Terms Of Plasticity Research Articles

Temporary inactivation of interpeduncular nucleus impairs long but not short term plasticity in the perforant-path dentate gyrus synapses in rats

The interconnectivity of the hippocampus, interpeduncular nucleus (IPN) and several brain structures which are involved in modulating hippocampal theta rhythm activity makes a complicated dynamic network of interconnected regions and highlights the role of IPN in the hippocampal dependent learning and memory. In the present study we aimed to address whether IPN is involved in the perforant path-dentate gyrus (PPDG) short term and long term synaptic plasticity in rats. To silent IPN transiently, lidocaine was injected through the implanted cannula above the IPN. To evaluate short term plasticity, paired pulses stimulation of PPDG synapses were used upon IPN temporary inactivation. Furthermore, long term plasticity was investigated by measuring the induction and maintenance of PPDG synapses long term potentiation (LTP) after high frequency stimulation (HFS) of the mentioned pathway following to IPN inactivation. The results showed that IPN reversible inactivation had no effect on short term plasticity of PPDG synapses. However, IPN inactivation before the PPDG high frequency stimulation could significantly suppress both the population spike (PS) and fEPSP-LTP induction compared to the saline group. Conversely, IPN inactivation had no significant effect on maintenance of both PS-LTP and fEPSP-LTP. All together our study suggests the contribution of IPN in the PPDG synaptic plasticity and excitability of DG granule cells which could be through direct and/or indirect pathways from IPN to the hippocampus.

NbOx based memristor as artificial synapse emulating short term plasticity

Memristors can mimic the functions of biological synapse, where it can simultaneously store the synaptic weight and modulate the transmitted signal. Here, we report Nb/Nb2O5/Pt based memristors with bipolar resistive switching, exhibiting synapse like property of gradual and continuously change of conductance with subsequent voltage signals. Mimicking of basic functions of remembering and forgetting processes of biological brain were demonstrated through short term plasticity, spike rate dependent plasticity, paired pulse facilitation and post-titanic potentiation. The device layer interface tuning was shown to affect the device properties shift from digital to analog behaviour. Demonstration of basic synaptic functions in the NbOx based devices makes them suitable for neuromorphic applications.

Preliminary Study of Distribution and Quantity of Plastic-debris on Beaches Along the Coast at Phuket Province

The beach sediment samples from Kalim, Tri Trang, and Patong Beaches, Phuket Province, southern of Thailand were collected for preliminary investigation on coastal debris. A total of 9 samples were taken from a 1 x 1 m quadrat at the depth of 5 cm, parallel with the shore during the period of maximum low tides in November, 2018. Microplastics (particles size < 5 mm) were extracted using sodium chloride (1.15 g mL-1) and their characteristics- including abundance (items m-2), weight (g), density (itemsm-2), color and shape- were determined using a stereo microscope. The results showed that microplastic debris varied in abundance from 1 to 35 items m-2 at the three selected beaches, depending on sampling location. In comparison, abundance of macroplastic (> 2.5 cm) and mesoplastic debris (5 mm to 2.5 cm) varied from 1 item m-2 quadrat (Kalim Beach) to 38 items (Patong Beach), 9 items (Tri Trang Beach) and 68 items (Patong Beach) m-2. Blue fibers were predominant among microplastic debris found at Kalim Beach; these are likely to have originated from pieces of rope, safeguard lines and fishing materials. In contrast, microplastic debris found in Patong and Tri Trang Beaches were predominantly green in color. The results of this study provide an overview of the sources of microplastics in coastal environments, which provides a basis for developing long term plastic management plans for these highly popular beaches in Phuket Province.

The best suitable alternative to diesel in a compression ignition engine between waste plastic oil and waste tire oil blends with diesel

ABSTRACT Depletion of conventional fossil fuels due to their increased consumption and the stringent emission norms, urge us to search alternative fuels for automotive engines. Alongside, serious challenge posed to the environment by the waste plastic in terms of its nondegradability is threatening the human sustainability. Both these issues can be addressed by converting the waste plastic into useful energy. In the present article, blends of diesel and oils derived from waste plastic and waste tire were used in a diesel engine, without any engine modifications to study the effect of blending waste plastic oil and waste tire oil to diesel up to 10% on the performance and combustion characteristics of the engine. Blending the pyrolysis oils to 10% with diesel could not improve the thermal efficiency but the change in the brake specific fuel consumption was to significant level. However, plastic oil-diesel blend yielded almost same brake specific fuel consumption which conveys that it is better to blend plastic oil rather than tire oil. But, the engine operation in case of P10 would not be as smooth as that in case of T10 and diesel owing to the higher rate of pressure rise of P10.

Optimal iron concentrations for growth-associated polyhydroxyalkanoate biosynthesis in the marine photosynthetic purple bacterium Rhodovulum sulfidophilum under photoheterotrophic condition.

Polyhydroxyalkanoates (PHAs) are a group of natural biopolyesters that resemble petroleum-derived plastics in terms of physical properties but are less harmful biologically to the environment and humans. Most of the current PHA producers are heterotrophs, which require expensive feeding materials and thus contribute to the high price of PHAs. Marine photosynthetic bacteria are promising alternative microbial cell factories for cost-effective, carbon neutral and sustainable production of PHAs. In this study, Rhodovulum sulfidophilum, a marine photosynthetic purple nonsulfur bacterium with a high metabolic versatility, was evaluated for cell growth and PHA production under the influence of various media components found in previous studies. We evaluated iron, using ferric citrate, as another essential factor for cell growth and efficient PHA production and confirmed that PHA production in R. sulfidophilum was growth-associated under microaerobic and photoheterotrophic conditions. In fact, a subtle amount of iron (1 to 2 μM) was sufficient to promote rapid cell growth and biomass accumulation, as well as a high PHA volumetric productivity during the logarithmic phase. However, an excess amount of iron did not enhance the growth rate or PHA productivity. Thus, we successfully confirmed that an optimum concentration of iron, an essential nutrient, promotes cell growth in R. sulfidophilum and also enhances PHA utilization.

Short Cationic Peptide Derived from Archaea with Dual Antibacterial Properties and Anti-Infective Potential.

Bacterial biofilms and associated infections represent one of the biggest challenges in the clinic, and as an alternative to counter bacterial infections, antimicrobial peptides have attracted great attention in the past decade. Here, ten short cationic antimicrobial peptides were generated through a sliding-window strategy on the basis of the 19-amino acid residue peptide, derived from a Pyrobaculum aerophilum ribosomal protein. PaDBS1R6F10 exhibited anti-infective potential as it decreased the bacterial burden in murine Pseudomonas aeruginosa cutaneous infections by more than 1000-fold. Adverse cytotoxic and hemolytic effects were not detected against mammalian cells. The peptide demonstrated structural plasticity in terms of its secondary structure in the different environments tested. PaDBS1R6F10 represents a promising antimicrobial agent against bacteria infections, without harming human cells.

Disproportional and paradoxical changes in blood pressure, heart rate and baroreflex under isoflurane anesthesia

For the biomedical researchers, the mandatory employment of anesthetics in experiments involving animals is often regarded as a major limitation because the results may be different from those obtained under a conscious state. For the anesthesiologists, whether patients may have been subjected to unnecessarily deep anesthesia that might jeopardize functions of the cardiovascular system and create inadvertent damage to the nervous system is a recurrent concern. Using isoflurane as the representative anesthetic agent, the goal of this study was to address the issue of whether general anesthetics induce their depressive actions equally on all aspects of cardiovascular functions and their regulations and whether the degree of depression is directly related to the doses. To mimic the clinical setting during surgery, changes of blood pressure (BP), heart rate (HR) and baroreflex in mice instrumented for radiotelemetry were recorded under a conscious state, to be followed by the delivery of incremental concentrations of isoflurane. We found that there was a significant but disproportional reduction in the cardiovascular parameters when C57BL/6 mice were subjected to 1.5% isoflurane anesthesia. Compared with the conscious state, the averaged reduction in BP or HR amounted to 23.5% or 20.5%. On the other hand, the experimental indices for baroreflex‐mediated sympathetic vasomotor tone or cardiac vagal baroreflex manifested a precipitous decline of 90.0% or 63.4%. On incremental concentrations of isoflurane up to a maximum of 4%, mice exhibited sustained BP and HR, alongside returning of both arms of the baroreflex towards the conscious level. We further found that bilateral adrenalectomy exerted minimal effects on the changes in BP, HR and baroreflex in mice subjected to incremental concentrations of isoflurane. It is therefore unlikely that norepinephrine and epinephrine released from the adrenal medulla may account for the disproportional and paradoxical changes in BP, HR and baroreflex under isoflurane anesthesia. These surprise observations offer at least two challenges to the general assumptions on general anesthesia. The effects of isoflurane on cardiovascular functions and their regulations are not exerted proportionally, and both baroreflex‐mediated sympathetic vasomotor tone and cardiac vagal baroreflex exhibit large functional capacity and plasticity in terms of regulating BP and HR.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Plasticity in Root Length and Volume Through the Alternate Wetting and Drying Water Management in Rice

Saving water via rational management in paddy rice require efforts to minimize risks to food security, whether consider that its adoption by farmers generally lead to lower grain productivity. Recently, studies by meta-analysis approaches highlight that when soil water potential was higher than -20 kPa, grain yields are not significantly decreased. In this context, new efforts should be done by rice breeders aiming to improve the plant performance when submitted to a more severe alternate wetting and drying (AWD) aiming to face the increasingly extreme climatic events in the next decades. Thus, in this first-tier of the study, our main objective was to evaluate the responses of a genotypes set (cultivars and elite line) for some root traits plasticity and its potential to change gas exchange attributes and grain yield when plants are subjected to severe AWD irrigation management, even when soil water potential beyond this threshold (when soils dried beyond -20 kPa, even reaching -40 kPa). Our data highlight that the mean grain yield across genotypes ranged from 9.25 to 12.65 ton/ha when maintained under continuous flooding (CF) and from 9.52 to 11.67 ton/ha at AWD water management. Root plasticity responses across evaluated genotypes under AWD management were highlighted; BRS Pampa cultivar and Titan CL hybrid showed the greater plasticity index for total root length and total root volume. Data suggests that under severe AWD management, root plasticity in terms of more total root length and total root volume at 0-20 cm depth can leads to some contribution degree for higher grain yield and for its stability under AWD practice. These results can serves as a starting point to additional efforts via physiological breeding approaches aiming the construction of rice plant ideotypes more suitable for AWD management, especially take into account its contributions to mitigate potential impacts of future climate changes on food security.

An epitaxial synaptic device made by a band-offset BaTiO3/Sr2IrO4 bilayer with high endurance and long retention

New types of artificial synaptic devices are important to develop highly reliable devices for high-intelligent neuromorphic information technologies. Here, we develop an epitaxial heterostructure with a small-gap spin-orbital-coupling-Mott insulator Sr2IrO4 and a large-gap ferroelectric BaTiO3 to implement robust artificial synapses. Electric-field-dependent synchrotron X-ray absorption spectroscopy indicates that oxygen vacancies are transferred to the bilayer surface by an applied voltage less than 5 V. Because of the epitaxial quality and the large band-gap offset, the prototype devices have robust bipolar-resistance-switching behaviors as demonstrated by the high endurance (>104 cycles) and the long retention (>104 s). The steady synaptic learning algorithm is made in the prototype device with multiple synaptic functions including the short term plasticity, long term plasticity, and spike timing dependent plasticity. Our study demonstrates the ferroelectric/spin-orbital-coupling-Mott oxide bilayer as a reliable prototype device that mimics the synapses in neural systems of the human brain.

Precipitation has dominant influences on the variation of plant hydraulics of the native Castanopsis fargesii (Fagaceae) in subtropical China

Understanding the roles of climate and intraspecific phylogeny in affecting the variation of plant hydraulics can provide insights into species distribution in different habitats. In the present study, we quantified ten functional traits characterizing branch and leaf hydraulic architecture of Castanopsis fargesii from 12 populations along a precipitation gradient (1120–1690 mm y−1), covering an 1800-km-long west-center-east transect in the subtropical region of China. We also conducted phylogenetic analyses to test the role of intraspecific phylogeny in affecting the variation of hydraulic architecture. We found that, with decreasing precipitation, branch vessel density remained unchanged while hydraulically weighted vessel diameter (Dh) declined by 31.9%, leading to a 74.3% reduction in theoretical hydraulic conductance (Kth). In parallel, leaf vein density (VD) and stomatal pore area index (SPI) declined by 14.6% and 29.9%, respectively. Leaf turgor loss point also declined significantly from −1.51 to −2.29 MPa along the precipitation gradient. In addition, functional traits related to hydraulic efficiency (i.e. Kth, Dh, VD and SPI) were positively correlated, whereas both trait variation and trait-trait correlations were not significantly affected by intraspecific phylogeny, as indicated by the values of Blomberg’s K < 1 and the consistency between principle component analysis and phylogenetic principle component analysis. We conclude that, hydraulic architectures of branch and leaf in C. fargesii varied remarkably under the primary influence of precipitation, suggesting that this subtropical tree species has a high degree of plasticity in terms of hydraulic adjustment, allowing it to cope with shifts in precipitation under future climate change.

The Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) Version 2.0: Modelling in vitro electrical stimulation of brain tissue

Neuronal circuits can be modelled in detail allowing us to predict the effects of stimulation on individual neurons. Electrical stimulation of neuronal circuits in vitro and in vivo excites a range of neurons within the tissue and measurements of neural activity, e.g the local field potential (LFP), are again an aggregate of a large pool of cells. The previous version of our Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) allowed for the simulation of the LFP generated by a patch of brain tissue. Here, we extend VERTEX to simulate the effect of electrical stimulation through a focal electric field. We observe both direct changes in neural activity and changes in synaptic plasticity. Testing our software in a model of a rat neocortical slice, we determine the currents contributing to the LFP, the effects of paired pulse stimulation to induce short term plasticity (STP), and the effect of theta burst stimulation (TBS) to induce long term potentiation (LTP).

Research and Development of Rehabilitation Systems for the Upper Limbs “PLEMO” Series

The human brain has excellent plasticity in terms of recovery from a stroke. It is expected that neurorehabilitation using an apparatus that applies robotic and virtual reality technology has rehabilitation training effects on stroke patients. Rehabilitation of the upper limbs consists of rehabilitation for shoulders and elbows, and rehabilitation of the fingers and wrists. Both rehabilitations are necessary to improve activities of daily living. Many rehabilitation systems for shoulders and elbows have been effective thus far. In this review, we introduce rehabilitation systems for the shoulders, elbows, and wrists of the upper limbs “PLEMO” series using force presentation technology with brakes. Rehabilitation systems using brakes are essentially safe unlike rehabilitation systems using actuators.

Scaling of recovery rates influences T-type Ca2+ channel availability following IPSPs

The excitability of neuronal membranes is crucially modulated by T-type Ca2+ channels (ICaT) due to their low threshold of activation. ICaT inactivates steeply at potentials close to the resting membrane potential. Therefore, the availability of ICaT following changes in membrane potential depends on the time course of the onset of inactivation as well as on the time course of recovery from inactivation.It was previously shown that the time course of recovery from inactivation depends on the duration of the conditioning pulse in cloned T-type Ca2+ channel subunits (Cav3.1-Cav3.3(Uebachs et al., 2006)). This provides a potential mechanism for an intrinsic form of short term plasticity. Here, we address the question, whether this mechanism results in altered availability of ICaT following physiological changes in membrane potential. We found that the recovery of ICaT during an IPSP depends on the duration of a preceding depolarized period.

The Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) Version 2.0: Modelling in vitro electrical stimulation of brain tissue.

Neuronal circuits can be modelled in detail allowing us to predict the effects of stimulation on individual neurons. Electrical stimulation of neuronal circuits in vitro and in vivo excites a range of neurons within the tissue and measurements of neural activity, e.g the local field potential (LFP), are again an aggregate of a large pool of cells. The previous version of our Virtual Electrode Recording Tool for EXtracellular Potentials (VERTEX) allowed for the simulation of the LFP generated by a patch of brain tissue. Here, we extend VERTEX to simulate the effect of electrical stimulation through a focal electric field. We observe both direct changes in neural activity and changes in synaptic plasticity. Testing our software in a model of a rat neocortical slice, we determine the currents contributing to the LFP, the effects of paired pulse stimulation to induce short term plasticity (STP), and the effect of theta burst stimulation (TBS) to induce long term potentiation (LTP).

Micropolar plasticity. Part II: a v.Mises version of micropolar plasticity in terms of curvature tensors related by mixed transformations

In Part I, we presented a general micropolar plasticity theory which rests on a class of micropolar curvature tensors related to each other by mixed transformations. In this paper, we derive, in the context of the theory of Part I, a micropolar counterpart of v.Mises conventional plasticity with kinematic and isotropic hardening. The predictive capabilities of the resulting model are illustrated for the case of tension loading of plates with a circular hole.

Impact of sleep bruxism on training-induced cortical plasticity

PurposeTo investigate if sleep bruxism (SB) influences training-induced cortical plasticity and performance in terms of accuracy and precision of a tooth-clenching task (TCT). MethodsThirty-eight participants were allocated into SB group (N=19) and control group (N=19) according to presence of SB based on a 2-week screening. The participants were instructed to perform a standardized TCT for 58min at three different force levels (10%, 20% and 40% of maximum voluntary contraction; MVC) in three series (first and third without visual-feedback and second with visual-feedback). Accuracy and precision of the TCT were calculated from actual bite force values. Transcranial magnetic stimulation was applied to elicit motor evoked potentials (MEPs) from the masseter and first dorsal interosseous muscle (FDI) before the TCT (pre-TCT-session) and 5-min after the TCT (post-TCT-session). ResultsAccuracy was significantly dependent on the series and target force level (P<0.001), however, there was a significant decrease only in the control group at 10% MVC from first to third session (P<0.001). No significant differences between groups were observed for the precision of the TCT. Masseter MEPs in the SB group in the pre-TCT-session at 120% and 160% motor threshold were significantly lower than in the control group (P<0.05). Masseter MEPs of the control group in the post-TCT-session were significantly higher than the pre-TCT-session (P<0.05) but not SB. FDI MEPs were only dependent on stimulus intensity (P<0.001). ConclusionsSB is associated with significant changes not only in excitability of corticomotor control but also motor learning of jaw movements and force control.

Non-reversible and Reversible Heat Tolerance Plasticity in Tropical Intertidal Animals: Responding to Habitat Temperature Heterogeneity.

The theory for thermal plasticity of tropical ectotherms has centered on terrestrial and open-water marine animals which experience reduced variation in diurnal and seasonal temperatures, conditions constraining plasticity selection. Tropical marine intertidal animals, however, experience complex habitat thermal heterogeneity, circumstances encouraging thermal plasticity selection. Using the tropical rocky-intertidal gastropod, Echinolittorina malaccana, we investigated heat tolerance plasticity in terms of laboratory acclimation and natural acclimatization of populations from thermally-dissimilar nearby shorelines. Laboratory treatments yielded similar capacities of snails from either population to acclimate their lethal thermal limit (LT50 variation was ∼2°C). However, the populations differed in the temperature range over which acclimatory adjustments could be made; LT50 plasticity occurred over a higher temperature range in the warm-shore snails compared to the cool-shore snails, giving an overall acclimation capacity for the populations combined of 2.9°C. In addition to confirming significant heat tolerance plasticity in tropical intertidal animals, these findings reveal two plasticity forms, reversible (laboratory acclimation) and non-reversible (population or shoreline specific) plasticity. The plasticity forms should account for different spatiotemporal scales of the environmental temperature variation; reversible plasticity for daily and tidal variations in microhabitat temperature and non-reversible plasticity for lifelong, shoreline temperature conditions. Non-reversible heat tolerance plasticity, likely established after larvae settle on the shore, should be energetically beneficial in preventing heat shock protein overexpression, but also should facilitate widespread colonization of coasts that support thermally-diverse shorelines. This first demonstration of different plasticity forms in benthic intertidal animals supports the hypothesis that habitat heterogeneity (irrespective of latitude) drives thermal plasticity selection. It further suggests that studies not making reference to different spatial scales of thermal heterogeneity, nor seeking how these may drive different thermal plasticity forms, risk misinterpreting ectothermic responses to environmental warming.

Early Programming during Attachment Development and its Relevance for Risk/Resilience of Neuropsychiatric and Cardiometabolic Diseases during Adulthood

Social and cultural environmental factors influence the development of susceptibility to diseases in adulthood since the peri-natal stages of life. Sociotype describes the way in which interactions between social, cultural and environmental factors influence health. It plays a role as important as that of the genotype and phenotype in the balance of the health/disease processes during all the life span. Attachment forms part of the sociotype and is defined as the innate biological system that characterizes the link between an infant and a bonding figure. It increases the possibility of survival to a reproductive age and determines empathy and intimacy that when incorrectly established may be the cause of a number of pathological conditions in the adult life. Different types of attachment have, as a consequence, physiological and endocrinological alterations that result from the exposure to stressful and/or traumatic events during early stages of life. These constitute long- term plastic changes in structures in the central nervous system that produce in alterations in signaling molecule production that may arise from epigenetic cues established during the early stages of life in trauma- exposed subjects and that may lead to increased risk of diseases in adulthood. Therefore, sociotype and attachment might determine epigenetic alterations that may act on biological pathways involved in the comorbidity of cardiometabolic and neuropsychiatric diseases.

No Clue About Bioplastics

We analyze recycling decisions for bioplastics using a natural field experiment. The potential environmental benefits of these new plastics may not materialize if they are recycled incorrectly. The field experiment that we set up to test this recycling behavior exploits the setting of a lemonade tasting. In our experimental treatments, subjects are exposed to different types of bioplastics logos on their cups as well as varying amounts of recycling information. We use two types of bioplastics and compare these to conventional plastics in terms of whether subjects recycle the cups correctly. Our results show that over 90% of subjects dispose of their cup with plastic waste and that none of our treatments can snap subjects out of this default behavior. We interpret this finding as subjects having no clue how to recycle bioplastics. More generelly, these results point to skepticism regarding new products or varieties whose environmental benefits depend on proper use or disposal.

Proton Conductor Gated Synaptic Transistor Based on Transparent IGZO for Realizing Electrical and UV Light Stimulus

Synaptic transistors mimicking the biological synapse’s short term plasticity and short-term memory property were demonstrated using the amorphous indium–gallium–zinc oxide channel in combination with the nanogranular SiO2 as the gate oxide. The lowest energy consumption was 1.08 pJ per pulse activity and the operating voltage was within 100 mV. The device’s plasticity and memory characteristics can be explained by the movement of protons in the insulating layer. The proton relaxation was revealed by two ways of dual sweeping: continuous and discontinuous sweepings. We observed that the excitatory postsynaptic current (EPSC) rose as the voltage decreased anomaly during the backward sweeping process. In the electrical stimulus, both the short-term potentiation and depression were observed for this proposed device. The amplitude of the EPSC changed with the pulse number following a saturating exponential function. For the electrical stimulus under constant illumination, the UV light wavelength, intensity and duration time were found to have little effect on the paired pulse facilitation. While in the light stimulus, the light frequency promoted the paired pulse facilitation and had more effect on the synapse’s plasticity than the other light pulse parameters including intensity, numbers and width.