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Cheng YP, Huang JJ, Yeh CI, Pei YC. Alternation of Neuronal Feature Selectivity Induced by Paired Optogenetic-Mechanical Stimulation in the Barrel Cortex. Front Neural Circuits 2021; 15:708459. [PMID: 34566582 PMCID: PMC8457523 DOI: 10.3389/fncir.2021.708459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/05/2021] [Indexed: 11/13/2022] Open
Abstract
Paired stimulation has been applied to modulate neuronal functions in the primary somatosensory cortex but its utility in the alternation of tuning function, such as direction tuning for whisker stimuli, remains unclear. In the present study, we attempted to manipulate feature preferences in barrel cortical neurons using repetitive paired whisker deflection combined with optogenetic stimulation and to obtain optimal parameters that can induce neuroplasticity. We found no significant response changes across stimulus parameters, such as onset asynchronies and paired directions. Only when paired stimulation was applied in the nonpreferred direction of the principal whisker of a neuron, were the neuron’s responses enhanced in that direction. Importantly, this effect was only observed when the optogenetic stimulus preceded the mechanical stimulus. Our findings indicate that repetitive paired optogenetic-mechanical stimulation can induce in vivo neuroplasticity of feature selectivity in limited situations.
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Affiliation(s)
- Yu-Po Cheng
- Department of Physical Medicine and Rehabilitation, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Psychology, College of Science, National Taiwan University, Taipei, Taiwan
| | - Jian-Jia Huang
- Department of Physical Medicine and Rehabilitation, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Center of Vascularized Tissue Allograft, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chun-I Yeh
- Department of Psychology, College of Science, National Taiwan University, Taipei, Taiwan
| | - Yu-Cheng Pei
- Department of Physical Medicine and Rehabilitation, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Center of Vascularized Tissue Allograft, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
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2
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Valdés-Hernández PA, Bae J, Song Y, Sumiyoshi A, Aubert-Vázquez E, Riera JJ. Validating Non-invasive EEG Source Imaging Using Optimal Electrode Configurations on a Representative Rat Head Model. Brain Topogr 2019; 32:599-624. [PMID: 27026168 DOI: 10.1007/s10548-016-0484-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 03/05/2016] [Indexed: 12/20/2022]
Abstract
The curtain of technical limitations impeding rat multichannel non-invasive electroencephalography (EEG) has risen. Given the importance of this preclinical model, development and validation of EEG source imaging (ESI) is essential. We investigate the validity of well-known human ESI methodologies in rats which individual tissue geometries have been approximated by those extracted from an MRI template, leading also to imprecision in electrode localizations. With the half and fifth sensitivity volumes we determine both the theoretical minimum electrode separation for non-redundant scalp EEG measurements and the electrode sensitivity resolution, which vary over the scalp because of the head geometry. According to our results, electrodes should be at least ~3 to 3.5 mm apart for an optimal configuration. The sensitivity resolution is generally worse for electrodes at the boundaries of the scalp measured region, though, by analogy with human montages, concentrates the sensitivity enough to localize sources. Cramér-Rao lower bounds of source localization errors indicate it is theoretically possible to achieve ESI accuracy at the level of anatomical structures, such as the stimulus-specific somatosensory areas, using the template. More validation for this approximation is provided through the comparison between the template and the individual lead field matrices, for several rats. Finally, using well-accepted inverse methods, we demonstrate that somatosensory ESI is not only expected but also allows exploring unknown phenomena related to global sensory integration. Inheriting the advantages and pitfalls of human ESI, rat ESI will boost the understanding of brain pathophysiological mechanisms and the evaluation of ESI methodologies, new pharmacological treatments and ESI-based biomarkers.
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Affiliation(s)
- Pedro A Valdés-Hernández
- Neuroimaging Department, Cuban Neuroscience Center, Havana, Cuba
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Jihye Bae
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Yinchen Song
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Akira Sumiyoshi
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | | | - Jorge J Riera
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA.
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3
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Lee LJ, Tsytsarev V, Erzurumlu RS. Structural and functional differences in the barrel cortex of Mecp2 null mice. J Comp Neurol 2017; 525:3951-3961. [PMID: 28857161 DOI: 10.1002/cne.24315] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/28/2017] [Accepted: 08/14/2017] [Indexed: 02/06/2023]
Abstract
Functional deficits in sensory systems are commonly noted in neurodevelopmental disorders, such as the Rett syndrome (RTT). Defects in methyl CpG binding protein gene (MECP2) largely accounts for RTT. Manipulations of the Mecp2 gene in mice provide useful models to probe into various aspects of brain development associated with the RTT. In this study, we focused on the somatosensory cortical phenotype in the Bird mouse model of RTT. We used voltage-sensitive dye imaging to evaluate whisker sensory evoked activity in the barrel cortex of mice. We coupled this functional assay with morphological analyses in postnatal mice and investigated the dendritic differentiation of barrel neurons and individual thalamocortical axon (TCA) arbors that synapse with them. We show that in Mecp2-deficient male mice, whisker-evoked activity is roughly topographic but weak in the barrel cortex. At the morphological level, we find that TCA arbors fail to develop into discrete, concentrated patches in barrel hollows, and the complexity of the dendritic branches in layer IV spiny stellate neurons is reduced. Collectively, our results indicate significant structural and functional impairments in the barrel cortex of the Bird mouse line, a popular animal model for the RTT. Such structural and functional anomalies in the primary somatosensory cortex may underlie orofacial tactile sensitivity issues and sensorimotor stereotypies characteristic of RTT.
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Affiliation(s)
- Li-Jen Lee
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan, ROC.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
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4
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Bale MR, Maravall M. Organization of sensory feature selectivity in the whisker system. Neuroscience 2017; 368:70-80. [PMID: 28918260 PMCID: PMC5798594 DOI: 10.1016/j.neuroscience.2017.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/14/2022]
Abstract
Neurons in the whisker system are selective to spatial and dynamical properties – features – of sensory stimuli. At each stage of the pathway, different neurons encode distinct features, generating a rich population representation. Whisker touch is robustly represented; neurons respond to touch-driven fast fluctuations in forces at the whisker base. Cortical neurons have more complex and context-dependent selectivity than subcortical, e.g., to collective whisker motion. Understanding how these signals are integrated to construct whisker-mediated percepts requires further research.
Our sensory receptors are faced with an onslaught of different environmental inputs. Each sensory event or encounter with an object involves a distinct combination of physical energy sources impinging upon receptors. In the rodent whisker system, each primary afferent neuron located in the trigeminal ganglion innervates and responds to a single whisker and encodes a distinct set of physical stimulus properties – features – corresponding to changes in whisker angle and shape and the consequent forces acting on the whisker follicle. Here we review the nature of the features encoded by successive stages of processing along the whisker pathway. At each stage different neurons respond to distinct features, such that the population as a whole represents diverse properties. Different neuronal types also have distinct feature selectivity. Thus, neurons at the same stage of processing and responding to the same whisker nevertheless play different roles in representing objects contacted by the whisker. This diversity, combined with the precise timing and high reliability of responses, enables populations at each stage to represent a wide range of stimuli. Cortical neurons respond to more complex stimulus properties – such as correlated motion across whiskers – than those at early subcortical stages. Temporal integration along the pathway is comparatively weak: neurons up to barrel cortex (BC) are sensitive mainly to fast (tens of milliseconds) fluctuations in whisker motion. The topographic organization of whisker sensitivity is paralleled by systematic organization of neuronal selectivity to certain other physical features, but selectivity to touch and to dynamic stimulus properties is distributed in “salt-and-pepper” fashion.
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Affiliation(s)
- Michael R Bale
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Miguel Maravall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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5
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Kwon SE, Tsytsarev V, Erzurumlu RS, O'Connor DH. Organization of orientation-specific whisker deflection responses in layer 2/3 of mouse somatosensory cortex. Neuroscience 2017; 368:46-56. [PMID: 28827090 DOI: 10.1016/j.neuroscience.2017.07.067] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/18/2022]
Abstract
The rodent whisker-barrel system is characterized by its patterned somatotopic mapping between the sensory periphery and multiple regions of the brain. While somatotopy in the whisker system is established, we know far less about how preferences for stimulus orientation or other features are organized. Mouse somatosensation is an increasingly popular model for circuit-based dissection of perceptual decision making and learning, yet our understanding of how stimulus feature representations are organized in the cortex is incomplete. Here, we used in vivo two-photon calcium imaging to monitor activity of populations of layer (L) 2/3 neurons in the mouse primary somatosensory cortex during deflections of a single whisker in two orthogonal orientations (azimuthal or elevational). We split the population response to whisker deflections into an orientation-specific component and a non-specific component that reflected overall excitability in response to deflection of a single whisker. Orientation-specific responses were organized in a locally heterogeneous and spatially distributed manner. Correlations in the stimulus-independent trial-to-trial variability of pairs of neurons were higher among neurons that preferred the same orientation. These correlations depended on similarity in both orientation-specific and non-specific components of responses to single-whisker deflections. Our results shed light on L2/3 organization in mouse somatosensory cortex, and lay a foundation for dissecting circuit mechanisms of perceptual learning and decision-making during orientation discrimination tasks.
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Affiliation(s)
- Sung Eun Kwon
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Daniel H O'Connor
- The Solomon H. Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Brain Science Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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6
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Tsytsarev V, Arakawa H, Zhao S, Chédotal A, Erzurumlu RS. Behavioral Consequences of a Bifacial Map in the Mouse Somatosensory Cortex. J Neurosci 2017; 37:7209-7218. [PMID: 28663199 PMCID: PMC5546400 DOI: 10.1523/jneurosci.0598-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 06/14/2017] [Accepted: 06/19/2017] [Indexed: 02/04/2023] Open
Abstract
The whisker system is an important sensory organ with extensive neural representations in the brain of the mouse. Patterned neural modules (barrelettes) in the ipsilateral principal sensory nucleus of the trigeminal nerve (PrV) correspond to the whiskers. Axons of the PrV barrelette neurons cross the midline and confer the whisker-related patterning to the contralateral ventroposteromedial nucleus of the thalamus, and subsequently to the cortex. In this way, specific neural modules called barreloids and barrels in the contralateral thalamus and cortex represent each whisker. Partial midline crossing of the PrV axons, in a conditional Robo3 mutant (Robo3R3-5cKO) mouse line, leads to the formation of bilateral whisker maps in the ventroposteromedial, as well as the barrel cortex. We used voltage-sensitive dye optical imaging and somatosensory and motor behavioral tests to characterize the consequences of bifacial maps in the thalamocortical system. Voltage-sensitive dye optical imaging verified functional, bilateral whisker representation in the barrel cortex and activation of distinct cortical loci following ipsilateral and contralateral stimulation of the specific whiskers. The mutant animals were comparable with the control animals in sensorimotor tests. However, they showed noticeable deficits in all of the whisker-dependent or -related tests, including Y-maze exploration, horizontal surface approach, bridge crossing, gap crossing, texture discrimination, floating in water, and whisking laterality. Our results indicate that bifacial maps along the thalamocortical system do not offer a functional advantage. Instead, they lead to impairments, possibly due to the smaller size of the whisker-related modules and interference between the ipsilateral and contralateral whisker representations in the same thalamus and cortex.SIGNIFICANCE STATEMENT The whisker sensory system plays a quintessentially important role in exploratory behavior of mice and other nocturnal rodents. Here, we studied a novel mutant mouse line, in which the projections from the brainstem to the thalamus are disrupted. This led to formation of bilateral whisker maps in both the thalamus and the cortex. The two whisker maps crowd in a space normally devoted to the contralateral map alone and in a nonoverlapping fashion. Stimulation of the whiskers on either side activates the corresponding region of the map. Mice with bilateral whisker maps perform well in general sensorimotor tasks but show poor performance in specific tests that require whisker-dependent tactile discrimination. These observations indicate that contralateral, instead of bilateral, representation of the sensory space plays a critical role in acuity and fine discrimination during somesthesis.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Hiroyuki Arakawa
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Shuxin Zhao
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Alain Chédotal
- Centre de Recherche Institut de la Vision, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche S968, 75012 Paris, France
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
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7
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Roe AW, Winberry JE, Friedman RM. Study of single and multidigit activation in monkey somatosensory cortex using voltage-sensitive dye imaging. NEUROPHOTONICS 2017; 4:031219. [PMID: 28573156 PMCID: PMC5446783 DOI: 10.1117/1.nph.4.3.031219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/02/2017] [Indexed: 06/02/2023]
Abstract
Toward the goal of understanding cutaneous sensory integration during manual behavior, we used voltage-sensitive dye (VSD) imaging to study the organization and dynamics of anesthetized monkey primary somatosensory cortex (SI) in response to single and multidigit tactile stimulation. We find that in both macaque and squirrel monkey SI, VSD reveals clear focal digit topography consistent with previous electrophysiological and intrinsic signal imaging studies. VSD also reveals interactions in SI in response to multidigit stimulation. With a tactile funneling paradigm in areas 3b and 1 in squirrel monkeys, VSD reveals two-digit induction of subthreshhold influences, consistent with lateral intracortical inhibition. In response to tactile apparent motion stimuli, VSD reveals preferential response to motion stimuli over static tactile stimuli in both areas 1 and 3b. Comparison of the response at different digit locations to "toward digit" stimuli suggests the presence of direction-selective response in area 1; however, further study is needed. These exciting results indicate that VSD constitutes a powerful tool for studying somatosensory cortical processing in nonhuman primates and should be further developed for future somatosensory studies in awake behaving monkeys.
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Affiliation(s)
- Anna Wang Roe
- Zhejiang University, Qiushi Academy for Advanced Studies, Interdisciplinary Institute of Neuroscience and Technology, Hangzhou, China
- Oregon Health and Science University, Oregon National Primate Research Center, Division of Neuroscience, Beaverton, Oregon, United States
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
| | - Jeremy E. Winberry
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
- The University of Chicago, Department of Organismal Biology and Anatomy, Chicago, Illinois, United States
| | - Robert M. Friedman
- Oregon Health and Science University, Oregon National Primate Research Center, Division of Neuroscience, Beaverton, Oregon, United States
- Vanderbilt University, Department of Psychology, Nashville, Tennessee, United States
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8
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Tang Q, Liu Y, Tsytsarev V, Lin J, Wang B, Kanniyappan U, Li Z, Chen Y. High-dynamic-range fluorescence laminar optical tomography (HDR-FLOT). BIOMEDICAL OPTICS EXPRESS 2017; 8:2124-2137. [PMID: 28736659 PMCID: PMC5516817 DOI: 10.1364/boe.8.002124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/16/2017] [Accepted: 03/04/2017] [Indexed: 05/21/2023]
Abstract
Three-dimensional fluorescence laminar optical tomography (FLOT) can achieve resolutions of 100-200 µm and penetration depths of 2-3 mm. FLOT has been used in tissue engineering, neuroscience, as well as oncology. The limited dynamic range of the charge-coupled device-based system makes it difficult to image fluorescent samples with a large concentration difference, limits its penetration depth, and diminishes the quantitative accuracy of 3D reconstruction data. Here, incorporating the high-dynamic-range (HDR) method widely used in digital cameras, we present HDR-FLOT, increasing penetration depth and improving the ability to image fluorescent samples with a large concentration difference. The method was tested using an agar phantom and a B6 mouse for brain imaging in vivo.
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Affiliation(s)
- Qinggong Tang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
- Contributed equally
| | - Yi Liu
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
- Contributed equally
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Jonathan Lin
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
| | - Bohan Wang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
| | - Udayakumar Kanniyappan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
| | - Zhifang Li
- Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350007, China
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
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9
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Tang Q, Lin J, Tsytsarev V, Erzurumlu RS, Liu Y, Chen Y. Review of mesoscopic optical tomography for depth-resolved imaging of hemodynamic changes and neural activities. NEUROPHOTONICS 2017; 4:011009. [PMID: 27990452 PMCID: PMC5108095 DOI: 10.1117/1.nph.4.1.011009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/19/2016] [Indexed: 05/18/2023]
Abstract
Understanding the functional wiring of neural circuits and their patterns of activation following sensory stimulations is a fundamental task in the field of neuroscience. Furthermore, charting the activity patterns is undoubtedly important to elucidate how neural networks operate in the living brain. However, optical imaging must overcome the effects of light scattering in the tissue, which limit the light penetration depth and affect both the imaging quantitation and sensitivity. Laminar optical tomography (LOT) is a three-dimensional (3-D) in-vivo optical imaging technique that can be used for functional imaging. LOT can achieve both a resolution of 100 to [Formula: see text] and a penetration depth of 2 to 3 mm based either on absorption or fluorescence contrast, as well as large field-of-view and high acquisition speed. These advantages make LOT suitable for 3-D depth-resolved functional imaging of the neural functions in the brain and spinal cords. We review the basic principles and instrumentations of representative LOT systems, followed by recent applications of LOT on 3-D imaging of neural activities in the rat forepaw stimulation model and mouse whisker-barrel system.
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Affiliation(s)
- Qinggong Tang
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Jonathan Lin
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Vassiliy Tsytsarev
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, 20 Penn Street, HSFII S251, Baltimore, Maryland 21201, United States
| | - Reha S. Erzurumlu
- University of Maryland School of Medicine, Department of Anatomy and Neurobiology, 20 Penn Street, HSFII S251, Baltimore, Maryland 21201, United States
| | - Yi Liu
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
| | - Yu Chen
- University of Maryland, Fischell Department of Bioengineering, 2334 Jeong H. Kim Engineering Building, College Park, Maryland 20742, United States
- Address all correspondence to: Yu Chen, E-mail:
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10
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Abstract
In this article, we review functional organization in sensory cortical regions—how the cortex represents the world. We consider four interrelated aspects of cortical organization: (1) the set of receptive fields of individual cortical sensory neurons, (2) how lateral interaction between cortical neurons reflects the similarity of their receptive fields, (3) the spatial distribution of receptive-field properties across the horizontal extent of the cortical tissue, and (4) how the spatial distributions of different receptive-field properties interact with one another. We show how these data are generally well explained by the theory of input-driven self-organization, with a family of computational models of cortical maps offering a parsimonious account for a wide range of map-related phenomena. We then discuss important challenges to this explanation, with respect to the maps present at birth, maps present under activity blockade, the limits of adult plasticity, and the lack of some maps in rodents. Because there is not at present another credible general theory for cortical map development, we conclude by proposing key experiments to help uncover other mechanisms that might also be operating during map development.
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Affiliation(s)
- James A. Bednar
- School of Informatics, University of Edinburgh, Edinburgh, UK
| | - Stuart P. Wilson
- Department of Psychology, University of Sheffield, Sheffield, UK
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11
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In Vivo Mesoscopic Voltage-Sensitive Dye Imaging of Brain Activation. Sci Rep 2016; 6:25269. [PMID: 27125318 PMCID: PMC4850485 DOI: 10.1038/srep25269] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/14/2016] [Indexed: 02/02/2023] Open
Abstract
Functional mapping of brain activity is important in elucidating how neural networks operate in the living brain. The whisker sensory system of rodents is an excellent model to study peripherally evoked neural activity in the central nervous system. Each facial whisker is represented by discrete modules of neurons all along the pathway leading to the neocortex. These modules are called "barrels" in layer 4 of the primary somatosensory cortex. Their location (approximately 300-500 μm below cortical surface) allows for convenient imaging of whisker-evoked neural activity in vivo. Fluorescence laminar optical tomography (FLOT) provides depth-resolved fluorescence molecular information with an imaging depth of a few millimeters. Angled illumination and detection configurations can improve both resolution and penetration depth. We applied angled FLOT (aFLOT) to record 3D neural activities evoked in the whisker system of mice by deflection of a single whisker in vivo. A 100 μm capillary and a pair of microelectrodes were inserted to the mouse brain to test the capability of the imaging system. The results show that it is possible to obtain 3D functional maps of the sensory periphery in the brain. This approach can be broadly applicable to functional imaging of other brain structures.
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12
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Tsytsarev V, Pumbo E, Tang Q, Chen CW, Kalchenko V, Chen Y. Study of the cortical representation of whisker frequency selectivity using voltage-sensitive dye optical imaging. INTRAVITAL 2016; 5:e1142637. [PMID: 28243518 DOI: 10.1080/21659087.2016.1142637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 12/17/2022]
Abstract
The facial whiskers of rodents act as a high-resolution tactile apparatus that allow the animal to detect the finest details of its environment. Previously it was shown that whisker-sensitive neurons in the somatosensory cortex show frequency selectivity to small amplitude stimuli, An intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation was used in order to visualize neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. Using the intravital voltage-sensitive dye optical imaging (VSDi) method in combination with the different frequency whisker stimulation we visualized neural activity in the mice somatosensory cortex in response to the stimulation of a single whisker by different frequencies. We found that whisker stimuli with different frequencies led to different optical signals in the barrel field. Our results provide evidence that different neurons of the barrel cortex have different frequency preferences. This supports prior research that whisker deflections cause responses in cortical neurons within the barrel field according to the frequency of the stimulation. Many studies of the whisker frequency selectivity were performed using unit recording but to map spatial organization, imaging methods are essential. In the work described in the present paper, we take a serious step toward detailed functional mapping of the somatosensory cortex using VSDi. To our knowledge, this is the first demonstration of whisker frequency sensitivity and selectivity of barrel cortex neurons with optical imaging methods.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine , Baltimore, MD, USA
| | - Elena Pumbo
- Center for Genetic Medicine, Children's National Medical Center , Washington, DC, USA
| | - Qinggong Tang
- Department of Bioengineering, University of Maryland , College Park, MD, USA
| | - Chao-Wei Chen
- Department of Bioengineering, University of Maryland , College Park, MD, USA
| | - Vyacheslav Kalchenko
- Department of Veterinary Resources, Weizmann Institute of Science , Rehovot, Israel
| | - Yu Chen
- Department of Bioengineering, University of Maryland , College Park, MD, USA
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13
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Tang Q, Tsytsarev V, Liang CP, Akkentli F, Erzurumlu RS, Chen Y. In Vivo Voltage-Sensitive Dye Imaging of Subcortical Brain Function. Sci Rep 2015; 5:17325. [PMID: 26612326 PMCID: PMC4661443 DOI: 10.1038/srep17325] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 10/28/2015] [Indexed: 12/29/2022] Open
Abstract
The whisker system of rodents is an excellent model to study peripherally evoked neural activity in the brain. Discrete neural modules represent each whisker in the somatosensory cortex (“barrels”), thalamus (“barreloids”), and brain stem (“barrelettes”). Stimulation of a single whisker evokes neural activity sequentially in its corresponding barrelette, barreloid, and barrel. Conventional optical imaging of functional activation in the brain is limited to surface structures such as the cerebral cortex. To access subcortical structures and image sensory-evoked neural activity, we designed a needle-based optical system using gradient-index (GRIN) rod lens. We performed voltage-sensitive dye imaging (VSDi) with GRIN rod lens to visualize neural activity evoked in the thalamic barreloids by deflection of whiskers in vivo. We stimulated several whiskers together to determine the sensitivity of our approach in differentiating between different barreloid responses. We also carried out stimulation of different whiskers at different times. Finally, we used muscimol in the barrel cortex to silence the corticothalamic inputs while imaging in the thalamus. Our results show that it is possible to obtain functional maps of the sensory periphery in deep brain structures such as the thalamic barreloids. Our approach can be broadly applicable to functional imaging of other core brain structures.
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Affiliation(s)
- Qinggong Tang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
| | - Vassiliy Tsytsarev
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA.,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Chia-Pin Liang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
| | - Fatih Akkentli
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201 USA
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742 USA
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Perronnet L, Vilarchao ME, Hucher G, Shulz DE, Peyré G, Ferezou I. An automated workflow for the anatomo-functional mapping of the barrel cortex. J Neurosci Methods 2015; 263:145-54. [PMID: 26384542 DOI: 10.1016/j.jneumeth.2015.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 09/04/2015] [Accepted: 09/07/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND The rodent barrel cortex is a widely used model to study the cortical processing of tactile sensory information. It is notable by the cytoarchitecture of its layer IV, which contains distinguishable structural units called barrels that can be considered as anatomical landmarks of the functional columnar organization of the cerebral cortex. To study sensory integration in the barrel cortex it is therefore essential to map recorded functional data onto the underlying barrel topography, which can be reconstructed from the post hoc alignment of tangential brain slices stained for cytochrome oxidase. NEW METHOD This article presents an automated workflow to perform the registration of histological slices of the barrel cortex followed by the 2-D reconstruction of the barrel map from the registered slices. The registration of two successive slices is obtained by computing a rigid transformation to align sets of detected blood vessel cross-sections. This is achieved by using a robust variant of the classical iterative closest point method. A single fused image of the barrel field is then generated by computing a nonlinear merging of the gradients from the registered images. COMPARISON WITH EXISTING METHODS This novel anatomo-functional mapping tool leads to a substantial gain in time and precision compared to conventional manual methods. It provides a flexible interface for the user with only a few parameters to tune. CONCLUSIONS We demonstrate here the usefulness of the method for voltage sensitive dye imaging of the mouse barrel cortex. The method could also benefit other experimental approaches and model species.
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Affiliation(s)
- Lorraine Perronnet
- CNRS and Ceremade, Université Paris-Dauphine, Place du Maréchal De Lattre De Tassigny, 75775, Paris Cedex 16, France; Unité de Neurosciences, Information et Complexité, CNRS FRE 3693, 91198 Gif-sur-Yvette Cedex, France
| | - María Eugenia Vilarchao
- Unité de Neurosciences, Information et Complexité, CNRS FRE 3693, 91198 Gif-sur-Yvette Cedex, France
| | - Guillaume Hucher
- Unité de Neurosciences, Information et Complexité, CNRS FRE 3693, 91198 Gif-sur-Yvette Cedex, France
| | - Daniel E Shulz
- Unité de Neurosciences, Information et Complexité, CNRS FRE 3693, 91198 Gif-sur-Yvette Cedex, France
| | - Gabriel Peyré
- CNRS and Ceremade, Université Paris-Dauphine, Place du Maréchal De Lattre De Tassigny, 75775, Paris Cedex 16, France
| | - Isabelle Ferezou
- Unité de Neurosciences, Information et Complexité, CNRS FRE 3693, 91198 Gif-sur-Yvette Cedex, France.
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15
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Mayrhofer JM, Haiss F, Helmchen F, Weber B. Sparse, reliable, and long-term stable representation of periodic whisker deflections in the mouse barrel cortex. Neuroimage 2015; 115:52-63. [PMID: 25934471 DOI: 10.1016/j.neuroimage.2015.04.045] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/24/2015] [Accepted: 04/21/2015] [Indexed: 12/24/2022] Open
Abstract
The rodent whisker system is a preferred model for studying plasticity in the somatosensory cortex (barrel cortex). Contrarily, only a small amount of research has been conducted to characterize the stability of neuronal population activity in the barrel cortex. We used the mouse whisker system to address the neuronal basis of stable perception in the somatosensory cortex. Cortical representation of periodic whisker deflections was studied in populations of neurons in supragranular layers over extended time periods (up to 3 months) with long-term two-photon Ca(2+) imaging in anesthetized mice. We found that in most of the neurons (87%), Ca(2+) responses increased sublinearly with increasing number of contralateral whisker deflections. The imaged population of neurons was activated in a stereotypic way over days and for different deflection rates (pulse frequencies). Thus, pulse frequencies are coded by response strength rather than by distinct neuronal sub-populations. A small population of highly responsive neurons (~3%) was sufficient to decode the whisker stimulus. This conserved functional map, led by a small set of highly responsive neurons, might form the foundation of stable sensory percepts.
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Affiliation(s)
- Johannes M Mayrhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, CH-8057 Zurich, Switzerland.
| | - Florent Haiss
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland; IZKF Aachen, Medical Faculty of the RWTH Aachen University, D-52062 Aachen, Germany; Institute for Neuropathology, RWTH Aachen University, D-52062 Aachen, Germany; Department of Ophthalmology, RWTH Aachen University, D-52062 Aachen, Germany
| | - Fritjof Helmchen
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
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16
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Thalamic NMDA receptor function is necessary for patterning of the thalamocortical somatosensory map and for sensorimotor behaviors. J Neurosci 2014; 34:12001-14. [PMID: 25186746 DOI: 10.1523/jneurosci.1663-14.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NMDARs play a major role in patterning of topographic sensory maps in the brain. Genetic knock-out of the essential subunit of NMDARs in excitatory cortical neurons prevents whisker-specific neural pattern formation in the barrel cortex. To determine the role of NMDARs en route to the cortex, we generated sensory thalamus-specific NR1 (Grin1)-null mice (ThNR1KO). A multipronged approach, using histology, electrophysiology, optical imaging, and behavioral testing revealed that, in these mice, whisker patterns develop in the trigeminal brainstem but do not develop in the somatosensory thalamus. Subsequently, there is no barrel formation in the neocortex yet a partial afferent patterning develops. Whisker stimulation evokes weak cortical activity and presynaptic neurotransmitter release probability is also affected. We found several behavioral deficits in tasks, ranging from sensorimotor to social and cognitive. Collectively, these results show that thalamic NMDARs play a critical role in the patterning of the somatosensory thalamic and cortical maps and their impairment may lead to pronounced behavioral defects.
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17
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Lo FS, Akkentli F, Tsytsarev V, Erzurumlu RS. Functional significance of cortical NMDA receptors in somatosensory information processing. J Neurophysiol 2013; 110:2627-36. [PMID: 24047907 DOI: 10.1152/jn.00052.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-methyl-d-aspartate receptor (NMDAR)-mediated activity is required for whisker-related neural patterning in the rodent brain. Deletion of the essential NMDAR subunit NR1 gene in excitatory cortical neurons prevents whisker-specific barrel formation and impairs thalamocortical afferent patterning. We used electrophysiological and voltage-sensitive dye imaging methods to assess synaptic and sensory evoked cortical activity and immunohistochemistry to examine immediate early gene expression following whisker stimulation in cortex-specific NR1 knockout (CxNR1KO) mice. In mutant mice, layer IV neurons lacked NMDAR-mediated excitatory postsynaptic currents, and temporal summation of excitatory postsynaptic potentials (EPSPs) was impaired. Barrel neurons showed both phasic and tonic responses to whisker deflection. The averaged tonic response in CxNR1KO mice was significantly less than that in control mice due to impaired EPSP temporal summation. Electrophysiological estimation of the number of thalamic neurons innervating single barrel neurons indicated a significant increase in CxNR1KO mice. Similarly, voltage-sensitive dye optical signals in response to whisker stimulation were widespread. Immediate early gene expression following whisker stimulation also showed a diffuse expression pattern in the CxNR1KO cortex compared with whisker-specific expression patterns in controls. Thus, when NMDAR function is impaired, spatial discrimination of whisker inputs is severely compromised, and sensory stimulation evokes diffuse, topographically misaligned activity in the barrel cortex.
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Affiliation(s)
- Fu-Sun Lo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland
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18
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Liao LD, Tsytsarev V, Delgado-Martínez I, Li ML, Erzurumlu R, Vipin A, Orellana J, Lin YR, Lai HY, Chen YY, Thakor NV. Neurovascular coupling: in vivo optical techniques for functional brain imaging. Biomed Eng Online 2013; 12:38. [PMID: 23631798 PMCID: PMC3655834 DOI: 10.1186/1475-925x-12-38] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/25/2013] [Indexed: 01/21/2023] Open
Abstract
Optical imaging techniques reflect different biochemical processes in the brain, which is closely related with neural activity. Scientists and clinicians employ a variety of optical imaging technologies to visualize and study the relationship between neurons, glial cells and blood vessels. In this paper, we present an overview of the current optical approaches used for the in vivo imaging of neurovascular coupling events in small animal models. These techniques include 2-photon microscopy, laser speckle contrast imaging (LSCI), voltage-sensitive dye imaging (VSDi), functional photoacoustic microscopy (fPAM), functional near-infrared spectroscopy imaging (fNIRS) and multimodal imaging techniques. The basic principles of each technique are described in detail, followed by examples of current applications from cutting-edge studies of cerebral neurovascular coupling functions and metabolic. Moreover, we provide a glimpse of the possible ways in which these techniques might be translated to human studies for clinical investigations of pathophysiology and disease. In vivo optical imaging techniques continue to expand and evolve, allowing us to discover fundamental basis of neurovascular coupling roles in cerebral physiology and pathophysiology.
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Affiliation(s)
- Lun-De Liao
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ignacio Delgado-Martínez
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Meng-Lin Li
- Department of Electrical Engineering, National Tsing Hua University, No. 101, Sec. 2, Kuang-Fu Rd, Hsinchu 300, R.O.C, Taiwan
| | - Reha Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn street, HSF-2, Baltimore, MD 21201, USA
| | - Ashwati Vipin
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Josue Orellana
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
| | - Yan-Ren Lin
- Department of Emergency Medicine, Changhua Christian Hospital, 135 Nanshsiao Street, Changhua 500, R.O.C, Taiwan
| | - Hsin-Yi Lai
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan 333, R.O.C, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, No.155, Sec.2, Linong St, Taipei 112, R.O.C, Taiwan
| | - Nitish V Thakor
- Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, 28 Medical Drive, #05-COR, Singapore 117456, Singapore
- Department of Biomedical Engineering, Johns Hopkins University, Traylor 701/720 Rutland Ave, Baltimore, MD 21205, USA
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19
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Tsytsarev V, Arakawa H, Borisov S, Pumbo E, Erzurumlu RS, Papkovsky DB. In vivo imaging of brain metabolism activity using a phosphorescent oxygen-sensitive probe. J Neurosci Methods 2013; 216:146-51. [PMID: 23624034 DOI: 10.1016/j.jneumeth.2013.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 12/12/2022]
Abstract
Several approaches have been adopted for real-time imaging of neural activity in vivo. We tested a new cell-penetrating phosphorescent oxygen-sensitive probe, NanO2-IR, to monitor temporal and spatial dynamics of oxygen metabolism in the neocortex following peripheral sensory stimulation. Probe solution was applied to the surface of anesthetized mouse brain; optical imaging was performed using a MiCAM-02 system. Trains of whisker stimuli were delivered and associated changes in phosphorescent signal were recorded in the contralateral somatosensory ("barrel") cortex. Sensory stimulation led to changes in oxygenation of activated areas of the barrel cortex. The oxygen imaging results were compared to those produced by the voltage-sensitive dye RH-1691. While the signals emitted by the two probes differed in shape and amplitude, they both faithfully indicated specific whisker evoked cortical activity. Thus, NanO2-IR probe can be used as a tool in visualization and real-time analysis of sensory-evoked neural activity in vivo.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II, 20 Penn Street, Baltimore, MD 21201-1075, USA.
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20
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Tsytsarev V, Rao B, Maslov KI, Li L, Wang LV. Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts. J Neurosci Methods 2013; 216:142-5. [PMID: 23603664 DOI: 10.1016/j.jneumeth.2013.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/01/2013] [Accepted: 04/04/2013] [Indexed: 01/26/2023]
Abstract
Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic changes of the microvasculature surrounding the epileptic neurons. The epilepsy mapping results were confirmed by a simultaneously recorded electroencephalogram signal during epileptic seizure. Our new epilepsy mapping tool, with high temporal and spatial resolution and dual optical contrasts, may find many applications, such as drug development and epilepsy surgery.
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Affiliation(s)
- Vassiliy Tsytsarev
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA
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21
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Lustig BR, Friedman RM, Winberry JE, Ebner FF, Roe AW. Voltage-sensitive dye imaging reveals shifting spatiotemporal spread of whisker-induced activity in rat barrel cortex. J Neurophysiol 2013; 109:2382-92. [PMID: 23390314 DOI: 10.1152/jn.00430.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In rats, navigating through an environment requires continuous information about objects near the head. Sensory information such as object location and surface texture are encoded by spike firing patterns of single neurons within rat barrel cortex. Although there are many studies using single-unit electrophysiology, much less is known regarding the spatiotemporal pattern of activity of populations of neurons in barrel cortex in response to whisker stimulation. To examine cortical response at the population level, we used voltage-sensitive dye (VSD) imaging to examine ensemble spatiotemporal dynamics of barrel cortex in response to stimulation of single or two adjacent whiskers in urethane-anesthetized rats. Single whisker stimulation produced a poststimulus fluorescence response peak within 12-16 ms in the barrel corresponding to the stimulated whisker (principal whisker). This fluorescence subsequently propagated throughout the barrel field, spreading anisotropically preferentially along a barrel row. After paired whisker stimulation, the VSD signal showed sublinear summation (less than the sum of 2 single whisker stimulations), consistent with previous electrophysiological and imaging studies. Surprisingly, we observed a spatial shift in the center of activation occurring over a 10- to 20-ms period with shift magnitudes of 1-2 barrels. This shift occurred predominantly in the posteromedial direction within the barrel field. Our data thus reveal previously unreported spatiotemporal patterns of barrel cortex activation. We suggest that this nontopographical shift is consistent with known functional and anatomic asymmetries in barrel cortex and that it may provide an important insight for understanding barrel field activation during whisking behavior.
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Affiliation(s)
- Brian R Lustig
- Department of Psychology, Vanderbilt University, Nashville, TN 37203, USA
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22
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Tsytsarev V, Bernardelli C, Maslov KI. Living Brain Optical Imaging: Technology, Methods and Applications. ACTA ACUST UNITED AC 2012; 1:180-192. [PMID: 28251038 DOI: 10.1166/jnsne.2012.1020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within the last few decades, optical imaging methods have yielded revolutionary results when applied to all parts of the central nervous system. The purpose of this review is to analyze research possibilities and limitations of several novel imaging techniques and show some of the most interesting achievements obtained by these methods. Here we covered intrinsic optical imaging, voltage-sensitive dye, photoacoustic, optical coherence tomography, near-infrared spectroscopy and some other techniques. All of them are mainly applicable for experimental neuroscience but some of them also suitable for the clinical studies.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II Room S251, 20 Penn Street, Baltimore, MD 21201-1075, USA
| | - Chad Bernardelli
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, HSF II Room S251, 20 Penn Street, Baltimore, MD 21201-1075, USA
| | - Konstantin I Maslov
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, USA
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23
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Imaging the spatio-temporal dynamics of supragranular activity in the rat somatosensory cortex in response to stimulation of the paws. PLoS One 2012; 7:e40174. [PMID: 22829873 PMCID: PMC3400596 DOI: 10.1371/journal.pone.0040174] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 06/03/2012] [Indexed: 11/25/2022] Open
Abstract
We employed voltage-sensitive dye (VSD) imaging to investigate the spatio-temporal dynamics of the responses of the supragranular somatosensory cortex to stimulation of the four paws in urethane-anesthetized rats. We obtained the following main results. (1) Stimulation of the contralateral forepaw evoked VSD responses with greater amplitude and smaller latency than stimulation of the contralateral hindpaw, and ipsilateral VSD responses had a lower amplitude and greater latency than contralateral responses. (2) While the contralateral stimulation initially activated only one focus, the ipsilateral stimulation initially activated two foci: one focus was typically medial to the focus activated by contralateral stimulation and was stereotaxically localized in the motor cortex; the other focus was typically posterior to the focus activated by contralateral stimulation and was stereotaxically localized in the somatosensory cortex. (3) Forepaw and hindpaw somatosensory stimuli activated large areas of the sensorimotor cortex, well beyond the forepaw and hindpaw somatosensory areas of classical somatotopic maps, and forepaw stimuli activated larger cortical areas with greater activation velocity than hindpaw stimuli. (4) Stimulation of the forepaw and hindpaw evoked different cortical activation dynamics: forepaw responses displayed a clear medial directionality, whereas hindpaw responses were much more uniform in all directions. In conclusion, this work offers a complete spatio-temporal map of the supragranular VSD cortical activation in response to stimulation of the paws, showing important somatotopic differences between contralateral and ipsilateral maps as well as differences in the spatio-temporal activation dynamics in response to forepaw and hindpaw stimuli.
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24
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Tsytsarev V, Maslov KI, Yao J, Parameswar AR, Demchenko AV, Wang LV. In vivo imaging of epileptic activity using 2-NBDG, a fluorescent deoxyglucose analog. J Neurosci Methods 2011; 203:136-40. [PMID: 21939688 DOI: 10.1016/j.jneumeth.2011.09.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 11/15/2022]
Abstract
Accurately locating epileptic foci has great importance in advancing the treatment of epilepsy. In this study, epileptic seizures were first induced by intracortical injection of 4-aminopyridine in rats. A fluorescent deoxyglucose substitute, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), was then continuously injected via the tail vein. Brain glucose metabolism was subsequently monitored by fluorescence imaging of 2-NBDG. The initial uptake rate of 2-NBDG at the injection site of 4-aminopyridine significantly exceeded that of the control injection site, which indicated local hypermetabolism induced by seizures. Our results show that 2-NBDG can be used for localizing epileptic foci.
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Affiliation(s)
- Vassiliy Tsytsarev
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130, USA.
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25
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Kannurpatti SS, Biswal BB. Frequency tuning in the rat whisker barrel cortex revealed through RBC flux maps. Brain Res 2011; 1417:16-26. [PMID: 21911212 DOI: 10.1016/j.brainres.2011.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 07/29/2011] [Accepted: 08/10/2011] [Indexed: 11/25/2022]
Abstract
The rodent whisker barrel cortex is ideal for studies related to sensory processing and neural plasticity in the brain. However, its small spatial dimensions challenge optical and other imaging technologies mapping cortical hemodynamics as functional resolution (the ability to spatially and selectively discriminate signals from microvascular compartments) limit measurement accuracy. To precisely map hemodynamic activity within the rat posteriomedial barrel subfield (PMBSF), we used functional Laser Doppler Imaging (fLDI) at high spatial resolution with optimized detection and analysis. In this configuration, we demonstrate prominent whisker deflection-induced fLDI hemodynamic responses from microvascular regions indicating the technique's specificity to smaller vessel compartments. Clusters of fLDI activation were confined within the PMBSF region during deflection of either single or all whiskers. Stereotaxic co-ordinate mapping was performed over all animals leading to an average maximum activity cluster at +5.3, -3.5 from the Bregma. The maximum activity cluster during all whisker stimulation combined with the principal activation cluster during deflection of the C1 whisker were used as a reference to characterize the fLDI maps within the PMBSF. fLDI activation area increased with the frequency of whisker deflection. In a quantitative analysis, we reveal the increase in the spatial extent of fLDI activation with stimulation frequency as spatially non-uniform with a bias towards the caudal region for low and rostral region for higher stimulation frequencies.
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26
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Farfán FD, Albarracín AL, Felice CJ. Electrophysiological characterization of texture information slip-resistance dependent in the rat vibrissal nerve. BMC Neurosci 2011; 12:32. [PMID: 21496307 PMCID: PMC3098809 DOI: 10.1186/1471-2202-12-32] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 04/16/2011] [Indexed: 11/10/2022] Open
Abstract
Background Studies in tactile discrimination agree that rats are able to learn a rough-smooth discrimination task by actively touching (whisking) objects with their vibrissae. In particular, we focus on recent evidence of how neurons at different levels of the sensory pathway carry information about tactile stimuli. Here, we analyzed the multifiber afferent discharge of one vibrissal nerve during active whisking. Vibrissae movements were induced by electrical stimulation of motor branches of the facial nerve. We used sandpapers of different grain size as roughness discrimination surfaces and we also consider the change of vibrissal slip-resistance as a way to improve tactile information acquisition. The amplitude of afferent activity was analyzed according to its Root Mean Square value (RMS). The comparisons among experimental situation were quantified by using the information theory. Results We found that the change of the vibrissal slip-resistance is a way to improve the roughness discrimination of surfaces. As roughness increased, the RMS values also increased in almost all cases. In addition, we observed a better discrimination performance in the retraction phase (maximum amount of information). Conclusions The evidence of amplitude changes due to roughness surfaces and slip-resistance levels allows to speculate that texture information is slip-resistance dependent at peripheral level.
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Affiliation(s)
- Fernando D Farfán
- Laboratorio de Medios e Interfases, Departamento de Bioingeniería, Universidad Nacional de Tucumán & Consejo Superior de Investigaciones Científicas y Técnicas, Tucumán, Argentina.
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