Terminal differentiation precedes functional circuit integration in the peduncle neurons in regenerating Hydra vulgaris

We demonstrate the use of SCAPE microscopy to image both neural activity via GCaMP and vascular hemodynamics in the awake behaving mouse brain at 10-20 volumes per second with cellular resolution over large fields of view. The performance of SCAPE is compared to in-vivo two-photon microscopy.

Decision letter: Identification of a GABAergic neural circuit governing leptin signaling deficiency-induced obesity

Editor's evaluation: Identification of a GABAergic neural circuit governing leptin signaling deficiency-induced obesity

Cell bodies of airway afferent nerves originate from vagal ganglia and vagal afferent nerves project to the respiratory tract. The inputs from these nerves converge at the brainstem to regulate respiratory reflexes. These vagal afferent nerves can be classified into various subtypes based on the origins of cell bodies in vagal ganglia, conduction velocity, size and stimuli required for activation. The polymodal nature of vagal afferent nerves complicates the study of respiratory reflexes. Transient receptor potential vanilloid 1 (TRPV1) is one of the ion channels expressed in bronchopulmonary C‐fibers. Tachykinin 1 (Tac1) encodes for a neuropeptide, Substance P, which is released from sensory nerve terminals in jugular originated afferent nerves. 5HT3 is expressed in nodose originated nociceptive C‐fibers. In the present study, we focused on defining afferent nerves subtypes in vagal ganglia based on ion channel/receptor expression as well as innervation into respiratory tract using a transgenic mouse model.The Cre‐LoxP reporter system was used to target specific populations of afferent nerve subtypes and to control red fluorescent protein (tdTomato) expression. Trpv1‐Cre, Tac1‐Cre and 5ht3‐Cre strains were bred with Floxed Ai9 ROSA tdTomato; thus, expressing red fluorescent in Trpv1, Tac1 and 5ht3 positive neurons. Mice (6 to 8‐week‐old) were euthanized and tissues were collected. Lungs were inflated with 3 % low‐melting agarose solution and sectioned at 100 μm using a vibratome. Immunohistochemistry was done using anti‐E‐Cadherin and anti‐dsRed antibodies. Vagal ganglia were dissected and cryo‐sectioned at 20 μm. Immunohistochemistry was done using anti‐Trpv1 antibody to compare with native tdTomato expression. Images were taken using Olympus FV1200 confocal microscope.Native tdTomato expression for Trpv1 positive afferent nerves were seen in both jugular and nodose ganglia. tdTomato tagged for Tac1 positive afferent nerves were mostly expressed in jugular and some in nodose ganglia, while 5ht3 positive afferent nerves were exclusively in nodose ganglia. The native tdTomato expression of 5ht3 positive afferent nerves did not completely overlap with anti‐TRPV1 staining. We further visualized the nerve endings that projected from vagal ganglia into lung and the tdTomato expression patterns of the nerve endings were different depending on strains. With Trpv1 strain, nerve endings spread out in all the lobes and those nerve endings resided in the epithelial layer, mainly around the bronchi.Overall, we were able to identify the distinct locations of cell bodies in vagal ganglia and nerve endings in lung of various subsets of airway afferent nerves using Cre‐LoxP reporter system. This information may be valuable to investigate the highly complicated mechanism of respiratory reflexes.Support or Funding InformationNIH Common Fund SPARC OT2This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Multiple Forms of Activity-Dependent Competition Refine Hippocampal Circuits In Vivo

Spatial coding defects of hippocampal neural ensemble calcium activities in the triple-transgenic Alzheimer's disease mouse model

All-optical interrogation of population neuron activity is a promising approach to deciphering the neural circuit mechanisms supporting brain functions. However, this interrogation is currently limited to local brain areas. Here, we incorporate patterned photo-stimulation into light-sheet microscopy, allowing simultaneous targeted optogenetic manipulation and brain-wide monitoring of the neuronal activities of head-restrained behaving larval zebrafish. Using this system, we photo-stimulate arbitrarily selected neurons (regions as small as ~10-20 neurons in 3D) in zebrafish larvae with pan-neuronal expression of a spectrally separated calcium indicator, GCaMP6f, and an activity actuator, ChrimsonR, and observe downstream neural circuit activation and behavior generation. This approach allows us to dissect the causal role of neural circuits in brain functions and behavior generation.

Event Abstract Back to Event Mapping the topology of functional neural networks with single cell resolution Gabriel A. Silva1* 1 University of California San Diego, Bioengineering and Ophthalmology and Neurosciences Program, United States Understanding how neural circuits and networks represent, store, and process information is a central pursuit in neuroscience. It is anticipated that this will directly contribute to the understanding of higher order cognitive processes and provide a fundamental understanding of the central nervous system in both health and disease. One of the principle pursuits towards these aims is the reverse engineering of how neural circuits and networks function, in order to ultimately understand their dynamic properties. Our lab in particular is interested in how stereotypical cellular processes that underlie functional dynamic signaling in neural circuits scale and give rise to the information rich content and resultant properties of biological neural networks. We approach this by combining mathematical and computational modeling and nanotechnology with cellular neurobiology and imaging, specifically using real time dynamic fluorescence calcium imaging as an indicator and measure of function in both neuronal and glial networks. This talk will present some of our on-going theoretical, engineering, and experimental efforts aimed at identifying and mapping the functional connectivity topology of neural circuits and networks with single cell and sub-cellular resolution. Keywords: neuroengineering Conference: The Monte Verita' Workshop on the Frontiers in Neuroengineering, Ascona, Switzerland, 5 Sep - 9 Sep, 2010. Presentation Type: Oral Presentation Topic: Frontiers in Neuroengineering Citation: Silva GA (2010). Mapping the topology of functional neural networks with single cell resolution. Front. Neuroeng. Conference Abstract: The Monte Verita' Workshop on the Frontiers in Neuroengineering. doi: 10.3389/conf.fneng.2010.10.00022 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 17 Aug 2010; Published Online: 10 Sep 2010. * Correspondence: Prof. Gabriel A Silva, University of California San Diego, Bioengineering and Ophthalmology and Neurosciences Program, San Diego, United States, gsilva@ucsd.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gabriel A Silva Google Gabriel A Silva Google Scholar Gabriel A Silva PubMed Gabriel A Silva Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Author response: Neural underpinning of a respiration-associated resting-state fMRI network

A striking feature of the nervous system is that it shows extensive plasticity of structure and function that allows animals to adjust to changes in their environment. Neural activity plays a key role in mediating experience-dependent neural plasticity and, thus, creates a link between the external environment, the nervous system, and behavior. One dramatic example of neural plasticity is ongoing neurogenesis in the adult brain. The role of neural activity in modulating neuronal addition, however, has not been well studied at the level of neural circuits. The avian song control system allows us to investigate how activity influences neuronal addition to a neural circuit that regulates song, a learned sensorimotor social behavior. In adult white-crowned sparrows, new neurons are added continually to the song nucleus HVC (proper name) and project their axons to its target nucleus, the robust nucleus of the arcopallium (RA). We report here that electrical activity in RA regulates neuronal addition to HVC. Decreasing neural activity in RA by intracerebral infusion of the GABAA receptor agonist muscimol decreased the number of new HVC neurons by 56%. Our results suggest that postsynaptic electrical activity influences the addition of new neurons into a functional neural circuit in adult birds.

Biological neurons can be approached by using some functional neural circuits, and the biophysical mechanism for signal processing can be explained. Chemical stimulus can adjust the intracellular and extracellular ions concentration, and thus the channel current can be regulated to trigger appropriate firing modes in the neural activities. A physical stimulus often injects kinds of energy, and the energy can be encoded in the components for generating a certain channel current. The energy driving on the cell can be effective to enhance the pumping of ions and mode transition is induced. Based on a simple neural circuit exposed to the external magnetic field, the mode selection is investigated to explore the biophysical mechanism of energy absorption by applying periodic, and stochastic magnetic fields, respectively. The external field energy is encoded in the induction coil of the neural circuit, and the channel current is induced. Two identical neural circuits are exposed to the same magnetic field and the synchronization approach is investigated without synapse coupling. It is found that two neurons in periodic firings can be synchronized under the same periodic or noise-like magnetic field even applying different initials, while intermittent phase lock is induced between two chaotic neurons. Stochastic variation in the external magnetic field can induce noisy induced electromotive force (IEF) and the firing mode is regulated effectively. When both noisy IEF and periodic stimulus are applied, synchronization stability between periodic neurons with initials diversity is enhanced while synchronization approach between chaotic neurons becomes difficult. In addition, the Hamilton energy in each neuron can keep pace with another neuron when complete synchronization is stabilized within a finite transient period. These results provide new insights to know the energy encoding mechanism in neural circuits and neurons exposed to external magnetic field.

A feasible neuron model can be effective to estimate the mode transition in neural activities in a complex electromagnetic environment. When neurons are exposed to electromagnetic field, the continuous magnetization and polarization can generate nonlinear effect on the exchange and propagation of ions in the cell, and then the firing patterns can be regulated completely. The conductivity of ion channels can be affected by the temperature and the channel current is adjusted for regulating the excitability of neurons. In this paper, a phototube and a thermistor are used to the functions of neural circuit. The phototube is used to capture external illumination for energy injection, and a continuous signal source is obtained. The thermistor is used to percept the changes of temperature, and the channel current is changed to adjust the excitability of neuron. This functional neural circuit can encode the external heat (temperature) and illumination excitation, and the dynamics of neural activities is investigated in detail. The photocurrent generated in the phototube can be used as a signal source for the neural circuit, and the thermistor is used to estimate the conduction dependence on the temperature for neurons under heat effect. Bifurcation analysis and Hamilton energy are calculated to explore the mode selection. It is found that complete dynamical properties of biological neurons can be reproduced in spiking, bursting, and chaotic firing when the phototube is activated as voltage source. The functional neural circuit mainly presents spiking states when the photocurrent is handled as a stable current source. Gaussian white noise is imposed to detect the occurrence of coherence resonance. This neural circuit can provide possible guidance for investigating dynamics of neural networks and potential application in designing sensitive sensors.

Healthy brain function requires a delicate balance between neural activity and local vascular dynamics. Perturbations to this balance, such as vessel diameter changes or fluctuations in red blood cell velocity, are thought to underlie a number of neurodegenerative and neurovascular diseases, including migraine, stroke, and epilepsy. Here, for the first time, we demonstrate high fidelity simultaneous acquisition of vascular and neural circuit dynamics in freely-moving animals using our newly developed nVue dual color miniscope. Our system enables simultaneous imaging of blood flow and neural activity in both superficial and deep-brain structures in awake, behaving rodents. By multiplexing two LEDs at up to 100hz, the nVue enables direct, real-time visualization of both hemodynamics and calcium activity in two channels. Additionally, we have augmented the Inscopix Data Processing Software package to capture time-varying estimates of vessel diameter and red blood cell (RBC) velocity in specific vessels. Vessel diameter is estimated as the full-width half maximum of a Lorentzian function fit to vessel cross-section, while RBC velocity is calculated based on time-lagged correlations between seed-pixels within individual regions of interest and all immediately neighboring pixels. Distances between correlation peaks are then plotted against time. Manual annotation of blood flow data was performed to establish a ground truth against which to validate the algorithm. The nVue blood flow imaging application offers a powerful, turn-key, multisystem workflow for simultaneously interrogating hemodynamics and neural circuit function in freely behaving animals which will profoundly expand the neurovascular coupling toolkit not only for basic and translational research but also for the development of novel preclinical therapeutics. Commercial This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Statistical Analysis of Multi-Cell Recordings: Linking Population Coding Models to Experimental Data

Neural wiring and activity are essential for proper brain function and behavioral outputs and rely on mechanisms that guide the formation, elimination, and remodeling of synapses. During development, it is therefore vital that synaptic densities and architecture are tightly regulated to allow for appropriate neural circuit formation and function. δ-Catenin, a component of the cadherin-catenin cell adhesion complex, has been demonstrated to be a critical regulator of synaptic density and function in the developing central neurons. In this study, we identified forms of δ-catenin that include only the N-terminal (DcatNT) or the C-terminal (DcatCT) regions. We found that these δ-catenin forms are differentially expressed in different regions of the male mouse brain. Our results also indicated that in rat primary cortical culture, these forms are generated in an activity-dependent manner by Ca2+-dependent and calpain-mediated cleavage of δ-catenin or in an activity-independent but lysosome-dependent manner. Functionally, loss of the domain containing the calpain-cleavage sites allowing for generation of DcatCT and DcatNT perturbed the density of a subpopulation of dendritic protrusions in rat hippocampal neurons. This subpopulation likely included protrusions that are either in transition toward becoming mature mushroom spines or in the process of being eliminated. By influencing this subpopulation of spines, proteolytic processing of δ-catenin can likely regulate the balance between mature and immature dendritic protrusions in coordination with neural activity. We conclude that by undergoing cleavage, δ-catenin differentially regulates the densities of subpopulations of dendritic spines and contributes to proper neural circuit wiring in the developing brain.