Ethanol Differentially Affects Excitatory and Inhibitory Synaptic Transmission in Visual Cortex of Wild-type and Adenosine AR Knock-out Mice.

Ethanol is one of the most commonly used and abused substances in the world. While the behavioral effects of ethanol are well characterized, mechanisms of its action on neurons and synapses remain elusive. Prior research suggested that ethanol could affect neurons by interfering with metabolism of biologically active molecules, such as adenosine.

[Cardiohemodynamic Changes and Cardiac Arrhythmias After Coronavirus Infection].

Aim      To study changes in cardiohemodynamic alterations of the myocardium and heart rhythm disorders at 3 and 6 months following the coronavirus infection.Material and methods   EchoCG, ECG Holter monitoring, and Doppler ultrasonography of hepatolienal blood vessels were performed for 77 patients (mean age, 35.9 years) at 3 and 6 months after coronavirus infection.

Synaptic Plasticity in Cortical Inhibitory Neurons: What Mechanisms May Help to Balance Synaptic Weight Changes?

Inhibitory neurons play a fundamental role in the normal operation of neuronal networks. Diverse types of inhibitory neurons serve vital functions in cortical networks, such as balancing excitation and taming excessive activity, organizing neuronal activity in spatial and temporal patterns, and shaping response selectivity. Serving these, and a multitude of other functions effectively requires fine-tuning of inhibition, mediated by synaptic plasticity.

Distinct Heterosynaptic Plasticity in Fast Spiking and Non-Fast-Spiking Inhibitory Neurons in Rat Visual Cortex.

Inhibition in neuronal networks of the neocortex serves a multitude of functions, such as balancing excitation and structuring neuronal activity in space and time. Plasticity of inhibition is mediated by changes at both inhibitory synapses, as well as excitatory synapses on inhibitory neurons. Using slices from visual cortex of young male rats, we describe a novel form of plasticity of excitatory synapses on inhibitory neurons, weight-dependent heterosynaptic plasticity.

Impaired Fear Extinction Due to a Deficit in Ca Influx Through L-Type Voltage-Gated Ca Channels in Mice Deficient for Tenascin-C.

Mice deficient in the extracellular matrix glycoprotein tenascin-C (TNC) express a deficit in specific forms of hippocampal synaptic plasticity, which involve the L-type voltage-gated Ca channels (L-VGCCs). The mechanisms underlying this deficit and its functional implications for learning and memory have not been investigated. In line with previous findings, we report on impairment in theta-burst stimulation (TBS)-induced long-term potentiation (LTP) in TNC mice in the CA1 hippocampal region and its rescue by the L-VGCC activator Bay K-8644.

Very low concentrations of ethanol suppress excitatory synaptic transmission in rat visual cortex.

Ethanol is one of the most commonly used substances in the world. Behavioral effects of alcohol are well described, however, cellular mechanisms of its action are poorly understood. There is an apparent contradiction between measurable behavioral changes produced by low concentrations of ethanol, and lack of evidence of synaptic changes at these concentrations.

Adenosine Shifts Plasticity Regimes between Associative and Homeostatic by Modulating Heterosynaptic Changes.

Endogenous extracellular adenosine level fluctuates in an activity-dependent manner and with sleep-wake cycle, modulating synaptic transmission and short-term plasticity. Hebbian-type long-term plasticity introduces intrinsic positive feedback on synaptic weight changes, making them prone to runaway dynamics. We previously demonstrated that co-occurring, weight-dependent heterosynaptic plasticity can robustly prevent runaway dynamics.

Partial Breakdown of Input Specificity of STDP at Individual Synapses Promotes New Learning.

Unlabelled: Hebbian-type learning rules, which underlie learning and refinement of neuronal connectivity, postulate input specificity of synaptic changes. However, theoretical analyses have long appreciated that additional mechanisms, not restricted to activated synapses, are needed to counteract positive feedback imposed by Hebbian-type rules on synaptic weight changes and to achieve stable operation of learning systems. The biological basis of such mechanisms has remained elusive.

Homeostatic role of heterosynaptic plasticity: models and experiments.

Homosynaptic Hebbian-type plasticity provides a cellular mechanism of learning and refinement of connectivity during development in a variety of biological systems. In this review we argue that a complimentary form of plasticity-heterosynaptic plasticity-represents a necessary cellular component for homeostatic regulation of synaptic weights and neuronal activity. The required properties of a homeostatic mechanism which acutely constrains the runaway dynamics imposed by Hebbian associative plasticity have been well-articulated by theoretical and modeling studies.

[The dynamics of indicators of selenium, glutathione and anti-oxidant defense of blood in patients with anemic cardiomyopathy against the background of treatment with preparations of iron and selenium].

The study was carried out on samplings of 46 patients with asiderotic anemia of severe degree and complicated by cardiomyopathy and 16 healthy persons. The content of selenium was analyzed using I.I.

Label-free, single molecule resonant cavity detection: a double-blind experimental study.

Optical resonant cavity sensors are gaining increasing interest as a potential diagnostic method for a range of applications, including medical prognostics and environmental monitoring. However, the majority of detection demonstrations to date have involved identifying a "known" analyte, and the more rigorous double-blind experiment, in which the experimenter must identify unknown solutions, has yet to be performed. This scenario is more representative of a real-world situation.

Adenosine effects on inhibitory synaptic transmission and excitation-inhibition balance in the rat neocortex.

Key Points: Adenosine might be the most widespread neuromodulator in the brain, but its effects on inhibitory transmission in the neocortex are not understood. Here we report that adenosine suppresses inhibitory transmission to layer 2/3 pyramidal neurons via activation of presynaptic A1 receptors. We present evidence for functional A2A receptors, which have a weak modulatory effect on the A1-mediated suppression, at about 50% of inhibitory synapses at pyramidal neurons.

Photoelastic ultrasound detection using ultra-high-Q silica optical resonators.

As a result of its non-invasive and non-destructive nature, ultrasound imaging has found a variety of applications in a wide range of fields, including healthcare and electronics. One accurate and sensitive approach for detecting ultrasound waves is based on optical microcavities. Previous research using polymer microring resonators demonstrated detection based on the deformation of the cavity induced by the ultrasound wave.

Optical detection of CO and CO2 temperature dependent desorption from carbon nanotube clusters.

The development of new materials relies on high precision methods to quantify adsorption/desorption of gases from surfaces. One commonly used approach is temperature programmed desorption spectroscopy. While this approach is very accurate, it requires complex instrumentation, and it is limited to performing experiments under high vacuum, thus restricting experimental scope.

Heterosynaptic plasticity: multiple mechanisms and multiple roles.

Plasticity is a universal property of synapses. It is expressed in a variety of forms mediated by a multitude of mechanisms. Here we consider two broad kinds of plasticity that differ in their requirement for presynaptic activity during the induction.

Modulation of synaptic transmission by adenosine in layer 2/3 of the rat visual cortex in vitro.

Adenosine is a wide-spread endogenous neuromodulator. In the central nervous system it activates A1 and A2A receptors (A1Rs and A2ARs) which have differential distributions, different affinities to adenosine, are coupled to different G-proteins, and have opposite effects on synaptic transmission. Although effects of adenosine are studied in detail in several brain areas, such as the hippocampus and striatum, the heterogeneity of the effects of A1R and A2AR activation and their differential distribution preclude generalization over brain areas and cell types.

Monitoring DNA hybridization using optical microcavities.

The development of DNA analysis methods is rapidly expanding as interest in characterizing subtle variations increases in biomedicine. A promising approach is based on evanescent field sensors that monitor the hybridization process in real time. However, one challenge is discriminating between nonspecific and specific attachment.

Heterosynaptic plasticity prevents runaway synaptic dynamics.

Spike timing-dependent plasticity (STDP) and other conventional Hebbian-type plasticity rules are prone to produce runaway dynamics of synaptic weights. Once potentiated, a synapse would have higher probability to lead to spikes and thus to be further potentiated, but once depressed, a synapse would tend to be further depressed. The runaway synaptic dynamics can be prevented by precisely balancing STDP rules for potentiation and depression; however, experimental evidence shows a great variety of potentiation and depression windows and magnitudes.

Cascaded Raman microlaser in air and buffer.

Optical microcavities provide an intriguing platform for the development of low threshold microlasers based on nonlinear effects. Long photon lifetimes within the cavity translate to high circulating optical intensities, thereby reducing the lasing threshold. It is therefore possible to create lasers that can operate in complex environments.

Heterosynaptic plasticity induced by intracellular tetanization in layer 2/3 pyramidal neurons in rat auditory cortex.

Associative Hebbian-type synaptic plasticity underlies the mechanisms of learning and memory; however, Hebbian learning rules lead to runaway dynamics of synaptic weights and lack mechanisms for synaptic competition.Heterosynaptic plasticity may solve these problems by complementing plasticity at synapses that were active during the induction, with opposite-sign changes at non-activated synapses. In visual cortex, a potential candidate mechanism for normalization is plasticity induced by a purely postsynaptic protocol, intracellular tetanization.

Search for production of invisible final states in single-photon decays of Υ(1S).

We search for single-photon decays of the Υ(1S) resonance, Υ → γ + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A⁰, or a pair of dark matter particles, χχ. Both A⁰ and χ are assumed to have zero spin. We tag Υ(1S) decays with a dipion transition Υ(2S) → π⁺π⁻Υ(1S) and look for events with a single energetic photon and significant missing energy.

Heterosynaptic plasticity in the neocortex.

Ongoing learning continuously shapes the distribution of neurons' synaptic weights in a system with plastic synapses. Plasticity may change the weights of synapses that were active during the induction-homosynaptic changes, but also may change synapses not active during the induction-heterosynaptic changes. Here we will argue, that heterosynaptic and homosynaptic plasticity are complementary processes, and that heterosynaptic plasticity might accompany homosynaptic plasticity induced by typical pairing protocols.

Onset dynamics of action potentials in rat neocortical neurons and identified snail neurons: quantification of the difference.

The generation of action potentials (APs) is a key process in the operation of nerve cells and the communication between neurons. Action potentials in mammalian central neurons are characterized by an exceptionally fast onset dynamics, which differs from the typically slow and gradual onset dynamics seen in identified snail neurons. Here we describe a novel method of analysis which provides a quantitative measure of the onset dynamics of action potentials.

[Peculiarities of systolic and diastolic function of left and right ventricles in elderly and geriatric patients with stable effort class II-III angina during formation of chronic heart failure].

In order to reveal peculiarities of function of cardiac ventricles in functional class (FC) II-III chronic heart failure (CHF) Doppler echocardiography (DE) and myocardial tissue Doppler echocardiography (TDE) were carried out in 108 middle aged, elderly and old patients. Patients with signs of FCIII CHF had pronounced impairment of global contractile function of left and right ventricles (LV and RV) with RV ejection fraction (EF) higher than LV EF. These patients had lower parameters of central hemodynamics, high parameters of pulmonary hypertension, increased thickness of RV free wall, greater percentage of irreversible LV and RV myocardium in response to deep breath, more pronounced derangements of RV and LV diastolic filling.

Adaptation at synaptic connections to layer 2/3 pyramidal cells in rat visual cortex.

Neocortical synapses express differential dynamic properties. When activated at high frequencies, the amplitudes of the subsequent postsynaptic responses may increase or decrease, depending on the stimulation frequency and on the properties of that particular synapse. Changes in the synaptic dynamics can dramatically affect the communication between nerve cells.