scholarly journals Fast two-photon volumetric imaging of an improved voltage indicator reveals electrical activity in deeply located neurons in the awake brain

2018 ◽  
Author(s):  
Mariya Chavarha ◽  
Vincent Villette ◽  
Ivan K. Dimov ◽  
Lagnajeet Pradhan ◽  
Stephen W. Evans ◽  
...  

ABSTRACTImaging of transmembrane voltage deep in brain tissue with cellular resolution has the potential to reveal information processing by neuronal circuits in living animals with minimal perturbation. Multi-photon voltage imaging in vivo, however, is currently limited by speed and sensitivity of both indicators and imaging methods. Here, we report the engineering of an improved genetically encoded voltage indicator, ASAP3, which exhibits up to 51% fluorescence responses in the physiological voltage range, sub-millisecond activation kinetics, and full responsivity under two-photon illumination. We also introduce an ultrafast local volume excitation (ULOVE) two-photon scanning method to sample ASAP3 signals in awake mice at kilohertz rates with increased stability and sensitivity. ASAP3 and ULOVE allowed continuous single-trial tracking of spikes and subthreshold events for minutes in deep locations, with subcellular resolution, and with repeated sampling over multiple days. By imaging voltage in visual cortex neurons, we found evidence for cell type-dependent subthreshold modulation by locomotion. Thus, ASAP3 and ULOVE enable continuous high-speed high-resolution imaging of electrical activity in deeply located genetically defined neurons during awake behavior.


2018 ◽  
Author(s):  
Shuting Han ◽  
Weijian Yang ◽  
Rafael Yuste

To capture the emergent properties of neural circuits, high-speed volumetric imaging of neural activity at cellular resolution is desirable. But while conventional two-photon calcium imaging is a powerful tool to study population activity in vivo, it is restrained to two-dimensional planes. Expanding it to 3D while maintaining high spatiotemporal resolution appears necessary. Here, we developed a two-photon microscope with dual-color laser excitation that can image neural activity in a 3D volume. We imaged the neuronal activity of primary visual cortex from awake mice, spanning from L2 to L5 with 10 planes, at a rate of 10 vol/sec, and demonstrated volumetric imaging of L1 long-range PFC projections and L2/3 somatas. Using this method, we map visually-evoked neuronal ensembles in 3D, finding a lack of columnar structure in orientation responses and revealing functional correlations between cortical layers which differ from trial to trial and are missed in sequential imaging. We also reveal functional interactions between presynaptic L1 axons and postsynaptic L2/3 neurons. Volumetric two-photon imaging appears an ideal method for functional connectomics of neural circuits.



2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.





Author(s):  
Zohreh Hosseinaee ◽  
Bingyao Tan ◽  
Kirsten Carter ◽  
Denise Hileeto ◽  
Luigina Sorbara ◽  
...  


2016 ◽  
Vol 110 (3) ◽  
pp. 165a ◽  
Author(s):  
Simon P. Poland ◽  
James A. Levitt ◽  
Nikola Krstajić ◽  
Ahmet Erdogen ◽  
Richard J. Walker ◽  
...  


2021 ◽  
Author(s):  
Connor James Darling ◽  
Samuel P.X. Davis ◽  
Sunil Kumar ◽  
Paul M.W. French ◽  
James A McGinty

We present a single-shot adaptation of Optical Projection Tomography (OPT) for high-speed volumetric snapshot imaging of dynamic mesoscopic samples. Conventional OPT has been applied to in vivo imaging of animal models such as D. rerio but the sequential acquisition of projection images required for volumetric reconstruction typically requires samples to be immobilised during the acquisition of an OPT data set. We present a proof-of-principle system capable of single-shot imaging of a 1 mm diameter volume, demonstrating camera-limited rates of up to 62.5 volumes/second, which we have applied to 3D imaging of a freely-swimming zebrafish embryo. This is achieved by recording 8 projection views simultaneously on 4 low-cost CMOS cameras. With no stage required to rotate the sample, this single-shot OPT system can be implemented with a component cost of under 5,000GBP. The system design can be adapted to different sized fields of view and may be applied to a broad range of dynamic samples, including fluid dynamics.



2013 ◽  
Vol 104 (2) ◽  
pp. 336a
Author(s):  
Walther Akemann ◽  
Hiroki Mutoh ◽  
Thomas Knöpfel


2011 ◽  
Vol 105 (6) ◽  
pp. 3106-3113 ◽  
Author(s):  
Jonathan D. Driscoll ◽  
Andy Y. Shih ◽  
Satish Iyengar ◽  
Jeffrey J. Field ◽  
G. Allen White ◽  
...  

We present a high-speed photon counter for use with two-photon microscopy. Counting pulses of photocurrent, as opposed to analog integration, maximizes the signal-to-noise ratio so long as the uncertainty in the count does not exceed the gain-noise of the photodetector. Our system extends this improvement through an estimate of the count that corrects for the censored period after detection of an emission event. The same system can be rapidly reconfigured in software for fluorescence lifetime imaging, which we illustrate by distinguishing between two spectrally similar fluorophores in an in vivo model of microstroke.



Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 634
Author(s):  
Ruheng Shi ◽  
Yuanlong Zhang ◽  
Tiankuang Zhou ◽  
Lingjie Kong

High-speed, optical-sectioning imaging is highly desired in biomedical studies, as most bio-structures and bio-dynamics are in three-dimensions. Compared to point-scanning techniques, line scanning temporal focusing microscopy (LSTFM) is a promising method that can achieve high temporal resolution while maintaining a deep penetration depth. However, the contrast and axial confinement would still be deteriorated in scattering tissue imaging. Here, we propose a HiLo-based LSTFM, utilizing structured illumination to inhibit the fluorescence background and, thus, enhance the image contrast and axial confinement in deep imaging. We demonstrate the superiority of our method by performing volumetric imaging of neurons and dynamical imaging of microglia in mouse brains in vivo.



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