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 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 The formin Fmn2 is required for the development of an excitatory interneuron module in the zebrafish acoustic startle circuit

2020 ◽  
Author(s):  
Dhriti Nagar ◽  
Tomin K James ◽  
Ratnakar Mishra ◽  
Shrobona Guha ◽  
Aurnab Ghose
Keyword(s):  
Growth Cone ◽  
Neurodevelopmental Disorders ◽  
High Speed ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Video Recording ◽  
Acoustic Startle ◽  
Neuronal Cultures

ABSTRACTThe formin family member, Fmn2, is a neuronally enriched cytoskeletal remodelling protein conserved across vertebrates. Recent studies have implicated Fmn2 in neurodevelopmental disorders, including sensory processing dysfunction and intellectual disability in humans. Cellular characterization of Fmn2 in primary neuronal cultures has identified its function in the regulation of cell-substrate adhesion and consequently growth cone translocation. However, the role of Fmn2 in the development of neural circuits in vivo, and its impact on associated behaviours have not been tested.Using automated analysis of behaviour and systematic investigation of the associated circuitry, we uncover the role of Fmn2 in zebrafish neural circuit development. As reported in other vertebrates, the zebrafish ortholog of Fmn2 is also enriched in the developing zebrafish nervous system. We find that Fmn2 is required for the development of an excitatory interneuron pathway, the spiral fiber neuron, which is an essential circuit component in the regulation of the Mauthner cell-mediated acoustic startle response. Consistent with the loss of the spiral fiber neurons tracts, high-speed video recording revealed a reduction in the short latency escape events while responsiveness to the stimuli was unaffected.Taken together, this study provides evidence for a circuit-specific requirement of Fmn2 in eliciting an essential behaviour in zebrafish. Our findings underscore the importance of Fmn2 in neural development across vertebrate lineages and highlight zebrafish models in understanding neurodevelopmental disorders.SIGNIFICANCE STATEMENTFmn2 is a neuronally enriched cytoskeletal remodelling protein linked to neurodevelopment and cognitive disorders in humans. Recent reports have characterized its function in growth cone motility and chemotaxis in cultured primary neurons. However, the role of Fmn2 in the development of neural circuits in vivo and its implications in associated behaviours remain unexplored. This study shows that Fmn2 is required for the development of neuronal processes in the acoustic startle circuit to ensure robust escape responses to aversive stimuli in zebrafish. Our study underscores the crucial role of the non-diaphanous formin, Fmn2, in establishing neuronal connectivity and related behaviour in zebrafish.

scholarly journals Exosomes regulate neurogenesis and circuit assembly

2019 ◽  
Vol 116 (32) ◽  
pp. 16086-16094 ◽  
Author(s):  
Pranav Sharma ◽  
Pinar Mesci ◽  
Cassiano Carromeu ◽  
Daniel R. McClatchy ◽  
Lucio Schiapparelli ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Neurodevelopmental Disorder ◽  
The Body ◽  
Signaling Networks ◽  
Neuronal Circuit ◽  
Circuit Development ◽  
Neural Cultures ◽  
Neuronal Proliferation

Exosomes are thought to be released by all cells in the body and to be involved in intercellular communication. We tested whether neural exosomes can regulate the development of neural circuits. We show that exosome treatment increases proliferation in developing neural cultures and in vivo in dentate gyrus of P4 mouse brain. We compared the protein cargo and signaling bioactivity of exosomes released by hiPSC-derived neural cultures lacking MECP2, a model of the neurodevelopmental disorder Rett syndrome, with exosomes released by isogenic rescue control neural cultures. Quantitative proteomic analysis indicates that control exosomes contain multiple functional signaling networks known to be important for neuronal circuit development. Treating MECP2-knockdown human primary neural cultures with control exosomes rescues deficits in neuronal proliferation, differentiation, synaptogenesis, and synchronized firing, whereas exosomes from MECP2-deficient hiPSC neural cultures lack this capability. These data indicate that exosomes carry signaling information required to regulate neural circuit development.

Imaging neural circuit dynamics with a voltage-sensitive fluorescent protein

2012 ◽  
Vol 108 (8) ◽  
pp. 2323-2337 ◽  
Author(s):  
Walther Akemann ◽  
Hiroki Mutoh ◽  
Amélie Perron ◽  
Yun Kyung Park ◽  
Yuka Iwamoto ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neural Circuit ◽  
Fluorescent Protein ◽  
Hippocampal Slices ◽  
Field Potential ◽  
Specific Cell ◽  
Fast Kinetics ◽  
Detection Range ◽  
Voltage Imaging

Population signals from neuronal ensembles in cortex during behavior are commonly measured with EEG, local field potential (LFP), and voltage-sensitive dyes. A genetically encoded voltage indicator would be useful for detection of such signals in specific cell types. Here we describe how this goal can be achieved with Butterfly, a voltage-sensitive fluorescent protein (VSFP) with a subthreshold detection range and enhancements designed for voltage imaging from single neurons to brain in vivo. VSFP-Butterfly showed reliable membrane targeting, maximum response gain around standard neuronal resting membrane potential, fast kinetics for single-cell synaptic responses, and a high signal-to-noise ratio. Butterfly reports excitatory postsynaptic potentials (EPSPs) in cortical neurons, whisker-evoked responses in barrel cortex, 25-Hz gamma oscillations in hippocampal slices, and 2- to 12-Hz slow waves during brain state modulation in vivo. Our findings demonstrate that cell class-specific voltage imaging is practical with VSFP-Butterfly, and expand the genetic toolbox for the detection of neuronal population dynamics.

Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus

2010 ◽  
Vol 104 (6) ◽  
pp. 3540-3550 ◽  
Author(s):  
Takafumi Kawai ◽  
Hideki Abe ◽  
Yasuhisa Akazome ◽  
Yoshitaka Oka
Keyword(s):  
Carassius Auratus ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Granule Cells ◽  
Glutamate Release ◽  
Sensory Information ◽  
Field Potential ◽  
Field Potentials ◽  
Goldfish Carassius Auratus

Gonadotropin-releasing hormone (GnRH) is well known as a hypophysiotropic hormone that is produced in the hypothalamus and facilitates the release of gonadotropins from the pituitary gonadotropes. On the other hand, the functions of extrahypothalamic GnRH systems still remain elusive. Here we examined whether the activity of the olfactory bulbar neural circuits is modulated by GnRH that originates mainly from the terminal nerve (TN) GnRH system in goldfish ( Carassius auratus). As the morphological basis, we first observed that goldfish TNs mainly express salmon GnRH (sGnRH) mRNA and that sGnRH-immunoreactive fibers are distributed in both the mitral and the granule cell layers. We then examined by extracellular recordings the effect of GnRH on the electrically evoked in vitro field potentials that arise from synaptic activities from mitral to granule cells. We found that GnRH enhances the amplitude of the field potentials. Furthermore, these effects were observed in both cases when the field potentials were evoked by stimulating either the lateral or the medial olfactory tract, conveying functionally different sensory information, separately, and suggesting that GnRH may modulate the responsiveness to wide categories of odorants in the olfactory bulb. Because GnRH also changed the paired-pulse ratio, it is suggested that the increased amplitude of the field potential results from changes in the presynaptic glutamate release of mitral cells rather than the increase in the glutamate receptor sensitivity of granule cells. These results suggest that TN regulates the olfactory responsiveness of animals appropriately by releasing sGnRH peptides in the olfactory bulbar neural circuits.

scholarly journals A Modified Miniscope System for Simultaneous Electrophysiology and Calcium Imaging in vivo

2021 ◽  
Vol 15 ◽  
Author(s):  
Xiaoting Wu ◽  
Xiangyu Yang ◽  
Lulu Song ◽  
Yang Wang ◽  
Yamin Li ◽  
...  
Keyword(s):  
Calcium Imaging ◽  
Adult Mouse ◽  
Field Potential ◽  
Simultaneous Recording ◽  
Ca1 Region ◽  
Volume Weight ◽  
The Brain ◽  
Local Field Potential Lfp ◽  
Deep Brain

The miniscope system is one of the calcium (Ca2+) imaging tools with small size and lightweight and can realize the deep-brain Ca2+ imaging not confined to the cerebral cortex. Combining Ca2+ imaging and electrophysiology recording has been an efficient method for extracting high temporal-spatial resolution signals in the brain. In this study, a particular electrode probe was developed and assembled on the imaging lens to modify the miniscope system. The electrode probe can be tightly integrated into the lens of the miniscope without increasing the volume, weight, and implantation complexity. In vivo tests verified that the proposed modified system has realized the simultaneous recording of Ca2+ signals and local field potential (LFP) signal in the hippocampus CA1 region of an adult mouse.

Functions of microglia in the central nervous system – beyond the immune response

2011 ◽  
Vol 7 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Hiroaki Wake ◽  
Andrew J. Moorhouse ◽  
Junichi Nabekura
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Brain Parenchyma ◽  
Synaptic Function ◽  
Mature Brain ◽  
The Central Nervous System ◽  
Sensory Activity

Microglia cells are the immune cells of the central nervous system and consequently play important roles in brain infections and inflammation. Recent in vivo imaging studies have revealed that in the resting healthy brain, microglia are highly dynamic, moving constantly to actively survey the brain parenchyma. These active microglia can rapidly respond to pathological insults, becoming activated to induce a range of effects that may contribute to both pathogenesis, or to confer neuronal protection. However, interactions between microglia and neurons are being recognized as important in shaping neural circuit activity under more normal, physiological conditions. During development and neurogenesis, microglia interactions with neurons help to shape the final patterns of neural circuits important for behavior and with implications for diseases. In the mature brain, microglia can respond to changes in sensory activity and can influence neuronal activity acutely and over the long term. Microglia seem to be particularly involved in monitoring the integrity of synaptic function. In this review, we discuss some of these new insights into the involvement of microglia in neural circuits.

scholarly journals Development of a rabies virus-based retrograde tracer with high trans-monosynaptic efficiency by reshuffling glycoprotein

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fan Jia ◽  
Li Li ◽  
Haizhou Liu ◽  
Pei Lv ◽  
Xiangwei Shi ◽  
...  
Keyword(s):  
Experimental Data ◽  
Rabies Virus ◽  
Oncolytic Virus ◽  
Neural Circuits ◽  
Bioinformatic Analysis ◽  
Cell Engineering ◽  
Bias Score ◽  
Codon Pair Bias ◽  
Codon Pair

AbstractRabies virus (RV) is the most widely used vector for mapping neural circuits. Previous studies have shown that the RV glycoprotein can be a target to improve the retrograde transsynaptic tracing efficiency. However, the current versions still label only a small portion of all presynaptic neurons. Here, we reshuffled the oG sequence, a chimeric glycoprotein, with positive codon pair bias score (CPBS) based on bioinformatic analysis of mouse codon pair bias, generating ooG, a further optimized glycoprotein. Our experimental data reveal that the ooG has a higher expression level than the oG in vivo, which significantly increases the tracing efficiency by up to 12.6 and 62.1-fold compared to oG and B19G, respectively. The new tool can be used for labeling neural circuits Therefore, the approach reported here provides a convenient, efficient and universal strategy to improve protein expression for various application scenarios such as trans-synaptic tracing efficiency, cell engineering, and vaccine and oncolytic virus designs.

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