alters sensitivity to acute ethanol-induced increases in functional connectivity in adulthood.
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Affiliation(s)
| | - Sung-Ho Lee
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Yang Yu
- Department of Statistics and Operations, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Hongtu Zhu
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Fulton T. Crews
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, USA
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Donita L. Robinson
- Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA
- Departments of Biomedical Research Imaging Center and Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA
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53
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Hadjiabadi DH, Pung L, Zhang J, Ward BD, Lim WT, Kalavar M, Thakor NV, Biswal BB, Pathak AP. Brain tumors disrupt the resting-state connectome. NEUROIMAGE-CLINICAL 2018; 18:279-289. [PMID: 29876248 PMCID: PMC5987800 DOI: 10.1016/j.nicl.2018.01.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/15/2018] [Accepted: 01/20/2018] [Indexed: 01/18/2023]
Abstract
Brain tumor patients often experience functional deficits that extend beyond the tumor site. While resting-state functional MRI (rsfMRI) has been used to map such functional connectivity changes in brain tumor patients, the interplay between abnormal tumor vasculature and the rsfMRI signal is still not well understood. Therefore, there is an exigent need for new tools to elucidate how the blood‑oxygenation-level-dependent (BOLD) rsfMRI signal is modulated in brain cancer. In this initial study, we explore the utility of a preclinical model for quantifying brain tumor-induced changes on the rsfMRI signal and resting-state brain connectivity. We demonstrate that brain tumors induce brain-wide alterations of resting-state networks that extend to the contralateral hemisphere, accompanied by global attenuation of the rsfMRI signal. Preliminary histology suggests that some of these alterations in brain connectivity may be attributable to tumor-related remodeling of the neurovasculature. Moreover, this work recapitulates clinical rsfMRI findings from brain tumor patients in terms of the effects of tumor size on the neurovascular microenvironment. Collectively, these results lay the foundation of a preclinical platform for exploring the usefulness of rsfMRI as a potential new biomarker in patients with brain cancer.
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Affiliation(s)
- Darian H Hadjiabadi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Leland Pung
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jiangyang Zhang
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - B D Ward
- Department of Biophysics, The Medical College of Wisconsin, Milwaukee, WI, USA
| | - Woo-Taek Lim
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Meghana Kalavar
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nitish V Thakor
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Bharat B Biswal
- Department of Biomedical Engineering, The New Jersey Institute of Technology, Newark NJ, USA
| | - Arvind P Pathak
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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54
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Bajic D, Craig MM, Mongerson CRL, Borsook D, Becerra L. Identifying Rodent Resting-State Brain Networks with Independent Component Analysis. Front Neurosci 2017; 11:685. [PMID: 29311770 PMCID: PMC5733053 DOI: 10.3389/fnins.2017.00685] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/22/2017] [Indexed: 01/08/2023] Open
Abstract
Rodent models have opened the door to a better understanding of the neurobiology of brain disorders and increased our ability to evaluate novel treatments. Resting-state functional magnetic resonance imaging (rs-fMRI) allows for in vivo exploration of large-scale brain networks with high spatial resolution. Its application in rodents affords researchers a powerful translational tool to directly assess/explore the effects of various pharmacological, lesion, and/or disease states on known neural circuits within highly controlled settings. Integration of animal and human research at the molecular-, systems-, and behavioral-levels using diverse neuroimaging techniques empowers more robust interrogations of abnormal/ pathological processes, critical for evolving our understanding of neuroscience. We present a comprehensive protocol to evaluate resting-state brain networks using Independent Component Analysis (ICA) in rodent model. Specifically, we begin with a brief review of the physiological basis for rs-fMRI technique and overview of rs-fMRI studies in rodents to date, following which we provide a robust step-by-step approach for rs-fMRI investigation including data collection, computational preprocessing, and brain network analysis. Pipelines are interwoven with underlying theory behind each step and summarized methodological considerations, such as alternative methods available and current consensus in the literature for optimal results. The presented protocol is designed in such a way that investigators without previous knowledge in the field can implement the analysis and obtain viable results that reliably detect significant differences in functional connectivity between experimental groups. Our goal is to empower researchers to implement rs-fMRI in their respective fields by incorporating technical considerations to date into a workable methodological framework.
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Affiliation(s)
- Dusica Bajic
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Michael M Craig
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
| | - Chandler R L Mongerson
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
| | - David Borsook
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Lino Becerra
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, United States.,Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States.,Department of Anaesthesia, Harvard Medical School, Harvard University, Boston, MA, United States
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55
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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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56
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Cho H, Kim CH, Knight EQ, Oh HW, Park B, Kim DG, Park HJ. Changes in brain metabolic connectivity underlie autistic-like social deficits in a rat model of autism spectrum disorder. Sci Rep 2017; 7:13213. [PMID: 29038507 PMCID: PMC5643347 DOI: 10.1038/s41598-017-13642-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/29/2017] [Indexed: 12/13/2022] Open
Abstract
The neurobiological basis of social dysfunction and the high male prevalence in autism spectrum disorder (ASD) remain poorly understood. Although network alterations presumably underlie the development of autistic-like behaviors, a clear pattern of connectivity differences specific to ASD has not yet emerged. Because the heterogeneous nature of ASD hinders investigations in human subjects, we explored brain connectivity in an etiologically homogenous rat model of ASD induced by exposure to valproic acid (VPA) in utero. We performed partial correlation analysis of cross-sectional resting-state 18F-fluorodeoxyglucose positron emission tomography scans from VPA-exposed and control rats to estimate metabolic connectivity and conducted canonical correlation analysis of metabolic activity and behavior scores. VPA-treated rats exhibited impairments in social behaviors, and this difference was more pronounced in male than female rats. Similarly, current analyses revealed sex-specific changes in network connectivity and identified distinct alterations in the distributed metabolic activity patterns associated with autistic-like social deficits. Specifically, diminished activity in the salience network and enhanced activity in a cortico-cerebellar circuit correlated with the severity of social behavioral deficits. Such metabolic connectivity features may represent neurobiological substrates of autistic-like behavior, particularly in males, and may serve as a pathognomonic sign in the VPA rat model of ASD.
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Affiliation(s)
- Hojin Cho
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Nuclear Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Chul Hoon Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Republic of Korea. .,BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea. .,Brain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea. .,Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | | | - Hye Won Oh
- BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Bumhee Park
- Department of Statistics, Hankuk University of Foreign Studies, Yong-In, Republic of Korea
| | - Dong Goo Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hae-Jeong Park
- BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea. .,Department of Nuclear Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea. .,Department of Psychiatry, Department of Cognitive Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
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57
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Thompson GJ. Neural and metabolic basis of dynamic resting state fMRI. Neuroimage 2017; 180:448-462. [PMID: 28899744 DOI: 10.1016/j.neuroimage.2017.09.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 02/07/2023] Open
Abstract
Resting state fMRI (rsfMRI) as a technique showed much initial promise for use in psychiatric and neurological diseases where diagnosis and treatment were difficult. To realize this promise, many groups have moved towards examining "dynamic rsfMRI," which relies on the assumption that rsfMRI measurements on short time scales remain relevant to the underlying neural and metabolic activity. Many dynamic rsfMRI studies have demonstrated differences between clinical or behavioral groups beyond what static rsfMRI measured, suggesting a neurometabolic basis. Correlative studies combining dynamic rsfMRI and other physiological measurements have supported this. However, they also indicate multiple mechanisms and, if using correlation alone, it is difficult to separate cause and effect. Hypothesis-driven studies are needed, a few of which have begun to illuminate the underlying neurometabolic mechanisms that shape observed differences in dynamic rsfMRI. While the number of potential noise sources, potential actual neurometabolic sources, and methodological considerations can seem overwhelming, dynamic rsfMRI provides a rich opportunity in systems neuroscience. Even an incrementally better understanding of the neurometabolic basis of dynamic rsfMRI would expand rsfMRI's research and clinical utility, and the studies described herein take the first steps on that path forward.
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Affiliation(s)
- Garth J Thompson
- iHuman Institute, ShanghaiTech University, Shanghai 201210, China.
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58
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Díaz-Parra A, Osborn Z, Canals S, Moratal D, Sporns O. Structural and functional, empirical and modeled connectivity in the cerebral cortex of the rat. Neuroimage 2017; 159:170-184. [PMID: 28739119 PMCID: PMC5724396 DOI: 10.1016/j.neuroimage.2017.07.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/10/2017] [Accepted: 07/20/2017] [Indexed: 11/19/2022] Open
Abstract
Connectomics data from animal models provide an invaluable opportunity to reveal the complex interplay between structure and function in the mammalian brain. In this work, we investigate the relationship between structural and functional connectivity in the rat brain cortex using a directed anatomical network generated from a carefully curated meta-analysis of published tracing data, along with resting-state functional MRI data obtained from a group of 14 anesthetized Wistar rats. We found a high correspondence between the strength of functional connections, measured as blood oxygen level dependent (BOLD) signal correlations between cortical regions, and the weight of the corresponding anatomical links in the connectome graph (maximum Spearman rank-order correlation ρ=0.48). At the network-level, regions belonging to the same functionally defined community tend to form more mutual weighted connections between each other compared to regions located in different communities. We further found that functional communities in resting-state networks are enriched in densely connected anatomical motifs. Importantly, these higher-order structural subgraphs cannot be explained by lower-order topological properties, suggesting that dense structural patterns support functional associations in the resting brain. Simulations of brain-wide resting-state activity based on neural mass models implemented on the empirical rat anatomical connectome demonstrated high correlation between the simulated and the measured functional connectivity (maximum Pearson correlation ρ=0.53), further suggesting that the topology of structural connections plays an important role in shaping functional cortical networks.
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Affiliation(s)
- Antonio Díaz-Parra
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Zachary Osborn
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Santiago Canals
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas & Universidad Miguel Hernández, Sant Joan d'Alacant, Spain
| | - David Moratal
- Center for Biomaterials and Tissue Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Olaf Sporns
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA; Indiana University Network Science Institute, Indiana University, Bloomington, IN 47405, USA.
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59
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Guevara E, Pierre WC, Tessier C, Akakpo L, Londono I, Lesage F, Lodygensky GA. Altered Functional Connectivity Following an Inflammatory White Matter Injury in the Newborn Rat: A High Spatial and Temporal Resolution Intrinsic Optical Imaging Study. Front Neurosci 2017; 11:358. [PMID: 28725174 PMCID: PMC5495836 DOI: 10.3389/fnins.2017.00358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/08/2017] [Indexed: 12/05/2022] Open
Abstract
Very preterm newborns have an increased risk of developing an inflammatory cerebral white matter injury that may lead to severe neuro-cognitive impairment. In this study we performed functional connectivity (fc) analysis using resting-state optical imaging of intrinsic signals (rs-OIS) to assess the impact of inflammation on resting-state networks (RSN) in a pre-clinical model of perinatal inflammatory brain injury. Lipopolysaccharide (LPS) or saline injections were administered in postnatal day (P3) rat pups and optical imaging of intrinsic signals were obtained 3 weeks later. (rs-OIS) fc seed-based analysis including spatial extent were performed. A support vector machine (SVM) was then used to classify rat pups in two categories using fc measures and an artificial neural network (ANN) was implemented to predict lesion size from those same fc measures. A significant decrease in the spatial extent of fc statistical maps was observed in the injured group, across contrasts and seeds (*p = 0.0452 for HbO2 and **p = 0.0036 for HbR). Both machine learning techniques were applied successfully, yielding 92% accuracy in group classification and a significant correlation r = 0.9431 in fractional lesion volume prediction (**p = 0.0020). Our results suggest that fc is altered in the injured newborn brain, showing the long-standing effect of inflammation.
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Affiliation(s)
- Edgar Guevara
- Terahertz Science and Technology National Lab, CONACYT-Universidad Autónoma de San Luis Potosí, Coordinación para la Innovación y Aplicación de la Ciencia y la TecnologíaSan Luis Potosí, Mexico
| | - Wyston C Pierre
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Camille Tessier
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Luis Akakpo
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Irène Londono
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada
| | - Frédéric Lesage
- Montreal Heart Institute, Research CenterMontreal, QC, Canada.,Department of Electrical Engineering, École Polytechnique de MontréalMontreal, QC, Canada
| | - Gregory A Lodygensky
- Sainte-Justine Hospital and Research Center, Department of Pediatrics, Université de MontréalMontreal, QC, Canada.,Montreal Heart Institute, Research CenterMontreal, QC, Canada.,Department of Pharmacology, Université de MontréalMontreal, QC, Canada.,Department of Neuroscience, Université de MontréalMontreal, QC, Canada
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60
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Wiesmann M, Roelofs M, van der Lugt R, Heerschap A, Kiliaan AJ, Claassen JAHR. Angiotensin II, hypertension and angiotensin II receptor antagonism: Roles in the behavioural and brain pathology of a mouse model of Alzheimer's disease. J Cereb Blood Flow Metab 2017; 37:2396-2413. [PMID: 27596834 PMCID: PMC5531339 DOI: 10.1177/0271678x16667364] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/26/2016] [Accepted: 08/08/2016] [Indexed: 12/11/2022]
Abstract
Elevated angiotensin II causes hypertension and contributes to Alzheimer's disease by affecting cerebral blood flow. Angiotensin II receptor blockers may provide candidates to reduce (vascular) risk factors for Alzheimer's disease. We studied effects of two months of angiotensin II-induced hypertension on systolic blood pressure, and treatment with the angiotensin II receptor blockers, eprosartan mesylate, after one month of induced hypertension in wild-type C57bl/6j and AβPPswe/PS1ΔE9 (AβPP/PS1/Alzheimer's disease) mice. AβPP/PS1 showed higher systolic blood pressure than wild-type. Subsequent eprosartan mesylate treatment restored this elevated systolic blood pressure in all mice. Functional connectivity was decreased in angiotensin II-infused Alzheimer's disease and wild-type mice, and only 12 months of Alzheimer's disease mice showed impaired cerebral blood flow. Only angiotensin II-infused Alzheimer's disease mice exhibited decreased spatial learning in the Morris water maze. Altogether, angiotensin II-induced hypertension not only exacerbated Alzheimer's disease-like pathological changes such as impairment of cerebral blood flow, functional connectivity, and cognition only in Alzheimer's disease model mice, but it also induced decreased functional connectivity in wild-type mice. However, we could not detect hypertension-induced overexpression of Aβ nor increased neuroinflammation. Our findings suggest a link between midlife hypertension, decreased cerebral hemodynamics and connectivity in an Alzheimer's disease mouse model. Eprosartan mesylate treatment restored and beneficially affected cerebral blood flow and connectivity. This model could be used to investigate prevention/treatment strategies in early Alzheimer's disease.
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Affiliation(s)
- Maximilian Wiesmann
- Department of Anatomy, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
- Department of Geriatric Medicine, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Monica Roelofs
- Department of Anatomy, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Robert van der Lugt
- Department of Anatomy, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Arend Heerschap
- Department of Radiology & Nuclear Medicine, Radboud university medical center, Nijmegen, The Netherlands
| | - Amanda J Kiliaan
- Department of Anatomy, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
| | - Jurgen AHR Claassen
- Department of Geriatric Medicine, Radboud Alzheimer Center, Donders Institute for Brain, Cognition & Behaviour, Radboud university medical center, Nijmegen, The Netherlands
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61
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Gorges M, Roselli F, Müller HP, Ludolph AC, Rasche V, Kassubek J. Functional Connectivity Mapping in the Animal Model: Principles and Applications of Resting-State fMRI. Front Neurol 2017; 8:200. [PMID: 28539914 PMCID: PMC5423907 DOI: 10.3389/fneur.2017.00200] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/24/2017] [Indexed: 12/25/2022] Open
Abstract
"Resting-state" fMRI has substantially contributed to the understanding of human and non-human functional brain organization by the analysis of correlated patterns in spontaneous activity within dedicated brain systems. Spontaneous neural activity is indirectly measured from the blood oxygenation level-dependent signal as acquired by echo planar imaging, when subjects quietly "resting" in the scanner. Animal models including disease or knockout models allow a broad spectrum of experimental manipulations not applicable in humans. The non-invasive fMRI approach provides a promising tool for cross-species comparative investigations. This review focuses on the principles of "resting-state" functional connectivity analysis and its applications to living animals. The translational aspect from in vivo animal models toward clinical applications in humans is emphasized. We introduce the fMRI-based investigation of the non-human brain's hemodynamics, the methodological issues in the data postprocessing, and the functional data interpretation from different abstraction levels. The longer term goal of integrating fMRI connectivity data with structural connectomes obtained with tracing and optical imaging approaches is presented and will allow the interrogation of fMRI data in terms of directional flow of information and may identify the structural underpinnings of observed functional connectivity patterns.
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Affiliation(s)
- Martin Gorges
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Francesco Roselli
- Department of Neurology, University of Ulm, Ulm, Germany
- Department of Anatomy and Cell Biology, University of Ulm, Ulm, Germany
| | | | | | - Volker Rasche
- Core Facility Small Animal MRI, University of Ulm, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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62
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Wiesmann M, Zerbi V, Jansen D, Lütjohann D, Veltien A, Heerschap A, Kiliaan AJ. Hypertension, cerebrovascular impairment, and cognitive decline in aged AβPP/PS1 mice. Theranostics 2017; 7:1277-1289. [PMID: 28435465 PMCID: PMC5399593 DOI: 10.7150/thno.18509] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 01/18/2017] [Indexed: 11/05/2022] Open
Abstract
Cardiovascular risk factors, especially hypertension, are also major risk factors for Alzheimer's disease (AD). To elucidate the underlying vascular origin of neurodegenerative processes in AD, we investigated the relation between systolic blood pressure (SBP) cerebral blood flow (CBF) and vasoreactivity with brain structure and function in a 16-18 months old double transgenic AβPPswe/PS1dE9 (AβPP/PS1) mouse model for AD. These aging AβPP/PS1 mice showed an increased SBP linked to a declined regional CBF. Furthermore, using advanced MRI techniques, decline of functional and structural connectivity was revealed in the AD-like mice coupled to impaired cognition, increased locomotor activity, and anxiety-related behavior. Post mortem analyses demonstrated also increased neuroinflammation, and both decreased synaptogenesis and neurogenesis in the AβPP/PS1 mice. Additionally, deviant levels of fatty acids and sterols were present in the brain tissue of the AβPP/PS1 mice indicating maladapted brain fatty acid metabolism. Our findings suggest a link between increased SBP, decreased cerebral hemodynamics and connectivity in an AD mouse model during aging, leading to behavioral and cognitive impairments. As these results mirror the complex clinical symptomatology in the prodromal phase of AD, we suggest that this AD-like murine model could be used to investigate prevention and treatment strategies for early AD patients. Moreover, this study helps to develop more efficient therapies and diagnostics for this very early stage of AD.
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63
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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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64
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Wu T, Grandjean J, Bosshard SC, Rudin M, Reutens D, Jiang T. Altered regional connectivity reflecting effects of different anaesthesia protocols in the mouse brain. Neuroimage 2017; 149:190-199. [PMID: 28159688 DOI: 10.1016/j.neuroimage.2017.01.074] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/17/2017] [Accepted: 01/30/2017] [Indexed: 01/19/2023] Open
Abstract
Studies in mice using resting-state functional magnetic resonance imaging (rs-fMRI) have provided opportunities to investigate the effects of pharmacological manipulations on brain function and map the phenotypes of mouse models of human brain disorders. Mouse rs-fMRI is typically performed under anaesthesia, which induces both regional suppression of brain activity and disruption of large-scale neural networks. Previous comparative studies using rodents investigating various drug effects on long-distance functional connectivity (FC) have reported agent-specific FC patterns, however, effects of regional suppression are sparsely explored. Here we examined changes in regional connectivity under six different anaesthesia conditions using mouse rs-fMRI with the goal of refining the framework of understanding the brain activation under anaesthesia at a local level. Regional homogeneity (ReHo) was used to map local synchronization in the brain, followed by analysis of several brain areas based on ReHo maps. The results revealed high local coherence in most brain areas. The primary somatosensory cortex and caudate-putamen showed agent-specific properties. Lower local coherence in the cingulate cortex was observed under medetomidine, particularly when compared to the combination of medetomidine and isoflurane. The thalamus was associated with retained local coherence across anaesthetic levels and multiple nuclei. These results show that anaesthesia induced by the investigated anaesthetics through different molecular targets promote agent-specific regional connectivity. In addition, ReHo is a data-driven method with minimum user interaction, easy to use and fast to compute. Given that examination of the brain at a local level is widely applied in human rs-fMRI studies, our results show its sensitivity to extract information on varied neuronal activity under six different regimens relevant to mouse functional imaging. These results, therefore, will inform future rs-fMRI studies on mice and the type of anaesthetic agent used, and will help to bridge observations between this burgeoning research field and ongoing human research across analytical scales.
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Affiliation(s)
- Tong Wu
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Joanes Grandjean
- Molecular Imaging and Functional Pharmacology, Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; Singapore BioImaging Consortium, Agency for Science, Technology and Research, Singapore
| | - Simone C Bosshard
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| | - Markus Rudin
- Molecular Imaging and Functional Pharmacology, Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - David Reutens
- The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
| | - Tianzi Jiang
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; Brainnetome Centre, Institute of Automation, Chinese Academy of Sciences, Beijing, China; Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 625014, China
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65
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Just N, Sonnay S. Investigating the Role of Glutamate and GABA in the Modulation of Transthalamic Activity: A Combined fMRI-fMRS Study. Front Physiol 2017; 8:30. [PMID: 28197105 PMCID: PMC5281558 DOI: 10.3389/fphys.2017.00030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/11/2017] [Indexed: 11/29/2022] Open
Abstract
The Excitatory-Inhibitory balance (EIB) between glutamatergic and GABAergic neurons is known to regulate the function of thalamocortical neurocircuits. The thalamus is known as an important relay for glutamatergic and GABAergic signals ascending/descending to/from the somatosensory cortex in rodents. However, new investigations attribute a larger role to thalamic nuclei as modulators of information processing within the cortex. In this study, functional Magnetic Resonance Spectroscopy (fMRS) was used to measure glutamate (Glu) and GABA associations with BOLD responses during activation of the thalamus to barrel cortex (S1BF) pathway at 9.4T. In line with previous studies in humans, resting GABA and Glu correlated negatively and positively respectively with BOLD responses in S1BF. Moreover, a significant negative correlation (R = −0.68, p = 0.0024) between BOLD responses in the thalamus and the barrel cortex was found. Rats with low Glu levels and high resting GABA levels in S1BF demonstrated lower BOLD responses in S1BF and high amplitude BOLD responses in the thalamus themselves linked to the release of high GABA levels during stimulation. In addition, early analysis of resting state functional connectivity suggested EIB controlled thalamocortical neuronal synchrony. We propose that the presented approach may be useful for further characterization of diseases affecting thalamocortical neurotransmission.
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Affiliation(s)
- Nathalie Just
- CIBM-AIT core, Ecole Polytechnique Fédérale de LausanneLausanne, Switzerland; University Hospital MünsterMünster, Germany
| | - Sarah Sonnay
- LIFMET, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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66
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Shim WH, Suh JY, Kim JK, Jeong J, Kim YR. Enhanced Thalamic Functional Connectivity with No fMRI Responses to Affected Forelimb Stimulation in Stroke-Recovered Rats. Front Neural Circuits 2017; 10:113. [PMID: 28119575 PMCID: PMC5222821 DOI: 10.3389/fncir.2016.00113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/21/2016] [Indexed: 01/21/2023] Open
Abstract
Neurological recovery after stroke has been extensively investigated to provide better understanding of neurobiological mechanism, therapy, and patient management. Recent advances in neuroimaging techniques, particularly functional MRI (fMRI), have widely contributed to unravel the relationship between the altered neural function and stroke-affected brain areas. As results of previous investigations, the plastic reorganization and/or gradual restoration of the hemodynamic fMRI responses to neural stimuli have been suggested as relevant mechanisms underlying the stroke recovery process. However, divergent study results and modality-dependent outcomes have clouded the proper interpretation of variable fMRI signals. Here, we performed both evoked and resting state fMRI (rs-fMRI) to clarify the link between the fMRI phenotypes and post-stroke functional recovery. The experiments were designed to examine the altered neural activity within the contra-lesional hemisphere and other undamaged brain regions using rat models with large unilateral stroke, which despite the severe injury, exhibited nearly full recovery at ∼6 months after stroke. Surprisingly, both blood oxygenation level-dependent and blood volume-weighted (CBVw) fMRI activities elicited by electrical stimulation of the stroke-affected forelimb were completely absent, failing to reveal the neural origin of the behavioral recovery. In contrast, the functional connectivity maps showed highly robust rs-fMRI activity concentrated in the contra-lesional ventromedial nucleus of thalamus (VM). The negative finding in the stimuli-induced fMRI study using the popular rat middle cerebral artery model denotes weak association between the fMRI hemodynamic responses and neurological improvement. The results strongly caution the indiscreet interpretation of stroke-affected fMRI signals and demonstrate rs-fMRI as a complementary tool for efficiently characterizing stroke recovery.
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Affiliation(s)
- Woo H Shim
- Department of Radiology, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; ASAN Institute for Life Sciences, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; Department of Bio and Brain Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, BostonMA, USA
| | - Ji-Yeon Suh
- Department of Radiology, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, BostonMA, USA
| | - Jeong K Kim
- Department of Radiology, ASAN Medical Center, University of Ulsan College of Medicine Ulsan, South Korea
| | - Jaeseung Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Young R Kim
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston MA, USA
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67
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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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68
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Zhou ZC, Salzwedel AP, Radtke-Schuller S, Li Y, Sellers KK, Gilmore JH, Shih YYI, Fröhlich F, Gao W. Resting state network topology of the ferret brain. Neuroimage 2016; 143:70-81. [PMID: 27596024 DOI: 10.1016/j.neuroimage.2016.09.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/17/2016] [Accepted: 09/01/2016] [Indexed: 12/22/2022] Open
Abstract
Resting state functional magnetic resonance imaging (rsfMRI) has emerged as a versatile tool for non-invasive measurement of functional connectivity patterns in the brain. RsfMRI brain dynamics in rodents, non-human primates, and humans share similar properties; however, little is known about the resting state functional connectivity patterns in the ferret, an animal model with high potential for developmental and cognitive translational study. To address this knowledge-gap, we performed rsfMRI on anesthetized ferrets using a 9.4T MRI scanner, and subsequently performed group-level independent component analysis (gICA) to identify functionally connected brain networks. Group-level ICA analysis revealed distributed sensory, motor, and higher-order networks in the ferret brain. Subsequent connectivity analysis showed interconnected higher-order networks that constituted a putative default mode network (DMN), a network that exhibits altered connectivity in neuropsychiatric disorders. Finally, we assessed ferret brain topological efficiency using graph theory analysis and found that the ferret brain exhibits small-world properties. Overall, these results provide additional evidence for pan-species resting-state networks, further supporting ferret-based studies of sensory and cognitive function.
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Affiliation(s)
- Zhe Charles Zhou
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Andrew P Salzwedel
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States
| | - Susanne Radtke-Schuller
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Yuhui Li
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Kristin K Sellers
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - John H Gilmore
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Yen-Yu Ian Shih
- Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Small Animal Imaging Facility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Flavio Fröhlich
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States; Neurobiology Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Wei Gao
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, United States.
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69
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Liebmann T, Renier N, Bettayeb K, Greengard P, Tessier-Lavigne M, Flajolet M. Three-Dimensional Study of Alzheimer's Disease Hallmarks Using the iDISCO Clearing Method. Cell Rep 2016; 16:1138-1152. [PMID: 27425620 DOI: 10.1016/j.celrep.2016.06.060] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 05/16/2016] [Accepted: 06/11/2016] [Indexed: 12/20/2022] Open
Abstract
Amyloidosis is a major problem in over one hundred diseases, including Alzheimer's disease (AD). Using the iDISCO visualization method involving targeted molecular labeling, tissue clearing, and light-sheet microscopy, we studied plaque formation in the intact AD mouse brain at up to 27 months of age. We visualized amyloid plaques in 3D together with tau, microglia, and vasculature. Volume imaging coupled to automated detection and mapping enables precise and fast quantification of plaques within the entire intact mouse brain. The present methodology is also applicable to analysis of frozen human brain samples without specialized preservation. Remarkably, amyloid plaques in human brain tissues showed greater 3D complexity and surprisingly large three-dimensional amyloid patterns, or TAPs. The ability to visualize amyloid in 3D, especially in the context of their micro-environment, and the discovery of large TAPs may have important scientific and medical implications.
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Affiliation(s)
- Thomas Liebmann
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | - Nicolas Renier
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - Karima Bettayeb
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | - Paul Greengard
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - Marc Flajolet
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA.
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70
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Gozzi A, Schwarz AJ. Large-scale functional connectivity networks in the rodent brain. Neuroimage 2015; 127:496-509. [PMID: 26706448 DOI: 10.1016/j.neuroimage.2015.12.017] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 02/08/2023] Open
Abstract
Resting-state functional Magnetic Resonance Imaging (rsfMRI) of the human brain has revealed multiple large-scale neural networks within a hierarchical and complex structure of coordinated functional activity. These distributed neuroanatomical systems provide a sensitive window on brain function and its disruption in a variety of neuropathological conditions. The study of macroscale intrinsic connectivity networks in preclinical species, where genetic and environmental conditions can be controlled and manipulated with high specificity, offers the opportunity to elucidate the biological determinants of these alterations. While rsfMRI methods are now widely used in human connectivity research, these approaches have only relatively recently been back-translated into laboratory animals. Here we review recent progress in the study of functional connectivity in rodent species, emphasising the ability of this approach to resolve large-scale brain networks that recapitulate neuroanatomical features of known functional systems in the human brain. These include, but are not limited to, a distributed set of regions identified in rats and mice that may represent a putative evolutionary precursor of the human default mode network (DMN). The impact and control of potential experimental and methodological confounds are also critically discussed. Finally, we highlight the enormous potential and some initial application of connectivity mapping in transgenic models as a tool to investigate the neuropathological underpinnings of the large-scale connectional alterations associated with human neuropsychiatric and neurological conditions. We conclude by discussing the translational potential of these methods in basic and applied neuroscience.
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Affiliation(s)
- Alessandro Gozzi
- Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems at UniTn, Rovereto, Italy.
| | - Adam J Schwarz
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA; Department of Radiology and Imaging Sciences, Indiana University, Indianapolis, IN 46202, USA
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