-
Annual Review of Cell and Developmental... Oct 2019Regulated synthesis and movement of proteins between cellular organelles are central to diverse forms of biological adaptation and plasticity. In neurons, the repertoire... (Review)
Review
Regulated synthesis and movement of proteins between cellular organelles are central to diverse forms of biological adaptation and plasticity. In neurons, the repertoire of channel, receptor, and adhesion proteins displayed on the cell surface directly impacts cellular development, morphology, excitability, and synapse function. The immensity of the neuronal surface membrane and its division into distinct functional domains present a challenging landscape over which proteins must navigate to reach their appropriate functional domains. This problem becomes more complex considering that neuronal protein synthesis is continuously refined in space and time by neural activity. Here we review our current understanding of how integral membrane and secreted proteins important for neuronal function travel from their sites of synthesis to their functional destinations. We discuss how unique adaptations to the function and distribution of neuronal secretory organelles may facilitate local protein trafficking at remote sites in neuronal dendrites to support diverse forms of synaptic plasticity.
Topics: Animals; Cell Compartmentation; Cell Membrane; Dendrites; Endoplasmic Reticulum; Endosomes; Golgi Apparatus; Membrane Proteins; Neuronal Plasticity; Neurons; Protein Transport; Synapses
PubMed: 31283381
DOI: 10.1146/annurev-cellbio-100818-125418 -
Current Opinion in Neurobiology Aug 2019Growing evidence implicates synaptic proteins in the pathogenesis of neuropsychiatric disorders such as autism spectrum disorder (ASD), intellectual disability (ID) and... (Review)
Review
Growing evidence implicates synaptic proteins in the pathogenesis of neuropsychiatric disorders such as autism spectrum disorder (ASD), intellectual disability (ID) and schizophrenia. In fact, mutations in genes encoding synaptic proteins are enriched and overlap among different conditions highlighting the complex and pleiotropic nature of these disorders. In this review, we discuss recently described candidate genes that affect excitatory synapse function and result in changes in spine number and morphology. Spine pathology has been observed in several animal models of disease and in human brain post-mortem samples from ID, ASD, and schizophrenia patients. Recent data point to convergent mechanisms, such as dysregulation of the actin cytoskeleton and dysfunction of microglia synaptic remodeling, underlying dendritic spine dysgenesis. Interestingly, the reversion of important pathologic features, including spine abnormalities, has been observed in adult animal models of neuropsychiatric disorders, suggesting that therapies may not be restricted to a specific developmental window. Shedding light on the specific mechanisms impacted in neuropsychiatric disorders will undeniably contribute to the development of more directed and personalized therapies.
Topics: Animals; Autism Spectrum Disorder; Dendrites; Dendritic Spines; Humans; Schizophrenia; Synapses
PubMed: 30743178
DOI: 10.1016/j.conb.2019.01.004 -
Current Opinion in Neurobiology Dec 2023The brain is a highly efficient system that has evolved to optimize performance under limited resources. In this review, we highlight recent theoretical and experimental... (Review)
Review
The brain is a highly efficient system that has evolved to optimize performance under limited resources. In this review, we highlight recent theoretical and experimental studies that support the view that dendrites make information processing and storage in the brain more efficient. This is achieved through the dynamic modulation of integration versus segregation of inputs and activity within a neuron. We argue that under conditions of limited energy and space, dendrites help biological networks to implement complex functions such as processing natural stimuli on behavioral timescales, performing the inference process on those stimuli in a context-specific manner, and storing the information in overlapping populations of neurons. A global picture starts to emerge, in which dendrites help the brain achieve efficiency through a combination of optimization strategies that balance the tradeoff between performance and resource utilization.
Topics: Dendrites; Neurons; Brain; Cognition
PubMed: 37980803
DOI: 10.1016/j.conb.2023.102812 -
Journal of Visualized Experiments : JoVE Sep 2020We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized...
We report two methods to create zinc-sponge electrodes that suppress dendrite formation and shape change for rechargeable zinc batteries. Both methods are characterized by creating a paste made of zinc particles, organic porogen, and viscosity-enhancing agent that is heated under an inert gas and then air. During heating under the inert gas, the zinc particles anneal together, and the porogen decomposes; under air, the zinc fuses and residual organic burns out, yielding an open-cell metal foam or sponge. We tune the mechanical and electrochemical properties of the zinc sponges by varying zinc-to-porogen mass ratio, heating time under inert gas and air, and size and shape of the zinc and porogen particles. An advantage of the reported methods is their ability to finely tune zinc-sponge architecture. The selected size and shape of the zinc and porogen particles influence the morphology of the pore structure. A limitation is that resulting sponges have disordered pore structures that result in low mechanical strength at low volume fractions of zinc (<30%). Applications for these zinc-sponge electrodes include batteries for grid-storage, personal electronics, electric vehicles, and electric aviation. Users can expect zinc-sponge electrodes to cycle up to 40% depth of discharge at technologically relevant rates and areal capacities without the formation of separator-piercing dendrites.
Topics: Air; Dendrites; Electric Power Supplies; Electrochemistry; Electrodes; Mechanical Phenomena; Porosity; Zinc
PubMed: 33074262
DOI: 10.3791/61770 -
Nature Computational Science Jan 2024The brain is an intricate assembly of intercommunicating neurons whose input-output function is only partially understood. The role of active dendrites in shaping...
The brain is an intricate assembly of intercommunicating neurons whose input-output function is only partially understood. The role of active dendrites in shaping spiking responses, in particular, is unclear. Although existing models account for active dendrites and spiking responses, they are too complex to analyze analytically and demand long stochastic simulations. Here we combine cable and renewal theory to describe how input fluctuations shape the response of neuronal ensembles with active dendrites. We found that dendritic input readily and potently controls interspike interval dispersion. This phenomenon can be understood by considering that neurons display three fundamental operating regimes: one mean-driven regime and two fluctuation-driven regimes. We show that these results are expected to appear for a wide range of dendritic properties and verify predictions of the model in experimental data. These findings have implications for the role of interspike interval dispersion in learning and for theories of attractor states.
Topics: Dendrites; Synapses; Neurons; Algorithms
PubMed: 38177495
DOI: 10.1038/s43588-023-00580-6 -
Molecular and Cellular Neurosciences Jun 2020Neuronal dendrites are highly branched and specialized compartments with distinct structures and secretory organelles (e.g., spines, Golgi outposts), and a unique... (Review)
Review
Neuronal dendrites are highly branched and specialized compartments with distinct structures and secretory organelles (e.g., spines, Golgi outposts), and a unique cytoskeletal organization that includes microtubules of mixed polarity. Dendritic membranes are enriched with proteins, which specialize in the formation and function of the post-synaptic membrane of the neuronal synapse. How these proteins partition preferentially in dendrites, and how they traffic in a manner that is spatiotemporally accurate and regulated by synaptic activity are long-standing questions of neuronal cell biology. Recent studies have shed new insights into the spatial control of dendritic membrane traffic, revealing new classes of proteins (e.g., septins) and cytoskeleton-based mechanisms with dendrite-specific functions. Here, we review these advances by revisiting the fundamental mechanisms that control membrane traffic at the levels of protein sorting and motor-driven transport on microtubules and actin filaments. Overall, dendrites possess unique mechanisms for the spatial control of membrane traffic, which might have specialized and co-evolved with their highly arborized morphology.
Topics: Animals; Cytoskeleton; Dendrites; Golgi Apparatus; Humans; Microtubules; Neurons; Protein Transport
PubMed: 32294508
DOI: 10.1016/j.mcn.2020.103492 -
Cell Reports Nov 2023Branching allows neurons to make synaptic contacts with large numbers of other neurons, facilitating the high connectivity of nervous systems. Neuronal arbors have...
Branching allows neurons to make synaptic contacts with large numbers of other neurons, facilitating the high connectivity of nervous systems. Neuronal arbors have geometric properties such as branch lengths and diameters that are optimal in that they maximize signaling speeds while minimizing construction costs. In this work, we asked whether neuronal arbors have topological properties that may also optimize their growth or function. We discovered that for a wide range of invertebrate and vertebrate neurons the distributions of their subtree sizes follow power laws, implying that they are scale invariant. The power-law exponent distinguishes different neuronal cell types. Postsynaptic spines and branchlets perturb scale invariance. Through simulations, we show that the subtree-size distribution depends on the symmetry of the branching rules governing arbor growth and that optimal morphologies are scale invariant. Thus, the subtree-size distribution is a topological property that recapitulates the functional morphology of dendrites.
Topics: Dendrites; Neurons; Morphogenesis
PubMed: 38007691
DOI: 10.1016/j.celrep.2023.113268 -
Scientific Reports Mar 2022The atomic level assembly of silver dendrite has never been disclosed despite the numerous studies published on fractal dendrite structures. We report for the first time...
The atomic level assembly of silver dendrite has never been disclosed despite the numerous studies published on fractal dendrite structures. We report for the first time an HRTEM investigation of the formation of atomic embryos (< 5 nm) and the self-assembly of atoms on an atomic plane of the tip of a dendrite arm. The mechanism of dendrite formation proceeds via the sequence of amorphous embryos aggregates (5-10 nm), nuclei, crystallites (10-20 nm), dendritelets (50-100 nm) and submicron dendrite protypes. The atomic plane is an entirely atomic-level zig-zag structure with d-spacing kink steps. The zig-zag structure triggers the self-assembly of atoms and thus directional growth to produce a dendrite arm with a high aspect ratio.
Topics: Dendrites; Silver
PubMed: 35296765
DOI: 10.1038/s41598-022-08586-2 -
Neuroscience May 2022There has been increasing interest in the measurement and comparison of activity across compartments of the pyramidal neuron. Dendritic activity can occur both locally,... (Review)
Review
There has been increasing interest in the measurement and comparison of activity across compartments of the pyramidal neuron. Dendritic activity can occur both locally, on a single dendritic segment, or globally, involving multiple compartments of the single neuron. Little is known about how these dendritic dynamics shape and contribute to information processing and behavior. Although it has been difficult to characterize local and global activity in vivo due to the technical challenge of simultaneously recording from the entire dendritic arbor and soma, the rise of calcium imaging has driven the increased feasibility and interest of these experiments. However, the distinction between local and global activity made by calcium imaging requires careful consideration. In this review we describe local and global activity, discuss the difficulties and caveats of this distinction, and present the evidence of local and global activity in information processing and behavior.
Topics: Action Potentials; Calcium; Dendrites; Neurons; Pyramidal Cells
PubMed: 34280492
DOI: 10.1016/j.neuroscience.2021.07.008 -
Trends in Neurosciences Apr 2021Pilot studies have hinted that serotonergic psychedelics such as psilocybin may relieve depression, and could possibly do so by promoting neural plasticity.... (Review)
Review
Pilot studies have hinted that serotonergic psychedelics such as psilocybin may relieve depression, and could possibly do so by promoting neural plasticity. Intriguingly, another psychotomimetic compound, ketamine, is a fast-acting antidepressant and induces synapse formation. The similarities in behavioral and neural effects have been puzzling because the compounds target distinct molecular receptors in the brain. In this opinion article, we develop a conceptual framework that suggests the actions of ketamine and serotonergic psychedelics may converge at the dendrites, to both enhance and suppress membrane excitability. We speculate that mismatches in the opposing actions on dendritic excitability may relate to these compounds' cell-type and region selectivity, their moderate range of effects and toxicity, and their plasticity-promoting capacities.
Topics: Antidepressive Agents; Dendrites; Depression; Hallucinogens; Humans; Ketamine; Neuronal Plasticity
PubMed: 33358035
DOI: 10.1016/j.tins.2020.11.008