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Huang J, Zhang Y, Zhang Q, Wei L, Zhang X, Jin C, Yang J, Li Z, Liang S. The current status and trend of the functional magnetic resonance combined with stimulation in animals. Front Neurosci 2022; 16:963175. [PMID: 36213733 PMCID: PMC9540855 DOI: 10.3389/fnins.2022.963175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
As a non-radiative, non-invasive imaging technique, functional magnetic resonance imaging (fMRI) has excellent effects on studying the activation of blood oxygen levels and functional connectivity of the brain in human and animal models. Compared with resting-state fMRI, fMRI combined with stimulation could be used to assess the activation of specific brain regions and the connectivity of specific pathways and achieve better signal capture with a clear purpose and more significant results. Various fMRI methods and specific stimulation paradigms have been proposed to investigate brain activation in a specific state, such as electrical, mechanical, visual, olfactory, and direct brain stimulation. In this review, the studies on animal brain activation using fMRI combined with different stimulation methods were retrieved. The instruments, experimental parameters, anesthesia, and animal models in different stimulation conditions were summarized. The findings would provide a reference for studies on estimating specific brain activation using fMRI combined with stimulation.
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2
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Miao X, Paez AG, Rajan S, Cao D, Liu D, Pantelyat AY, Rosenthal LI, van Zijl PCM, Bassett SS, Yousem DM, Kamath V, Hua J. Functional Activities Detected in the Olfactory Bulb and Associated Olfactory Regions in the Human Brain Using T2-Prepared BOLD Functional MRI at 7T. Front Neurosci 2021; 15:723441. [PMID: 34588949 PMCID: PMC8476065 DOI: 10.3389/fnins.2021.723441] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/16/2021] [Indexed: 11/17/2022] Open
Abstract
Olfaction is a fundamental sense that plays a vital role in daily life in humans, and can be altered in neuropsychiatric and neurodegenerative diseases. Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) using conventional echo-planar-imaging (EPI) based sequences can be challenging in brain regions important for olfactory processing, such as the olfactory bulb (OB) and orbitofrontal cortex, mainly due to the signal dropout and distortion artifacts caused by large susceptibility effects from the sinonasal cavity and temporal bone. To date, few studies have demonstrated successful fMRI in the OB in humans. T2-prepared (T2prep) BOLD fMRI is an alternative approach developed especially for performing fMRI in regions affected by large susceptibility artifacts. The purpose of this technical study is to evaluate T2prep BOLD fMRI for olfactory functional experiments in humans. Olfactory fMRI scans were performed on 7T in 14 healthy participants. T2prep BOLD showed greater sensitivity than GRE EPI BOLD in the OB, orbitofrontal cortex and the temporal pole. Functional activation was detected using T2prep BOLD in the OB and associated olfactory regions. Habituation effects and a bi-phasic pattern of fMRI signal changes during olfactory stimulation were observed in all regions. Both positively and negatively activated regions were observed during olfactory stimulation. These signal characteristics are generally consistent with literature and showed a good intra-subject reproducibility comparable to previous human BOLD fMRI studies. In conclusion, the methodology demonstrated in this study holds promise for future olfactory fMRI studies in the OB and other brain regions that suffer from large susceptibility artifacts.
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Affiliation(s)
- Xinyuan Miao
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Adrian G Paez
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Suraj Rajan
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Di Cao
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Dapeng Liu
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Alex Y Pantelyat
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Liana I Rosenthal
- Department of Neurology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Peter C M van Zijl
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
| | - Susan S Bassett
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - David M Yousem
- Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States
| | - Vidyulata Kamath
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Jun Hua
- Neurosection, Division of MRI Research, Russell H. Morgan Department of Radiology and Radiological Science, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
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3
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Strauch C, Hoang TH, Angenstein F, Manahan-Vaughan D. Olfactory Information Storage Engages Subcortical and Cortical Brain Regions That Support Valence Determination. Cereb Cortex 2021; 32:689-708. [PMID: 34379749 PMCID: PMC8841565 DOI: 10.1093/cercor/bhab226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 01/08/2023] Open
Abstract
The olfactory bulb (OB) delivers sensory information to the piriform cortex (PC) and other components of the olfactory system. OB-PC synapses have been reported to express short-lasting forms of synaptic plasticity, whereas long-term potentiation (LTP) of the anterior PC (aPC) occurs predominantly by activating inputs from the prefrontal cortex. This suggests that brain regions outside the olfactory system may contribute to olfactory information processing and storage. Here, we compared functional magnetic resonance imaging BOLD responses triggered during 20 or 100 Hz stimulation of the OB. We detected BOLD signal increases in the anterior olfactory nucleus (AON), PC and entorhinal cortex, nucleus accumbens, dorsal striatum, ventral diagonal band of Broca, prelimbic–infralimbic cortex (PrL-IL), dorsal medial prefrontal cortex, and basolateral amygdala. Significantly stronger BOLD responses occurred in the PrL-IL, PC, and AON during 100 Hz compared with 20 Hz OB stimulation. LTP in the aPC was concomitantly induced by 100 Hz stimulation. Furthermore, 100 Hz stimulation triggered significant nuclear immediate early gene expression in aPC, AON, and PrL-IL. The involvement of the PrL-IL in this process is consistent with its putative involvement in modulating behavioral responses to odor experience. Furthermore, these results indicate that OB-mediated information storage by the aPC is embedded in a connectome that supports valence evaluation.
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Affiliation(s)
- Christina Strauch
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
| | - Thu-Huong Hoang
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
| | - Frank Angenstein
- Functional Neuroimaging Group, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 39118 Magdeburg, Germany.,Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.,Medical Faculty, Otto-von Guericke University, 39118 Magdeburg, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
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4
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A methodological investigation of a flexible surface MRI coil to obtain functional signals from the human olfactory bulb. J Neurosci Methods 2020; 335:108624. [PMID: 32032715 DOI: 10.1016/j.jneumeth.2020.108624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/21/2020] [Accepted: 02/03/2020] [Indexed: 11/21/2022]
Abstract
BACKGROUND Mammalian olfaction begins with transduction in olfactory receptors, continues with extensive processing in the olfactory bulb, and culminates in cortical representation. Most rodent studies on the functional neuroanatomy of olfaction have concentrated on the olfactory bulb, yet whether this structure is tuned only to basic chemical features of odorants or also to higher-order perceptual features is unclear. NEW METHOD Whereas studies of the human brain can typically uncover involvement of higher-order feature extraction, this has not been possible in the case of the olfactory bulb, inaccessible to fMRI. The present study examined whether a novel method of acquisition using a facial coil could overcome this limitation. RESULTS A series of experiments provided preliminary evidence of odor-driven responses in the human olfactory bulb, and found that these responses differed between individuals. COMPARISON WITH EXISTING METHODS AND CONCLUSIONS The present preliminary technical achievement renders possible to design novel human odor fMRI studies by considering the olfactory system from the olfactory bulb to associative areas.
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5
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Life without a brain: Neuroradiological and behavioral evidence of neuroplasticity necessary to sustain brain function in the face of severe hydrocephalus. Sci Rep 2019; 9:16479. [PMID: 31712649 PMCID: PMC6848215 DOI: 10.1038/s41598-019-53042-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/22/2019] [Indexed: 12/31/2022] Open
Abstract
A two-year old rat, R222, survived a life-time of extreme hydrocephaly affecting the size and organization of its brain. Much of the cortex was severely thinned and replaced by cerebrospinal fluid, yet R222 had normal motor function, could hear, see, smell, and respond to tactile stimulation. The hippocampus was malformed and compressed into the lower hindbrain together with the hypothalamus midbrain and pons, yet R222 showed normal spatial memory as compared to age-matched controls. BOLD MRI was used to study the reorganization of R222’s brain function showing global activation to visual, olfactory and tactile stimulation, particularly in the brainstem/cerebellum. The results are discussed in the context of neuroadaptation in the face of severe hydrocephaly and subsequent tissue loss, with an emphasis on what is the “bare minimum” for survival.
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6
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Mesoscopic and microscopic imaging of sensory responses in the same animal. Nat Commun 2019; 10:1110. [PMID: 30846689 PMCID: PMC6405955 DOI: 10.1038/s41467-019-09082-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 02/20/2019] [Indexed: 01/09/2023] Open
Abstract
Imaging based on blood flow dynamics is widely used to study sensory processing. Here we investigated the extent to which local neuronal and capillary responses (two-photon microscopy) are correlated to mesoscopic responses detected with fast ultrasound (fUS) and BOLD-fMRI. Using a specialized chronic olfactory bulb preparation, we report that sequential imaging of the same mouse allows quantitative comparison of odour responses, imaged at both microscopic and mesoscopic scales. Under these conditions, functional hyperaemia occurred at the threshold of neuronal activation and fUS-CBV signals could be detected at the level of single voxels with activation maps varying according to blood velocity. Both neuronal and vascular responses increase non-linearly as a function of odour concentration, whereas both microscopic and mesoscopic vascular responses are linearly correlated to local neuronal calcium. These data establish strengths and limits of mesoscopic imaging techniques to report neural activity. Neuronal activity leads to a local increase in blood flow and volume, a process termed hyperaemia. Here, the authors employ multiple imaging approaches of neuronal and vascular activity at varying resolution to delineate the spatiotemporal dynamics of neurovascular coupling evoked by odours in the olfactory bulb.
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7
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Non-imaged based method for matching brains in a common anatomical space for cellular imagery. J Neurosci Methods 2018; 304:136-145. [DOI: 10.1016/j.jneumeth.2018.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/06/2018] [Accepted: 04/07/2018] [Indexed: 11/18/2022]
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Thompson GJ, Sanganahalli BG, Baker KL, Herman P, Shepherd GM, Verhagen JV, Hyder F. Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb. Neuroimage 2018; 172:586-596. [PMID: 29374582 DOI: 10.1016/j.neuroimage.2018.01.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/16/2018] [Accepted: 01/20/2018] [Indexed: 12/12/2022] Open
Abstract
Fluctuations in spontaneous activity have been observed by many neuroimaging techniques, but because these resting-state changes are not evoked by stimuli, it is difficult to determine how they relate to task-evoked activations. We conducted multi-modal neuroimaging scans of the rat olfactory bulb, both with and without odor, to examine interaction between spontaneous and evoked activities. Independent component analysis of spontaneous fluctuations revealed resting-state networks, and odor-evoked changes revealed activation maps. We constructed simulated activation maps using resting-state networks that were highly correlated to evoked activation maps. Simulated activation maps derived by intrinsic optical signal (IOS), which covers the dorsal portion of the glomerular sheet, significantly differentiated one odor's evoked activation map from the other two. To test the hypothesis that spontaneous activity of the entire glomerular sheet is relevant for representing odor-evoked activations, we used functional magnetic resonance imaging (fMRI) to map the entire glomerular sheet. In contrast to the IOS results, the fMRI-derived simulated activation maps significantly differentiated all three odors' evoked activation maps. Importantly, no evoked activation maps could be significantly differentiated using simulated activation maps produced using phase-randomized resting-state networks. Given that some highly organized resting-state networks did not correlate with any odors' evoked activation maps, we posit that these resting-state networks may characterize evoked activation maps associated with odors not studied. These results emphasize that fluctuations in spontaneous activity form a foundation for active processing, signifying the relevance of resting-state mapping to functional neuroimaging.
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Affiliation(s)
- Garth J Thompson
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Basavaraju G Sanganahalli
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA
| | - Keeley L Baker
- Department of Neuroscience, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT USA
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA
| | | | - Justus V Verhagen
- Department of Neuroscience, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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9
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Activity Patterns Elicited by Airflow in the Olfactory Bulb and Their Possible Functions. J Neurosci 2017; 37:10700-10711. [PMID: 28972124 DOI: 10.1523/jneurosci.2210-17.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/23/2017] [Accepted: 09/28/2017] [Indexed: 12/29/2022] Open
Abstract
Olfactory sensory neurons (OSNs) can sense both odorants and airflows. In the olfactory bulb (OB), the coding of odor information has been well studied, but the coding of mechanical stimulation is rarely investigated. Unlike odor-sensing functions of OSNs, the airflow-sensing functions of OSNs are also largely unknown. Here, the activity patterns elicited by mechanical airflow in male rat OBs were mapped using fMRI and correlated with local field potential recordings. In an attempt to reveal possible functions of airflow sensing, the relationship between airflow patterns and physiological parameters was also examined. We found the following: (1) the activity pattern in the OB evoked by airflow in the nasal cavity was more broadly distributed than patterns evoked by odors; (2) the pattern intensity increases with total airflow, while the pattern topography with total airflow remains almost unchanged; and (3) the heart rate, spontaneous respiratory rate, and electroencephalograph power in the β band decreased with regular mechanical airflow in the nasal cavity. The mapping results provide evidence that the signals elicited by mechanical airflow in OSNs are transmitted to the OB, and that the OB has the potential to code and process mechanical information. Our functional data indicate that airflow rhythm in the olfactory system can regulate the physiological and brain states, providing an explanation for the effects of breath control in meditation, yoga, and Taoism practices.SIGNIFICANCE STATEMENT Presentation of odor information in the olfactory bulb has been well studied, but studies about breathing features are rare. Here, using blood oxygen level-dependent functional MRI for the first time in such an investigation, we explored the global activity patterns in the rat olfactory bulb elicited by airflow in the nasal cavity. We found that the activity pattern elicited by airflow is broadly distributed, with increasing pattern intensity and similar topography under increasing total airflow. Further, heart rate, spontaneous respiratory rate in the lung, and electroencephalograph power in the β band decreased with regular airflow in the nasal cavity. Our study provides further understanding of the airflow map in the olfactory bulb in vivo, and evidence for the possible mechanosensitivity functions of olfactory sensory neurons.
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10
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Zhao F, Wang X, Zariwala HA, Uslaner JM, Houghton AK, Evelhoch JL, Hostetler E, Winkelmann CT, Hines CD. fMRI study of the role of glutamate NMDA receptor in the olfactory adaptation in rats: Insights into cellular and molecular mechanisms of olfactory adaptation. Neuroimage 2017; 149:348-360. [DOI: 10.1016/j.neuroimage.2017.01.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/23/2016] [Accepted: 01/28/2017] [Indexed: 11/16/2022] Open
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11
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Activity in the rat olfactory cortex is correlated with behavioral response to odor: a microPET study. Brain Struct Funct 2016; 222:577-586. [PMID: 27194619 DOI: 10.1007/s00429-016-1235-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
Abstract
How olfactory cortical areas interpret odor maps evoked in the olfactory bulb and translate odor information into behavioral responses is still largely unknown. Indeed, rat olfactory cortices encompass an extensive network located in the ventral part of the brain, thus complicating the use of invasive functional methods. In vivo imaging techniques that were previously developed for brain activation studies in humans have been adapted for use in rodents and facilitate the non-invasive mapping of the whole brain. In this study, we report an initial series of experiments designed to demonstrate that microPET is a powerful tool to investigate the neural processes underlying odor-induced behavioral response in a large-scale olfactory neuronal network. After the intravenous injection of [18F]Fluorodeoxyglucose ([18F]FDG), awake rats were placed in a ventilated Plexiglas cage for 50 min, where odorants were delivered every 3 min for a 10-s duration in a random order. Individual behavioral responses to odor were classified into categories ranging from 1 (head movements associated with a short sniffing period in response to a few stimulations) to 4 (a strong reaction, including rearing, exploring and sustained sniffing activity, to several stimulations). After [18F]FDG uptake, rats were anesthetized to perform a PET scan. This experimental session was repeated 2 weeks later using the same animals without odor stimulation to assess the baseline level of activation in each individual. Two voxel-based statistical analyses (SPM 8) were performed: (1) a two-sample paired t test analysis contrasting baseline versus odor scan and (2) a correlation analysis between voxel FDG activity and behavioral score. As expected, the contrast analysis between baseline and odor session revealed activations in various olfactory cortical areas. Significant increases in glucose metabolism were also observed in other sensory cortical areas involved in whisker movement and in several modules of the cerebellum involved in motor and sensory function. Correlation analysis provided new insight into these results. [18F]FDG uptake was correlated with behavioral response in a large part of the anterior piriform cortex and in some lobules of the cerebellum, in agreement with the previous data showing that both piriform cortex and cerebellar activity in humans can be driven by sniffing activity, which was closely related to the high behavioral scores observed in our experiment. The present data demonstrate that microPET imaging offers an original perspective for rat behavioral neuroimaging.
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12
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Zhao F, Wang X, Zariwala HA, Uslaner JM, Houghton AK, Evelhoch JL, Williams DS, Winkelmann CT. fMRI study of olfaction in the olfactory bulb and high olfactory structures of rats: Insight into their roles in habituation. Neuroimage 2015; 127:445-455. [PMID: 26522425 DOI: 10.1016/j.neuroimage.2015.10.080] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 10/24/2015] [Accepted: 10/27/2015] [Indexed: 01/09/2023] Open
Abstract
Cerebral blood volume (CBV) fMRI with ultrasmall superparamagnetic iron oxide particles (USPIO) as a contrast agent was used to investigate olfactory processing in rats. fMRI data were acquired in sixteen 0.75-mm coronal slices covering the olfactory bulb (OB) and higher olfactory regions (HOR), including the anterior olfactory nucleus and piriform cortex. For each animal, multiple consecutive fMRI measurements were made during a 3-h experiment session, with each measurement consisting of a baseline period, an odorant stimulation period, and a recovery period. Two different stimulation paradigms with a stimulation period of 40s or 80s, respectively, were used to study olfactory processing. Odorant-induced CBV increases were robustly observed in the OB and HOR of each individual animal. Olfactory adaptation, which is characterized by an attenuation of responses to continuous exposure or repeated stimulations, has different characteristics in the OB and HOR. For adaptation to repeated stimuli, while it was observed in both the OB and HOR, CBV responses in the HOR were attenuated more significantly than responses in the OB. In contrast, within each continuous 40-s or 80-s odor exposure, CBV responses in the OB were stable and did not show adaptation, but the CBV responses in the HOR were state dependent, with no adaptation during initial exposures, but significant adaptation during following exposures. These results support previous reports that HOR plays a more significant role than OB in olfactory habituation. The technical approach presented in this study should enable more extensive fMRI studies of olfactory processing in rats.
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Zhao F, Holahan MA, Houghton AK, Hargreaves R, Evelhoch JL, Winkelmann CT, Williams DS. Functional imaging of olfaction by CBV fMRI in monkeys: Insight into the role of olfactory bulb in habituation. Neuroimage 2015; 106:364-72. [DOI: 10.1016/j.neuroimage.2014.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/04/2014] [Accepted: 12/01/2014] [Indexed: 11/26/2022] Open
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14
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Li B, Gong L, Wu R, Li A, Xu F. Complex relationship between BOLD-fMRI and electrophysiological signals in different olfactory bulb layers. Neuroimage 2014; 95:29-38. [DOI: 10.1016/j.neuroimage.2014.03.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 03/06/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023] Open
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15
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Jia H, Pustovyy OM, Waggoner P, Beyers RJ, Schumacher J, Wildey C, Barrett J, Morrison E, Salibi N, Denney TS, Vodyanoy VJ, Deshpande G. Functional MRI of the olfactory system in conscious dogs. PLoS One 2014; 9:e86362. [PMID: 24466054 PMCID: PMC3900535 DOI: 10.1371/journal.pone.0086362] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 12/07/2013] [Indexed: 11/19/2022] Open
Abstract
We depend upon the olfactory abilities of dogs for critical tasks such as detecting bombs, landmines, other hazardous chemicals and illicit substances. Hence, a mechanistic understanding of the olfactory system in dogs is of great scientific interest. Previous studies explored this aspect at the cellular and behavior levels; however, the cognitive-level neural substrates linking them have never been explored. This is critical given the fact that behavior is driven by filtered sensory representations in higher order cognitive areas rather than the raw odor maps of the olfactory bulb. Since sedated dogs cannot sniff, we investigated this using functional magnetic resonance imaging of conscious dogs. We addressed the technical challenges of head motion using a two pronged strategy of behavioral training to keep dogs' head as still as possible and a single camera optical head motion tracking system to account for residual jerky movements. We built a custom computer-controlled odorant delivery system which was synchronized with image acquisition, allowing the investigation of brain regions activated by odors. The olfactory bulb and piriform lobes were commonly activated in both awake and anesthetized dogs, while the frontal cortex was activated mainly in conscious dogs. Comparison of responses to low and high odor intensity showed differences in either the strength or spatial extent of activation in the olfactory bulb, piriform lobes, cerebellum, and frontal cortex. Our results demonstrate the viability of the proposed method for functional imaging of the olfactory system in conscious dogs. This could potentially open up a new field of research in detector dog technology.
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Affiliation(s)
- Hao Jia
- MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, Alabama, United States of America
| | - Oleg M. Pustovyy
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama, United States of America
| | - Paul Waggoner
- Canine Detection Research Institute, Auburn University, Auburn, Alabama, United States of America
| | - Ronald J. Beyers
- MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, Alabama, United States of America
| | - John Schumacher
- Department of Clinical Sciences, Auburn University, Auburn, Alabama, United States of America
| | | | - Jay Barrett
- College of Veterinary Medicine, Auburn University, Auburn, Alabama, United States of America
| | - Edward Morrison
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama, United States of America
| | - Nouha Salibi
- MR R&D, Siemens Healthcare, Malvern, Pennsylvania, United States of America
| | - Thomas S. Denney
- MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, Alabama, United States of America
- Department of Psychology, Auburn University, Auburn, Alabama, United States of America
| | - Vitaly J. Vodyanoy
- Department of Anatomy, Physiology & Pharmacology, Auburn University, Auburn, Alabama, United States of America
| | - Gopikrishna Deshpande
- MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, Alabama, United States of America
- Department of Psychology, Auburn University, Auburn, Alabama, United States of America
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16
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Poplawsky AJ, Kim SG. Layer-dependent BOLD and CBV-weighted fMRI responses in the rat olfactory bulb. Neuroimage 2014; 91:237-51. [PMID: 24418506 DOI: 10.1016/j.neuroimage.2013.12.067] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 12/10/2013] [Accepted: 12/29/2013] [Indexed: 10/25/2022] Open
Abstract
The olfactory bulb is a laminarized brain structure involved in odor sensation that has important implications to basic neuroscience research, like mechanisms for neurovascular coupling and early disease diagnosis. To investigate laminar-dependent responses to odor exposure, blood oxygenation level-dependent (BOLD) and cerebral blood volume weighted (CBVw) fMRI with iron oxide nanoparticle contrast agent were obtained with 110×110×500μm(3) resolution in urethane-anesthetized rats at 9.4T. The baseline total CBV is the largest at the olfactory bulb surface and midline, and decreases in the deeper layers, while a band of increased microvasculature density is observed at the glomerular, external plexiform and mitral cell layers. With odor exposure, CBVw fMRI is more sensitive and reproducible than BOLD. BOLD fMRI had the greatest activation on the bulb surface, midline, olfactory nerve and glomerular layers, while CBVw activation peaked in glomerular and external plexiform layers, but was still significant in mitral cell layer. Negative BOLD responses were observed in the bulb midline and near large blood vessels. CBVw laminar profiles are similar to the layer-dependent metabolic changes to the same odor exposure reported by previous glucose metabolism studies. Unique activation patterns for two different odor conditions were also differentiated with CBVw fMRI. Our study suggests that CBVw activation better represents the spatial location of metabolic activity in the olfactory bulb than BOLD.
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Affiliation(s)
- Alexander John Poplawsky
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Seong-Gi Kim
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience Imaging Research, Institute of Basic Science (IBS), Sungkyunkwan University, Suwon 440-746, Republic of Korea; Department of Biological Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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Lau C, Zhang JW, Cheng JS, Zhou IY, Cheung MM, Wu EX. Noninvasive fMRI investigation of interaural level difference processing in the rat auditory subcortex. PLoS One 2013; 8:e70706. [PMID: 23940631 PMCID: PMC3733930 DOI: 10.1371/journal.pone.0070706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/21/2013] [Indexed: 12/02/2022] Open
Abstract
Objective Interaural level difference (ILD) is the difference in sound pressure level (SPL) between the two ears and is one of the key physical cues used by the auditory system in sound localization. Our current understanding of ILD encoding has come primarily from invasive studies of individual structures, which have implicated subcortical structures such as the cochlear nucleus (CN), superior olivary complex (SOC), lateral lemniscus (LL), and inferior colliculus (IC). Noninvasive brain imaging enables studying ILD processing in multiple structures simultaneously. Methods In this study, blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is used for the first time to measure changes in the hemodynamic responses in the adult Sprague-Dawley rat subcortex during binaural stimulation with different ILDs. Results and Significance Consistent responses are observed in the CN, SOC, LL, and IC in both hemispheres. Voxel-by-voxel analysis of the change of the response amplitude with ILD indicates statistically significant ILD dependence in dorsal LL, IC, and a region containing parts of the SOC and LL. For all three regions, the larger amplitude response is located in the hemisphere contralateral from the higher SPL stimulus. These findings are supported by region of interest analysis. fMRI shows that ILD dependence occurs in both hemispheres and multiple subcortical levels of the auditory system. This study is the first step towards future studies examining subcortical binaural processing and sound localization in animal models of hearing.
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Affiliation(s)
- Condon Lau
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, China
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Esclassan F, Courtiol E, Thévenet M, Garcia S, Buonviso N, Litaudon P. Faster, deeper, better: the impact of sniffing modulation on bulbar olfactory processing. PLoS One 2012; 7:e40927. [PMID: 22815871 PMCID: PMC3398873 DOI: 10.1371/journal.pone.0040927] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/15/2012] [Indexed: 11/18/2022] Open
Abstract
A key feature of mammalian olfactory perception is that sensory input is intimately related to respiration. Different authors have considered respiratory dynamics not only as a simple vector for odor molecules but also as an integral part of olfactory perception. Thus, rats adapt their sniffing strategy, both in frequency and flow rate, when performing odor-related tasks. The question of how frequency and flow rate jointly impact the spatio-temporal representation of odor in the olfactory bulb (OB) has not yet been answered. In the present paper, we addressed this question using a simulated nasal airflow protocol on anesthetized rats combined with voltage-sensitive dye imaging (VSDi) of odor-evoked OB glomerular maps. Glomerular responses displayed a tonic component during odor stimulation with a superimposed phasic component phase-locked to the sampling pattern. We showed that a high sniffing frequency (10 Hz) retained the ability to shape OB activity and that the tonic and phasic components of the VSDi responses were dependent on flow rate and inspiration volume, respectively. Both sniffing parameters jointly affected OB responses to odor such that the reduced activity level induced by a frequency increase was compensated by an increased flow rate.
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Affiliation(s)
- Frédéric Esclassan
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
| | - Emmanuelle Courtiol
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
| | - Marc Thévenet
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
| | - Samuel Garcia
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
| | - Nathalie Buonviso
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
| | - Philippe Litaudon
- Centre de Recherche en Neurosciences de Lyon (CRNL) Equipe Olfaction : du codage à la mémoire, CNRS UMR 5292 - INSERM U1028 - Université Lyon 1 – Université de Lyon, Lyon, France
- * E-mail:
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Gaultier A, Meunier-Salaün MC, Malbert CH, Val-Laillet D. Flavour exposures after conditioned aversion or preference trigger different brain processes in anaesthetised pigs. Eur J Neurosci 2011; 34:1500-11. [DOI: 10.1111/j.1460-9568.2011.07848.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pain F, L'heureux B, Gurden H. Visualizing odor representation in the brain: a review of imaging techniques for the mapping of sensory activity in the olfactory glomeruli. Cell Mol Life Sci 2011; 68:2689-709. [PMID: 21584811 PMCID: PMC11114686 DOI: 10.1007/s00018-011-0708-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 03/30/2011] [Accepted: 04/21/2011] [Indexed: 01/15/2023]
Abstract
The brain transforms clues from the external world, the sensory stimuli, into activities in neuroglial networks. These circuits are activated in specialized sensory cortices where specific functional modules are responsible for the spatiotemporal coding of the stimulus. A major challenge in the neuroscience field has been to image the spatial distribution and follow the temporal dynamics of the activation of such large populations in vivo. Functional imaging techniques developed in the last 30 years have enabled researchers to solve this critical issue, and are reviewed here. These techniques utilize sources of contrast of radioisotopic, magnetic and optical origins and exploit two major families of signals to image sensory activity: the first class uses sources linked to cellular energy metabolism and hemodynamics, while the second involves exogenous indicators of neuronal activity. The whole panel of imaging techniques has fostered the functional exploration of the olfactory bulb which is one of the most studied sensory structures. We summarize the major results obtained using these techniques that describe the spatial and temporal activity patterns in the olfactory glomeruli, the first relay of olfactory information processing in the main olfactory bulb. We conclude this review by describing promising technical developments in optical imaging and future directions in the study of olfactory spatiotemporal coding.
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Affiliation(s)
- F Pain
- Laboratoire Imagerie et Modélisation en Neurobiologie et Cancérologie, UMR Université Paris Sud, CNRS, Campus d'Orsay Bat, France.
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Nudelman AS, DiRocco DP, Lambert TJ, Garelick MG, Le J, Nathanson NM, Storm DR. Neuronal activity rapidly induces transcription of the CREB-regulated microRNA-132, in vivo. Hippocampus 2010; 20:492-8. [PMID: 19557767 DOI: 10.1002/hipo.20646] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Activity-dependent changes in gene-expression are believed to underlie the molecular representation of memory. In this study, we report that in vivo activation of neurons rapidly induces the CREB-regulated microRNA miR-132. To determine if production of miR-132 is regulated by neuronal activity its expression in mouse brain was monitored by quantitative RT-PCR (RT-qPCR). Pilocarpine-induced seizures led to a robust, rapid, and transient increase in the primary transcript of miR-132 (pri-miR-132) followed by a subsequent rise in mature microRNA (miR-132). Activation of neurons in the hippocampus, olfactory bulb, and striatum by contextual fear conditioning, odor-exposure, and cocaine-injection, respectively, also increased pri-miR-132. Induction kinetics of pri-miR-132 were monitored and found to parallel those of immediate early genes, peaking at 45 min and returning to basal levels within 2 h of stimulation. Expression levels of primary and mature-miR-132 increased significantly between postnatal Days 10 and 24. We conclude that miR-132 is an activity-dependent microRNA in vivo, and may contribute to the long-lasting proteomic changes required for experience-dependent neuronal plasticity.
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Affiliation(s)
- Aaron S Nudelman
- Department of Pharmacology, University of Washington, Seattle, Washington
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23
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Sanganahalli BG, Bailey CJ, Herman P, Hyder F. Tactile and non-tactile sensory paradigms for fMRI and neurophysiologic studies in rodents. Methods Mol Biol 2009; 489:213-42. [PMID: 18839094 PMCID: PMC3703391 DOI: 10.1007/978-1-59745-543-5_10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has become a popular functional imaging tool for human studies. Future diagnostic use of fMRI depends, however, on a suitable neurophysiologic interpretation of the blood oxygenation level dependent (BOLD) signal change. This particular goal is best achieved in animal models primarily due to the invasive nature of other methods used and/or pharmacological agents applied to probe different nuances of neuronal (and glial) activity coupled to the BOLD signal change. In the last decade, we have directed our efforts towards the development of stimulation protocols for a variety of modalities in rodents with fMRI. Cortical perception of the natural world relies on the formation of multi-dimensional representation of stimuli impinging on the different sensory systems, leading to the hypothesis that a sensory stimulus may have very different neurophysiologic outcome(s) when paired with a near simultaneous event in another modality. Before approaching this level of complexity, reliable measures must be obtained of the relatively small changes in the BOLD signal and other neurophysiologic markers (electrical activity, blood flow) induced by different peripheral stimuli. Here we describe different tactile (i.e., forepaw, whisker) and non-tactile (i.e., olfactory, visual) sensory paradigms applied to the anesthetized rat. The main focus is on development and validation of methods for reproducible stimulation of each sensory modality applied independently or in conjunction with one another, both inside and outside the magnet. We discuss similarities and/or differences across the sensory systems as well as advantages they may have for studying essential neuroscientific questions. We envisage that the different sensory paradigms described here may be applied directly to studies of multi-sensory interactions in anesthetized rats, en route to a rudimentary understanding of the awake functioning brain where various sensory cues presumably interrelate.
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Affiliation(s)
- Basavaraju G. Sanganahalli
- Department of Diagnostic Radiology Yale University, New Haven, Connecticut, USA,Department of Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, Connecticut, USA,Department of Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
| | - Christopher J. Bailey
- Department of Diagnostic Radiology Yale University, New Haven, Connecticut, USA,Department of Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA,Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Peter Herman
- Department of Diagnostic Radiology Yale University, New Haven, Connecticut, USA,Department of Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, Connecticut, USA,Department of Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA,Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary
| | - Fahmeed Hyder
- Department of Diagnostic Radiology Yale University, New Haven, Connecticut, USA,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA,Department of Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, Connecticut, USA,Department of Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
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Sanganahalli BG, Herman P, Hyder F. Frequency-dependent tactile responses in rat brain measured by functional MRI. NMR IN BIOMEDICINE 2008; 21:410-6. [PMID: 18435491 PMCID: PMC2774500 DOI: 10.1002/nbm.1259] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We measured frequency-dependent functional MRI (fMRI) activations (at 11.7 T) in the somatosensory cortex with whisker and forepaw stimuli in the same alpha-chloralose anesthetized rats. Whisker and forepaw stimuli were attained by computer-controlled pulses of air puffs and electrical currents, respectively. Air puffs deflected (+/-2 mm) the chosen whisker(s) in the right snout in the rostral to caudal direction, and electrical currents (2 mA amplitude, 0.3 ms duration) stimulated the left forepaw with subcutaneous copper electrodes placed between the second and fourth digits. In the same subject, unimodal stimulation of whisker and forepaw gave rise to significant blood oxygen level-dependent (BOLD) signal increases in corresponding contralateral somatosensory areas of whisker barrel field (S1BF) and forelimb (S1FL), respectively, with no significant spatial overlap between these regions. The BOLD responses in S1(BF) and S1(FL) regions were found to be differentially variable with frequency of each stimulus type. In the S1BF, a linear increase in the BOLD response was observed with whisker stimulation frequency of up to approximately 12 Hz, beyond which the response seemed to saturate (and/or slightly attenuate) up to the maximum frequency studied (i.e. 30 Hz). In the S1FL, the magnitude of the BOLD response was largest at forepaw stimulation frequency between 1.5 and 3 Hz, beyond which the response diminished with little or no activity at frequencies higher than 20 Hz. The volume of tissue activated by each stimulus type followed a similar pattern to that of the stimulation frequency dependence. These results of bimodal whisker and forepaw stimuli in the same subject may provide a framework to study interactions of different tactile modules, with both fMRI and neurophysiology (i.e. inside and outside the magnet).
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Affiliation(s)
- Basavaraju G. Sanganahalli
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT 06520, USA
- Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, CT 06520, USA
- Department of Diagnostic Radiology, Yale University, New Haven, CT 06520, USA
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT 06520, USA
- Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, CT 06520, USA
- Department of Diagnostic Radiology, Yale University, New Haven, CT 06520, USA
- Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT 06520, USA
- Quantitative Neuroscience with Magnetic Resonance (QNMR), Yale University, New Haven, CT 06520, USA
- Department of Diagnostic Radiology, Yale University, New Haven, CT 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
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