scholarly journals Precise, 3-D optogenetic control of the diameter of single arterioles

2021 ◽  
Author(s):  
Philip J. O’Herron ◽  
David A. Hartmann ◽  
Kun Xie ◽  
Prakash Kara ◽  
Andy Y. Shih
Keyword(s):  
Blood Flow ◽  
Neural Activity ◽  
Light Modulator ◽  
Spatiotemporal Resolution ◽  
Two Photon ◽  
Light Pulses ◽  
All Optical ◽  
Health And Disease ◽  
And Control

AbstractModulation of brain arteriole diameter is critical for maintenance of cerebral blood pressure and control of hyperemia during regional neural activity. However, studies of hemodynamic function in health and disease have lacked a method to control and monitor blood flow with high spatiotemporal resolution. Here, we describe a new all-optical approach to precisely control and monitor arteriolar contractility in vivo using combined two-photon optogenetics and imaging. The expression of the excitatory opsin, ReaChR, in vascular smooth muscle cells enabled rapid and repeated vasoconstriction following brief light pulses. Targeted two-photon activation of ReaCHR using a spatial light modulator (SLM) produced highly localized constrictions when targeted to individual arteries within the neocortex. We demonstrate the utility of this method for examining arteriole contractile dynamics and creating transient blood flow reductions. Additionally, we show that optogenetic constriction can offset or completely block sensory stimulus evoked vasodilation, providing a valuable tool to dissociate blood flow changes from neural activity.

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

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.

scholarly journals Dual-color volumetric imaging of neural activity of cortical columns

2018 ◽  
Author(s):  
Shuting Han ◽  
Weijian Yang ◽  
Rafael Yuste
Keyword(s):  
Neural Activity ◽  
High Speed ◽  
Neural Circuits ◽  
Emergent Properties ◽  
Spatiotemporal Resolution ◽  
Population Activity ◽  
Volumetric Imaging ◽  
Two Photon ◽  
Dual Color

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.

scholarly journals Multiplexed temporally focused light shaping through a GRIN lens for precise in-depth optogenetic photostimulation

2019 ◽  
Author(s):  
Nicolò Accanto ◽  
I-Wen Chen ◽  
Emiliano Ronzitti ◽  
Clément Molinier ◽  
Christophe Tourain ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Three Dimensions ◽  
Optical Methods ◽  
Optical Investigation ◽  
Two Photon ◽  
Grin Lens ◽  
All Optical ◽  
Living Tissues ◽  
And Control

AbstractIn the past 10 years, the use of light has become irreplaceable for the optogenetic study and control of neurons and neural circuits. Optical techniques are however limited by scattering and can only see through a depth of few hundreds µm in living tissues. GRIN lens based micro-endoscopes represent a powerful solution to reach deeper regions. In this work we demonstrate that cutting edge optical methods for the precise photostimulation of multiple neurons in three dimensions can be performed through a GRIN lens. By spatio-temporally shaping a laser beam in the two-photon regime we project several tens of targets, spatially confined to the size of a single cell, in a volume of 150×150×400 μm3. We then apply such concept to the optogenetic stimulation of multiple neurons simultaneously in vivo in mice. Our work paves the way for an all-optical investigation of neural circuits at previously unattainable depths.

scholarly journals Single cell in vivo brain optogenetic stimulation by two-photon excitation fluorescence transfer

2020 ◽  
Author(s):  
Lei Tong ◽  
Peng Yuan ◽  
Minggang Chen ◽  
Fuyi Chen ◽  
Joerg Bewersdorf ◽  
...  
Keyword(s):  
Single Cell ◽  
Cross Sections ◽  
Single Photon ◽  
Photon Absorption ◽  
Two Photon ◽  
Photon Excitation ◽  
All Optical ◽  
Stimulation Efficiency ◽  
And Control

AbstractOptogenetics at single-cell resolution can be achieved by two-photon stimulation; however, this requires intense or holographic illumination. We markedly improve stimulation efficiency by positioning fluorophores with high two-photon cross-sections adjacent to opsins. The two-photon-excited fluorescence matches the opsin absorbance and can stimulate opsins in a highly localized manner through efficient single-photon absorption. This indirect fluorescence transfer illumination allows experiments difficult to implement in the live brain such as all-optical neural interrogation and control of regional cerebral blood flow.

scholarly journals Kilohertz two-photon fluorescence microscopy imaging of neural activity in vivo

2019 ◽  
Author(s):  
Jianglai Wu ◽  
Yajie Liang ◽  
Shuo Chen ◽  
Ching-Lung Hsu ◽  
Mariya Chavarha ◽  
...  
Keyword(s):  
Neural Activity ◽  
Laser Scanning ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Microscopy Imaging ◽  
Two Photon ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence ◽  
The Brain

Understanding information processing in the brain requires us to monitor neural activity in vivo at high spatiotemporal resolution. Using an ultrafast two-photon fluorescence microscope (2PFM) empowered by all-optical laser scanning, we imaged neural activity in vivo at up to 3,000 frames per second and submicron spatial resolution. This ultrafast imaging method enabled monitoring of both supra- and sub-threshold electrical activity down to 345 μm below the brain surface in head fixed awake mice.

scholarly journals Simultaneous two-photon imaging and two-photon optogenetics of cortical circuits in three dimensions

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Weijian Yang ◽  
Luis Carrillo-Reid ◽  
Yuki Bando ◽  
Darcy S Peterka ◽  
Rafael Yuste
Keyword(s):  
Neural Activity ◽  
Pyramidal Neurons ◽  
Three Dimensions ◽  
Cortical Circuits ◽  
Two Photon ◽  
Simultaneous Imaging ◽  
All Optical ◽  
Holographic Approach ◽  
Mouse Visual Cortex

The simultaneous imaging and manipulating of neural activity could enable the functional dissection of neural circuits. Here we have combined two-photon optogenetics with simultaneous volumetric two-photon calcium imaging to measure and manipulate neural activity in mouse neocortex in vivo in three-dimensions (3D) with cellular resolution. Using a hybrid holographic approach, we simultaneously photostimulate more than 80 neurons over 150 μm in depth in layer 2/3 of the mouse visual cortex, while simultaneously imaging the activity of the surrounding neurons. We validate the usefulness of the method by photoactivating in 3D selected groups of interneurons, suppressing the response of nearby pyramidal neurons to visual stimuli in awake animals. Our all-optical approach could be used as a general platform to read and write neuronal activity.

scholarly journals Microglia motility depends on neuronal activity and promotes structural plasticity in the hippocampus

2019 ◽  
Author(s):  
Felix C. Nebeling ◽  
Stefanie Poll ◽  
Lena C. Schmid ◽  
Manuel Mittag ◽  
Julia Steffen ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Dendritic Spines ◽  
Synapse Formation ◽  
Brain Parenchyma ◽  
Two Photon ◽  
Contact Rates ◽  
Health And Disease ◽  
The Impact ◽  
The Brain

AbstractMicroglia, the resident immune cells of the brain, play a complex role in health and disease. They actively survey the brain parenchyma by physically interacting with other cells and structurally shaping the brain. Yet, the mechanisms underlying microglia motility and their significance for synapse stability, especially during adulthood, remain widely unresolved. Here we investigated the impact of neuronal activity on microglia motility and its implication for synapse formation and survival. We used repetitive two-photon in vivo imaging in the hippocampus of awake mice to simultaneously study microglia motility and their interaction with synapses. We found that microglia process motility depended on neuronal activity. Simultaneously, more dendritic spines emerged in awake compared to anesthetized mice. Interestingly, microglia contact rates with individual dendritic spines were associated with their stability. These results suggest that microglia are not only sensing neuronal activity, but participate in synaptic rewiring of the hippocampus during adulthood, which has profound relevance for learning and memory processes.

scholarly journals Modulation of the fungal mycobiome is regulated by the chitin-binding receptor FIBCD1

2019 ◽  
Vol 216 (12) ◽  
pp. 2689-2700 ◽  
Author(s):  
Jesper B. Moeller ◽  
Irina Leonardi ◽  
Anders Schlosser ◽  
Anne-Laure Flamar ◽  
Nicholas J. Bessman ◽  
...  
Keyword(s):  
Intestinal Inflammation ◽  
Fungal Colonization ◽  
Intestinal Epithelial ◽  
Fungal Cell ◽  
Specific Expression ◽  
Direct Binding ◽  
Health And Disease ◽  
Chitin Binding Protein ◽  
And Control

Host–microbiota interactions are critical in regulating mammalian health and disease. In addition to bacteria, parasites, and viruses, beneficial communities of fungi (the mycobiome) are important modulators of immune- and tissue-homeostasis. Chitin is a major component of the fungal cell wall, and fibrinogen C containing domain 1 (FIBCD1) is a chitin-binding protein; however, the role of this molecule in influencing host–mycobiome interactions in vivo has never been examined. Here, we identify direct binding of FIBCD1 to intestinal-derived fungi and demonstrate that epithelial-specific expression of FIBCD1 results in significantly reduced fungal colonization and amelioration of fungal-driven intestinal inflammation. Collectively, these results identify FIBCD1 as a previously unrecognized microbial pattern recognition receptor through which intestinal epithelial cells can recognize and control fungal colonization, limit fungal dysbiosis, and dampen intestinal inflammation.

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