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Advanced Materials (Deerfield Beach,... Sep 2023Diverse microscopic ionic dynamics help mediate the ability of a biological neural network to handle complex tasks with low energy consumption. Thus, rich internal ionic...
Diverse microscopic ionic dynamics help mediate the ability of a biological neural network to handle complex tasks with low energy consumption. Thus, rich internal ionic dynamics in memristors based on transition metal oxide are expected to provide a unique and useful platform for implementing energy-efficient neuromorphic computing. To this end, a titanium oxide (TiO )-based interface-type dynamic memristor and an niobium oxide (NbO )-based Mott memristor are integrated as an artificial dendrite and spike-firing soma, respectively, to construct a dendritic neuron unit for realizing high-efficiency spatial-temporal information processing. Further, a dendritic neural network is hardware-implemented for spatial-temporal information processing to highlight the computational advantages achieved by incorporating dendritic functions in the network. Human motion recognition is demonstrated using the Nanyang Technological University-Red Green Blue (NTU-RGB) dataset as a benchmark spatial-temporal task; it shows a nearly 20% improvement in accuracy for the memristors-based hardware incorporating dendrites and a 1000× advantage in power efficiency compared to that of the graphics processing unit (GPU). The dendritic neuron developed in this study can be considered a critical building block for implementing more bio-plausible neural networks that can manage complex spatial-temporal tasks with high efficiency.
PubMed: 35735048
DOI: 10.1002/adma.202203684 -
The Journal of Neuroscience : the... Dec 2023Mammalian target of rapamycin (mTOR) pathway has emerged as a key molecular mechanism underlying memory processes. Although mTOR inhibition is known to block memory...
Mammalian target of rapamycin (mTOR) pathway has emerged as a key molecular mechanism underlying memory processes. Although mTOR inhibition is known to block memory processes, it remains elusive whether and how an enhancement of mTOR signaling may improve memory processes. Here we found in male mice that the administration of VO-OHpic, an inhibitor of the phosphatase and tensin homolog (PTEN) that negatively modulates AKT-mTOR pathway, enhanced auditory fear memory for days and weeks, while it left short-term memory unchanged. Memory enhancement was associated with a long-lasting increase in immature-type dendritic spines of pyramidal neurons into the auditory cortex. The persistence of spine remodeling over time arose by the interplay between PTEN inhibition and memory processes, as VO-OHpic induced only a transient immature spine growth in the somatosensory cortex, a region not involved in long-term auditory memory. Both the potentiation of fear memories and increase in immature spines were hampered by rapamycin, a selective inhibitor of mTORC1. These data revealed that memory can be potentiated over time by the administration of a selective PTEN inhibitor. In addition to disclosing new information on the cellular mechanisms underlying long-term memory maintenance, our study provides new insights on the molecular processes that aid enhancing memories over time. The neuronal mechanisms that may help improve the maintenance of long-term memories are still elusive. The inhibition of mammalian-target of rapamycin (mTOR) signaling shows that this pathway plays a crucial role in synaptic plasticity and memory formation. However, whether its activation may strengthen long-term memory storage is unclear. We assessed the consequences of positive modulation of AKT-mTOR pathway obtained by VO-OHpic administration, a phosphatase and tensin homolog inhibitor, on memory retention and underlying synaptic modifications. We found that mTOR activation greatly enhanced memory maintenance for weeks by producing a long-lasting increase of immature-type dendritic spines in pyramidal neurons of the auditory cortex. These results offer new insights on the cellular and molecular mechanisms that can aid enhancing memories over time.
Topics: Male; Mice; Animals; Mechanistic Target of Rapamycin Complex 1; Proto-Oncogene Proteins c-akt; Auditory Cortex; Dendritic Spines; Tensins; Memory, Long-Term; TOR Serine-Threonine Kinases; Memory, Short-Term; Sirolimus; Fear; Phosphoric Monoester Hydrolases; Mammals
PubMed: 37857485
DOI: 10.1523/JNEUROSCI.0204-23.2023 -
Nano Letters Jan 2024Dendritic Li deposition, an unstable solid-electrolyte interphase (SEI), and a nearly infinite relative volume change during cycling are three major obstacles to the...
Dendritic Li deposition, an unstable solid-electrolyte interphase (SEI), and a nearly infinite relative volume change during cycling are three major obstacles to the practical application of Li metal batteries. Herein, we introduce a compressible and elastic reduced graphene oxide sponge (rGO-S) to simultaneously eliminate Li dendrite growth, stabilize the SEI, and accommodate the volume change. The volume change is contained by compressing and expanding the rGO-S anode, which effectively releases the Li plating-induced stress during cycling. The smooth and dense Li metal is deposited on rGO-S without dendrites, which preserves the SEI, reduces consumption of the electrolyte, and prevents the formation of Li debris. The half-cells employing rGO-S show a steady and high Coulombic efficiency. The Li@rGO-S symmetric cells demonstrate excellent cycling stability over 1200 cycles with a low overpotential. When paired with LiFePO (LFP), the Li@rGO-S||LFP full cells exhibit a high specific capacity (150.3 mAh g at 1C), superior rate performance, and good capacity retention.
PubMed: 38166484
DOI: 10.1021/acs.nanolett.3c03973 -
Neuron Apr 2024Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder...
Dysfunction in sodium channels and their ankyrin scaffolding partners have both been implicated in neurodevelopmental disorders, including autism spectrum disorder (ASD). In particular, the genes SCN2A, which encodes the sodium channel Na1.2, and ANK2, which encodes ankyrin-B, have strong ASD association. Recent studies indicate that ASD-associated haploinsufficiency in Scn2a impairs dendritic excitability and synaptic function in neocortical pyramidal cells, but how Na1.2 is anchored within dendritic regions is unknown. Here, we show that ankyrin-B is essential for scaffolding Na1.2 to the dendritic membrane of mouse neocortical neurons and that haploinsufficiency of Ank2 phenocopies intrinsic dendritic excitability and synaptic deficits observed in Scn2a conditions. These results establish a direct, convergent link between two major ASD risk genes and reinforce an emerging framework suggesting that neocortical pyramidal cell dendritic dysfunction can contribute to neurodevelopmental disorder pathophysiology.
Topics: Animals; Mice; Ankyrins; Autism Spectrum Disorder; Autistic Disorder; Dendrites; NAV1.2 Voltage-Gated Sodium Channel; Neocortex; Pyramidal Cells
PubMed: 38290518
DOI: 10.1016/j.neuron.2024.01.003 -
Proceedings of the National Academy of... Nov 2023L-type voltage-gated calcium (Ca) channels (L-VGCC) dysfunction is implicated in several neurological and psychiatric diseases. While a popular therapeutic target, it is...
L-type voltage-gated calcium (Ca) channels (L-VGCC) dysfunction is implicated in several neurological and psychiatric diseases. While a popular therapeutic target, it is unknown whether molecular mechanisms leading to disrupted L-VGCC across neurodegenerative disorders are conserved. Importantly, L-VGCC integrate synaptic signals to facilitate a plethora of cellular mechanisms; however, mechanisms that regulate L-VGCC channel density and subcellular compartmentalization are understudied. Herein, we report that in disease models with overactive mammalian target of rapamycin complex 1 (mTORC1) signaling (or mTORopathies), deficits in dendritic L-VGCC activity are associated with increased expression of the RNA-binding protein (RBP) Parkinsonism-associated deglycase (DJ-1). DJ-1 binds the mRNA coding for the alpha and auxiliary Ca channel subunits Ca1.2 and α2δ2, and represses their mRNA translation, only in the disease states, specifically preclinical models of tuberous sclerosis complex (TSC) and Alzheimer's disease (AD). In agreement, DJ-1-mediated repression of Ca1.2/α2δ2 protein synthesis in dendrites is exaggerated in mouse models of AD and TSC, resulting in deficits in dendritic L-VGCC calcium activity. Finding of DJ-1-regulated L-VGCC activity in dendrites in TSC and AD provides a unique signaling pathway that can be targeted in clinical mTORopathies.
Topics: Animals; Mice; Alzheimer Disease; Calcium; Calcium Channels, L-Type; Dendrites; Mammals; Tuberous Sclerosis
PubMed: 37903257
DOI: 10.1073/pnas.2301534120 -
Journal of Anatomy Aug 2023The precise specification of cellular fate is thought to ensure the production of the correct number of neurons within a population. Programmed cell death may be an... (Review)
Review
The precise specification of cellular fate is thought to ensure the production of the correct number of neurons within a population. Programmed cell death may be an additional mechanism controlling cell number, believed to refine the proper ratio of pre- to post-synaptic neurons for a given species. Here, we consider the size of three different neuronal populations in the rod pathway of the mouse retina: rod photoreceptors, rod bipolar cells, and AII amacrine cells. Across a collection of 28 different strains of mice, large variation in the numbers of all three cell types is present. The variation in their numbers is not correlated, so that the ratio of rods to rod bipolar cells, as well as rod bipolar cells to AII amacrine cells, varies as well. Establishing connectivity between such variable pre- and post-synaptic populations relies upon plasticity that modulates process outgrowth and morphological differentiation, which we explore experimentally for both rod bipolar and AII amacrine cells in a mouse retina with elevated numbers of each cell type. While both rod bipolar dendritic and axonal arbors, along with AII lobular arbors, modulate their areal size in relation to local homotypic cell densities, the dendritic appendages of the AII amacrine cells do not. Rather, these processes exhibit a different form of plasticity, regulating the branching density of their overlapping arbors. Each form of plasticity should ensure uniformity in retinal coverage in the presence of the independent specification of afferent and target cell number.
Topics: Mice; Animals; Dendrites; Retina; Amacrine Cells; Axons
PubMed: 35292986
DOI: 10.1111/joa.13653 -
Current Biology : CB Jul 2023Animals use active sensing to investigate their environment. The active sense inputs must be discriminated from those arising independently from environmental signals....
Animals use active sensing to investigate their environment. The active sense inputs must be discriminated from those arising independently from environmental signals. An experimental and modelling study has revealed how precise control of dendritic spike backpropagation contributes to such discrimination.
Topics: Animals; Noise; Action Potentials; Dendrites; Sensation
PubMed: 37433273
DOI: 10.1016/j.cub.2023.05.049 -
Cerebral Cortex (New York, N.Y. : 1991) May 2024The basic building block of the cerebral cortex, the pyramidal cell, has been shown to be characterized by a markedly different dendritic structure among layers,...
The basic building block of the cerebral cortex, the pyramidal cell, has been shown to be characterized by a markedly different dendritic structure among layers, cortical areas, and species. Functionally, differences in the structure of their dendrites and axons are critical in determining how neurons integrate information. However, within the human cortex, these neurons have not been quantified in detail. In the present work, we performed intracellular injections of Lucifer Yellow and 3D reconstructed over 200 pyramidal neurons, including apical and basal dendritic and local axonal arbors and dendritic spines, from human occipital primary visual area and associative temporal cortex. We found that human pyramidal neurons from temporal cortex were larger, displayed more complex apical and basal structural organization, and had more spines compared to those in primary sensory cortex. Moreover, these human neocortical neurons displayed specific shared and distinct characteristics in comparison to previously published human hippocampal pyramidal neurons. Additionally, we identified distinct morphological features in human neurons that set them apart from mouse neurons. Lastly, we observed certain consistent organizational patterns shared across species. This study emphasizes the existing diversity within pyramidal cell structures across different cortical areas and species, suggesting substantial species-specific variations in their computational properties.
Topics: Humans; Pyramidal Cells; Animals; Male; Female; Mice; Adult; Dendritic Spines; Temporal Lobe; Dendrites; Middle Aged; Axons; Species Specificity
PubMed: 38745556
DOI: 10.1093/cercor/bhae180 -
Journal of Colloid and Interface Science Oct 2023Zn-ion energy storage devices will play important roles in the future energy storage field. However, Zn-ion device development suffers significantly from adverse...
Zn-ion energy storage devices will play important roles in the future energy storage field. However, Zn-ion device development suffers significantly from adverse chemical reactions (dendrite formation, corrosion, and deformation) on the Zn anode surface. Zn dendrite formation, hydrogen evolution corrosion, and deformation combine to degrade Zn-ion devices. Zincophile modulation and protection using covalent organic frameworks (COF) inhibited dendritic growth by induced uniform Zn ion deposition, which also prevented chemical corrosion. The Zn@COF anode circulated stably for more than 1800 cycles even at high current density in symmetric cells and maintained a low and stable voltage hysteresis. This work explains the surface state of the Zn anode and provides information for further research.
PubMed: 37307608
DOI: 10.1016/j.jcis.2023.05.175 -
Progress in Neurobiology Aug 2024Dendrites are injured in a variety of clinical conditions such as traumatic brain and spinal cord injuries and stroke. How neurons detect injury directly to their...
Dendrites are injured in a variety of clinical conditions such as traumatic brain and spinal cord injuries and stroke. How neurons detect injury directly to their dendrites to initiate a pro-regenerative response has not yet been thoroughly investigated. Calcium plays a critical role in the early stages of axonal injury detection and is also indispensable for regeneration of the severed axon. Here, we report cell and neurite type-specific differences in laser injury-induced elevations of intracellular calcium levels. Using a human KCNJ2 transgene, we demonstrate that hyperpolarizing neurons only at the time of injury dampens dendrite regeneration, suggesting that inhibition of injury-induced membrane depolarization (and thus early calcium influx) plays a role in detecting and responding to dendrite injury. In exploring potential downstream calcium-regulated effectors, we identify L-type voltage-gated calcium channels, inositol triphosphate signaling, and protein kinase D activity as drivers of dendrite regeneration. In conclusion, we demonstrate that dendrite injury-induced calcium elevations play a key role in the regenerative response of dendrites and begin to delineate the molecular mechanisms governing dendrite repair.
Topics: Dendrites; Animals; Calcium; Nerve Regeneration; Humans; Mice; Potassium Channels, Inwardly Rectifying; Mice, Transgenic
PubMed: 38825174
DOI: 10.1016/j.pneurobio.2024.102635