Perineuronal Nets in the Superior Olivary Complex

2018 ◽  
pp. 420-444 ◽  
Author(s):  
Markus Morawski ◽  
Mandy Sonntag
Keyword(s):  
Experimental Data ◽  
Extracellular Matrix ◽  
Synaptic Plasticity ◽  
Neuronal Excitability ◽  
Auditory Brainstem ◽  
Specific Form ◽  
Superior Olivary Complex ◽  
Perineuronal Nets ◽  
Neuronal Somata ◽  
Main Components

This chapter addresses perineuronal nets in the superior olivary complex, a collection of nuclei in the auditory brainstem that are involved in the processing of sound source location. Perineuronal nets, a specific form of extracellular matrix, are believed to control synaptic plasticity. They surround neuronal somata and dendrites of specific types of neurons, among which are many neurons of the superior olivary complex. The chapter describes the distribution of perineuronal nets in the superior olivary complex, focusing on controversial results and discussing underlying reasons. In addition, it considers the development of perineuronal nets and highlights differences between the main components of perineuronal nets, including the proteoglycans aggrecan, brevican, and neurocan. Finally, it introduces current concepts on the function of perineuronal nets that are specifically based on experimental data collected in the superior olivary complex and point to a contribution of perineuronal nets to synaptic transmission and neuronal excitability.

scholarly journals Alteration of Extracellular Matrix Molecules and Perineuronal Nets in the Hippocampus of Pentylenetetrazol-Kindled Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Hiroshi Ueno ◽  
Shunsuke Suemitsu ◽  
Shinji Murakami ◽  
Naoya Kitamura ◽  
Kenta Wani ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Synaptic Plasticity ◽  
Neural Circuit ◽  
Perineuronal Nets ◽  
Cellular Mechanisms ◽  
Kindling Model ◽  
Ptz Kindling ◽  
Extracellular Matrix Molecules ◽  
Model Mouse ◽  
Wisteria Floribunda

The pathophysiological processes leading to epilepsy are poorly understood. Understanding the molecular and cellular mechanisms involved in the onset of epilepsy is crucial for drug development. Epileptogenicity is thought to be associated with changes in synaptic plasticity; however, whether extracellular matrix molecules—known regulators of synaptic plasticity—are altered during epileptogenesis is unknown. To test this, we used a pentylenetetrazole- (PTZ-) kindling model mouse to investigate changes to hippocampal parvalbumin- (PV-) positive neurons, extracellular matrix molecules, and perineuronal nets (PNNs) after the last kindled seizure. We found an increase in Wisteria floribunda agglutinin- (WFA-) and Cat-315-positive PNNs and a decrease in PV-positive neurons not surrounded by PNNs, in the hippocampus of PTZ-kindled mice compared to control mice. Furthermore, the expression of WFA- and Cat-315-positive molecules increased in the extracellular space of PTZ-kindled mice. In addition, consistent with previous studies, astrocytes were activated in PTZ-kindled mice. We propose that the increase in PNNs after kindling decreases neuroplasticity in the hippocampus and helps maintain the neural circuit for recurrent seizures. This study shows that possibility of changes in extracellular matrix molecules due to astrocyte activation is associated with epilepticus in PTZ-kindled mice.

scholarly journals Lateralized expression of cortical perineuronal nets during maternal experience is dependent on MECP2

2019 ◽  
Author(s):  
Billy Y.B. Lau ◽  
Dana E. Layo ◽  
Brett Emery ◽  
Matthew Everett ◽  
Anushree Kumar ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Synaptic Plasticity ◽  
Adult Female ◽  
Social Contexts ◽  
Gabaergic Neurons ◽  
Perineuronal Nets ◽  
Critical Periods ◽  
Early Postnatal Development ◽  
Female Mice ◽  
Maternal Experience

Cortical neuronal circuits along the sensorimotor pathways are shaped by experience during critical periods of heightened plasticity in early postnatal development. After closure of critical periods, measured histologically by the formation and maintenance of extracellular matrix structures called perineuronal nets (PNNs), the adult mouse brain exhibits restricted plasticity and maturity. Mature PNNs are typically considered to be stable structures that restrict synaptic plasticity on cortical parvalbumin+ GABAergic neurons. Changes in environment (i.e. novel behavioral training) or social contexts (i.e. motherhood) are known to elicit synaptic plasticity in relevant neural circuitry. However, little is known about concomitant changes in the PNNs surrounding the cortical parvalbumin+ GABAergic neurons. Here, we show novel changes in PNN density in the primary somatosensory cortex (SS1) of adult female mice after maternal experience, using systematic microscopy analysis of a whole brain region. On average, PNNs were increased in the right barrel field and decreased in the left forelimb regions. Individual mice had left hemisphere dominance in PNN density. Using adult female mice deficient in methyl-CpG-binding protein 2 (MECP2), an epigenetic regulator involved in regulating experience-dependent plasticity, we found that MECP2 is critical for this precise and dynamic expression of PNN. Adult naïve Mecp2-heterozygous females (Het) had increased PNN density in specific subregions in both hemispheres before maternal experience. The laterality in PNN expression seen in naïve Het was lost after maternal experience, suggesting possible intact mechanisms for plasticity. Together, our results identify subregion and hemisphere-specific alterations in PNN expression in adult females, suggesting extracellular matrix plasticity as a possible neurobiological mechanism for adult behaviors in rodents.

scholarly journals The tetrapartite synapse: a key concept in the pathophysiology of schizophrenia

2018 ◽  
Vol 50 ◽  
pp. 60-69 ◽  
Author(s):  
Gabriele Chelini ◽  
Harry Pantazopoulos ◽  
Peter Durning ◽  
Sabina Berretta
Keyword(s):  
Extracellular Matrix ◽  
Synaptic Plasticity ◽  
Glial Cells ◽  
Brain Regions ◽  
Spine Density ◽  
Altered Expression ◽  
Functional Aspects ◽  
Synaptic Pathology ◽  
Main Components ◽  
Molecular Components

AbstractGrowing evidence points to synaptic pathology as a core component of the pathophysiology of schizophrenia (SZ). Significant reductions of dendritic spine density and altered expression of their structural and molecular components have been reported in several brain regions, suggesting a deficit of synaptic plasticity. Regulation of synaptic plasticity is a complex process, one that requires not only interactions between pre- and post-synaptic terminals, but also glial cells and the extracellular matrix (ECM). Together, these elements are referred to as the ‘tetrapartite synapse’, an emerging concept supported by accumulating evidence for a role of glial cells and the extracellular matrix in regulating structural and functional aspects of synaptic plasticity. In particular, chondroitin sulfate proteoglycans (CSPGs), one of the main components of the ECM, have been shown to be synthesized predominantly by glial cells, to form organized perisynaptic aggregates known as perineuronal nets (PNNs), and to modulate synaptic signaling and plasticity during postnatal development and adulthood. Notably, recent findings from our group and others have shown marked CSPG abnormalities in several brain regions of people with SZ. These abnormalities were found to affect specialized ECM structures, including PNNs, as well as glial cells expressing the corresponding CSPGs. The purpose of this review is to bring forth the hypothesis that synaptic pathology in SZ arises from a disruption of the interactions between elements of the tetrapartite synapse.

scholarly journals Dysregulation of Astrocyte–Neuronal Communication in Alzheimer’s Disease

2021 ◽  
Vol 22 (15) ◽  
pp. 7887
Author(s):  
Carmen Nanclares ◽  
Andres Mateo Baraibar ◽  
Alfonso Araque ◽  
Paulo Kofuji
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Synaptic Plasticity ◽  
Neuronal Excitability ◽  
Active Role ◽  
Ionic Homeostasis ◽  
Neuronal Communication ◽  
Structural Support

Recent studies implicate astrocytes in Alzheimer’s disease (AD); however, their role in pathogenesis is poorly understood. Astrocytes have well-established functions in supportive functions such as extracellular ionic homeostasis, structural support, and neurovascular coupling. However, emerging research on astrocytic function in the healthy brain also indicates their role in regulating synaptic plasticity and neuronal excitability via the release of neuroactive substances named gliotransmitters. Here, we review how this “active” role of astrocytes at synapses could contribute to synaptic and neuronal network dysfunction and cognitive impairment in AD.

scholarly journals Origins, potency, and heterogeneity of skeletal muscle fibro-adipogenic progenitors—time for new definitions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Osvaldo Contreras ◽  
Fabio M. V. Rossi ◽  
Marine Theret
Keyword(s):  
Extracellular Matrix ◽  
Muscle Development ◽  
Striated Muscle ◽  
Body Movement ◽  
Well Being ◽  
Lineage Tracing ◽  
Extracellular Matrix Components ◽  
Main Components ◽  
Muscle Homeostasis ◽  
Activated Fibroblasts

AbstractStriated muscle is a highly plastic and regenerative organ that regulates body movement, temperature, and metabolism—all the functions needed for an individual’s health and well-being. The muscle connective tissue’s main components are the extracellular matrix and its resident stromal cells, which continuously reshape it in embryonic development, homeostasis, and regeneration. Fibro-adipogenic progenitors are enigmatic and transformative muscle-resident interstitial cells with mesenchymal stem/stromal cell properties. They act as cellular sentinels and physiological hubs for adult muscle homeostasis and regeneration by shaping the microenvironment by secreting a complex cocktail of extracellular matrix components, diffusible cytokines, ligands, and immune-modulatory factors. Fibro-adipogenic progenitors are the lineage precursors of specialized cells, including activated fibroblasts, adipocytes, and osteogenic cells after injury. Here, we discuss current research gaps, potential druggable developments, and outstanding questions about fibro-adipogenic progenitor origins, potency, and heterogeneity. Finally, we took advantage of recent advances in single-cell technologies combined with lineage tracing to unify the diversity of stromal fibro-adipogenic progenitors. Thus, this compelling review provides new cellular and molecular insights in comprehending the origins, definitions, markers, fate, and plasticity of murine and human fibro-adipogenic progenitors in muscle development, homeostasis, regeneration, and repair.

Synaptic Plasticity In Vitro and In Silico: Insights into an Intracellular Signaling Maze

Physiology ◽  
2006 ◽  
Vol 21 (4) ◽  
pp. 289-296 ◽  
Author(s):  
Sriram M. Ajay ◽  
Upinder S. Bhalla
Keyword(s):  
Experimental Data ◽  
Synaptic Plasticity ◽  
Neuronal Activity ◽  
In Silico ◽  
Intracellular Signaling ◽  
Signaling Networks ◽  
Functional Roles ◽  
Current State ◽  
History Of

Synaptic plasticity provides a record of neuronal activity and is a likely basis for memory. The early apparent simplicity of the process of synaptic plasticity has been lost in a flood of experimental data that now implicates some 200 signaling molecules in cellular memory. It is now clear that these signaling networks perform surprisingly sophisticated cellular decisions that weigh factors such as input patterns, location of stimulus, history of activity, and context. Computer models have followed experiments into this maze of molecular detail, often matching closely with their experimental counterparts, but perhaps losing simplicity in the process. Here, we suggest that the merger of models and experiment have begun to restore the earlier simplicity by outlining a few key functional roles for signaling networks in synaptic plasticity. In this review, we discuss the current state of understanding of synaptic plasticity in terms of models and experiments.

scholarly journals The Extracellular Matrix Molecule Hyaluronic Acid Regulates Hippocampal Synaptic Plasticity by Modulating Postsynaptic L-Type Ca2+ Channels

Neuron ◽  
2010 ◽  
Vol 67 (1) ◽  
pp. 116-128 ◽  
Author(s):  
Gaga Kochlamazashvili ◽  
Christian Henneberger ◽  
Olena Bukalo ◽  
Elena Dvoretskova ◽  
Oleg Senkov ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Synaptic Plasticity ◽  
Matrix Molecule ◽  
Hippocampal Synaptic Plasticity ◽  
Extracellular Matrix Molecule ◽  
Ca2 Channels

scholarly journals Hysteresis in Muscle

2017 ◽  
Vol 27 (01) ◽  
pp. 1730003 ◽  
Author(s):  
Jorgelina Ramos ◽  
Stephen Lynch ◽  
David Jones ◽  
Hans Degens
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Hysteresis Loop ◽  
Mechanical Systems ◽  
Single Fibre ◽  
Scientific Disciplines ◽  
Main Components ◽  
First Time ◽  
Muscle Models ◽  
Clockwise Hysteresis

This paper presents examples of hysteresis from a broad range of scientific disciplines and demonstrates a variety of forms including clockwise, counterclockwise, butterfly, pinched and kiss-and-go, respectively. These examples include mechanical systems made up of springs and dampers which have been the main components of muscle models for nearly one hundred years. For the first time, as far as the authors are aware, hysteresis is demonstrated in single fibre muscle when subjected to both lengthening and shortening periodic contractions. The hysteresis observed in the experiments is of two forms. Without any relaxation at the end of lengthening or shortening, the hysteresis loop is a convex clockwise loop, whereas a concave clockwise hysteresis loop (labeled as kiss-and-go) is formed when the muscle is relaxed at the end of lengthening and shortening. This paper also presents a mathematical model which reproduces the hysteresis curves in the same form as the experimental data.

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