scholarly journals Comparison of synaptic transmission and plasticity between sensory and cortical synapses on relay neurons in the ventrobasal nucleus of the rat thalamus

2010 ◽  
Vol 588 (22) ◽  
pp. 4347-4363 ◽  
Author(s):  
Ching-Lung Hsu ◽  
Hsiu-Wen Yang ◽  
Cheng-Tung Yen ◽  
Ming-Yuan Min
Keyword(s):  
Synaptic Transmission ◽  
Ventrobasal Nucleus ◽  
Cortical Synapses ◽  
Relay Neurons

scholarly journals Cortical synapses in acute hepatic encephalopathy: morphology and expression of proteins involved in synaptic transmission

SpringerPlus ◽  
2015 ◽  
Vol 4 (S1) ◽  
Author(s):  
Mariusz Popek ◽  
Małgorzata Frontczak-Baniewicz ◽  
Barbara Zabłocka ◽  
Jan Albrecht ◽  
Magdalena Zielińska
Keyword(s):  
Hepatic Encephalopathy ◽  
Synaptic Transmission ◽  
Acute Hepatic Encephalopathy ◽  
Cortical Synapses

scholarly journals Astroglia-Derived BDNF and MSK-1 Mediate Experience- and Diet-Dependent Synaptic Plasticity

2020 ◽  
Vol 10 (7) ◽  
pp. 462
Author(s):  
Ulyana Lalo ◽  
Alexander Bogdanov ◽  
Guy W. Moss ◽  
Yuriy Pankratov
Keyword(s):  
Synaptic Plasticity ◽  
Synaptic Transmission ◽  
Environmental Enrichment ◽  
Aging Brain ◽  
Excitatory Synapses ◽  
Calcium Dependent ◽  
Beneficial Effects ◽  
Cortical Synapses ◽  
The Impact

Experience- and diet-dependent regulation of synaptic plasticity can underlie beneficial effects of active lifestyle on the aging brain. Our previous results demonstrate a key role for brain-derived neurotrophic factor (BDNF) and MSK1 kinase in experience-related homeostatic synaptic scaling. Astroglia has been recently shown to release BDNF via a calcium-dependent mechanism. To elucidate a role for astroglia-derived BDNF in homeostatic synaptic plasticity in the aging brain, we explored the experience- and diet-related alterations of synaptic transmission and plasticity in transgenic mice with impairment of the BDNF/MSK1 pathway (MSK1 kinase dead knock-in mice, MSK1 KD) and impairment of glial exocytosis (dnSNARE mice). We found that prolonged tonic activation of astrocytes caused BDNF-dependent increase in the efficacy of excitatory synapses accompanied by enlargement of synaptic boutons. We also observed that exposure to environmental enrichment (EE) and caloric restriction (CR) enhanced the Ca2+ signalling in cortical astrocytes and strongly up-regulated the excitatory and down-regulated inhibitory synaptic currents in old wild-type mice, thus counterbalancing the impact of ageing on astroglial and synaptic signalling. The EE- and CR-induced up-scaling of excitatory synaptic transmission in neocortex was accompanied by the enhancement of long-term synaptic potentiation. Importantly, effects of EE and CR on synaptic transmission and plasticity was significantly reduced in the MSK1 KD and dnSNARE mice. Combined, our results suggest that astroglial release of BDNF is important for the homeostatic regulation of cortical synapses and beneficial effects of EE and CR on synaptic transmission and plasticity in aging brain.

scholarly journals Detecting and Estimating Signals over Noisy and Unreliable Synapses: Information-Theoretic Analysis

2001 ◽  
Vol 13 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Amit Manwani ◽  
Christof Koch
Keyword(s):  
Synaptic Transmission ◽  
Information Transfer ◽  
Optimal Strategies ◽  
Presynaptic Neuron ◽  
Noise Sources ◽  
Temporal Precision ◽  
Cortical Synapses ◽  
Cellular Components ◽  
Parameter Values ◽  
Probabilistic Nature

The temporal precision with which neurons respond to synaptic inputs has a direct bearing on the nature of the neural code. A characterization of the neuronal noise sources associated with different sub-cellular components (synapse, dendrite, soma, axon, and so on) is needed to understand the relationship between noise and information transfer. Here we study the effect of the unreliable, probabilistic nature of synaptic transmission on information transfer in the absence of interaction among presynaptic inputs. We derive theoretical lower bounds on the capacity of a simple model of a cortical synapse under two different paradigms. In signal estimation, the signal is assumed to be encoded in the mean firing rate of the presynaptic neuron, and the objective is to estimate the continuous input signal from the postsynaptic voltage. In signal detection, the input is binary, and the presence or absence of a presynaptic action potential is to be detected from the postsynaptic voltage. The efficacy of information transfer in synaptic transmission is characterized by deriving optimal strategies under these two paradigms. On the basis of parameter values derived from neocortex, we find that single cortical synapses cannot transmit information reliably, but redundancy obtained using a small number of multiple synapses leads to a significant improvement in the information capacity of synaptic transmission.

scholarly journals Axonal Na+ channels detect and transmit levels of input synchrony in local brain circuits

2020 ◽  
Vol 6 (19) ◽  
pp. eaay4313 ◽  
Author(s):  
Mickaël Zbili ◽  
Sylvain Rama ◽  
Pierre Yger ◽  
Yanis Inglebert ◽  
Norah Boumedine-Guignon ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Sodium Channels ◽  
Sensory Processing ◽  
Coincidence Detection ◽  
Network Activity ◽  
Brain Circuits ◽  
Presynaptic Spike ◽  
Cortical Synapses ◽  
Powerful Mechanism ◽  
Local Brain

Sensory processing requires mechanisms of fast coincidence detection to discriminate synchronous from asynchronous inputs. Spike threshold adaptation enables such a discrimination but is ineffective in transmitting this information to the network. We show here that presynaptic axonal sodium channels read and transmit precise levels of input synchrony to the postsynaptic cell by modulating the presynaptic action potential (AP) amplitude. As a consequence, synaptic transmission is facilitated at cortical synapses when the presynaptic spike is produced by synchronous inputs. Using dual soma-axon recordings, imaging, and modeling, we show that this facilitation results from enhanced AP amplitude in the axon due to minimized inactivation of axonal sodium channels. Quantifying local circuit activity and using network modeling, we found that spikes induced by synchronous inputs produced a larger effect on network activity than spikes induced by asynchronous inputs. Therefore, this input synchrony–dependent facilitation may constitute a powerful mechanism, regulating synaptic transmission at proximal synapses.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

Synaptic Transmission. 2nd ed.

1970 ◽  
Vol 15 (6) ◽  
pp. 431-431
Author(s):  
GARTH J. THOMAS
Keyword(s):  
Synaptic Transmission
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