scholarly journals Fine-Tuning an Auditory Synapse for Speed and Fidelity: Developmental Changes in Presynaptic Waveform, EPSC Kinetics, and Synaptic Plasticity

2000 ◽  
Vol 20 (24) ◽  
pp. 9162-9173 ◽  
Author(s):  
Holger Taschenberger ◽  
Henrique von Gersdorff
Keyword(s):  
Synaptic Plasticity ◽  
Fine Tuning ◽  
Developmental Changes

scholarly journals Development of dendritic tonic GABAergic inhibition regulates excitability and plasticity in CA1 pyramidal neurons

2014 ◽  
Vol 112 (2) ◽  
pp. 287-299 ◽  
Author(s):  
Martine R. Groen ◽  
Ole Paulsen ◽  
Enrique Pérez-Garci ◽  
Thomas Nevian ◽  
J. Wortel ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Action Potential ◽  
Pyramidal Neurons ◽  
Spike Timing ◽  
Tonic Inhibition ◽  
Developmental Changes ◽  
Gabaergic Inhibition ◽  
Gaba A ◽  
Ca1 Pyramidal Neurons ◽  
Mature Neurons

Synaptic plasticity rules change during development: while hippocampal synapses can be potentiated by a single action potential pairing protocol in young neurons, mature neurons require burst firing to induce synaptic potentiation. An essential component for spike timing-dependent plasticity is the backpropagating action potential (BAP). BAP along the dendrites can be modulated by morphology and ion channel composition, both of which change during late postnatal development. However, it is unclear whether these dendritic changes can explain the developmental changes in synaptic plasticity induction rules. Here, we show that tonic GABAergic inhibition regulates dendritic action potential backpropagation in adolescent, but not preadolescent, CA1 pyramidal neurons. These developmental changes in tonic inhibition also altered the induction threshold for spike timing-dependent plasticity in adolescent neurons. This GABAergic regulatory effect on backpropagation is restricted to distal regions of apical dendrites (>200 μm) and mediated by α5-containing GABA(A) receptors. Direct dendritic recordings demonstrate α5-mediated tonic GABA(A) currents in adolescent neurons which can modulate BAPs. These developmental modulations in dendritic excitability could not be explained by concurrent changes in dendritic morphology. To explain our data, model simulations propose a distally increasing or localized distal expression of dendritic α5 tonic inhibition in mature neurons. Overall, our results demonstrate that dendritic integration and plasticity in more mature dendrites are significantly altered by tonic α5 inhibition in a dendritic region-specific and developmentally regulated manner.

scholarly journals Fine Tuning of Synaptic Plasticity and Filtering by GABA Released from Hippocampal Autaptic Granule Cells

2015 ◽  
Vol 26 (3) ◽  
pp. 1149-1167 ◽  
Author(s):  
Pierluigi Valente ◽  
Marta Orlando ◽  
Andrea Raimondi ◽  
Fabio Benfenati ◽  
Pietro Baldelli
Keyword(s):  
Synaptic Plasticity ◽  
Granule Cells ◽  
Fine Tuning

scholarly journals Hebbian plasticity requires compensatory processes on multiple timescales

2017 ◽  
Vol 372 (1715) ◽  
pp. 20160259 ◽  
Author(s):  
Friedemann Zenke ◽  
Wulfram Gerstner
Keyword(s):  
Synaptic Plasticity ◽  
Experimental Research ◽  
Neural Circuits ◽  
Homeostatic Plasticity ◽  
Fine Tuning ◽  
Control Mechanisms ◽  
Network Stability ◽  
Multiple Timescales ◽  
Hebbian Plasticity ◽  
Compensatory Process

We review a body of theoretical and experimental research on Hebbian and homeostatic plasticity, starting from a puzzling observation: while homeostasis of synapses found in experiments is a slow compensatory process, most mathematical models of synaptic plasticity use rapid compensatory processes (RCPs). Even worse, with the slow homeostatic plasticity reported in experiments, simulations of existing plasticity models cannot maintain network stability unless further control mechanisms are implemented. To solve this paradox, we suggest that in addition to slow forms of homeostatic plasticity there are RCPs which stabilize synaptic plasticity on short timescales. These rapid processes may include heterosynaptic depression triggered by episodes of high postsynaptic firing rate. While slower forms of homeostatic plasticity are not sufficient to stabilize Hebbian plasticity, they are important for fine-tuning neural circuits. Taken together we suggest that learning and memory rely on an intricate interplay of diverse plasticity mechanisms on different timescales which jointly ensure stability and plasticity of neural circuits. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’.

scholarly journals Neuromodulation of Hippocampal-Prefrontal Cortical Synaptic Plasticity and Functional Connectivity: Implications for Neuropsychiatric Disorders

2021 ◽  
Vol 15 ◽  
Author(s):  
Rafael Naime Ruggiero ◽  
Matheus Teixeira Rossignoli ◽  
Danilo Benette Marques ◽  
Bruno Monteiro de Sousa ◽  
Rodrigo Neves Romcy-Pereira ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Functional Connectivity ◽  
Neuropsychiatric Symptoms ◽  
Neuropsychiatric Disorders ◽  
Long Term Potentiation ◽  
Mental Illnesses ◽  
Fine Tuning ◽  
Comprehensive Overview ◽  
Neurophysiological Studies

The hippocampus-prefrontal cortex (HPC-PFC) pathway plays a fundamental role in executive and emotional functions. Neurophysiological studies have begun to unveil the dynamics of HPC-PFC interaction in both immediate demands and long-term adaptations. Disruptions in HPC-PFC functional connectivity can contribute to neuropsychiatric symptoms observed in mental illnesses and neurological conditions, such as schizophrenia, depression, anxiety disorders, and Alzheimer’s disease. Given the role in functional and dysfunctional physiology, it is crucial to understand the mechanisms that modulate the dynamics of HPC-PFC communication. Two of the main mechanisms that regulate HPC-PFC interactions are synaptic plasticity and modulatory neurotransmission. Synaptic plasticity can be investigated inducing long-term potentiation or long-term depression, while spontaneous functional connectivity can be inferred by statistical dependencies between the local field potentials of both regions. In turn, several neurotransmitters, such as acetylcholine, dopamine, serotonin, noradrenaline, and endocannabinoids, can regulate the fine-tuning of HPC-PFC connectivity. Despite experimental evidence, the effects of neuromodulation on HPC-PFC neuronal dynamics from cellular to behavioral levels are not fully understood. The current literature lacks a review that focuses on the main neurotransmitter interactions with HPC-PFC activity. Here we reviewed studies showing the effects of the main neurotransmitter systems in long- and short-term HPC-PFC synaptic plasticity. We also looked for the neuromodulatory effects on HPC-PFC oscillatory coordination. Finally, we review the implications of HPC-PFC disruption in synaptic plasticity and functional connectivity on cognition and neuropsychiatric disorders. The comprehensive overview of these impairments could help better understand the role of neuromodulation in HPC-PFC communication and generate insights into the etiology and physiopathology of clinical conditions.

scholarly journals Spinal cord synaptic plasticity by GlyRβ release from receptor fields and syndapin-dependent uptake

2021 ◽  
Author(s):  
Jessica Tröger ◽  
Eric Seemann ◽  
Rainer Heintzmann ◽  
Michael M. Kessels ◽  
Britta Qualmann
Keyword(s):  
Spinal Cord ◽  
Synaptic Plasticity ◽  
Steady State ◽  
Glycine Receptor ◽  
Receptor Internalization ◽  
Fine Tuning ◽  
Inhibitory Synapses ◽  
Synaptic Efficacy ◽  
Receptor Field ◽  
Spinal Cord Function

Glycine receptor-mediated inhibitory neurotransmission is key for spinal cord function. Recent observations suggested that by largely elusive mechanisms also glycinergic synapses display synaptic plasticity. We here identify syndapin I as critical player. Interestingly, syndapin I cooperates but in part also competes with gephyrin. Syndapin I deficiency led to fragmentation of glycine receptor fields, more disperse receptors and increased receptor mobility. Kainate treatment highlighted syndapin I's importance even more. Our analyses unveiled that PKC-mediated S403 phosphorylation-mediated glycine receptor β decoupling from gephyrin scaffolds simultaneously promoted syndapin I association. In line, kainate-treated syndapin I KO spinal cords showed even more severe receptor field fragmentation. Furthermore, syndapin I deficiency completely disrupted kainate-induced glycine receptor internalization. Together, this unveiled important mechanisms controlling the number and organization of glycine receptor fields at inhibitory postsynapses during both steady-state and kainate-induced synaptic rearrangement - principles organizing and fine-tuning synaptic efficacy of inhibitory synapses in the spinal cord.

scholarly journals Fine-tuning synaptic plasticity by modulation of CaV2.1 channels with Ca2+ sensor proteins

2012 ◽  
Vol 109 (42) ◽  
pp. 17069-17074 ◽  
Author(s):  
K. Leal ◽  
S. Mochida ◽  
T. Scheuer ◽  
W. A. Catterall
Keyword(s):  
Synaptic Plasticity ◽  
Fine Tuning ◽  
Sensor Proteins

scholarly journals Selective Changes in Complexity of Visual Scanning for Social Stimuli in Infancy

2021 ◽  
Vol 12 ◽  
Author(s):  
Przemysław Tomalski ◽  
David López Pérez ◽  
Alicja Radkowska ◽  
Anna Malinowska-Korczak
Keyword(s):  
Cognitive Skills ◽  
Repeated Sequences ◽  
Fine Tuning ◽  
Developmental Changes ◽  
Visual Scanning ◽  
Social Stimuli ◽  
Age Related ◽  
Quantification Analysis ◽  
Increased Sensitivity ◽  
Social Scenes

In the 1st year of life, infants gradually gain the ability to control their eye movements and explore visual scenes, which support their learning and emerging cognitive skills. These gains include domain-general skills such as rapid orienting or attention disengagement as well as domain-specific ones such as increased sensitivity to social stimuli. However, it remains unknown whether these developmental changes in what infants fixate and for how long in naturalistic scenes lead to the emergence of more complex, repeated sequences of fixations, especially when viewing human figures and faces, and whether these changes are related to improvements in domain-general attentional skills. Here we tested longitudinally the developmental changes in the complexity of fixation sequences at 5.5 and 11 months of age using Recurrence Quantification Analysis. We measured changes in how fixations recur in the same location and changes in the patterns (repeated sequences) of fixations in social and non-social scenes that were either static or dynamic. We found more complex patterns (i.e., repeated and longer sequences) of fixations in social than non-social scenes, both static and dynamic. There was also an age-related increase in the length of repeated fixation sequences only for social static scenes, which was independent of individual differences in orienting and attention disengagement. Our results can be interpreted as evidence for fine-tuning of infants' visual scanning skills. They selectively produce longer and more complex sequences of fixations on faces and bodies before reaching the end of the 1st year of life.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

Fine-Tuning Futures

ASHA Leader ◽  
2017 ◽  
Vol 22 (6) ◽  
Author(s):  
Christi Miller
Keyword(s):  
Fine Tuning
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