scholarly journals All-optical interrogation of neural circuits in behaving mice

2021 ◽  
Author(s):  
Lloyd E. Russell ◽  
Henry W.P. Dalgleish ◽  
Rebecca Nutbrown ◽  
Oliver Gauld ◽  
Dustin Herrmann ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Barrel Cortex ◽  
Brain Area ◽  
Imaging Data ◽  
Temporal Precision ◽  
Two Photon ◽  
All Optical ◽  
The Impact

Recent advances combining two-photon calcium imaging and two-photon optogenetics with digital holography now allow us to read and write neural activity in vivo at cellular resolution with millisecond temporal precision. Such 'all-optical' techniques enable experimenters to probe the impact of functionally defined neurons on neural circuit function and behavioural output with new levels of precision. This protocol describes the experimental strategy and workflow for successful completion of typical all-optical interrogation experiments in awake, behaving head-fixed mice. We describe modular procedures for the setup and calibration of an all-optical system, the preparation of an indicator and opsin-expressing and task-performing animal, the characterization of functional and photostimulation responses and the design and implementation of an all-optical experiment. We discuss optimizations for efficiently selecting and targeting neuronal ensembles for photostimulation sequences, as well as generating photostimulation response maps from the imaging data that can be used to examine the impact of photostimulation on the local circuit. We demonstrate the utility of this strategy using all-optical experiments in three different brain areas - barrel cortex, visual cortex and hippocampus - using different experimental setups. This approach can in principle be adapted to any brain area for all-optical interrogation experiments to probe functional connectivity in neural circuits and for investigating the relationship between neural circuit activity and behaviour.

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 All-optical electrophysiology reveals excitation, inhibition, and neuromodulation in cortical layer 1

2019 ◽  
Author(s):  
Linlin Z. Fan ◽  
Simon Kheifets ◽  
Urs L. Böhm ◽  
Kiryl D. Piatkevich ◽  
Hao Wu ◽  
...  
Keyword(s):  
Neural Circuit ◽  
Barrel Cortex ◽  
Cortical Layer ◽  
Optical Recording ◽  
Tight Coupling ◽  
Basic Principles ◽  
All Optical ◽  
The Stability ◽  
Circuit Function

AbstractThe stability of neural dynamics arises through a tight coupling of excitatory (E) and inhibitory (I) signals. Genetically encoded voltage indicators (GEVIs) can report both spikes and subthreshold dynamics in vivo, but voltage only reveals the combined effects of E and I synaptic inputs, not their separate contributions individually. Here we combine optical recording of membrane voltage with simultaneous optogenetic manipulation to probe E and I individually in barrel cortex Layer 1 (L1) neurons in awake mice. Our studies reveal how the L1 microcircuit integrates thalamocortical excitation, lateral inhibition and top-down neuromodulatory inputs. We develop a simple computational model of the L1 microcircuit which captures the main features of our data. Together, these results suggest a model for computation in L1 interneurons consistent with their hypothesized role in attentional gating of the underlying cortex. Our results demonstrate that all-optical electrophysiology can reveal basic principles of neural circuit function in vivo.One Sentence SummaryAll-optical electrophysiology revealed the function in awake mice of an inhibitory microcircuit in barrel cortex Layer 1.

scholarly journals How many neurons are sufficient for perception of cortical activity?

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Henry WP Dalgleish ◽  
Lloyd E Russell ◽  
Adam M Packer ◽  
Arnd Roth ◽  
Oliver M Gauld ◽  
...  
Keyword(s):  
Lower Bound ◽  
Pyramidal Neurons ◽  
Barrel Cortex ◽  
Cortical Activity ◽  
Network Activity ◽  
Local Network ◽  
Two Photon ◽  
All Optical ◽  
The Face ◽  
The Impact

Many theories of brain function propose that activity in sparse subsets of neurons underlies perception and action. To place a lower bound on the amount of neural activity that can be perceived, we used an all-optical approach to drive behaviour with targeted two-photon optogenetic activation of small ensembles of L2/3 pyramidal neurons in mouse barrel cortex while simultaneously recording local network activity with two-photon calcium imaging. By precisely titrating the number of neurons stimulated, we demonstrate that the lower bound for perception of cortical activity is ~14 pyramidal neurons. We find a steep sigmoidal relationship between the number of activated neurons and behaviour, saturating at only ~37 neurons, and show this relationship can shift with learning. Furthermore, activation of ensembles is balanced by inhibition of neighbouring neurons. This surprising perceptual sensitivity in the face of potent network suppression supports the sparse coding hypothesis, and suggests that cortical perception balances a trade-off between minimizing the impact of noise while efficiently detecting relevant signals.

NeuroSeg: automated cell detection and segmentation for in vivo two-photon Ca2+ imaging data

2017 ◽  
Vol 223 (1) ◽  
pp. 519-533 ◽  
Author(s):  
Jiangheng Guan ◽  
Jingcheng Li ◽  
Shanshan Liang ◽  
Ruijie Li ◽  
Xingyi Li ◽  
...  
Keyword(s):  
Cell Detection ◽  
Imaging Data ◽  
Two Photon

scholarly journals Mathematical Modelling Based on In Vivo Imaging Suggests CD137-Stimulated Cytotoxic T Lymphocytes Exert Superior Tumour Control Due to an Enhanced Antimitotic Effect on Tumour Cells

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2567
Author(s):  
Richard J. Beck ◽  
Bettina Weigelin ◽  
Joost B. Beltman
Keyword(s):  
Checkpoint Inhibitors ◽  
Cytolytic Activity ◽  
Adoptive Cell Transfer ◽  
Antiproliferative Effect ◽  
Imaging Data ◽  
Tumour Control ◽  
Treatment Conditions ◽  
Antimitotic Effect ◽  
The Impact

Several immunotherapeutic strategies for the treatment of cancer are under development. Two prominent strategies are adoptive cell transfer (ACT) of CTLs and modulation of CTL function with immune checkpoint inhibitors or with costimulatory antibodies. Despite some success with these approaches, there remains a lack of detailed and quantitative descriptions of the events following CTL transfer and the impact of immunomodulation. Here, we have applied ordinary differential equation models to two photon imaging data derived from a B16F10 murine melanoma. Models were parameterised with data from two different treatment conditions: either ACT-only, or ACT with intratumoural costimulation using a CD137 targeted antibody. Model dynamics and best fitting parameters were compared, in order to assess the mode of action of the CTLs and examine how the CD137 antibody influenced their activities. We found that the cytolytic activity of the transferred CTLs was minimal without CD137 costimulation, and that the CD137 targeted antibody did not enhance the per-capita killing ability of the transferred CTLs. Instead, the results of our modelling study suggest that an antiproliferative effect of CTLs exerted upon the tumour likely accounted for the majority of the reduction in tumour growth after CTL transfer. Moreover, we found that CD137 most likely improved tumour control via enhancement of this antiproliferative effect, as well as prolonging the period in which CTLs were inside the tumour, leading to a sustained duration of their antitumour effects following CD137 stimulation.

Sensory Transmission is Bi-directionally Modulated by Astrocytic Ca2+ in Barrel Cortex of Behaving Mice

2021 ◽  
Author(s):  
Simeng Gu ◽  
Wei Wang ◽  
Kuan Zhang ◽  
Rou Feng ◽  
Naling Li ◽  
...  
Keyword(s):  
Sensory Input ◽  
Barrel Cortex ◽  
Synaptic Function ◽  
Metabolic Clearance ◽  
Sleep State ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Sensory Transmission

Abstract Different effects of astrocyte during sleep and awake have been extensively studied, especially for metabolic clearance by the glymphatic system, which works during sleep and stops working during waking states. However, how astrocytes contribute to modulation of sensory transmission during sleep and awake animals remain largely unknown. Recent advances in genetically encoded Ca2+ indicators have provided a wealth of information on astrocytic Ca2+, especially in their fine perisynaptic processes, where astrocytic Ca2+ most likely affects the synaptic function. Here we use two-photon microscopy to image astrocytic Ca2+ signaling in freely moving mice trained to run on a wheel in combination with in vivo whole-cell recordings to evaluate the role of astrocytic Ca2+ signaling in different behavior states. We found that there are two kinds of astrocytic Ca2+ signaling: a small long-lasting Ca2+ increase during sleep state and a sharp widespread but short-long-lasting Ca2+ spike when the animal was awake (fluorescence increases were 23.2 ± 14.4% for whisker stimulation at sleep state, compared with 73.3 ± 11.7% for at awake state, paired t-test, p < 0.01). The small Ca2+ transients decreased extracellular K+, hyperpolarized the neurons, and suppressed sensory transmission; while the large Ca2+ wave enhanced sensory input, contributing to reliable sensory transmission in aroused states. Locus coeruleus activation works as a switch between these two kinds of astrocytic Ca2+ elevation. Thus, we show that cortical astrocytes play an important role in processing of sensory input. These two types of events appear to have different pharmacological sources and may play a different role in facilitating the efficacy of sensory transmission.

scholarly journals Oscillatory integration windows in neurons

2016 ◽  
Author(s):  
Nitin Gupta ◽  
Swikriti Saran Singh ◽  
Mark Stopfer
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Field Potential ◽  
Coincidence Detection ◽  
Uniform Structure ◽  
Detection Mechanism ◽  
Oscillation Frequencies ◽  
Local Field Potential Lfp ◽  
Oscillatory Cycle

AbstractOscillatory synchrony among neurons occurs in many species and brain areas, and has been proposed to help neural circuits process information. One hypothesis states that oscillatory input creates cyclic integration windows: specific times in each oscillatory cycle when postsynaptic neurons become especially responsive to inputs. With paired local field potential (LFP) and intracellular recordings and controlled stimulus manipulations we directly tested this idea in the locust olfactory system. We found that inputs arriving in Kenyon cells (KCs) sum most effectively in a preferred window of the oscillation cycle. With a computational model, we found that the non-uniform structure of noise in the membrane potential helps mediate this process. Further experiments performed in vivo demonstrated that integration windows can form in the absence of inhibition and at a broad range of oscillation frequencies. Our results reveal how a fundamental coincidence-detection mechanism in a neural circuit functions to decode temporally organized spiking.

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 Efficient implementation of convolutional neural networks in the data processing of two-photon in vivo imaging

2019 ◽  
Vol 35 (17) ◽  
pp. 3208-3210 ◽  
Author(s):  
Yangzhen Wang ◽  
Feng Su ◽  
Shanshan Wang ◽  
Chaojuan Yang ◽  
Yonglu Tian ◽  
...  
Keyword(s):  
Neural Networks ◽  
Convolutional Neural Networks ◽  
Detection Methods ◽  
Supplementary Information ◽  
Imaging Data ◽  
Two Photon ◽  
Processing Power ◽  
Fluctuation Method ◽  
The Brain

Abstract Motivation Functional imaging at single-neuron resolution offers a highly efficient tool for studying the functional connectomics in the brain. However, mainstream neuron-detection methods focus on either the morphologies or activities of neurons, which may lead to the extraction of incomplete information and which may heavily rely on the experience of the experimenters. Results We developed a convolutional neural networks and fluctuation method-based toolbox (ImageCN) to increase the processing power of calcium imaging data. To evaluate the performance of ImageCN, nine different imaging datasets were recorded from awake mouse brains. ImageCN demonstrated superior neuron-detection performance when compared with other algorithms. Furthermore, ImageCN does not require sophisticated training for users. Availability and implementation ImageCN is implemented in MATLAB. The source code and documentation are available at https://github.com/ZhangChenLab/ImageCN. Supplementary information Supplementary data are available at Bioinformatics online.

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