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Seitzman BA, Reynoso FJ, Mitchell TJ, Bice AR, Jarang A, Wang X, Mpoy C, Strong L, Rogers BE, Yuede CM, Rubin JB, Perkins SM, Bauer AQ. Functional network disorganization and cognitive decline following fractionated whole-brain radiation in mice. GeroScience 2024; 46:543-562. [PMID: 37749370 PMCID: PMC10828348 DOI: 10.1007/s11357-023-00944-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 09/11/2023] [Indexed: 09/27/2023] Open
Abstract
Cognitive dysfunction following radiotherapy (RT) is one of the most common complications associated with RT delivered to the brain, but the precise mechanisms behind this dysfunction are not well understood, and to date, there are no preventative measures or effective treatments. To improve patient outcomes, a better understanding of the effects of radiation on the brain's functional systems is required. Functional magnetic resonance imaging (fMRI) has shown promise in this regard, however, compared to neural activity, hemodynamic measures of brain function are slow and indirect. Understanding how RT acutely and chronically affects functional brain organization requires more direct examination of temporally evolving neural dynamics as they relate to cerebral hemodynamics for bridging with human studies. In order to adequately study the underlying mechanisms of RT-induced cognitive dysfunction, the development of clinically mimetic RT protocols in animal models is needed. To address these challenges, we developed a fractionated whole-brain RT protocol (3Gy/day for 10 days) and applied longitudinal wide field optical imaging (WFOI) of neural and hemodynamic brain activity at 1, 2, and 3 months post RT. At each time point, mice were subject to repeated behavioral testing across a variety of sensorimotor and cognitive domains. Disruptions in cortical neuronal and hemodynamic activity observed 1 month post RT were significantly worsened by 3 months. While broad changes were observed in functional brain organization post RT, brain regions most impacted by RT occurred within those overlapping with the mouse default mode network and other association areas similar to prior reports in human subjects. Further, significant cognitive deficits were observed following tests of novel object investigation and responses to auditory and contextual cues after fear conditioning. Our results fill a much-needed gap in understanding the effects of whole-brain RT on systems level brain organization and how RT affects neuronal versus hemodynamic signaling in the cortex. Having established a clinically-relevant injury model, future studies can examine therapeutic interventions designed to reduce neuroinflammation-based injury following RT. Given the overlap of sequelae that occur following RT with and without chemotherapy, these tools can also be easily incorporated to examine chemotherapy-related cognitive impairment.
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Affiliation(s)
- Benjamin A Seitzman
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Francisco J Reynoso
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Timothy J Mitchell
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Annie R Bice
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, Campus Box 8225, St. Louis, MO, 63110, USA
| | - Anmol Jarang
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, Campus Box 8225, St. Louis, MO, 63110, USA
| | - Xiaodan Wang
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, Campus Box 8225, St. Louis, MO, 63110, USA
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Cedric Mpoy
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Lori Strong
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Buck E Rogers
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA
| | - Carla M Yuede
- Department of Psychiatry, School of Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | - Joshua B Rubin
- Department of Pediatrics, School of Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | - Stephanie M Perkins
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, 4921 Parkview Place, Campus Box 8224, St. Louis, MO, 63110, USA.
| | - Adam Q Bauer
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, 660 S. Euclid Ave, Campus Box 8225, St. Louis, MO, 63110, USA.
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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Gong L, Huang X, Hu Z, Chen C, Zhang Z, Liao H, Xiao Y, Fan J, Zeng L, Chen S, Xie Y. Altered functional connectivity after pilocarpine-induced seizures revealed by intrinsic optical signals imaging in awake mice. NEUROPHOTONICS 2024; 11:015001. [PMID: 38125610 PMCID: PMC10729166 DOI: 10.1117/1.nph.11.1.015001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/05/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
Significance Comorbidities such as mood and cognitive disorders are often found in individuals with epilepsy after seizures. Cortex processes sensory, motor, and cognitive information. Brain circuit changes can be studied by observing functional network changes in epileptic mice's cortex. Aim The cortex is easily accessible for non-invasive brain imaging and electroencephalogram recording (EEG). However, the impact of seizures on cortical activity and functional connectivity has been rarely studied in vivo. Approach Intrinsic optical signal and EEG were used to monitor cortical activity in awake mice within 4 h after pilocarpine induction. It was divided into three periods according to the behavior and EEG of the mice: baseline, onset of seizures (onset, including seizures and resting in between seizure events), and after seizures (post, without seizures). Changes in cortical activity were compared between the baseline and after seizures. Results Hemoglobin levels increased significantly, particularly in the parietal association cortex (PT), retrosplenial cortex (RS), primary visual cortex (V1), and secondary visual cortex (V2). The network-wide functional connectivity changed post seizures, e.g., hypoconnectivity between PT and visual-associated cortex (e.g., V1 and V2). In contrast, connectivity between the motor-associated cortex and most other regions increased. In addition, the default mode network (DMN) also changed after seizures, with decreased connectivity between primary somatosensory region (SSp) and visual region (VIS), but increased connectivity involving anterior cingulate cortex (AC) and RS. Conclusions Our results provide references for understanding the mechanisms behind changes in brain circuits, which may explain the profound effects of seizures on comorbid health conditions.
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Affiliation(s)
- Lifen Gong
- Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Department of Neonatal Surgery, Hangzhou, China
- The First Affiliated Hospital, Zhejiang University School of Medicine, Department of Neurosurgery and Pediatrics, Hangzhou, China
| | - Xin Huang
- The First Affiliated Hospital, Zhejiang University School of Medicine, Department of Neurosurgery and Pediatrics, Hangzhou, China
| | - Zhe Hu
- Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Department of Neonatal Surgery, Hangzhou, China
| | - Chen Chen
- Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Department of Neonatal Surgery, Hangzhou, China
| | - Ziqi Zhang
- Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Hongxuan Liao
- Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Yinglin Xiao
- Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Jianchen Fan
- Hangzhou City University, School of Medicine, Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, Hangzhou, China
| | - Linghui Zeng
- Hangzhou City University, School of Medicine, Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, Hangzhou, China
| | - Shangbin Chen
- Huazhong University of Science and Technology, Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Yicheng Xie
- Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Department of Neonatal Surgery, Hangzhou, China
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3
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Akther S, Mikkelsen MB, Postnov DD. Choosing a polarisation configuration for dynamic light scattering and laser speckle contrast imaging. BIOMEDICAL OPTICS EXPRESS 2024; 15:336-345. [PMID: 38223196 PMCID: PMC10783896 DOI: 10.1364/boe.507367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/06/2023] [Accepted: 12/12/2023] [Indexed: 01/16/2024]
Abstract
Laser speckle contrast imaging (LSCI) is applied in various biomedical applications for full-field characterization of blood flow and tissue perfusion. The accuracy of the contrast interpretation and its conversion to the blood flow index depends on specific parameters of the optical system and scattering media. One such parameter is the polarisation of detected light, which is often adjusted to minimize specular reflections and image artefacts. The polarisation's effect on the detected light scattering dynamics and, therefore, the accuracy of LSCI data interpretation requires more detailed investigation. In this study, we used LSCI and Dynamic Light Scattering Imaging to evaluate the effects of the detected light polarisation when imaging perfusion in the mouse cortex. We found that cross-polarisation results in a shorter decorrelation time constant, a higher coherence degree and stronger dynamic scattering compared to the parallel-polarisation or no-polariser configurations. These results support the cross-polarisation configuration as the most optimal for brain cortex imaging and suggest against direct or calibrated comparisons between the contrast recordings made with different polarisation configurations.
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Affiliation(s)
| | | | - Dmitry D. Postnov
- Aarhus University, Department of Clinical Medicine, Aarhus, 8200, Denmark
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González Olmos A, Zilpelwar S, Sunil S, Boas DA, Postnov DD. Optimizing the precision of laser speckle contrast imaging. Sci Rep 2023; 13:17970. [PMID: 37864006 PMCID: PMC10589309 DOI: 10.1038/s41598-023-45303-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023] Open
Abstract
Laser speckle contrast imaging (LSCI) is a rapidly developing technology broadly applied for the full-field characterization of tissue perfusion. Over the recent years, significant advancements have been made in interpreting LSCI measurements and improving the technique's accuracy. On the other hand, the method's precision has yet to be studied in detail, despite being as important as accuracy for many biomedical applications. Here we combine simulation, theory and animal experiments to systematically evaluate and re-analyze the role of key factors defining LSCI precision-speckle-to-pixel size ratio, polarisation, exposure time and camera-related noise. We show that contrary to the established assumptions, smaller speckle size and shorter exposure time can improve the precision, while the camera choice is less critical and does not affect the signal-to-noise ratio significantly.
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Affiliation(s)
| | - Sharvari Zilpelwar
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Smrithi Sunil
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Dmitry D Postnov
- Department of Clinical Medicine, Aarhus University, 8200, Aarhus, Denmark.
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5
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Padawer-Curry JA, Bowen RM, Jarang A, Wang X, Lee JM, Bauer AQ. Wide-Field Optical Imaging in Mouse Models of Ischemic Stroke. Methods Mol Biol 2023; 2616:113-151. [PMID: 36715932 DOI: 10.1007/978-1-0716-2926-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Functional neuroimaging is a powerful tool for evaluating how local and global brain circuits evolve after focal ischemia and how these changes relate to functional recovery. For example, acutely after stroke, changes in functional brain organization relate to initial deficit and are predictive of recovery potential. During recovery, the reemergence and restoration of connections lost due to stroke correlate with recovery of function. Thus, information gleaned from functional neuroimaging can be used as a proxy for behavior and inform on the efficacy of interventional strategies designed to affect plasticity mechanisms after injury. And because these findings are consistently observed across species, bridge measurements can be made in animal models to enrich findings in human stroke populations. In mice, genetic engineering techniques have provided several new opportunities for extending optical neuroimaging methods to more direct measures of neuronal activity. These developments are especially useful in the context of stroke where neurovascular coupling can be altered, potentially limiting imaging measures based on hemodynamic activity alone. This chapter is designed to give an overview of functional wide-field optical imaging (WFOI) for applications in rodent models of stroke, primarily in the mouse. The goal is to provide a protocol for laboratories that want to incorporate an affordable functional neuroimaging assay into their current research thrusts, but perhaps lack the background knowledge or equipment for developing a new arm of research in their lab. Within, we offer a comprehensive guide developing and applying WFOI technology with the hope of facilitating accessibility of neuroimaging technology to other researchers in the stroke field.
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Affiliation(s)
- Jonah A Padawer-Curry
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, USA
- Imaging Science PhD Program, Washington University in St. Louis, St. Louis, MO, USA
| | - Ryan M Bowen
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Anmol Jarang
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Xiaodan Wang
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jin-Moo Lee
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Adam Q Bauer
- Department of Radiology, Washington University in St. Louis, St. Louis, MO, USA.
- Imaging Science PhD Program, Washington University in St. Louis, St. Louis, MO, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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6
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Clarke JV, Brier LM, Rahn RM, Diwan D, Yuan JY, Bice AR, Imai SI, Vellimana AK, Culver JP, Zipfel GJ. SIRT1 mediates hypoxic postconditioning- and resveratrol-induced protection against functional connectivity deficits after subarachnoid hemorrhage. J Cereb Blood Flow Metab 2022; 42:1210-1223. [PMID: 35137611 PMCID: PMC9207494 DOI: 10.1177/0271678x221079902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Functional connectivity (FC) is a sensitive metric that provides a readout of whole cortex coordinate neural activity in a mouse model. We examine the impact of experimental SAH modeled through endovascular perforation, and the effectiveness of subsequent treatment on FC, through three key questions: 1) Does the endovascular perforation model of SAH induce deficits in FC; 2) Does exposure to hypoxic conditioning provide protection against these FC deficits and, if so, is this neurovascular protection SIRT1-mediated; and 3) does treatment with the SIRT1 activator resveratrol alone provide protection against these FC deficits? Cranial windows were adhered on skull-intact mice that were then subjected to either sham or SAH surgery and either left untreated or treated with hypoxic post-conditioning (with or without EX527) or resveratrol for 3 days. Mice were imaged 3 days post-SAH/sham surgery, temporally aligned with the onset of major SAH sequela in mice. Here we show that the endovascular perforation model of SAH induces global and network-specific deficits in FC by day 3, corresponding with the time frame of DCI in mice. Hypoxic conditioning provides SIRT1-mediated protection against these network-specific FC deficits post-SAH, as does treatment with resveratrol. Conditioning-based strategies provide multifaceted neurovascular protection in experimental SAH.
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Affiliation(s)
- Julian V Clarke
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, USA
| | - Lindsey M Brier
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, USA
| | - Rachel M Rahn
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, USA
| | - Deepti Diwan
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, USA
| | - Jane Y Yuan
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, USA
| | - Annie R Bice
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, USA
| | - Shin-Ichiro Imai
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, USA
| | - Ananth K Vellimana
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, USA
| | - Joseph P Culver
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, USA
| | - Gregory J Zipfel
- Department of Neurological Surgery, Washington University School of Medicine, St. Louis, USA
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7
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Wang Y, Chu TS, Lin YR, Tsao CH, Tsai CH, Ger TR, Chen LT, Chang WSW, Liao LD. Assessment of Brain Functional Activity Using a Miniaturized Head-Mounted Scanning Photoacoustic Imaging System in Awake and Freely Moving Rats. BIOSENSORS 2021; 11:bios11110429. [PMID: 34821645 PMCID: PMC8615926 DOI: 10.3390/bios11110429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 12/25/2022]
Abstract
Understanding the relationship between brain function and natural behavior remains a significant challenge in neuroscience because there are very few convincing imaging/recording tools available for the evaluation of awake and freely moving animals. Here, we employed a miniaturized head-mounted scanning photoacoustic imaging (hmPAI) system to image real-time cortical dynamics. A compact photoacoustic (PA) probe based on four in-house optical fiber pads and a single custom-made 48-MHz focused ultrasound transducer was designed to enable focused dark-field PA imaging, and miniature linear motors were included to enable two-dimensional (2D) scanning. The total dimensions and weight of the proposed hmPAI system are only approximately 50 × 64 × 48 mm and 58.7 g (excluding cables). Our ex vivo phantom experimental tests revealed that a spatial resolution of approximately 0.225 mm could be achieved at a depth of 9 mm. Our in vivo results further revealed that the diameters of cortical vessels draining into the superior sagittal sinus (SSS) could be clearly imaged and continuously observed in both anesthetized rats and awake, freely moving rats. Statistical analysis showed that the full width at half maximum (FWHM) of the PA A-line signals (relative to the blood vessel diameter) was significantly increased in the selected SSS-drained cortical vessels of awake rats (0.58 ± 0.17 mm) compared with those of anesthetized rats (0.31 ± 0.09 mm) (p < 0.01, paired t-test). In addition, the number of pixels in PA B-scan images (relative to the cerebral blood volume (CBV)) was also significantly increased in the selected SSS-drained blood vessels of awake rats (107.66 ± 23.02 pixels) compared with those of anesthetized rats (81.99 ± 21.52 pixels) (p < 0.01, paired t-test). This outcome may result from a more active brain in awake rats than in anesthetized rats, which caused cerebral blood vessels to transport more blood to meet the increased nutrient demand of the tissue, resulting in an obvious increase in blood vessel volume. This hmPAI system was further validated for utility in the brains of awake and freely moving rats, showing that their natural behavior was unimpaired during vascular imaging, thereby providing novel opportunities for studies of behavior, cognition, and preclinical models of brain diseases.
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Affiliation(s)
- Yuhling Wang
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan; (Y.W.); (T.-S.C.); (C.-H.T.); (C.-H.T.)
| | - Tsung-Sheng Chu
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan; (Y.W.); (T.-S.C.); (C.-H.T.); (C.-H.T.)
- Department of Biomedical Engineering, College of Engineering, Chung Yuan Christian University, Chung Li District, Taoyuan City 32023, Taiwan;
| | - Yan-Ren Lin
- Department of Emergency and Critical Care Medicine, Changhua Christian Hospital, Changhua County 50006, Taiwan;
- College of Medicine, National Chung Hsing University, Taichung 402, Taiwan
| | - Chia-Hui Tsao
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan; (Y.W.); (T.-S.C.); (C.-H.T.); (C.-H.T.)
| | - Chia-Hua Tsai
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan; (Y.W.); (T.-S.C.); (C.-H.T.); (C.-H.T.)
| | - Tzong-Rong Ger
- Department of Biomedical Engineering, College of Engineering, Chung Yuan Christian University, Chung Li District, Taoyuan City 32023, Taiwan;
| | - Li-Tzong Chen
- National Institute of Cancer Research, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan;
- Kaohsiung Medical University Hospital, Kaohsiung Medical University, Sanmin District, Kaohsiung City 80708, Taiwan
| | - Wun-Shaing Wayne Chang
- National Institute of Cancer Research, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan;
- Correspondence: (W.-S.W.C.); (L.-D.L.)
| | - Lun-De Liao
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan Township, Miaoli County 35053, Taiwan; (Y.W.); (T.-S.C.); (C.-H.T.); (C.-H.T.)
- Correspondence: (W.-S.W.C.); (L.-D.L.)
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8
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Liu C, Kılıç K, Erdener SE, Boas DA, Postnov DD. Choosing a model for laser speckle contrast imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:3571-3583. [PMID: 34221679 PMCID: PMC8221943 DOI: 10.1364/boe.426521] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/08/2021] [Accepted: 05/18/2021] [Indexed: 05/02/2023]
Abstract
Laser speckle contrast imaging (LSCI) is a real-time full-field non-invasive technique, which is broadly applied to visualize blood flow in biomedical applications. In its foundation is the link between the speckle contrast and dynamics of light scattering particles-erythrocytes. The mathematical form describing this relationship, which is critical for accurate blood flow estimation, depends on the sample's light-scattering properties. However, in biological applications, these properties are often unknown, thus requiring assumptions to be made to perform LSCI analysis. Here, we review the most critical assumptions in the LSCI theory and simulate how they affect blood flow estimation accuracy. We show that the most commonly applied model can severely underestimate the flow change, particularly when imaging brain parenchyma or other capillary perfused tissue (e.g. skin) under ischemic conditions. Based on these observations and guided by the recent experimental results, we propose an alternative model that allows measuring blood flow changes with higher accuracy.
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Affiliation(s)
- Chang Liu
- Department of Biomedical Engineering, Boston University, Massachusetts 02215, USA
- Department of Bioengineering, Northeastern University, Massachusetts 02115, USA
| | - Kıvılcım Kılıç
- Neurophotonics Center, Boston University, Massachusetts 02215, USA
| | - Sefik Evren Erdener
- Neurophotonics Center, Boston University, Massachusetts 02215, USA
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - David A. Boas
- Department of Biomedical Engineering, Boston University, Massachusetts 02215, USA
- Neurophotonics Center, Boston University, Massachusetts 02215, USA
| | - Dmitry D. Postnov
- Neurophotonics Center, Boston University, Massachusetts 02215, USA
- Department of Biomedical Sciences, Copenhagen University, Copenhagen, Denmark
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9
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Lee J, Stile CL, Bice AR, Rosenthal ZP, Yan P, Snyder AZ, Lee JM, Bauer AQ. Opposed hemodynamic responses following increased excitation and parvalbumin-based inhibition. J Cereb Blood Flow Metab 2021; 41:841-856. [PMID: 33736512 PMCID: PMC7983494 DOI: 10.1177/0271678x20930831] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/24/2020] [Accepted: 04/30/2020] [Indexed: 02/05/2023]
Abstract
Understanding cellular contributions to hemodynamic activity is essential for interpreting blood-based brain mapping signals. Optogenetic studies examining cell-specific influences on local hemodynamics have reported that excitatory activity results in cerebral perfusion and blood volume increase, while inhibitory activity contributes to both vasodilation and vasoconstriction. How specific subpopulations of interneurons regulate the brain's blood supply is less examined. Parvalbumin interneurons are the largest subpopulation of GABAergic neurons in the brain, critical for brain development, plasticity, and long-distance excitatory neurotransmission. Despite their essential role in brain function, the contribution of parvalbumin neurons to neurovascular coupling has been relatively unexamined. Using optical intrinsic signal imaging and laser speckle contrast imaging, we photostimulated awake and anesthetized transgenic mice expressing channelrhodopsin under a parvalbumin promoter. Increased parvalbumin activity reduced local oxygenation, cerebral blood volume, and cerebral blood flow. These "negative" hemodynamic responses were consistent within and across mice and reproducible across a broad range of photostimulus parameters. However, the sign and magnitude of the hemodynamic response resulting from increased parvalbumin activity depended on the type and level of anesthesia used. Opposed hemodynamic responses following increased excitation or parvalbumin-based inhibition suggest unique contributions from different cell populations to neurovascular coupling.
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Affiliation(s)
- Joonhyuk Lee
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Chloe L Stile
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Zachary P Rosenthal
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Ping Yan
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jin-Moo Lee
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA
| | - Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA
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10
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White BR, Padawer-Curry JA, Ko T, Baker W, Breimann J, Cohen AS, Licht DJ, Yodh AG. Wavelength censoring for spectroscopy in optical functional neuroimaging. Phys Med Biol 2021; 66:065026. [PMID: 33326946 DOI: 10.1088/1361-6560/abd418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Optical neuromonitoring provides insight into neurovascular physiology and brain structure and function. These methods rely on spectroscopy to relate light absorption changes to variation of concentrations of physiologic chromophores such as oxy- and deoxyhemoglobin. In clinical or preclinical practice, data quality can vary significantly across wavelengths. In such situations, standard spectroscopic methods may perform poorly, resulting in data loss and limiting field-of-view. To address this issue, and thereby improve the robustness of optical neuromonitoring, we develop, in this manuscript, novel methods to perform spectroscopy even when data quality exhibits wavelength-dependent spatial variation. We sought to understand the impact of spatial, wavelength-based censoring on the physiologic accuracy and utility of hemoglobin spectroscopy. The principles of our analysis are quite general, but to make the methodology tangible we focused on optical intrinsic signal imaging of resting-state functional connectivity in mice. Starting with spectroscopy using four sources, all possible subset spectroscopy matrices were assessed theoretically, using simulated data, and using experimental data. These results were compared against the use of the full spectroscopy matrix to determine which subsets yielded robust results. Our results demonstrated that accurate calculation of changes in hemoglobin concentrations and the resulting functional connectivity network maps was possible even with censoring of some wavelengths. Additionally, we found that the use of changes in total hemoglobin (rather than oxy- or deoxyhemoglobin) yielded results more robust to experimental noise and allowed for the preservation of more data. This new and rigorous image processing method should improve the fidelity of clinical and preclinical functional neuroimaging studies.
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Affiliation(s)
- Brian R White
- Division of Pediatric Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, 3401 Civic Center Blvd., Pediatric Cardiology-8NW, Philadelphia, PA 19104, United States of America
| | - Jonah A Padawer-Curry
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, United States of America
| | - Tiffany Ko
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, United States of America
| | - Wesley Baker
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, United States of America
| | - Jake Breimann
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, United States of America
| | - Akiva S Cohen
- Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia. 3615 Civic Center Blvd., Abramson Research Center, Room 816-H, Philadelphia, PA 19104, United States of America
| | - Daniel J Licht
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia and The Perelman School of Medicine at the University of Pennsylvania, United States of America
| | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, United States of America
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11
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Mohammadzadeh L, Latifi H, Khaksar S, Feiz MS, Motamedi F, Asadollahi A, Ezzatpour M. Measuring the Frequency-Specific Functional Connectivity Using Wavelet Coherence Analysis in Stroke Rats Based on Intrinsic Signals. Sci Rep 2020; 10:9429. [PMID: 32523058 PMCID: PMC7286921 DOI: 10.1038/s41598-020-66246-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/17/2020] [Indexed: 12/28/2022] Open
Abstract
Optical intrinsic signal imaging (OISi) method is an optical technique to evaluate the functional connectivity (FC) of the cortex in animals. Already, using OISi, the FC of the cortex has been measured in time or frequency domain separately, and at frequencies below 0.08 Hz, which is not in the frequency range of hemodynamic oscillations which are able to track fast cortical events, including neurogenic, myogenic, cardiac and respiratory activities. In the current work, we calculated the wavelet coherence (WC) transform of the OISi time series to evaluate the cerebral response changes in the stroke rats. Utilizing WC, we measured FC at frequencies up to 4.5 Hz, and could monitor the time and frequency dependency of the FC simultaneously. The results showed that the WC of the brain diminished significantly in ischemic motor and somatosensory cortices. According to the statistical results, the signal amplitude, responsive area size, correlation, and wavelet coherence of the motor and the somatosensory cortices for stroke hemisphere were found to be significantly lower compared to the healthy hemisphere. The obtained results confirm that the OISi-based WC analysis is an efficient method to diagnose the relative severity of infarction and the size of the infarcted region after ischemic stroke.
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Affiliation(s)
- Leila Mohammadzadeh
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Hamid Latifi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran. .,Department of Physics, Shahid Beheshti University, Tehran, 1983963113, Iran.
| | - Sepideh Khaksar
- Department of Plant Sciences, Faculty of Biological Sciences, Alzahra University, Tehran, 1993893973, Iran
| | - Mohammad-Sadegh Feiz
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Fereshteh Motamedi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, 1983963113, Iran
| | - Amir Asadollahi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran
| | - Marzieh Ezzatpour
- Department of Physics, Shahid Beheshti University, Tehran, 1983963113, Iran
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12
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Orukari IE, Siegel JS, Warrington NM, Baxter GA, Bauer AQ, Shimony JS, Rubin JB, Culver JP. Altered hemodynamics contribute to local but not remote functional connectivity disruption due to glioma growth. J Cereb Blood Flow Metab 2020; 40:100-115. [PMID: 30334672 PMCID: PMC6928560 DOI: 10.1177/0271678x18803948] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glioma growth can cause pervasive changes in the functional connectivity (FC) of brain networks, which has been associated with re-organization of brain functions and development of functional deficits in patients. Mechanisms underlying functional re-organization in brain networks are not understood and efforts to utilize functional imaging for surgical planning, or as a biomarker of functional outcomes are confounded by the heterogeneity in available human data. Here we apply multiple imaging modalities in a well-controlled murine model of glioma with extensive validation using human data to explore mechanisms of FC disruption due to glioma growth. We find gliomas cause both local and distal changes in FC. FC changes in networks proximal to the tumor occur secondary to hemodynamic alterations but surprisingly, remote FC changes are independent of hemodynamic mechanisms. Our data strongly implicate hemodynamic alterations as the main driver of local changes in measurements of FC in patients with glioma.
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Affiliation(s)
- Inema E Orukari
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Joshua S Siegel
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, USA
| | - Nicole M Warrington
- Department of Pediatrics, Washington University in St. Louis, St Louis, MO, USA
| | - Grant A Baxter
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St Louis, MO, USA
| | - Adam Q Bauer
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St Louis, MO, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St Louis, MO, USA
| | - Joshua B Rubin
- Department of Pediatrics, Washington University in St. Louis, St Louis, MO, USA.,Department of Neuroscience, Washington University in St. Louis, St Louis, MO, USA
| | - Joseph P Culver
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.,Mallinckrodt Institute of Radiology, Washington University in St. Louis, St Louis, MO, USA.,Department of Physics, Washington University in St. Louis, St. Louis, MO, USA
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13
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Senarathna J, Yu H, Deng C, Zou AL, Issa JB, Hadjiabadi DH, Gil S, Wang Q, Tyler BM, Thakor NV, Pathak AP. A miniature multi-contrast microscope for functional imaging in freely behaving animals. Nat Commun 2019; 10:99. [PMID: 30626878 PMCID: PMC6327063 DOI: 10.1038/s41467-018-07926-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/03/2018] [Indexed: 12/27/2022] Open
Abstract
Neurovascular coupling, cerebrovascular remodeling and hemodynamic changes are critical to brain function, and dysregulated in neuropathologies such as brain tumors. Interrogating these phenomena in freely behaving animals requires a portable microscope with multiple optical contrast mechanisms. Therefore, we developed a miniaturized microscope with: a fluorescence (FL) channel for imaging neural activity (e.g., GCaMP) or fluorescent cancer cells (e.g., 9L-GFP); an intrinsic optical signal (IOS) channel for imaging hemoglobin absorption (i.e., cerebral blood volume); and a laser speckle contrast (LSC) channel for imaging perfusion (i.e., cerebral blood flow). Following extensive validation, we demonstrate the microscope’s capabilities via experiments in unanesthetized murine brains that include: (i) multi-contrast imaging of neurovascular changes following auditory stimulation; (ii) wide-area tonotopic mapping; (iii) EEG-synchronized imaging during anesthesia recovery; and (iv) microvascular connectivity mapping over the life-cycle of a brain tumor. This affordable, flexible, plug-and-play microscope heralds a new era in functional imaging of freely behaving animals. Measuring multiple neurophysiologic variables usually requires bulky benchtop optical systems and working with anesthetized animals. Here the authors present a miniature portable microscope for neurovascular imaging in awake rodents, combining fluorescence, intrinsic optical signals and laser speckle contrast.
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Affiliation(s)
- Janaka Senarathna
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Hang Yu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Callie Deng
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Alice L Zou
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - John B Issa
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Darian H Hadjiabadi
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Stacy Gil
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Qihong Wang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Betty M Tyler
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Nitish V Thakor
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Arvind P Pathak
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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14
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Yoshida Y, Nakao M, Katayama N. Resting-state functional connectivity analysis of the mouse brain using intrinsic optical signal imaging of cerebral blood volume dynamics. Physiol Meas 2018; 39:054003. [PMID: 29697052 DOI: 10.1088/1361-6579/aac033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Resting-state functional connectivity (rsFC) of the human brain is closely related with neurological and psychiatric disorders. Mice are widely used to investigate the physiological mechanisms of such disorders, because of the applicability of invasive experimental techniques. Thus, studies on rsFC of the mouse brain are essential to link physiological mechanisms with these disorders in humans. In this study, we investigated the applicability of intrinsic optical signal imaging of cerebral blood volume (IOSI-CBV) for rsFC analysis of the mouse brain. APPROACH Transcranial IOSI-CBV images were collected from the brains of un-anesthetized wild-type mice with a cooled-CCD camera. The time traces of all pixels were averaged to create a global signal (GS). Marginal and partial correlation analyses were performed to estimate the rsFC based on CBV signals both with and without GS removal. The consistency of the results were confirmed by comparing them with to the rsFCs data reported in the previous studies. MAIN RESULTS We confirmed that GS correlated with heart rate fluctuation in the FC frequency band. The marginal correlation coefficient of CBV with GS removal was consistent with measurements using conventional optical imaging methods relying on oxygenated hemoglobin concentration and cerebral blood flow. SIGNIFICANCE These results suggest the applicability and usefulness of the transcranial IOSI-CBV method to estimate rsFC of the mouse brain.
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Affiliation(s)
- Yuto Yoshida
- Research Fellow of Japan Society for the Promotion of Science (JSPS), 6-6-05, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi prefecture, 980-8579, Japan. Biomodeling Laboratory, Graduate School of Information Sciences, Tohoku University, 6-6-05, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi prefecture, 980-8579, Japan
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15
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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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16
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Kura S, Xie H, Fu B, Ayata C, Boas DA, Sakadžić S. Intrinsic optical signal imaging of the blood volume changes is sufficient for mapping the resting state functional connectivity in the rodent cortex. J Neural Eng 2018; 15:035003. [PMID: 29451130 DOI: 10.1088/1741-2552/aaafe4] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Resting state functional connectivity (RSFC) allows the study of functional organization in normal and diseased brain by measuring the spontaneous brain activity generated under resting conditions. Intrinsic optical signal imaging (IOSI) based on multiple illumination wavelengths has been used successfully to compute RSFC maps in animal studies. The IOSI setup complexity would be greatly reduced if only a single wavelength can be used to obtain comparable RSFC maps. APPROACH We used anesthetized mice and performed various comparisons between the RSFC maps based on single wavelength as well as oxy-, deoxy- and total hemoglobin concentration changes. MAIN RESULTS The RSFC maps based on IOSI at a single wavelength selected for sensitivity to the blood volume changes are quantitatively comparable to the RSFC maps based on oxy- and total hemoglobin concentration changes obtained by the more complex IOSI setups. Moreover, RSFC maps do not require CCD cameras with very high frame acquisition rates, since our results demonstrate that they can be computed from the data obtained at frame rates as low as 5 Hz. SIGNIFICANCE Our results will have general utility for guiding future RSFC studies based on IOSI and making decisions about the IOSI system designs.
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Affiliation(s)
- Sreekanth Kura
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, MGH/HMS/MIT Athinoula A Martinos Center for Biomedical Imaging, 149 13th Street, Charlestown, MA 02129, United States of America. Department of Biomedical Engineering, Neurophotonics Center, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America
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17
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Li J, Poon CS, Kress J, Rohrbach DJ, Sunar U. Resting-state functional connectivity measured by diffuse correlation spectroscopy. JOURNAL OF BIOPHOTONICS 2018; 11. [PMID: 28708329 DOI: 10.1002/jbio.201700165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 05/17/2023]
Abstract
Near-infrared diffuse correlation spectroscopy (DCS) is used to record spontaneous cerebral blood flow fluctuations in the frontal cortex. Nine adult subjects participated in the experiments, in which 8-minute spontaneous fluctuations were simultaneously recorded from the left and right dorsolateral and inferior frontal regions. Resting-state functional connectivity (RSFC) was measured by the temporal correlation of the low frequency fluctuations. Our data shows the RSFC within the dorsolateral region is significantly stronger than that between the inferior and dorsolateral regions, in line with previous observations with functional near-infrared spectroscopy. This indicates that DCS is capable of investigating brain functional connectivity in terms of cerebral blood flow.
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Affiliation(s)
- Jun Li
- Department of Biomedical, Industrial and Human Factors, Wright State University, Dayton, Ohio
| | - Chien-Sing Poon
- Department of Biomedical, Industrial and Human Factors, Wright State University, Dayton, Ohio
| | - Jeremy Kress
- Department of Biomedical, Industrial and Human Factors, Wright State University, Dayton, Ohio
| | - Daniel J Rohrbach
- Department of Biomedical, Industrial and Human Factors, Wright State University, Dayton, Ohio
| | - Ulas Sunar
- Department of Biomedical, Industrial and Human Factors, Wright State University, Dayton, Ohio
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18
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Changes in resting-state functional connectivity after stroke in a mouse brain lacking extracellular matrix components. Neurobiol Dis 2018; 112:91-105. [PMID: 29367009 DOI: 10.1016/j.nbd.2018.01.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 12/26/2017] [Accepted: 01/17/2018] [Indexed: 12/30/2022] Open
Abstract
In the brain, focal ischemia results in a local region of cell death and disruption of both local and remote functional neuronal networks. Tissue reorganization following stroke can be limited by factors such as extracellular matrix (ECM) molecules that prevent neuronal growth and synaptic plasticity. The brain's ECM plays a crucial role in network formation, development, and regeneration of the central nervous system. Further, the ECM is essential for proper white matter tract development and for the formation of structures called perineuronal nets (PNNs). PNNs mainly surround parvalbumin/GABA inhibitory interneurons, of importance for processing sensory information. Previous studies have shown that downregulating PNNs after stroke reduces the neurite-inhibitory environment, reactivates plasticity, and promotes functional recovery. Resting-state functional connectivity (RS-FC) within and across hemispheres has been shown to correlate with behavioral recovery after stroke. However, the relationship between PNNs and RS-FC has not been examined. Here we studied a quadruple knock-out mouse (Q4) that lacks four ECM components: brevican, neurocan, tenascin-C and tenascin-R. We applied functional connectivity optical intrinsic signal (fcOIS) imaging in Q4 mice and wild-type (129S1 mice) before and 14 days after photothrombotic stroke (PT) to understand how the lack of crucial ECM components affects neuronal networks and functional recovery after stroke. Limb-placement ability was evaluated at 2, 7 and 14 days of recovery through the paw-placement test. Q4 mice exhibited significantly impaired homotopic RS-FC compared to wild-type mice, especially in the sensory and parietal regions. Changes in RS-FC were significantly correlated with the number of interhemispheric callosal crossings in those same regions. PT caused unilateral damage to the sensorimotor cortex and deficits of tactile-proprioceptive placing ability in contralesional fore- and hindlimbs, but the two experimental groups did not present significant differences in infarct size. Two weeks after PT, a general down-scaling of regional RS-FC as well as the number of regional functional connections was visible for all cortical regions and most notable in the somatosensory areas of both Q4 and wild-type mice. Q4 mice exhibited higher intrahemispheric RS-FC in contralesional sensory and motor cortices compared to control mice. We propose that the lack of growth inhibiting ECM components in the Q4 mice potentially worsen behavioral outcome in the early phase after stroke, but subsequently facilitates modulation of contralesional RS-FC which is relevant for recovery of sensory motor function. We conclude that Q4 mice represent a valuable model to study how the elimination of ECM genes compromises neuronal function and plasticity mechanisms after stroke.
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Tong LS, Guo ZN, Ou YB, Yu YN, Zhang XC, Tang J, Zhang JH, Lou M. Cerebral venous collaterals: A new fort for fighting ischemic stroke? Prog Neurobiol 2017; 163-164:172-193. [PMID: 29199136 DOI: 10.1016/j.pneurobio.2017.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/03/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022]
Abstract
Stroke therapy has entered a new era highlighted by the use of endovascular therapy in addition to intravenous thrombolysis. However, the efficacy of current therapeutic regimens might be reduced by their associated adverse events. For example, over-reperfusion and futile recanalization may lead to large infarct, brain swelling, hemorrhagic complication and neurological deterioration. The traditional pathophysiological understanding on ischemic stroke can hardly address these occurrences. Accumulating evidence suggests that a functional cerebral venous drainage, the major blood reservoir and drainage system in brain, may be as critical as arterial infusion for stroke evolution and clinical sequelae. Further exploration of the multi-faceted function of cerebral venous system may add new implications for stroke outcome prediction and future therapeutic decision-making. In this review, we emphasize the anatomical and functional characteristics of the cerebral venous system and illustrate its necessity in facilitating the arterial infusion and maintaining the cerebral perfusion in the pathological stroke content. We then summarize the recent critical clinical studies that underscore the associations between cerebral venous collateral and outcome of ischemic stroke with advanced imaging techniques. A novel three-level venous system classification is proposed to demonstrate the distinct characteristics of venous collaterals in the setting of ischemic stroke. Finally, we discuss the current directions for assessment of cerebral venous collaterals and provide future challenges and opportunities for therapeutic strategies in the light of these new concepts.
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Affiliation(s)
- Lu-Sha Tong
- Department of Neurology, The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China; Departments of Physiology, Loma Linda University, School of Medicine, CA, USA
| | - Zhen-Ni Guo
- Department of Neurology, The First Affiliated Hospital of Jilin University, Changchun, China; Departments of Physiology, Loma Linda University, School of Medicine, CA, USA
| | - Yi-Bo Ou
- Department of Neurosurgery, Tong-ji Hospital, Wuhan, China; Departments of Physiology, Loma Linda University, School of Medicine, CA, USA
| | - Yan-Nan Yu
- Department of Neurology, The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
| | - Xiao-Cheng Zhang
- Department of Neurology, The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China
| | - Jiping Tang
- Department of Anesthesiology, Loma Linda University, School of Medicine, CA, USA
| | - John H Zhang
- Departments of Physiology, Loma Linda University, School of Medicine, CA, USA.
| | - Min Lou
- Department of Neurology, The 2nd Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, China.
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20
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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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21
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Wright PW, Brier LM, Bauer AQ, Baxter GA, Kraft AW, Reisman MD, Bice AR, Snyder AZ, Lee JM, Culver JP. Functional connectivity structure of cortical calcium dynamics in anesthetized and awake mice. PLoS One 2017; 12:e0185759. [PMID: 29049297 PMCID: PMC5648115 DOI: 10.1371/journal.pone.0185759] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 09/19/2017] [Indexed: 11/30/2022] Open
Abstract
The interplay between hemodynamic-based markers of cortical activity (e.g. fMRI and optical intrinsic signal imaging), which are an indirect and relatively slow report of neural activity, and underlying synaptic electrical and metabolic activity through neurovascular coupling is a topic of ongoing research and debate. As application of resting state functional connectivity measures is extended further into topics such as brain development, aging and disease, the importance of understanding the fundamental physiological basis for functional connectivity will grow. Here we extend functional connectivity analysis from hemodynamic- to calcium-based imaging. Transgenic mice (n = 7) expressing a fluorescent calcium indicator (GCaMP6) driven by the Thy1 promoter in glutamatergic neurons were imaged transcranially in both anesthetized (using ketamine/xylazine) and awake states. Sequential LED illumination (λ = 454, 523, 595, 640nm) enabled concurrent imaging of both GCaMP6 fluorescence emission (corrected for hemoglobin absorption) and hemodynamics. Functional connectivity network maps were constructed for infraslow (0.009–0.08Hz), intermediate (0.08–0.4Hz), and high (0.4–4.0Hz) frequency bands. At infraslow and intermediate frequencies, commonly used in BOLD fMRI and fcOIS studies of functional connectivity and implicated in neurovascular coupling mechanisms, GCaMP6 and HbO2 functional connectivity structures were in high agreement, both qualitatively and also quantitatively through a measure of spatial similarity. The spontaneous dynamics of both contrasts had the highest correlation when the GCaMP6 signal was delayed with a ~0.6–1.5s temporal offset. Within the higher-frequency delta band, sensitive to slow wave sleep oscillations in non-REM sleep and anesthesia, we evaluate the speed with which the connectivity analysis stabilized and found that the functional connectivity maps captured putative network structure within time window lengths as short as 30 seconds. Homotopic GCaMP6 functional connectivity maps at 0.4–4.0Hz in the anesthetized states show a striking correlated and anti-correlated structure along the anterior to posterior axis. This structure is potentially explained in part by observed propagation of delta-band activity from frontal somatomotor regions to visuoparietal areas. During awake imaging, this spatio-temporal quality is altered, and a more complex and detailed functional connectivity structure is observed. The combined calcium/hemoglobin imaging technique described here will enable the dissociation of changes in ionic and hemodynamic functional structure and neurovascular coupling and provide a framework for subsequent studies of neurological disease such as stroke.
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Affiliation(s)
- Patrick W. Wright
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lindsey M. Brier
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Adam Q. Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Grant A. Baxter
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andrew W. Kraft
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Matthew D. Reisman
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Annie R. Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Abraham Z. Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jin-Moo Lee
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Joseph P. Culver
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
- * E-mail:
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22
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Lee H, Jung S, Lee P, Jeong Y. Altered intrinsic functional connectivity in the latent period of epileptogenesis in a temporal lobe epilepsy model. Exp Neurol 2017; 296:89-98. [PMID: 28729114 DOI: 10.1016/j.expneurol.2017.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/17/2017] [Accepted: 07/11/2017] [Indexed: 10/19/2022]
Abstract
The latent period, a seizure-free phase, is the duration between brain injury and the onset of spontaneous recurrent seizures (SRSs) during epileptogenesis. The latent period is thought to involve several progressive pathophysiological events that lead to the evolution of the chronic epilepsy phase. Hence, it is vital to investigate the changes in the latent period during epileptogenesis in order to better understand temporal lobe epilepsy (TLE), and to achieve early diagnosis and appropriate management of the condition. Accordingly, recent studies with patients with TLE using resting-state functional magnetic resonance imaging (rs-fMRI) have reported that alterations of resting-state functional connectivity (rsFC) during the chronic period are associated with some clinical manifestations, including learning and memory impairments, emotional instability, and social behavior deficits, in addition to repetitive seizure episodes. In contrast, the changes in the intrinsic rsFC during epileptogenesis, particularly during the latent period, remain unclear. In this study, we investigated the alterations in intrinsic rsFC during the latent and chronic periods in a pilocarpine-induced TLE mouse model using intrinsic optical signal imaging (IOSI). This technique can monitor the changes in the local hemoglobin concentration according to neuronal activity and can help investigate large-scale brain intrinsic networks. After seeding on the anatomical regions of interest (ROIs) and calculating the correlation coefficients between each ROI, we established and compared functional correlation matrices and functional connectivity maps during the latent and chronic periods of epilepsy. We found a decrease in the interhemispheric rsFC at the frontal and temporal regions during both the latent and chronic periods. Furthermore, a significant decrease in the interhemispheric rsFC was observed in the somatosensory area during the chronic period. Changes in network configurations during epileptogenesis were examined by graph theoretical network analysis. Interestingly, increase in the power of low frequency oscillations was observed during the latent period. These results suggest that, even if there are no apparent ictal seizure events during the latent period, there are ongoing changes in the rsFC in the epileptic brain. Furthermore, these results suggest that the pathophysiology of epilepsy may be related to widespread altered intrinsic functional connectivity. These findings can help enhance our understanding of epileptogenesis, and accordingly, changes in intrinsic functional connectivity can serve as an early diagnosis.
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Affiliation(s)
- Hyoin Lee
- Department of Bio and Brain Engineering, KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Seungmoon Jung
- Department of Bio and Brain Engineering, KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Peter Lee
- Department of Bio and Brain Engineering, KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Yong Jeong
- Department of Bio and Brain Engineering, KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea.
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23
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Mesoscale Mapping of Mouse Cortex Reveals Frequency-Dependent Cycling between Distinct Macroscale Functional Modules. J Neurosci 2017; 37:7513-7533. [PMID: 28674167 DOI: 10.1523/jneurosci.3560-16.2017] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 06/13/2017] [Accepted: 06/19/2017] [Indexed: 12/17/2022] Open
Abstract
Connectivity mapping based on resting-state activity in mice has revealed functional motifs of correlated activity. However, the rules by which motifs organize into larger functional modules that lead to hemisphere wide spatial-temporal activity sequences is not clear. We explore cortical activity parcellation in head-fixed, quiet awake GCaMP6 mice from both sexes by using mesoscopic calcium imaging. Spectral decomposition of spontaneous cortical activity revealed the presence of two dominant frequency modes (<1 and ∼3 Hz), each of them associated with a unique spatial signature of cortical macro-parcellation not predicted by classical cytoarchitectonic definitions of cortical areas. Based on assessment of 0.1-1 Hz activity, we define two macro-organizing principles: the first being a rotating polymodal-association pinwheel structure around which activity flows sequentially from visual to barrel then to hindlimb somatosensory; the second principle is correlated activity symmetry planes that exist on many levels within a single domain such as intrahemispheric reflections of sensory and motor cortices. In contrast, higher frequency activity >1 Hz yielded two larger clusters of coactivated areas with an enlarged default mode network-like posterior region. We suggest that the apparent constrained structure for intra-areal cortical activity flow could be exploited in future efforts to normalize activity in diseases of the nervous system.SIGNIFICANCE STATEMENT Increasingly, functional connectivity mapping of spontaneous activity is being used to reveal the organization of the brain. However, because the brain operates across multiple space and time domains a more detailed understanding of this organization is necessary. We used in vivo wide-field calcium imaging of the indicator GCaMP6 in head-fixed, awake mice to characterize the organization of spontaneous cortical activity at different spatiotemporal scales. Correlation analysis defines the presence of two to three superclusters of activity that span traditionally defined functional territories and were frequency dependent. This work helps define the rules for how different cortical areas interact in time and space. We provide a framework necessary for future studies that explore functional reorganization of brain circuits in disease models.
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24
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Functional connectivity alterations in a murine model of optic neuritis. Exp Neurol 2017; 295:18-22. [PMID: 28502610 DOI: 10.1016/j.expneurol.2017.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/14/2017] [Accepted: 05/11/2017] [Indexed: 12/17/2022]
Abstract
The basis for neuronal dysfunction following inflammatory demyelination of the central nervous system (CNS) remains poorly understood. We characterized the network response to white matter injury in the anterior visual pathway using an experimental model of optic neuritis (ON), as ON is often an early manifestation of immune-mediated CNS demyelination in multiple sclerosis (MS). Optical intrinsic signal imaging was performed before and after the induction of ON in mice to measure changes in cortical network functional connectivity. We observed a greater loss of connectivity between homotopic visual cortices in ON mice compared to controls. Further, decreases in homotopic visual cortex connectivity were associated with visual acuity loss in ON mice. These results demonstrate that network connectivity changes resulting from ON can be modeled in an experimental murine system. Future studies will identify the mechanisms that cause neuronal dysfunction due to white matter injury seen in MS.
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Reisman MD, Markow ZE, Bauer AQ, Culver JP. Structured illumination diffuse optical tomography for noninvasive functional neuroimaging in mice. NEUROPHOTONICS 2017; 4:021102. [PMID: 28439519 PMCID: PMC5391480 DOI: 10.1117/1.nph.4.2.021102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/01/2017] [Indexed: 05/15/2023]
Abstract
Optical intrinsic signal (OIS) imaging has been a powerful tool for capturing functional brain hemodynamics in rodents. Recent wide field-of-view implementations of OIS have provided efficient maps of functional connectivity from spontaneous brain activity in mice. However, OIS requires scalp retraction and is limited to superficial cortical tissues. Diffuse optical tomography (DOT) techniques provide noninvasive imaging, but previous DOT systems for rodent neuroimaging have been limited either by sparse spatial sampling or by slow speed. Here, we develop a DOT system with asymmetric source-detector sampling that combines the high-density spatial sampling (0.4 mm) detection of a scientific complementary metal-oxide-semiconductor camera with the rapid (2 Hz) imaging of a few ([Formula: see text]) structured illumination (SI) patterns. Analysis techniques are developed to take advantage of the system's flexibility and optimize trade-offs among spatial sampling, imaging speed, and signal-to-noise ratio. An effective source-detector separation for the SI patterns was developed and compared with light intensity for a quantitative assessment of data quality. The light fall-off versus effective distance was also used for in situ empirical optimization of our light model. We demonstrated the feasibility of this technique by noninvasively mapping the functional response in the somatosensory cortex of the mouse following electrical stimulation of the forepaw.
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Affiliation(s)
- Matthew D. Reisman
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
| | - Zachary E. Markow
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Adam Q. Bauer
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
| | - Joseph P. Culver
- Washington University in St. Louis, Department of Physics, St. Louis, Missouri, United States
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Washington University School of Medicine, Department of Radiology, St. Louis, Missouri, United States
- Address all correspondence to: Joseph P. Culver, E-mail:
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Abstract
PURPOSE OF REVIEW This article provides an overview of the recent literature regarding the application of in-vivo brain imaging techniques to animal models of ischemic stroke. RECENT FINDINGS Major breakthroughs concerned the effects of sensory stimulation on neuronal function, local hemodynamics, and tissue outcome in the hyperacute phase of stroke; the novel application to stroke of hybrid scanners allowing simultaneous PET and magnetic resonance; the refinements of magnetic resonance-based oxygen imaging, allowing to map the ischemic penumbra in a completely noninvasive way; the implementation of new PET ligands to selectively map poststroke neuronal death and neuroinflammation; and the use of novel mesoscale imaging techniques to demonstrate the major role of interhemispheric connectivity in poststroke plasticity and functional recovery. SUMMARY The array of techniques to map in vivo the key pathophysiological brain processes involved in stroke is currently enlarging at an amazing pace. This is paralleled by ever-increasing sophistication in postprocessing tools. The combination of techniques allowing simultaneous access to several variables is particularly powerful as it affords unprecedented insights into the intimate processes underlying the tissue and neuronal changes that follow a stroke. These major leaps forward will hopefully lead to therapeutic breakthroughs aiming at improving functional outcome after stroke.
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Zhang X, Noor MS, McCracken CB, Kiss ZHT, Yadid-Pecht O, Murari K. CMOS Image Sensor and System for Imaging Hemodynamic Changes in Response to Deep Brain Stimulation. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2016; 10:632-642. [PMID: 26357405 DOI: 10.1109/tbcas.2015.2453256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Deep brain stimulation (DBS) is a therapeutic intervention used for a variety of neurological and psychiatric disorders, but its mechanism of action is not well understood. It is known that DBS modulates neural activity which changes metabolic demands and thus the cerebral circulation state. However, it is unclear whether there are correlations between electrophysiological, hemodynamic and behavioral changes and whether they have any implications for clinical benefits. In order to investigate these questions, we present a miniaturized system for spectroscopic imaging of brain hemodynamics. The system consists of a 144 ×144, [Formula: see text] pixel pitch, high-sensitivity, analog-output CMOS imager fabricated in a standard 0.35 μm CMOS process, along with a miniaturized imaging system comprising illumination, focusing, analog-to-digital conversion and μSD card based data storage. This enables stand alone operation without a computer, nor electrical or fiberoptic tethers. To achieve high sensitivity, the pixel uses a capacitive transimpedance amplifier (CTIA). The nMOS transistors are in the pixel while pMOS transistors are column-parallel, resulting in a fill factor (FF) of 26%. Running at 60 fps and exposed to 470 nm light, the CMOS imager has a minimum detectable intensity of 2.3 nW/cm(2) , a maximum signal-to-noise ratio (SNR) of 49 dB at 2.45 μW/cm(2) leading to a dynamic range (DR) of 61 dB while consuming 167 μA from a 3.3 V supply. In anesthetized rats, the system was able to detect temporal, spatial and spectral hemodynamic changes in response to DBS.
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28
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Woolsey TA. Re: Woolsey TA, van der Loos H. 1970. The structural organization of layer IV in the somatosensory region (S I) of mouse cerebral cortex. Brain Res. 17: 205-242. Brain Res 2016; 1645:22-4. [PMID: 27086973 DOI: 10.1016/j.brainres.2016.04.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 04/13/2016] [Indexed: 10/22/2022]
Abstract
UNLABELLED Axoplasmically transported proteins synthesized in neuronal somata labeled by radioactively labeled amino acids (tritium), following local targeted injections for tracing of pathways in the central nervous system using autoradiography. Results from a number of neuronal systems, including: the rat olfactory bulb; cortico-thalamic projections in the mouse; commissural connections of the rat hippocampus; and retinal projections in the monkey and chick are documented. Pathway origins are clear, as the number and distribution of the labeled cells and the normal structure of the injection site is preserved. Light and electron microscopic autoradiography shows that proteins are transported, at two rates: rapid transport (>100mm/day) of fewer proteins accumulating in axon terminals; and, slow transport (1-5mm/day) of the bulk of labeled proteins distributed along the length of axons. Different survival times can be selected to evaluate terminal projection field(s) or pathways from origin to termination. The clarity of autoradiographic labeling of pathways and their terminations is comparable to other techniques (such as the Nauta-Gygax and the Fink-Heimer methods and the electron microscopy of terminal degeneration). Labeled amino acids do not label molecules in fibers of passage and there is no retrograde transport of labeled material from the axon terminals. The functional polarity of fiber pathways can be easily established. We summarize the merits of this technique is based upon an established physiological properties of neurons that are summarized in contrast to currently used techniques dependent upon pathological changes in neurons, axons, or axonal terminals. ABSTRACT The cytoarchitecture of layer IV in mouse SmI cerebral cortex was examined in.formalin-fixed, Nissl-stained and Cox-fixed, Golgi-Nissl-stained sections cut coronally and tangentially to the pia, A multicellular cytoarchitectonic unit is described in layer IV, roughly cylindrical, 100-400um in diameter, and perpendicular to the pia. Because of their characteristic shape we call these structures barrels. Each barrel is a ring of neurons, the side, which surrounds a less cellular hollow. The nearly acellular reigion surrounding each barrel and separating adjacent barrels is the septum. Barrels are discussed in relation to observations reported in several earlier papers on the mouse cortex. The barrel field (all barrels) has remarkable constancy by all measures: from one hemisphere to the next and from one specimen to the next. A consistent part of the barrel field is the postero-medial barrel subield (PMBSF). Barrels in the PMBSF are larger, elliptical in shape, organized into five distinct rows and their numbers are constant. It is postulated that each barrel in the PMBSF is the cortical correlate of a contralateral mystacial vibrissa (whisker). On the basis of counts of barrels and of all facial sinus hairs a 'one barrel-one vibrissa' hypothesis is proposed. The general hypothesis is that barrels are the morphological manifestation in layer IV of the functional cortical columns discovered by physiologists. The barrels offer excellent opportunities for integrated studies of sensory cerebral cortex at a degree of resolution previously not possible. This article is part of a Special Issue entitled SI:50th Anniversary Issue.
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Affiliation(s)
- Thomas A Woolsey
- Biology, Neurosurgery, Neurology, Anatomy and Neurobiology, Biomedical Engineering , Washington University in St. Louis, United States.
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29
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Mapping the mouse brain with rs-fMRI: An optimized pipeline for functional network identification. Neuroimage 2015; 123:11-21. [PMID: 26296501 DOI: 10.1016/j.neuroimage.2015.07.090] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/06/2015] [Accepted: 07/27/2015] [Indexed: 11/21/2022] Open
Abstract
The use of resting state fMRI (rs-fMRI) in translational research is a powerful tool to assess brain connectivity and investigate neuropathology in mouse models. However, despite encouraging initial results, the characterization of consistent and robust resting state networks in mice remains a methodological challenge. One key reason is that the quality of the measured MR signal is degraded by the presence of structural noise from non-neural sources. Notably, in the current pipeline of the Human Connectome Project, a novel approach has been introduced to clean rs-fMRI data, which involves automatic artifact component classification and data cleaning (FIX). FIX does not require any external recordings of physiology or the segmentation of CSF and white matter. In this study, we evaluated the performance of FIX for analyzing mouse rs-fMRI data. Our results showed that FIX can be easily applied to mouse datasets and detects true signals with 100% accuracy and true noise components with very high accuracy (>98%), thus reducing both within- and between-subject variability of rs-fMRI connectivity measurements. Using this improved pre-processing pipeline, maps of 23 resting state circuits in mice were identified including two networks that displayed default mode network-like topography. Hierarchical clustering grouped these neural networks into meaningful larger functional circuits. These mouse resting state networks, which are publicly available, might serve as a reference for future work using mouse models of neurological disorders.
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30
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Pan WJ, Billings JCW, Grooms JK, Shakil S, Keilholz SD. Considerations for resting state functional MRI and functional connectivity studies in rodents. Front Neurosci 2015; 9:269. [PMID: 26300718 PMCID: PMC4525377 DOI: 10.3389/fnins.2015.00269] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/16/2015] [Indexed: 12/31/2022] Open
Abstract
Resting state functional MRI (rs-fMRI) and functional connectivity mapping have become widely used tools in the human neuroimaging community and their use is rapidly spreading into the realm of rodent research as well. One of the many attractive features of rs-fMRI is that it is readily translatable from humans to animals and back again. Changes in functional connectivity observed in human studies can be followed by more invasive animal experiments to determine the neurophysiological basis for the alterations, while exploratory work in animal models can identify possible biomarkers for further investigation in human studies. These types of interwoven human and animal experiments have a potentially large impact on neuroscience and clinical practice. However, impediments exist to the optimal application of rs-fMRI in small animals, some similar to those encountered in humans and some quite different. In this review we identify the most prominent of these barriers, discuss differences between rs-fMRI in rodents and in humans, highlight best practices for animal studies, and review selected applications of rs-fMRI in rodents. Our goal is to facilitate the integration of human and animal work to the benefit of both fields.
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Affiliation(s)
- Wen-Ju Pan
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University Atlanta, GA, USA
| | | | - Joshua K Grooms
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University Atlanta, GA, USA
| | - Sadia Shakil
- School of Electrical and Computer Engineering, Georgia Institute of Technology Atlanta, GA, USA
| | - Shella D Keilholz
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University Atlanta, GA, USA ; Neuroscience Program, Emory University Atlanta, GA, USA
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31
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Real-time imaging of brain activity in freely moving rats using functional ultrasound. Nat Methods 2015; 12:873-8. [DOI: 10.1038/nmeth.3482] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/11/2015] [Indexed: 01/09/2023]
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