Genetically encoded voltage indicators for large scale cortical imaging come of age

Knöpfel, Thomas; Gallero‐Salas, Yasir; Song, Chenchen

doi:10.1016/j.cbpa.2015.06.006

Cited by 61 publications

(50 citation statements)

References 48 publications

(40 reference statements)

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“…There are two main classes of GEVIs [reviewed in 74], voltage sensitive fluorescent proteins (VSFPs), which make use of a voltage sensing domain and microbial opsin based GEVIs. There have been numerous developments in both families in recent years.…”

Section: Labelling Neural Circuits With Activity-dependent Fluorophmentioning

confidence: 99%

“…There have been numerous developments in both families in recent years. Voltage sensing domain based sensors have been improved with the development of a number of variants of the VSFP family (VSFP2s, VSFP3s, VSFP-Butterflies) [74], ArcLight, and recently the highly sensitive ASAP1 [75]. At the same time, work progressed on voltage sensors based on the rhodopsin Arch, with modifications based on mutation and designed manipulations yielding sensors with improved kinetics and sensitivity, although still low quantum yields [76].…”

Section: Labelling Neural Circuits With Activity-dependent Fluorophmentioning

confidence: 99%

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Advances in Two-Photon Scanning and Scanless Microscopy Technologies for Functional Neural Circuit Imaging

et al. 2017

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Recent years have seen substantial developments in technology for imaging neural circuits, raising the prospect of large scale imaging studies of neural populations involved in information processing, with the potential to lead to step changes in our understanding of brain function and dysfunction. In this article we will review some key recent advances: improved fluorophores for single cell resolution functional neuroimaging using a two photon microscope; improved approaches to the problem of scanning active circuits; and the prospect of scanless microscopes which overcome some of the bandwidth limitations of current imaging techniques. These advances in technology for experimental neuroscience have in themselves led to technical challenges, such as the need for the development of novel signal processing and data analysis tools in order to make the most of the new experimental tools. We review recent work in some active topics, such as region of interest segmentation algorithms capable of demixing overlapping signals, and new highly accurate algorithms for calcium transient detection. These advances motivate the development of new data analysis tools capable of dealing with spatial or spatiotemporal patterns of neural activity, that scale well with pattern size.

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Section: Labelling Neural Circuits With Activity-dependent Fluorophmentioning

confidence: 99%

Section: Labelling Neural Circuits With Activity-dependent Fluorophmentioning

confidence: 99%

Advances in Two-Photon Scanning and Scanless Microscopy Technologies for Functional Neural Circuit Imaging

et al. 2017

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“…Genetically encoded voltage indicators (GEVIs) have developed greatly in recent years 9–11 but still face major limitations in their ability to detect measurable in vivo signals. Sensitivity, dynamic range, and signal-to-noise ratio of GEVIs are currently surpassed by calcium-sensitive fluorescent proteins such as GCaMP.…”

Section: Introductionmentioning

confidence: 99%

Optical Read-out of Neural Activity in Mammalian Peripheral Axons: Calcium Signaling at Nodes of Ranvier

Fontaine¹,

Gibson²,

Caldwell³

et al. 2017

Sci Rep

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Current neural interface technologies have serious limitations for advanced prosthetic and therapeutic applications due primarily to their lack of specificity in neural communication. An optogenetic approach has the potential to provide single cell/axon resolution in a minimally invasive manner by optical interrogation of light-sensitive reporters and actuators. Given the aim of reading neural activity in the peripheral nervous system, this work has investigated an activity-dependent signaling mechanism in the peripheral nerve. We demonstrate action potential evoked calcium signals in mammalian tibial nerve axons using an in vitro mouse model with a dextran-conjugated fluorescent calcium indicator. Spatial and temporal dynamics of the signal are presented, including characterization of frequency-modulated amplitude. Pharmacological experiments implicate T-type CaV channels and sodium-calcium exchanger (NCX) as predominant mechanisms of calcium influx. This work shows the potential of using calcium-associated optical signals for neural activity read-out in peripheral nerve axons.

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Section: Optogenetic Indicatorsmentioning

confidence: 99%

“…A growing variety of indicators are now available for imaging neuronal dynamics, including genetically-encoded indicators for voltage (Knöpfel et al, 2015), calcium (Tian et al, 2012), glutamate (Hires et al, 2008), chloride (Markova et al, 2008) and pH (Sankaranarayanan et al, 2000). While the latter two have specific roles in the analysis of inhibitory circuits, voltage sensors remain the fastest and most direct measure of neuronal activity (Knöpfel et al, 2015). Voltage sensors are either based on a voltage-sensing domain, such as VSFP (Sakai et al, 2001), VSFP2.1 (Lundby et al, 2010) and VSFP-Butterfly 1.2 (Akemann et al, 2012), or on opsins, such as Arch(D95N) (Kralj et al, 2012) and QuasAr1 and 2 (Hochbaum et al, 2014).…”

Section: Optogenetic Indicatorsmentioning

confidence: 99%

Functional investigation of neural circuits in larval zebrafish

Thompson¹

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A fundamental goal of modern neuroscience is to understand the principles by which neural circuits within the brain lead to cognition and behaviour. Technological advances in the fields of microscopy and optogenetics have very recently allowed for the activity of all cells within a functional circuit to be observed and recorded, meaning that this goal is now within reach. Due to the physical and optical properties of neural tissue, these technologies remain most useful for the analysis of circuits that span very small volumes, meaning that small animal model organisms, with brains less than approximately 1 mm across, are most amenable to these types of analyses. The larval zebrafish model has emerged as an optimal balance between small size and the high complexity of a vertebrate brain. This thesis describes the development and application of several of these technological advances to examine neural circuits underlying perception and behaviour in the larval zebrafish.Due to the relative recency of zebrafish as a model for functional neuroscience, the genetic and experimental tools required for in depth circuit analysis have not been widely available. Thirteen transgenic zebrafish lines have been developed during this thesis for expressing optogenetic proteins throughout the brain, such as GCaMP5G for imaging neuronal calcium dynamics, and ChR2(ET/TC) and eNpHR3.0 for activating and silencing neuronal activity, respectively. These biological tools were developed in combination with optical techniques for probing neural circuits. This thesis describes the design and construction of a custom selective plane illumination microscope for the rapid imaging of neuronal activity across large areas of the zebrafish brain. The use of a spatial light modulator is also described for the targeted stimulation of ChR2(ET/TC) in the cerebellum of larval zebrafish. This experiment provided preliminary data for the functional investigation of connections between cerebellar cells and the optic tectum, as well as confirming the validity of this technique for analysis of other neuronal circuits in vivo.Since learning is one of the most interesting yet ill-defined processes controlled by the brain, this thesis aimed to use the tools developed above to examine the changes across neuronal circuit activity responsible for learning in larval zebrafish, specifically those in the cerebellum responsible for motor learning. A classical P ag e 2 conditioning assay was administered to 7-day-old zebrafish by pairing a non-startling tone with an aversive tail shock stimulus. This paradigm has been extensively used in other model organisms, however failed to produce a significant learning behaviour in the experiments performed for this thesis. More recent evidence suggests that zebrafish only begin to show learning from approximately one month of age.However, the data presented here indicate that zebrafish up to six weeks of age were still unable to undergo classical conditioning to pairings of auditory and electric stimuli. A number of is...

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Genetically encoded voltage indicators for large scale cortical imaging come of age

Cited by 61 publications

References 48 publications

Advances in Two-Photon Scanning and Scanless Microscopy Technologies for Functional Neural Circuit Imaging

Advances in Two-Photon Scanning and Scanless Microscopy Technologies for Functional Neural Circuit Imaging

Optical Read-out of Neural Activity in Mammalian Peripheral Axons: Calcium Signaling at Nodes of Ranvier

Functional investigation of neural circuits in larval zebrafish

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