Neural Synapses Research Articles

Optical Bio-Inspired Synaptic Devices.

The traditional computer with von Neumann architecture has the characteristics of separate storage and computing units, which leads to sizeable time and energy consumption in the process of data transmission, which is also the famous "von Neumann storage wall" problem. Inspired by neural synapses, neuromorphic computing has emerged as a promising solution to address the von Neumann problem due to its excellent adaptive learning and parallel capabilities. Notably, in 2016, researchers integrated light into neuromorphic computing, which inspired the extensive exploration of optoelectronic and all-optical synaptic devices. These optical synaptic devices offer obvious advantages over traditional all-electric synaptic devices, including a wider bandwidth and lower latency. This review provides an overview of the research background on optoelectronic and all-optical devices, discusses their implementation principles in different scenarios, presents their application scenarios, and concludes with prospects for future developments.

Multistable Memristor Synapse-Based Coupled Bi-Hopfield Neuron Model: Dynamic Analysis, Microcontroller Implementation and Image Encryption

The memristor, a revolutionary electronic component, mimics both neural synapses and electromagnetic induction phenomena. Recent study challenges are the development of effective neural models and discovering their dynamics. In this study, we propose a novel Hopfield neural network model leveraging multistable memristors, showcasing its efficacy in encoding biomedical images. We investigate the equilibrium states and dynamic behaviors of our designed model through comprehensive numerical simulations, revealing a rich array of phenomena including periodic orbits, chaotic dynamics, and homogeneous coexisting attractors. The practical realization of our model is achieved using a microcontroller, with experimental results demonstrating strong agreement with theoretical analyses. Furthermore, harnessing the chaos inherent in the neural network, we develop a robust biomedical image encryption technique, validated through rigorous computational performance tests.

Multiparametric AFM insights into electron transport mechanisms in biomemristors

Biomemristors have attracted significant attention due to their applications in biodegradable and flexible electronic devices, and their prospective functions in information storage, neural synapses, and neuromorphic computation. Hence, understanding biomaterials' resistive switching (RS) mechanism is essential to design novel biomemristors with enhanced performance. In the last decade, various atomic force microscopy (AFM) modes, such as Kelvin probe force microscopy (KPFM) and conductive atomic force microscopy (cAFM), in situ/operando visualize the electron transport behaviors within biomemristors at the nanoscale. This review provides a comprehensive discussion of multiparametric AFM techniques to characterize biomemristors and inspire new ideas in developing next-generation consumer electronics. We also summarize the progress of revealing the internal mechanism of biomemristors with functional AFM to visualize and understand the switching behavior. Finally, the opportunities and challenges of further utilizing multiparametric AFM to explore the electron transport mechanisms in biomemristors are presented.

Xuefu Zhuyu decoction promotes synaptic plasticity by targeting miR-191a-5p/BDNF-TrkB axis in severe traumatic brain injury

BackgroundXuefu Zhuyu decoction (XFZYD) is a traditional Chinese herbal formula known for its ability to eliminate blood stasis and improve blood circulation, providing neuroprotection against severe traumatic brain injury (sTBI). However, the underlying mechanism is still unclear. PurposeWe aim to investigate the neuroprotective effects of XFZYD in sTBI from a novel mechanistic perspective of miRNA-mRNA. Additionally, we sought to elucidate a potential specific mechanism by integrating transcriptomics, bioinformatics, and conducting both in vitro and in vivo experiments. MethodsThe sTBI rat model was established, and the rats were treated with XFZYD for 14 days. The neuroprotective effects of XFZYD were evaluated using a modified neurological severity score, hematoxylin and eosin staining, as well as Nissl staining. The anti-inflammatory effects of XFZYD were explored using quantitative real-time PCR (qRT-PCR), Western blot analysis, and immunofluorescence. Next, miRNA sequencing of the hippocampus was performed to determine which miRNAs were differentially expressed. Subsequently, qRT-PCR was used to validate the differentially expressed miRNAs. Target core mRNAs were determined using various methods, including miRNA prediction targets, mRNA sequencing, miRNA-mRNA network, and protein-protein interaction (PPI) analysis. The miRNA/mRNA regulatory axis were verified through qRT-PCR or Western blot analysis. Finally, morphological changes in the neural synapses were observed using transmission electron microscopy and immunofluorescence. ResultsXFZYD exhibited significant neuroprotective and anti-inflammatory effects on subacute sTBI rats' hippocampus. The analyses of miRNA/mRNA sequences combined with the PPI network revealed that the therapeutic effects of XFZYD on sTBI were associated with the regulation of the rno-miR-191a-5p/BDNF axis. Subsequently, qRT-PCR and Western blot analysis confirmed XFZYD reversed the decrease of BDNF and TrkB in the hippocampus caused by sTBI. Additionally, XFZYD treatment potentially increased the number of synaptic connections, and the expression of the synapse-related protein PSD95, axon-related protein GAP43 and neuron-specific protein TUBB3. ConclusionsXFZYD exerts neuroprotective effects by promoting hippocampal synaptic remodeling and improving cognition during the subacute phase of sTBI through downregulating of rno-miR-191a-5p/BDNF axis, further activating BDNF-TrkB signaling.

Investigation on Synaptic Adaptation and Fatigue in ZnO/HfZrO-Based Memristors under Continuous Electrical Pulse Stimulation

This study investigates the behavior of memristive devices characterized by oxygen-deficient ZnO and HfZrO films under continuous pulse stimulation. This dynamic reflects the adaptability observed in neural synapses when repeatedly subjected to stress, ultimately resulting in a mitigated response to pressure. Observations show that the conductivity of memristors increases with the augmentation of continuous electrical pulses. However, the momentum of this growth trend gradually diminishes, highlighting the devices’ capability to adapt to repetitive pressure. This adjustment correlates with the transition of biological synapses from short-term to persistent memory stages, aligning with the principles of the Ebbinghaus memory model. The architecture of memristors, integrating ZnO and HfZrO in a layered manner, holds promising prospects in replicating the inherent synaptic features found in biological organisms.

Resistance switching stability of STO memristor under Au ion implantation

The alteration in microstructure, induced by ion migration due to applied voltage, constitutes a pivotal factor influencing the performance of the memristor. This phenomenon adversely impacts the stability of the memristor, posing challenges for its practical applications. Notably, the defects present in oxide films, serving as the functional layer in the memristor, assume a crucial role in determining the stability of the artificial synapse—a fundamental component of neuromorphic computing. The precise regulation of defect distribution and density at the nanoscale by growing films directly poses a formidable challenge. In this investigation, a memristor composed of strontium titanate (SrTiO3) was fabricated, exhibiting improved stability in resistive switching during I–V cycles and enhanced multilevel storage performance through the implementation of Au ions implantation. Furthermore, these devices were simulated as neural synapses and integrated into artificial neural networks. A comprehensive array of characterizations was executed to scrutinize the microscopic effects of ion implantation. This involved analyzing changes in elemental composition, structural damage, and spectral characteristics of the films. These findings offer a viable strategy for enhancing the resistive switching performance of oxide thin film devices through the judicious application of ion implantation.

Journal Digest: CBT With Cardiac Rehab, PMDD Neurochemistry, and More

Journal Digest: CBT With Cardiac Rehab, PMDD Neurochemistry, and More

The neurotoxicity and mechanism of TBBPA-DHEE exposure in mature zebrafish (Danio rerio)

Tetrabromobisphenol A-bis (2-hydroxyethyl) ether (TBBPA-DHEE) has been detected in various environmental media and organisms, and its ecological risks and health hazards have attracted great attention, but sufficient toxicological data have not proved the toxic effects of TBBPA-DHEE exposure on aquatic organism. In this study, the neurotoxicity and mechanism of zebrafish (3-month-old) exposed to TBBPA-DHEE (0.86 μg/L, 12.9 μg/L, 193.5 μg/L) were studied. Furthermore, the neurotoxicity susceptibility of different sexes of zebrafish was revealed. Behavioral studies revealed that TBBPA-DHEE exposure has significant differences in average speed, duration of mania, the distance between objects, and ATP content between male and female zebrafish. Slight damage in brain tissue of male zebrafish was found. The transcriptome analysis revealed that the molecular mechanism of neurotoxicity in mature female and male zebrafish is different. For mature female zebrafish, TBBPA-DHEE significantly affected the expression of genes related to behavior and development, and its mechanism may be that it can produce neurotoxicity by affecting related genes in the hormone, synapse, and Ca2+ signaling pathway. For mature male zebrafish, TBBPA-DHEE can significantly affect their behavior and expression of nerve-related genes. Results from the transcriptomic analysis suggests that the possible molecular mechanism may be through the inhibition of Ca2+ signal transmission and produce neurotoxicity by affecting the expression of related genes in neural synapses, Ca2+ signal, and MAPK signal in brain tissue of zebrafish. The results suggested that exposure to low-dose TBBPA-DHEE could induce neurotoxicity in zebrafish, and female and male zebrafish showed different toxic effects and molecular mechanisms.

Memory association circuit based on memristor for neural networks

Memristors have been favored in artificial intelligence, neural networks, and chaotic circuits, especially in neural synapses because of their unique advantages such as resistance variability, nonvolatile nature, and nanometer size. Benefits such as integration scale and low power consumption contribute toward simulating the biological synaptic function. Compared with memory association circuits using traditional CMOS transistors, memristors will reduce the complexity of the circuit and the power consumption. Therefore, it is greatly promising to use memristors as synapses to construct neural networks to mimic human brain functions. This paper successfully establishes a recognition circuit based on memristors to recognize some characteristics (size, color, shape, and smooth) of fruits, which is a learning function. After a few seconds, the output signal voltage drops, and this is a forgetting function. Through the establishment of a recognition circuit, the neural network and human complex behavior were simulated. This work lays the foundation for further research of human neural networks.

The Architect of Neurotransmission in C. elegans : How FLP-3 Neuropeptides' Structures Direct their Function.

Neuropeptides direct functions in the nervous, endocrine, and immune systems of all animals by altering the activity at neural synapses. A single neuropeptide gene can be post-translationally modified to create multiple active peptides. These individual active peptides can have unique functions and drive discrete binding partners. We have previously shown that specific peptides encoded by the C. elegans neuropeptide gene, flp- 3, have sex-specific roles in response to a pheromone released by hermaphrodite C. elegans, ascaroside #8 (ascr#8). Using structural predictions of select FLP-3 neuropeptides, we identify individual amino acids within specific neuropeptides that regulate specific behaviors suggesting structure-function relationships of neuropeptides in regulate sex-specific behaviors.

Anomalies in neurovascular coupling during early diabetes: A review.

Diabetic retinopathy is the most feared complication for those with diabetes. Although visible vascular pathology traditionally defines the management of this condition, it is now recognised that a range of cellular changes occur in the retina from an early stage of diabetes. One of the most significant functional changes that occurs in those with diabetes is a loss of vasoregulation in response to changes in neural activity. There are several retinal cell types that are critical for mediating so-called neurovascular coupling, including Müller cells, microglia and pericytes. Although there is a great deal of evidence that suggests that Müller cells are integral to regulating the vasculature, they only modulate part of the vascular tree, highlighting the complexity of vasoregulation within the retina. Recent studies suggest that retinal immune cells, microglia, play an important role in mediating vasoconstriction. Importantly, retinal microglia contact both the vasculature and neural synapses and induce vasoconstriction in response to neurally expressed chemokines such as fractalkine. This microglial-dependent regulation occurs via the vasomediator angiotensinogen. Diabetes alters the way microglia regulate the retinal vasculature, by increasing angiotensinogen expression, causing capillary vasoconstriction and contributing to a loss of vascular reactivity to physiological signals. This article summarises recent studies showing changes in vascular regulation during diabetes, the potential mechanisms by which this occurs and the significance of these early changes to the progression of diabetic retinopathy.

Stochastic Resonance in Organic Electronic Devices.

Stochastic Resonance (SR) is a phenomenon in which noise improves the performance of a system. With the addition of noise, a weak input signal to a nonlinear system, which may exceed its threshold, is transformed into an output signal. In the other words, noise-driven signal transfer is achieved. SR has been observed in nonlinear response systems, such as biological and artificial systems, and this review will focus mainly on examples of previous studies of mathematical models and experimental realization of SR using poly(hexylthiophene)-based organic field-effect transistors (OFETs). This phenomenon may contribute to signal processing with low energy consumption. However, the generation of SR requires a noise source. Therefore, the focus is on OFETs using materials such as organic materials with unstable electrical properties and critical elements due to unidirectional signal transmission, such as neural synapses. It has been reported that SR can be observed in OFETs by application of external noise. However, SR does not occur under conditions where the input signal exceeds the OFET threshold without external noise. Here, we present an example of a study that analyzes the behavior of SR in OFET systems and explain how SR can be made observable. At the same time, the role of internal noise in OFETs will be explained.

Change of BDNF expression in traumatic brain injury after Kaempferia galanga L. administration

BDNF has potent effects on neural synapses and its pathway affects cell survival and other biological processes. Kaempferia galanga L. has many active substances with antioxidant and anti-inflammatory effects. We analyzes BDNF in four different group of Wistar rats (Ratus novergicus) into Groups A (no trauma & extract), B (with trauma & no extract), C (with trauma and 600 mg/kgbw extract), and D (with trauma and 1200 mg/kgbw extract). Groups B, C, and D are further divided into those who had their BDNF measured on 24- (B24, C24, and D24) and 48-hours. BDNF expression were found to be statistically significant between Group A with both B24 (p = 0,009) and D24 (p = 0,009) on the 24-hour post-trauma decapitation analysis. On the 48 hours after trauma and extract administration, Group B48 (p = 0,002), C48 (p = <0,001), and D48 (p <0,001) were found to be significantly different with Group A. The administration of Kaempferia galanga L. extract can be considered as an option in increasing brain BDNF levels which are neuroprotective. Larger and specific studies are needed to determine the appropriate dose and duration.

Spintronics Nanodevices: An Edge Over Photonic synapses and CMOS

With the increasing dependency on neural networks, many novel technologies are being derived. Among the most powerful and compact advances, is the development of neuromorphic computing. Neuromorphic computing is concerned with emulating the design and neural function of the human brain. In this paper, we discuss one of the most important categories in neuromorphic computing: Spintronics. We also provide a brief review of CMOS, CMOS with neural synapses, and photonic synapses.

Solution NMR Structure of the SH3 Domain of Human Caskin1 Validates the Lack of a Typical Peptide Binding Groove and Supports a Role in Lipid Mediator Binding.

SH3 domains constitute an important class of protein modules involved in a variety of cellular functions. They participate in protein-protein interactions via their canonical ligand binding interfaces composed of several evolutionarily conserved aromatic residues forming binding grooves for typical (PxxP) and atypical (PxxxPR, RxxK, RKxxY) binding motifs. The calcium/calmodulin-dependent serine protein kinase (CASK)-interacting protein 1, or Caskin1, a multidomain scaffold protein regulating the cortical actin filaments, is enriched in neural synapses in mammals. Based on its known interaction partners and knock-out animal studies, Caskin1 may play various roles in neural function and it is thought to participate in several pathological processes of the brain. Caskin1 has a single, atypical SH3 domain in which key aromatic residues are missing from the canonical binding groove. No protein interacting partner for this SH3 domain has been identified yet. Nevertheless, we have recently demonstrated the specific binding of this SH3 domain to the signaling lipid mediator lysophospatidic acid (LPA) in vitro. Here we report the solution NMR structure of the human Caskin1 SH3 domain and analyze its structural features in comparison with other SH3 domains exemplifying different strategies in target selectivity. The key differences revealed by our structural study show that the canonical binding groove found in typical SH3 domains accommodating proline-rich motifs is missing in Caskin1 SH3, most likely excluding a bona fide protein target for the domain. The LPA binding site is distinct from the altered protein binding groove. We conclude that the SH3 domain of Caskin1 might mediate the association of Caskin1 with membrane surfaces with locally elevated LPA content.

Tropical Reservoir Computing Hardware

In recent years Reservoir Computing has arisen as an emerging machine-learning technique that is highly suitable for time-series processing. Nevertheless, due to the high cost in terms of hardware resources, the implementation of these systems in one single chip is complex. In this brief, we propose a hardware implementation of a reservoir computing system with morphological neurons that allows us to reduce considerably the area cost associated with the neural synapses. The main consequence of using tropical algebra is that input multipliers are substituted by adders, leading to much lower hardware requirements. The proposed design is synthesized on a Field-Programmable Gate Array (FPGA) and evaluated for two classical time-series prediction benchmarks. The current approach achieves significant improvements in terms of energy efficiency and hardware resources, as well as an appreciably higher precision compared to classical reservoir systems.

The genesis of art and the digital age

The complete translation of cultural heritage into a digital format acutely poses the question of art’s place in the digital era. The search for an answer is built upon the foundation of proposed evolutionary models of the genesis of art. Transitional periods from one historical cultural era to the next are characterized by a change in the most popular types of art. The establishment of one or another type of art is rigidly connected with the introduction of new data storage media and coding techniques. The constant increase in the variety of genres and media has culminated in the digital display. The appearance of a universal digital media must be reflected in the energetic reconstruction of the artistic world, but the birth of new types of art will lag behind. Moreover, the problem of the existence or non-existence of art also becomes relevant. In parallel with the elimination of literature, a virtual excarnation of object plasticity is occurring. It is possible that art is irreversibly forsaking sensual and bodily language, but the idea that it is using such an unexpected lexicon in an attempt to break through to the individual directly seems more productive. The purpose of art is to expand the space of consciousness. The digital age is distinguished by its possibility to transform this space in surprising ways. Digitalization of a work has a clear basic similarity to the physiological process of convolution of a sensory signal in the depths of the brain. Computer-based dipoles and neural synapses are binary structures, described in binary symbols. A work that has been translated into digits can be seen as the projection of a certain neural configuration that has come together in the depths of consciousness and is revealed in the form of an image. The likely prospects of obtaining, instead of projections, a multi-dimensional digital display, as well as the potential possibility for the psyche to adequately decipher it, portend a holistic reading of the work and even closer contact between the artist and the addressee. Right on the horizon is the path towards a synthesis of images that go beyond the limits of the usual forms and sensations. And nowadays unimaginable classes of feelings are capable of generating many vibrant “types and genres”. At the same time, threatening to the habitual methods of sensory perception and facilitating the liberation of the spirit, the excarnation of art works promise a categorically new stage in the genesis of art as well as a different level of creation and perception.

Novel missense alleles of SIGMAR1 as tools to understand emerin-dependent gene silencing in response to cocaine.

Sigma-1 receptor (Sigma1R; SIGMAR1), an integral membrane protein of the endoplasmic reticulum and nuclear envelope, has a hydrophobic drug-binding pocket that binds with high affinity to addictive drugs (cocaine, methamphetamine) and therapeutics used to treat a wide spectrum of neurological disorders. Cocaine enhances Sigma1R association with three nuclear lamina proteins (emerin, lamin A/C, BANF1), causing Sigma1R-dependent and emerin-dependent recruitment and transcriptional repression of a gene, MAOB1, involved in dopamine removal from neural synapses. The mechanism of Sigma1R association with emerin and the molecular impact of cocaine on their association are unknown. Mutations in Sigma1R, as a proposed regulator or mis-regulator of the nuclear lamina, have the potential to alter nuclear lamina function in brain or other tissues. We examined the frequency of SIGMAR1 missense alleles among 60,706 unrelated individuals in the ExAC database. We identified two novel SIGMAR1 missense variants of particular interest due to their frequency and potential to impact molecular association with emerin or other nuclear lamina proteins. Variant p.Q2P was widespread in ExAC (overall allele frequency 18.4%) with broad ethnic distribution among non-Finnish Europeans, Africans, South Asians, Latinx (allele frequencies ∼15% to 23%), and East Asians (∼38%). The p.R208W allele was identified in ∼0.78% of individuals overall with enrichment in Africans, Latinx, and East Asians (∼1.9–2.9%). These and other novel Sigma1R variants provide tools for future studies to determine the molecular basis of Sigma1R association with emerin and the mechanism of nuclear lamina misregulation by cocaine and potentially other Sigma1R agonists. Impact statement The Sigma-1 Receptor (Sigma1R; SIGMAR1) binds neuroactive drugs—both therapeutic and addictive—and associates with the nuclear membrane protein emerin and its partners lamin A/C and BANF1 in response to cocaine, through unknown mechanisms. We identified two novel SIGMAR1 missense variants of special interest due to their prevalence in human populations and their potential to perturb Sigma1R function at the nuclear envelope. Despite its importance in physiology and pharmacology, many aspects of Sigma1R including its membrane topology are unclear. Our findings lay the foundation for future molecular studies to understand how Sigma1R associates with emerin, lamin A/C, and BANF1 and manipulates their activity in response to agonist.

Validating a model of benzodiazepine refractory nerve agent-induced status epilepticus by evaluating the anticonvulsant and neuroprotective effects of scopolamine, memantine, and phenobarbital

IntroductionOrganophosphorus nerve agents (OPNAs) irreversibly block acetylcholinesterase activity, resulting in accumulation of excess acetylcholine at neural synapses, which can lead to a state of prolonged seizures known as status epilepticus (SE). Benzodiazepines, the current standard of care for SE, become less effective as latency to treatment increases. In a mass civilian OPNA exposure, concurrent trauma and limited resources would likely cause a delay in first response time. To address this issue, we have developed a rat model to test novel anticonvulsant/ neuroprotectant adjuncts at delayed time points. MethodsFor model development, adult male rats with cortical electroencephalographic (EEG) electrodes were exposed to soman and administered saline along with atropine, 2-PAM, and midazolam 5, 20, or 40 min after SE onset. We validated our model using three drugs: scopolamine, memantine, and phenobarbital. Using the same procedure outlined above, rats were given atropine, 2-PAM, midazolam and test treatment 20 min after SE onset. ResultsUsing gamma power, delta power, and spike rate to quantify EEG activity, we found that scopolamine was effective, memantine was minimally effective, and phenobarbital had a delayed effect on terminating SE. Fluoro-Jade B staining was used to assess neuroprotection in five brain regions. Each treatment provided significant protection compared to saline + midazolam in at least two brain regions. DiscussionBecause our data agree with previously published studies on the efficacy of these compounds, we conclude that this model is a valid way to test novel anticonvulsants/ neuroprotectants for controlling benzodiazepine-resistant OPNA-induced SE and subsequent neuropathology.

Exploring the Acetone Evaporation and Airborne Neurotoxicity Bioassay against Adult Mosquito in the Enclosed Environment of Peet Grady Chamber

Mosquito has comprehensive and sensitive olfactory neuro-sensory located at antenna utilized for detecting airborne organic compounds in search of blood host. Mosquito is also known to have similar neurotransmitters function with human at neural synapses e.g. acetylcholinesterase, esterases and oxidases enzymes. Thus, there is potential use mosquito in predicting neurotoxicity of exogenic volatile organic compounds (VOC) e.g. manufactured acetone. Hence, the study evaluates the suitability to conduct bioassay of VOC neurotoxicity against mosquito in Peet Grady chamber that is commonly used for insecticidal bioassay. Acetone as the representative of VOC is easily evaporized at laboratory temperature of 26 to 29 °C without heating. The acetone evaporation profile on liquid surface and porous solid surface under the Peet Grady chamber is studied to ascertain the consistency of vaporization rate with homogenized distribution. The study showed the acetone has shown consistent vaporization rate of 23 mg/min from liquid surface and 116.3 mg/min from porous surface (filter paper) without heating, in a linear regression of very high positive correlation (r = 1.000) between time and mass of acetone vaporized. However, the non-homogenized distribution of acetone vapours in the Peet Grady chamber directly affected the accuracy to elucidate the neurotoxicity bioassay against mosquito in term of mosquito knockdown. The study suggests the positioning of mosquitoes in the Peet Grady chamber should be lower than the point of acetone vaporization, whereby the mosquitoes are knockdown by acetone vapours within the 20th minute upon reaching concentration of 170.3 to 196.1 ppm.