Synaptic connections of the cuticular stress detectors in crayfish: mono- and polysynaptic reflexes and the entrainment of fictive locomotion in an in vitro preparation

1996 ◽  
Vol 178 (5) ◽  
Author(s):  
C.S. Leibrock ◽  
A.R. Marchand ◽  
W.J.P. Barnes ◽  
F. Clarac
Keyword(s):  
Fictive Locomotion ◽  
Synaptic Connections ◽  
Polysynaptic Reflexes

scholarly journals Oxytocin shapes spontaneous activity patterns in the developing visual cortex by activating somatostatin interneurons

2019 ◽  
Author(s):  
Paloma P Maldonado ◽  
Alvaro Nuno-Perez ◽  
Jan Kirchner ◽  
Elizabeth Hammock ◽  
Julijana Gjorgjieva ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Spontaneous Activity ◽  
Sensory Processing ◽  
Activity Patterns ◽  
Network Activity ◽  
Synaptic Connections ◽  
Pairwise Correlations ◽  
Early Brain Development

SummarySpontaneous network activity shapes emerging neuronal circuits during early brain development, however how neuromodulation influences this activity is not fully understood. Here, we report that the neuromodulator oxytocin powerfully shapes spontaneous activity patterns. In vivo, oxytocin strongly decreased the frequency and pairwise correlations of spontaneous activity events in visual cortex (V1), but not in somatosensory cortex (S1). This differential effect was a consequence of oxytocin only increasing inhibition in V1 and increasing both inhibition and excitation in S1. The increase in inhibition was mediated by the depolarization and increase in excitability of somatostatin+ (SST) interneurons specifically. Accordingly, silencing SST+ neurons pharmacogenetically fully blocked oxytocin’s effect on inhibition in vitro as well its effect on spontaneous activity patterns in vivo. Thus, oxytocin decreases the excitatory/inhibitory ratio and modulates specific features of V1 spontaneous activity patterns that are crucial for refining developing synaptic connections and sensory processing later in life.

scholarly journals Model-based detection of putative synaptic connections from spike recordings with latency and type constraints

2020 ◽  
Vol 124 (6) ◽  
pp. 1588-1604
Author(s):  
Naixin Ren ◽  
Shinya Ito ◽  
Hadi Hafizi ◽  
John M. Beggs ◽  
Ian H. Stevenson
Keyword(s):  
Linear Model ◽  
Generalized Linear Model ◽  
Large Scale ◽  
Statistical Problem ◽  
Detection Methods ◽  
Multielectrode Array ◽  
Synaptic Connections ◽  
Synaptic Effects ◽  
Synapse Detection

Detecting synaptic connections using large-scale extracellular spike recordings is a difficult statistical problem. Here, we develop an extension of a generalized linear model that explicitly separates fast synaptic effects and slow background fluctuations in cross-correlograms between pairs of neurons while incorporating circuit properties learned from the whole network. This model outperforms two previously developed synapse detection methods in the simulated networks and recovers plausible connections from hundreds of neurons in in vitro multielectrode array data.

Identification of excitatory interneurons contributing to generation of locomotion in lamprey: structure, pharmacology, and function

1989 ◽  
Vol 62 (1) ◽  
pp. 59-69 ◽  
Author(s):  
J. T. Buchanan ◽  
S. Grillner ◽  
S. Cullheim ◽  
M. Risling
Keyword(s):  
Spinal Cord ◽  
Membrane Potential ◽  
Excitatory Amino Acid ◽  
Postsynaptic Membrane ◽  
Fictive Locomotion ◽  
Potential Oscillations ◽  
And Function ◽  
Spherical Vesicles ◽  
Membrane Potential Oscillations

1. In the in vitro preparation of the lamprey spinal cord, paired intracellular recordings of membrane potential were used to identify interneurons producing excitatory postsynaptic potentials (EPSPs) on myotomal motoneurons. 2. Seventy-nine interneurons (8.4% of all neuron-motoneuron pairs tested) elicited unitary EPSPs that followed one-for-one at short, constant latencies and were therefore considered monosynaptic according to conventional criteria. Evidence was obtained for selectivity and divergence of excitatory interneuron (EIN) outputs and for convergence of EIN input to motoneurons. 3. The neurotransmitter released by EINs may be an excitatory amino acid such as glutamate, because the EPSPs were depressed by antagonists of excitatory amino acids. 4. Intracellular dye injection revealed that EINs have small cell bodies (average 11 x 27 microns), transversely oriented dendrites, and thin (less than 3 microns) slowly conducting axons (0.7 m/s) that project caudally and ipsilaterally. One EIN exhibited a system of thin multi-branching axon collaterals with periodic swellings. Ultrastructurally, these swellings contained clear spherical vesicles, and they apposed postsynaptic membrane specializations. 5. During fictive locomotion, the membrane-potential oscillations of EINs were greater in amplitude than, but similar in shape and timing to, those of their postsynaptic motoneurons. EINs fired action potentials during fictive locomotion and contributed to the depolarization of motoneurons. 6. These interneurons are proposed to be a source of excitation to motoneurons and interneurons in the lamprey spinal cord, participating in motor activity including locomotion.

Antidromic Modulation of a Proprioceptor Sensory Discharge in Crayfish

1997 ◽  
Vol 78 (2) ◽  
pp. 1180-1183 ◽  
Author(s):  
Michelle Bévengut ◽  
François Clarac ◽  
Daniel Cattaert
Keyword(s):  
Nervous System ◽  
Sensory Neurons ◽  
Sensory Information ◽  
Primary Afferents ◽  
Fictive Locomotion ◽  
Current Pulses ◽  
Cell Somata

Bévengut, Michelle, François Clarac, and Daniel Cattaert. Antidromic modulation of a proprioceptor sensory discharge in crayfish. J. Neurophysiol. 78: 1180–1183, 1997. In the proprioceptive neurons of the coxo-basal chortotonal organ, orthodromic spikes convey the sensory information from the cell somata (located peripherally) to the central output terminals. During fictive locomotion, presynaptic depolarizations of these central terminals elicit bursts of antidromic spikes that travel back to the periphery. To determine whether the antidromic spikes modified the orthodromic activity of the sensory neurons, single identified primary afferents of the proprioceptor were recorded intracellularly and stimulated in in vitro preparations of crayfish nervous system. Depolarizing current pulses were delivered in trains whose frequency and duration were controlled to reproduce bursts of antidromic spikes similar to those elicited during fictive locomotion. According to their frequencies, these antidromic bursts reduce or suppress the orthodromic discharges in both position- and movement-sensitive neurons. They induce both a long-lasting silence and a gradual recovery after their occurrences. Neither the collision between the afferent and the efferent messages nor the release of serotonin by the sensory neurons can explain these results. We therefore conclude that antidromic bursts produce a peripheral modulation of the orthodromic activity of the sensory neurons, modifying their sensitivity by mechanisms yet unknown.

scholarly journals Dopaminergic modulation of basal ganglia output through coupled excitation–inhibition

2017 ◽  
Vol 114 (22) ◽  
pp. 5713-5718 ◽  
Author(s):  
Agata Budzillo ◽  
Alison Duffy ◽  
Kimberly E. Miller ◽  
Adrienne L. Fairhall ◽  
David J. Perkel
Keyword(s):  
Basal Ganglia ◽  
Dynamic Change ◽  
Vocal Learning ◽  
Synaptic Connections ◽  
Biophysical Mechanism ◽  
Output Neurons ◽  
Neural Variability ◽  
Vocal Variability ◽  
Selection Of

Learning and maintenance of skilled movements require exploration of motor space and selection of appropriate actions. Vocal learning and social context-dependent plasticity in songbirds depend on a basal ganglia circuit, which actively generates vocal variability. Dopamine in the basal ganglia reduces trial-to-trial neural variability when the bird engages in courtship song. Here, we present evidence for a unique, tonically active, excitatory interneuron in the songbird basal ganglia that makes strong synaptic connections onto output pallidal neurons, often linked in time with inhibitory events. Dopamine receptor activity modulates the coupling of these excitatory and inhibitory events in vitro, which results in a dynamic change in the synchrony of a modeled population of basal ganglia output neurons receiving excitatory and inhibitory inputs. The excitatory interneuron thus serves as one biophysical mechanism for the introduction or modulation of neural variability in this circuit.

scholarly journals iPSC and optogenetics technologies for interrogating functional synaptic connections in vitro

2016 ◽  
Vol 10 ◽  
Author(s):  
Chin Eunice ◽  
Marcy Guillaume ◽  
Yoon Su-In ◽  
Ma Dongliang ◽  
Augustine George ◽  
...  
Keyword(s):  
Synaptic Connections

scholarly journals Neural basis of teeth coordination during gastric mill rhythms in spiny lobsters, Panulirus interruptus

1985 ◽  
Vol 114 (1) ◽  
pp. 99-119
Author(s):  
D. F. Russell
Keyword(s):  
Synaptic Connections ◽  
Gastric Mill ◽  
Food Particle ◽  
Phase Pattern ◽  
Neural Basis ◽  
Panulirus Interruptus ◽  
Spiny Lobsters ◽  
Coordination System ◽  
Rhythm Production

Motoneurones that drive the closing of the lateral teeth during gastric mill rhythms in spiny lobsters start firing before the motoneurones that drive the medial tooth powerstroke. This has the expected behavioural interpretation that the lateral teeth must close on a food particle before the medial tooth is pulled across it. The neural basis of the teeth coordination was examined. Experiments were made during gastric rhythms in in vitro preparations comprising the stomatogastric, oesophageal and (paired) commissural ganglia. Identified neurones in the stomatogastric ganglion were polarized to study their functional effects on the phasing and amplitude of bursts in other cells. Evoked firing of the lateral teeth closer motoneurones (especially LC) would evoke a discharge in the medial tooth powerstroke (GM) motoneurones, and suppress the firing of the medial tooth returnstroke (CP) motoneurone. Therefore the coordination pathway starts directly with the lateral teeth closer motoneurones. The CI interneurone was found to be an important link in the coordination pathway. It exerted opposite effects on the medial tooth motoneurones, suppressing firing of the powerstroke GM cells while evoking bursts in the returnstroke CP cell. CI affected other features of the pattern as well. Non-spiking inhibition from the lateral teeth closer motoneurones (LC and GP) to the lateral teeth opener motoneurones (LGs) was found to occur conjointly with spike-mediated IPSPs. Hyperpolarization of the LC, GP or CI neurones could temporarily abolish the gastric rhythm, but bursting in some or all of the other cells would eventually return, although in some cases the phase pattern was altered. It appears that no individual neurone in the gastric network is necessary for rhythm production. The coordination system can be viewed as several ‘levels’ of synaptic connections, each level being redundant and synergistic with the others.

scholarly journals Prediction of the Molecular Mechanisms Underlying Erlong Zuoci Treatment of Age-Related Hearing Loss via Network Pharmacology-Based Analyses Combined with Experimental Validation

2021 ◽  
Vol 12 ◽  
Author(s):  
Qing Liu ◽  
Ning Li ◽  
Yifang Yang ◽  
Xirui Yan ◽  
Yang Dong ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Experimental Validation ◽  
Molecular Mechanisms ◽  
Enrichment Analysis ◽  
Network Pharmacology ◽  
Synaptic Connections ◽  
Target Proteins ◽  
Age Related ◽  
Age Related Hearing Loss

Background: The traditional Chinese medicine formula ErLong ZuoCi (ELZC) has been extensively used to treat age-related hearing loss (ARHL) in clinical practice in China for centuries. However, the underlying molecular mechanisms are still poorly understood.Objective: Combine network pharmacology with experimental validation to explore the potential molecular mechanisms underlying ELZC with a systematic viewpoint.Methods: The chemical components of ELZC were collected from the Traditional Chinese Medicine System Pharmacology database, and their possible target proteins were predicted using the SwissTargetPrediction database. The putative ARHL-related target proteins were identified from the database: GeneCards and OMIM. We constructed the drug-target network as well as drug-disease specific protein-protein interaction networks and performed clustering and topological property analyses. Functional annotation and signaling pathways were performed by gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. Finally, in vitro experiments were also performed to validate ELZC’s key target proteins and treatment effects on ARHL.Results: In total, 63 chemical compounds from ELZC and 365 putative ARHL-related targets were identified, and 1860 ARHL-related targets were collected from the OMIM and GeneCards. A total of 145 shared targets of ELZC and ARHL were acquired by Venn diagram analysis. Functional enrichment analysis suggested that ELZC might exert its pharmacological effects in multiple biological processes, such as cell proliferation, apoptosis, inflammatory response, and synaptic connections, and the potential targets might be associated with AKT, ERK, and STAT3, as well as other proteins. In vitro experiments revealed that ELZC pretreatment could decrease senescence-associated β-galactosidase activity in hydrogen peroxide-induced auditory hair cells, eliminate DNA damage, and reduce cellular senescence protein p21 and p53. Finally, Western blot analysis confirmed that ELZC could upregulate the predicted target ERK phosphorylation.Conclusion: We provide an integrative network pharmacology approach, in combination with in vitro experiments to explore the underlying molecular mechanisms governing ELZC treatment of ARHL. The protective effects of ELZC against ARHL were predicted to be associated with cellular senescence, inflammatory response, and synaptic connections which might be linked to various pathways such as JNK/STAT3 and ERK cascade signaling pathways. As a prosperous possibility, our experimental data suggest phosphorylation ERK is essential for ELZC to prevent degeneration of cochlear.

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