FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W3093146038> ?p ?o ?g. }

• W3093146038 endingPage "43" @default.
• W3093146038 startingPage "33" @default.
• W3093146038 abstract "Optical imaging has revolutionized our ability to monitor brain activity, spanning spatial scales from synapses to cells to circuits. Here, we summarize the rapid development and application of mesoscopic imaging, a widefield fluorescence-based approach that balances high spatiotemporal resolution with extraordinarily large fields of view. By leveraging the continued expansion of fluorescent reporters for neuronal activity and novel strategies for indicator expression, mesoscopic analysis enables measurement and correlation of network dynamics with behavioral state and task performance. Moreover, the combination of widefield imaging with cellular resolution methods such as two-photon microscopy and electrophysiology is bridging boundaries between cellular and network analyses. Overall, mesoscopic imaging provides a powerful option in the optical toolbox for investigation of brain function. Optical imaging has revolutionized our ability to monitor brain activity, spanning spatial scales from synapses to cells to circuits. Here, we summarize the rapid development and application of mesoscopic imaging, a widefield fluorescence-based approach that balances high spatiotemporal resolution with extraordinarily large fields of view. By leveraging the continued expansion of fluorescent reporters for neuronal activity and novel strategies for indicator expression, mesoscopic analysis enables measurement and correlation of network dynamics with behavioral state and task performance. Moreover, the combination of widefield imaging with cellular resolution methods such as two-photon microscopy and electrophysiology is bridging boundaries between cellular and network analyses. Overall, mesoscopic imaging provides a powerful option in the optical toolbox for investigation of brain function. The use of various imaging modalities to monitor the electrical activity of neurons has provided essential insights into the workings of the nervous system. Early studies made use of autoradiography to map neuronal signaling indirectly by reading out metabolic activity (Thompson et al., 1983Thompson I.D. Kossut M. Blakemore C. Development of orientation columns in cat striate cortex revealed by 2-deoxyglucose autoradiography.Nature. 1983; 301: 712-715Crossref PubMed Google Scholar; Tootell et al., 1988Tootell R.B.H. Silverman M.S. Hamilton S.L. Switkes E. De Valois R.L. Functional anatomy of macaque striate cortex. V. Spatial frequency.J. Neurosci. 1988; 8: 1610-1624Crossref PubMed Google Scholar). Activity-dependent changes in blood flow provide the basis for both intrinsic signal imaging and functional magnetic resonance imaging (Grinvald et al., 1986Grinvald A. Lieke E. Frostig R.D. Gilbert C.D. Wiesel T.N. Functional architecture of cortex revealed by optical imaging of intrinsic signals.Nature. 1986; 324: 361-364Crossref PubMed Scopus (921) Google Scholar; Logothetis et al., 2001Logothetis N.K. Pauls J. Augath M. Trinath T. Oeltermann A. Neurophysiological investigation of the basis of the fMRI signal.Nature. 2001; 412: 150-157Crossref PubMed Scopus (4304) Google Scholar), techniques that have broadly shaped our understanding of brain function. More recently, the development of molecular probes that couple neuronal signals to fluorescence have revolutionized neuroscience, contributing to discoveries at the cellular and network levels (Lin and Schnitzer, 2016Lin M.Z. Schnitzer M.J. Genetically encoded indicators of neuronal activity.Nat. Neurosci. 2016; 19: 1142-1153Crossref PubMed Scopus (264) Google Scholar). Indeed, the impressive breadth of spatial and temporal scales over which neuronal activity is generated and organized remains an ongoing challenge to current research efforts. Single cells integrate thousands of synaptic inputs and are, in turn, connected into local microcircuits. These circuits are further organized into dynamic networks that may conceptually span the entire nervous system. In the mammalian neocortex, such large-scale networks are thought to provide the basis for cognition and complex behavior (Damoiseaux et al., 2006Damoiseaux J.S. Rombouts S.A. Barkhof F. Scheltens P. Stam C.J. Smith S.M. Beckmann C.F. Consistent resting-state networks across healthy subjects.Proc. Natl. Acad. Sci. USA. 2006; 103: 13848-13853Crossref PubMed Scopus (2906) Google Scholar; Rubinov and Sporns, 2010Rubinov M. Sporns O. Complex network measures of brain connectivity: uses and interpretations.Neuroimage. 2010; 52: 1059-1069Crossref PubMed Scopus (5278) Google Scholar; Stafford et al., 2014Stafford J.M. Jarrett B.R. Miranda-Dominguez O. Mills B.D. Cain N. Mihalas S. Lahvis G.P. Lattal K.M. Mitchell S.H. David S.V. et al.Large-scale topology and the default mode network in the mouse connectome.Proc. Natl. Acad. Sci. USA. 2014; 111: 18745-18750Crossref PubMed Scopus (119) Google Scholar). A number of imaging strategies have emerged in recent decades for investigating distinct niches of spatiotemporal dynamics. However, there are limited methodologies that can provide high spatial and temporal resolution combined with the extremely large field of view necessary for answering questions about network function. In this Primer, we provide an overview of mesoscopic fluorescence imaging, a rapidly developing approach that directly addresses this challenge. We define mesoscopic imaging as a widefield, single-photon, fluorescence-based modality that can monitor activity across multiple millimeters of tissue at video frame rate. This approach enables recording from the entire dorsal neocortex in awake, behaving rodents. Here, we will summarize some of the central methods, highlight advantages and limitations, and discuss some recent biological discoveries that have emerged through this imaging modality. Recent groundbreaking work from many laboratories has developed a number of distinct genetically encoded fluorescent indicators capable of reporting intracellular calcium (Ca2+) (Chen et al., 2013Chen T.W. Wardill T.J. Sun Y. Pulver S.R. Renninger S.L. Baohan A. Schreiter E.R. Kerr R.A. Orger M.B. Jayaraman V. et al.Ultrasensitive fluorescent proteins for imaging neuronal activity.Nature. 2013; 499: 295-300Crossref PubMed Scopus (2675) Google Scholar; Dana et al., 2016Dana H. Mohar B. Sun Y. Narayan S. Gordus A. Hasseman J.P. Tsegaye G. Holt G.T. Hu A. Walpita D. et al.Sensitive red protein calcium indicators for imaging neural activity.eLife. 2016; 5: 5Crossref Scopus (347) Google Scholar), transmembrane voltage (Hochbaum et al., 2014Hochbaum D.R. Zhao Y. Farhi S.L. Klapoetke N. Werley C.A. Kapoor V. Zou P. Kralj J.M. Maclaurin D. Smedemark-Margulies N. et al.All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins.Nat. Methods. 2014; 11: 825-833Crossref PubMed Google Scholar; Villette et al., 2019Villette V. Chavarha M. Dimov I.K. Bradley J. Pradhan L. Mathieu B. Evans S.W. Chamberland S. Shi D. Yang R. et al.Ultrafast Two-Photon Imaging of a High-Gain Voltage Indicator in Awake Behaving Mice.Cell. 2019; 179: 1590-1608.e23Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar), and extracellular transmitter molecules including glutamate, acetylcholine, and norepinephrine (Feng et al., 2019Feng J. Zhang C. Lischinsky J.E. Jing M. Zhou J. Wang H. Zhang Y. Dong A. Wu Z. Wu H. et al.A Genetically Encoded Fluorescent Sensor for Rapid and Specific In Vivo Detection of Norepinephrine.Neuron. 2019; 102: 745-761.e8Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar; Jing et al., 2018Jing M. Zhang P. Wang G. Feng J. Mesik L. Zeng J. Jiang H. Wang S. Looby J.C. Guagliardo N.A. et al.A genetically encoded fluorescent acetylcholine indicator for in vitro and in vivo studies.Nat. Biotechnol. 2018; 36: 726-737Crossref PubMed Scopus (108) Google Scholar; Marvin et al., 2018Marvin J.S. Scholl B. Wilson D.E. Podgorski K. Kazemipour A. Müller J.A. Schoch S. Quiroz F.J.U. Rebola N. Bao H. et al.Stability, affinity, and chromatic variants of the glutamate sensor iGluSnFR.Nat. Methods. 2018; 15: 936-939Crossref PubMed Scopus (86) Google Scholar). Most of these probes are fully compatible with widefield microscopy and will undoubtedly provide critical new insight into nervous system function. However, for the present Primer on mesoscopic imaging, we will primarily focus on fluorescent Ca2+ sensors as the most common exemplar of this growing field. Fluorescence refers to the emission of photons by molecules that have previously absorbed light, typically of shorter wavelength. Excitation and emission spectra are highly dependent on the chemical properties of the individual fluorophore, a feature widely exploited in the development of fluorescent reporters for neuronal activity (Chen et al., 2013Chen T.W. Wardill T.J. Sun Y. Pulver S.R. Renninger S.L. Baohan A. Schreiter E.R. Kerr R.A. Orger M.B. Jayaraman V. et al.Ultrasensitive fluorescent proteins for imaging neuronal activity.Nature. 2013; 499: 295-300Crossref PubMed Scopus (2675) Google Scholar; Hochbaum et al., 2014Hochbaum D.R. Zhao Y. Farhi S.L. Klapoetke N. Werley C.A. Kapoor V. Zou P. Kralj J.M. Maclaurin D. Smedemark-Margulies N. et al.All-optical electrophysiology in mammalian neurons using engineered microbial rhodopsins.Nat. Methods. 2014; 11: 825-833Crossref PubMed Google Scholar; Jin et al., 2012Jin L. Han Z. Platisa J. Wooltorton J.R. Cohen L.B. Pieribone V.A. Single action potentials and subthreshold electrical events imaged in neurons with a fluorescent protein voltage probe.Neuron. 2012; 75: 779-785Abstract Full Text Full Text PDF PubMed Scopus (289) Google Scholar; Lin and Schnitzer, 2016Lin M.Z. Schnitzer M.J. Genetically encoded indicators of neuronal activity.Nat. Neurosci. 2016; 19: 1142-1153Crossref PubMed Scopus (264) Google Scholar). In general, such indicators shift their sensitivity or spectral range as a function of their atomic conformation. For example, membrane-tethered sensors that undergo conformational shifts in response to changes in local electric fields can provide a readout of transmembrane voltage. Many of the earliest studies using widefield imaging to monitor cortical function in vivo made use of voltage indicators, revealing spontaneous and sensory-evoked patterns of activity that spread over large regions (Ferezou et al., 2006Ferezou I. Bolea S. Petersen C.C.H. Visualizing the cortical representation of whisker touch: voltage-sensitive dye imaging in freely moving mice.Neuron. 2006; 50: 617-629Abstract Full Text Full Text PDF PubMed Scopus (332) Google Scholar, Ferezou et al., 2007Ferezou I. Haiss F. Gentet L.J. Aronoff R. Weber B. Petersen C.C.H. Spatiotemporal dynamics of cortical sensorimotor integration in behaving mice.Neuron. 2007; 56: 907-923Abstract Full Text Full Text PDF PubMed Scopus (422) Google Scholar; Mohajerani et al., 2010Mohajerani M.H. McVea D.A. Fingas M. Murphy T.H. Mirrored bilateral slow-wave cortical activity within local circuits revealed by fast bihemispheric voltage-sensitive dye imaging in anesthetized and awake mice.J. Neurosci. 2010; 30: 3745-3751Crossref PubMed Scopus (170) Google Scholar). Complementary to voltage sensing, a variety of engineered molecules shift their fluorescent properties upon binding ionic Ca2+. As neuronal depolarization can drive the opening of voltage-gated Ca2+ channels, the large signal-to-noise afforded by many Ca2+ indicators has made them a critical, albeit indirect, sensor of activity at the cellular and network scale (Chen et al., 2013Chen T.W. Wardill T.J. Sun Y. Pulver S.R. Renninger S.L. Baohan A. Schreiter E.R. Kerr R.A. Orger M.B. Jayaraman V. et al.Ultrasensitive fluorescent proteins for imaging neuronal activity.Nature. 2013; 499: 295-300Crossref PubMed Scopus (2675) Google Scholar; Higley and Sabatini, 2008Higley M.J. Sabatini B.L. Calcium signaling in dendrites and spines: practical and functional considerations.Neuron. 2008; 59: 902-913Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar). Given the key role of Ca2+ indicators in many recent studies using mesoscopic imaging, we will discuss this class of probes in greater detail. Indicators for intracellular Ca2+ are generally developed from either synthetic buffers (e.g., BAPTA) or calcium-binding proteins (e.g., calmodulin) that are covalently bonded to a suitable fluorophore (Brain and Bennett, 1997Brain K.L. Bennett M.R. Calcium in sympathetic varicosities of mouse vas deferens during facilitation, augmentation and autoinhibition.J. Physiol. 1997; 502: 521-536Crossref PubMed Scopus (0) Google Scholar; Nakai et al., 2001Nakai J. Ohkura M. Imoto K. A high signal-to-noise Ca(2+) probe composed of a single green fluorescent protein.Nat. Biotechnol. 2001; 19: 137-141Crossref PubMed Scopus (922) Google Scholar; Tsien et al., 1996Tsien J.Z. Chen D.F. Gerber D. Tom C. Mercer E.H. Anderson D.J. Mayford M. Kandel E.R. Tonegawa S. Subregion- and cell type-restricted gene knockout in mouse brain.Cell. 1996; 87: 1317-1326Abstract Full Text Full Text PDF PubMed Scopus (874) Google Scholar). For example, the widely used genetically encoded Ca2+ indicator (GECI) GCaMP is a fusion protein comprising calmodulin, the M13 myosin light-chain kinase sequence, and circularly permuted GFP (Chen et al., 2013Chen T.W. Wardill T.J. Sun Y. Pulver S.R. Renninger S.L. Baohan A. Schreiter E.R. Kerr R.A. Orger M.B. Jayaraman V. et al.Ultrasensitive fluorescent proteins for imaging neuronal activity.Nature. 2013; 499: 295-300Crossref PubMed Scopus (2675) Google Scholar; Nakai et al., 2001Nakai J. Ohkura M. Imoto K. A high signal-to-noise Ca(2+) probe composed of a single green fluorescent protein.Nat. Biotechnol. 2001; 19: 137-141Crossref PubMed Scopus (922) Google Scholar; Tian et al., 2009Tian L. Hires S.A. Mao T. Huber D. Chiappe M.E. Chalasani S.H. Petreanu L. Akerboom J. McKinney S.A. Schreiter E.R. et al.Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators.Nat. Methods. 2009; 6: 875-881Crossref PubMed Scopus (1284) Google Scholar). GCaMP increases its excitation efficiency upon Ca2+ binding, resulting in increased green fluorescence during neuronal activity. Recent versions, including GCaMP6 and GCaMP7, provide incredibly bright, faithful reporting of intracellular Ca2+, and specific variants exist that are “tuned” for variations in affinity, signal to noise, and decay kinetics (Chen et al., 2013Chen T.W. Wardill T.J. Sun Y. Pulver S.R. Renninger S.L. Baohan A. Schreiter E.R. Kerr R.A. Orger M.B. Jayaraman V. et al.Ultrasensitive fluorescent proteins for imaging neuronal activity.Nature. 2013; 499: 295-300Crossref PubMed Scopus (2675) Google Scholar; Dana et al., 2019Dana H. Sun Y. Mohar B. Hulse B.K. Kerlin A.M. Hasseman J.P. Tsegaye G. Tsang A. Wong A. Patel R. et al.High-performance calcium sensors for imaging activity in neuronal populations and microcompartments.Nat. Methods. 2019; 16: 649-657Crossref PubMed Scopus (141) Google Scholar). In addition, the emergence of red-shifted GECIs has expanded the chromatic palette and enabled simultaneous imaging of multiple cell types expressing different indicators (Dana et al., 2016Dana H. Mohar B. Sun Y. Narayan S. Gordus A. Hasseman J.P. Tsegaye G. Holt G.T. Hu A. Walpita D. et al.Sensitive red protein calcium indicators for imaging neural activity.eLife. 2016; 5: 5Crossref Scopus (347) Google Scholar). Nevertheless, there are some caveats associated with the application of Ca2+ sensors. Most notably, as buffers, these indicators sequester intracellular Ca2+ and prevent its interaction with endogenous partners. This buffering reduces peak Ca2+ concentration, prolongs temporal decay, and expands diffusional spread in response to transient activity (Higley and Sabatini, 2008Higley M.J. Sabatini B.L. Calcium signaling in dendrites and spines: practical and functional considerations.Neuron. 2008; 59: 902-913Abstract Full Text Full Text PDF PubMed Scopus (134) Google Scholar). The potential consequences of these actions for cellular health and function will likely vary with indicator affinity, concentration, and cell type and must be considered when interpreting imaging data. For example, some (but not all) transgenic mouse lines expressing GCaMP6 are reported to exhibit aberrant cortical electrophysiology, including epileptiform activity (Daigle et al., 2018Daigle T.L. Madisen L. Hage T.A. Valley M.T. Knoblich U. Larsen R.S. Takeno M.M. Huang L. Gu H. Larsen R. et al.A Suite of Transgenic Driver and Reporter Mouse Lines with Enhanced Brain-Cell-Type Targeting and Functionality.Cell. 2018; 174: 465-480.e22Abstract Full Text Full Text PDF PubMed Scopus (126) Google Scholar; Steinmetz et al., 2017Steinmetz N.A. Buetfering C. Lecoq J. Lee C.R. Peters A.J. Jacobs E.A.K. Coen P. Ollerenshaw D.R. Valley M.T. de Vries S.E.J. et al.Aberrant Cortical Activity in Multiple GCaMP6-Expressing Transgenic Mouse Lines.eNeuro. 2017; 4: 4Crossref Scopus (87) Google Scholar), although the exact mechanisms underlying this pathology remain unclear. As noted above, biochemical and electrical signaling by neurons spans multiple orders of magnitude in spatial and temporal scale, bridging molecular, cellular, systems, and behavioral subfields of neuroscience. A wide range of imaging modalities have been applied, in conjunction with fluorescent reporters, to investigate neural function. However, this methodological diversity means that finding the right match between tools and questions can be critical. Differences in imaging systems largely arise from variations in spatiotemporal resolution and invasiveness to the subject (see Box 1 for additional details). For example, two-photon microscopy provides cellular and subcellular resolution of neurons in awake, behaving mice. However, fields of view are typically restricted to a few hundred microns, and imaging requires a surgical opening through the skull for sufficient light penetration and imaging quality. Temporal resolution in most systems is limited to a few tens of frames per second due to the relatively slow rate of raster scanning across the sample, which may be insufficient to record fast events such as action potentials. Single-photon microscopy (including mesoscopic imaging) lacks the axial sectioning inherent to multiphoton modalities, and spatial resolution is highly limited by light scattering unless indicator expression is sparse. However, imaging can be performed (in some cases) through the intact skull, sampling rates can be very high (>1 kHz for some cameras), and fields of view can span several millimeters in diameter. Moreover, many scientific questions do not require cellular resolution (see below), and the relative simplicity of widefield imaging systems enables the implementation of head-mounted microscopes on freely moving mice (Rynes et al., 2020Rynes M.L. Surinach D. Linn S. Laroque M. Rajendran V. Dominguez J. Hadjistamolou O. Navabi Z.S. Ghanbari L. Johnson G.W. et al.Miniaturized head-mounted device for whole cortex mesoscale imaging in freely behaving mice.bioRxiv. 2020; https://doi.org/10.1101/2020.05.25.114892Crossref Scopus (0) Google Scholar). In the following sections, we will provide an overview of mesoscopic imaging, a subclass of widefield, single-photon microscopy, that is currently experiencing rapid growth in neuroscientific applications.Box 1Neural activity comprises both electrical and biochemical signals that can be monitored using a variety of optical approaches that differ in their ability to resolve spatial and temporal components. Advantages and disadvantages of each method must be weighed against specific experimental goals. Here, we briefly summarize several approaches with complementary benefits and limitations. We also identify a non-comprehensive list of representative studies to illustrate the different strategies, and additional references are found in the main text.Widefield Fluorescence ImagingWidefield imaging refers to a modality in which the entire sample is exposed to excitation light. Signals are typically collected and images formed via a camera (i.e., CCD or sCMOS). Temporal resolution is limited by the kinetics of the indicators and the camera frame rate, which can span a few frames per second to >1 kHz. Spatial resolution is limited by the microscope optics and pixel density of the camera. Many studies using small (<1 mm2) fields of view have resolved individual neurons, collecting signals through an objective placed above the tissue or via an inserted lens. This modality has also given rise to head-mounted systems for monitoring brain activity in freely moving animals. Given the inherent lack of optical z-sectioning with widefield illumination, assigning emitted photons to a single imaging plane (versus multiple cells in close vertical register) can be a limitation. Mesoscopic widefield imaging, which trades spatial resolution for much larger fields of view (>100 mm2), is a complementary approach. Thus, single cells are not resolved, but activity across wide areas (e.g., the entire dorsal cortical surface) can be imaged simultaneously at high frame rates. Selected references: Ackman et al., 2012Ackman J.B. Burbridge T.J. Crair M.C. Retinal waves coordinate patterned activity throughout the developing visual system.Nature. 2012; 490: 219-225Crossref PubMed Scopus (225) Google Scholar; Aharoni et al., 2019Aharoni D. Khakh B.S. Silva A.J. Golshani P. All the light that we can see: a new era in miniaturized microscopy.Nat. Methods. 2019; 16: 11-13Crossref PubMed Scopus (36) Google Scholar; Barson et al., 2020Barson D. Hamodi A.S. Shen X. Lur G. Constable R.T. Cardin J.A. Crair M.C. Higley M.J. Simultaneous mesoscopic and two-photon imaging of neuronal activity in cortical circuits.Nat. Methods. 2020; 17: 107-113Crossref PubMed Scopus (11) Google Scholar; Kim et al., 2016Kim T.H. Zhang Y. Lecoq J. Jung J.C. Li J. Zeng H. Niell C.M. Schnitzer M.J. Long-Term Optical Access to an Estimated One Million Neurons in the Live Mouse Cortex.Cell Rep. 2016; 17: 3385-3394Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar; Kingsbury et al., 2019Kingsbury L. Huang S. Wang J. Gu K. Golshani P. Wu Y.E. Hong W. Correlated Neural Activity and Encoding of Behavior across Brains of Socially Interacting Animals.Cell. 2019; 178: 429-446.e16Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar; Musall et al., 2019Musall S. Kaufman M.T. Juavinett A.L. Gluf S. Churchland A.K. Single-trial neural dynamics are dominated by richly varied movements.Nat. Neurosci. 2019; 22: 1677-1686Crossref PubMed Scopus (83) Google Scholar; Senarathna et al., 2019Senarathna J. Yu H. Deng C. Zou A.L. Issa J.B. Hadjiabadi D.H. Gil S. Wang Q. Tyler B.M. Thakor N.V. Pathak A.P. A miniature multi-contrast microscope for functional imaging in freely behaving animals.Nat. Commun. 2019; 10: 99Crossref PubMed Scopus (12) Google Scholar; Skocek et al., 2018Skocek O. Nöbauer T. Weilguny L. Martínez Traub F. Xia C.N. Molodtsov M.I. Grama A. Yamagata M. Aharoni D. Cox D.D. et al.High-speed volumetric imaging of neuronal activity in freely moving rodents.Nat. Methods. 2018; 15: 429-432Crossref PubMed Scopus (49) Google Scholar; Vanni et al., 2017Vanni M.P. Chan A.W. Balbi M. Silasi G. Murphy T.H. Mesoscale mapping of mouse cortex reveals frequency-dependent cycling between distinct macroscale functional modules.J. Neurosci. 2017; 37: 7513-7533Crossref PubMed Scopus (36) Google Scholar.Multiphoton Fluorescence ImagingMultiphoton imaging (including two- and three-photon variants) relies on exciting molecules with focused, high-intensity light that results in absorption of multiple infrared photons, followed by emission in standard visible ranges. The focused spot is scanned across the sample, and signals are collected via photomultiplier tubes. Images are formed post hoc by alignment of the collected signal with the known location of the focal position. Scanning is typically performed with galvanometric mirrors, and frame rates are limited in most cases to <100 Hz. These systems rely on high numerical aperture objectives that are usually limited to small fields of view (<1 mm2). However, spatial resolution is high (<1 μm), providing excellent imaging of cellular and subcellular structures. Moreover, multiphoton imaging provides inherent optical z-sectioning as only molecules near the focal plane are excited. Recent developments have increased the functional field of view by use of multi-beam scanning or translating the imaging window across different positions. Multiphoton imaging systems typically much more expensive than their widefield counterparts due to the necessity for complex microscopes and laser light sources. Selected references: Barson et al., 2020Barson D. Hamodi A.S. Shen X. Lur G. Constable R.T. Cardin J.A. Crair M.C. Higley M.J. Simultaneous mesoscopic and two-photon imaging of neuronal activity in cortical circuits.Nat. Methods. 2020; 17: 107-113Crossref PubMed Scopus (11) Google Scholar; Denk and Svoboda, 1997Denk W. Svoboda K. Photon upmanship: why multiphoton imaging is more than a gimmick.Neuron. 1997; 18: 351-357Abstract Full Text Full Text PDF PubMed Scopus (539) Google Scholar; Smith et al., 2013Smith S.L. Smith I.T. Branco T. Häusser M. Dendritic spikes enhance stimulus selectivity in cortical neurons in vivo.Nature. 2013; 503: 115-120Crossref PubMed Scopus (186) Google Scholar; Sofroniew et al., 2016Sofroniew N.J. Flickinger D. King J. Svoboda K. A large field of view two-photon mesoscope with subcellular resolution for in vivo imaging.eLife. 2016; 5: 5Crossref Google Scholar; Stirman et al., 2016Stirman J.N. Smith I.T. Kudenov M.W. Smith S.L. Wide field-of-view, multi-region, two-photon imaging of neuronal activity in the mammalian brain.Nat. Biotechnol. 2016; 34: 857-862Crossref PubMed Google Scholar; Wang et al., 2020bWang T. Wu C. Ouzounov D.G. Gu W. Xia F. Kim M. Yang X. Warden M.R. Xu C. Quantitative analysis of 1300-nm three-photon calcium imaging in the mouse brain.eLife. 2020; 9: 9Google Scholar; Xu et al., 2012Xu N.L. Harnett M.T. Williams S.R. Huber D. O’Connor D.H. Svoboda K. Magee J.C. Nonlinear dendritic integration of sensory and motor input during an active sensing task.Nature. 2012; 492: 247-251Crossref PubMed Scopus (259) Google Scholar.Fiber PhotometryA relatively new approach in fluorescence-based monitoring of neuronal activity, fiber photometry relies on exciting the sample and collecting emitted photons through a fiber optic that can be implanted anywhere in the brain. Temporal resolution is essentially unlimited, while there is no spatial resolution as all photons emitted from the target region are integrated into a single channel in the fiber. Multiple wavelengths can be combined in the same fiber for imaging different cellular populations. Thus, photometry can provide a relatively inexpensive yet powerful tool for monitoring neural activity in deep brain structures and is also readily combined with other imaging and electrophysiology modalities. Selected references: Gunaydin et al., 2014Gunaydin L.A. Grosenick L. Finkelstein J.C. Kauvar I.V. Fenno L.E. Adhikari A. Lammel S. Mirzabekov J.J. Airan R.D. Zalocusky K.A. et al.Natural neural projection dynamics underlying social behavior.Cell. 2014; 157: 1535-1551Abstract Full Text Full Text PDF PubMed Scopus (550) Google Scholar; Meng et al., 2018Meng C. Zhou J. Papaneri A. Peddada T. Xu K. Cui G. Spectrally Resolved Fiber Photometry for Multi-component Analysis of Brain Circuits.Neuron. 2018; 98: 707-717.e4Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar; Pisano et al., 2019Pisano F. Pisanello M. Lee S.J. Lee J. Maglie E. Balena A. Sileo L. Spagnolo B. Bianco M. Hyun M. et al.Depth-resolved fiber photometry with a single tapered optical fiber implant.Nat. Methods. 2019; 16: 1185-1192Crossref PubMed Scopus (8) Google Scholar. Neural activity comprises both electrical and biochemical signals that can be monitored using a variety of optical approaches that differ in their ability to resolve spatial and temporal components. Advantages and disadvantages of each method must be weighed against specific experimental goals. Here, we briefly summarize several approaches with complementary benefits and limitations. We also identify a non-comprehensive list of representative studies to illustrate the different strategies, and additional references are found in the main text.Widefield Fluorescence Imaging Widefield imaging refers to a modality in which the entire sample is exposed to excitation light. Signals are typically collected and images formed via a camera (i.e., CCD or sCMOS). Temporal resolution is limited by the kinetics of the indicators and the camera frame rate, which can span a few frames per second to >1 kHz. Spatial resolution is limited by the microscope optics and pixel density of the camera. Many studies using small (<1 mm2) fields of view have resolved individual neurons, collecting signals through an objective placed above the tissue or via an inserted lens. This modality has also given rise to head-mounted systems for monitoring brain activity in freely moving animals. Given the inherent lack of optical z-sectioning with widefield illumination, assigning emitted photons to a single imaging plane (versus multiple cells in close vertical register) can be a limitation. Mesoscopic widefield imaging, which trades spatial resolution for much larger fields of view (>100 mm2), is a complementary approach. Thus, single cells are not resolved, but activity across wide areas (e.g., the entire dorsal cortical surface) can be imaged simultaneously at high frame rates. Selected references: Ackman et al., 2012Ackman J.B. Burbridge T.J. Crair M.C. Retinal waves coordinate patterned activity throughout the developing visual system.Nature. 2012; 490: 219-225Crossref PubMed Scopus (225) Google Scholar; Aharoni et al., 2019Aharoni D. Khakh B.S. Silva A.J. Golshani P. All the lig" @default.
• W3093146038 created "2020-10-22" @default.
• W3093146038 creator A5031151569 @default.
• W3093146038 creator A5057862535 @default.
• W3093146038 creator A5073499106 @default.
• W3093146038 date "2020-10-01" @default.
• W3093146038 modified "2023-10-16" @default.
• W3093146038 title "Mesoscopic Imaging: Shining a Wide Light on Large-Scale Neural Dynamics" @default.
• W3093146038 cites W1529779289 @default.
• W3093146038 cites W1571164133 @default.
• W3093146038 cites W176484045 @default.
• W3093146038 cites W1773061051 @default.
• W3093146038 cites W1964314167 @default.
• W3093146038 cites W1973275441 @default.
• W3093146038 cites W1975032719 @default.
• W3093146038 cites W1977514547 @default.
• W3093146038 cites W1979838741 @default.
• W3093146038 cites W1984390450 @default.
• W3093146038 cites W1984436346 @default.
• W3093146038 cites W1987249697 @default.
• W3093146038 cites W1987777969 @default.
• W3093146038 cites W2000137090 @default.
• W3093146038 cites W2002923643 @default.
• W3093146038 cites W2007494471 @default.
• W3093146038 cites W2015376003 @default.
• W3093146038 cites W2036021747 @default.
• W3093146038 cites W2040574649 @default.
• W3093146038 cites W2047378045 @default.
• W3093146038 cites W2047405616 @default.
• W3093146038 cites W2050215536 @default.
• W3093146038 cites W2055725584 @default.
• W3093146038 cites W2067474937 @default.
• W3093146038 cites W2069601330 @default.
• W3093146038 cites W2069950623 @default.
• W3093146038 cites W2083060092 @default.
• W3093146038 cites W2086338669 @default.
• W3093146038 cites W2090206974 @default.
• W3093146038 cites W2099044759 @default.
• W3093146038 cites W2109234881 @default.
• W3093146038 cites W2111128547 @default.
• W3093146038 cites W2114104729 @default.
• W3093146038 cites W2120606872 @default.
• W3093146038 cites W2131039108 @default.
• W3093146038 cites W2133659563 @default.
• W3093146038 cites W2145909957 @default.
• W3093146038 cites W2147800368 @default.
• W3093146038 cites W2158229994 @default.
• W3093146038 cites W2163507641 @default.
• W3093146038 cites W2167822639 @default.
• W3093146038 cites W2171332611 @default.
• W3093146038 cites W2256579886 @default.
• W3093146038 cites W2280009513 @default.
• W3093146038 cites W2291957660 @default.
• W3093146038 cites W2341571008 @default.
• W3093146038 cites W2394641095 @default.
• W3093146038 cites W2402398548 @default.
• W3093146038 cites W2417964944 @default.
• W3093146038 cites W2471644372 @default.
• W3093146038 cites W2472683490 @default.
• W3093146038 cites W2512047842 @default.
• W3093146038 cites W2513047215 @default.
• W3093146038 cites W2513986326 @default.
• W3093146038 cites W2527794060 @default.
• W3093146038 cites W2529957121 @default.
• W3093146038 cites W2530742534 @default.
• W3093146038 cites W2546343095 @default.
• W3093146038 cites W2566652232 @default.
• W3093146038 cites W2567050542 @default.
• W3093146038 cites W2584632106 @default.
• W3093146038 cites W2616012590 @default.
• W3093146038 cites W2708579841 @default.
• W3093146038 cites W2728287400 @default.
• W3093146038 cites W2766888300 @default.
• W3093146038 cites W2773803332 @default.
• W3093146038 cites W2800089816 @default.
• W3093146038 cites W2802223125 @default.
• W3093146038 cites W2807128224 @default.
• W3093146038 cites W2807588602 @default.
• W3093146038 cites W2878370351 @default.
• W3093146038 cites W2885162916 @default.
• W3093146038 cites W2897480633 @default.
• W3093146038 cites W2898267661 @default.
• W3093146038 cites W2903842495 @default.
• W3093146038 cites W2911151360 @default.
• W3093146038 cites W2939938327 @default.
• W3093146038 cites W2950053601 @default.
• W3093146038 cites W2950615496 @default.
• W3093146038 cites W2950849463 @default.
• W3093146038 cites W2950996676 @default.
• W3093146038 cites W2951215498 @default.
• W3093146038 cites W2952059832 @default.
• W3093146038 cites W2952729407 @default.
• W3093146038 cites W2953100281 @default.
• W3093146038 cites W2956118984 @default.
• W3093146038 cites W2959162700 @default.
• W3093146038 cites W2975273565 @default.
• W3093146038 cites W2976024218 @default.
• W3093146038 cites W2978062907 @default.

• next