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Questions tagged [synapses]

A connection between neurons, which is either continuous (in electrical synapses) or interrupted by a cleft (in chemical synapses), through which communication is established.

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How does Sodium Valproate cause neural plasticity

I have been reading a fascinating paper: Valproate reopens critical-period learning of absolute pitch 18 individuals were given Sodium Valproate (VPA) for a fortnight during which they trained on a ...
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3 answers
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Under what conditions do dendritic spines form?

I'm looking for resources or any information about the formation of dendritic spines and synaptogenesis, especially in relation to how new connections are formed on a daily basis. Does the ...
hiddensunset4's user avatar
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How do neurons find each other?

Neurons form complicated networks in brains, but their connections can't be random (at least not entirely). Brains function similarly among all members of individual species, and that functionality is ...
CircleSquared's user avatar
10 votes
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How does an inhibitory synapse communicate to the cell body of a neuron?

I picture a neuron as having multiple trees of dendrites attached to the cell body with a single axon leaving the cell body. I believe the cell body near the axon root makes the decision to fire or ...
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Can a neuron make a synapse onto itself?

I was wondering if a neuron can make a synapse to itself? I suspect that it would be extremely unusual for a neuron to do this. Anyway, has anyone seen even a single instance of this? Is the process ...
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Is it possible to lose synapses over time?

I mean, what if a person is for a long time submitted to conditions in which his mental capacities are not explored, are the synapses undone? I've heard that drugs may cause such an effect, but what ...
ClayKaboom's user avatar
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What is the latency between paired neuronal responses in the brain?

Is there any data on how long it takes for signals to propagate from one neuron to its neighbors in complex networks, such as the brain (particularly the neo-cortex)? If not, is there any reasonable ...
back2dos's user avatar
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7 votes
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How long does a spiking signal last?

It is surprisingly hard to find information about the timing of neurons, in particular how long an action potential can contribute to the summation of a neuron. Is it on the order of milliseconds or ...
Lenar Hoyt's user avatar
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How are synaptic vesicles brought to the synapse?

I'm reading about how synaptobrevin is used to identify synaptic vesicles for tethering near the synaptic cleft. Since neurons have a synapse and dendrites, I'd like to know how exactly the vesicles ...
Ultimate Gobblement's user avatar
6 votes
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How does the synaptic cleft exist?

I'm not asking why the synaptic cleft exists, i.e. what function it holds, rather how. So I know that the neurotransmitter diffuses across it, it is 20-40 nm wide and contains basal lamina (in NMJs at ...
joe_young's user avatar
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How is a synapse held in place?

Here is a question I've never asked myself until now: All textbooks show synapses with a decently large synaptic cleft between the axon terminal and the dendrite. How is this connection held in place ...
Moppentapper's user avatar
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Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
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Is colocalisation of a protein with a presynaptic marker sufficient evidence to say that the protein is a component of axon terminals?

I am reading journal papers about the subcellular localisation of the insulin receptor (IR) in neurons. I have read a paper stating that IR is highly enriched at synapses, localising to both the ...
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Can neurotransmitter concentrations in the synaptic cleft add up if there are several impulses in quick succession?

When an electric signal reaches a chemical synapse, the signal is transmitted using neurotransmitters. Afterwards, the neurotransmitters are removed from the synaptic cleft. My question is whether it ...
vauge's user avatar
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What are the total number of action potentials in the human brain?

Is there an approximate figure of the total number of action potentials in the human brain? It's my understanding that there are ~ 60 billion neurons in the brain with ~ 100 trillion connections ...
greenMamBa's user avatar
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Biological advantage of electric synapses

Electric synapses are synapses that do not process information but simply foward one action potential from one neuron to the next. There are no neurotransmitters, no inhibitory and exitatory ...
tomet's user avatar
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Differences between synaptic connections

Consider the following synaptic connections (from here): axodendritic - A term pertaining to an excitatory or inhibitory synaptic connection between the presynaptic axon of a transmitting neuron and ...
Jean-Paul's user avatar
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Do presynaptic neurons and postsynaptic neurons have different compositions of neurotransmitter receptors and transporters?

For example if certain neurotransmitter is released, will there be neurons that won’t be even potentially affected, because it doesn’t have such type receptors?
Vy.Iv's user avatar
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What does fail-safe mean in transmission at electrical synapses?

I'm reading a book named Neuroscience:Exploring the Brain recently. And in the chapter about synaptic transmission, it says "Transmission at electrical synapses is very fast and, if the synapse is ...
louisedec's user avatar
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What makes synapses stay "fixed"?

What makes synapses not move or pre- and postsynaptic cells neither touch nor move away from each other? I mean the synaptic cleft is a gap between the pre- and postsynaptic cells that is about 20 nm ...
Karlb's user avatar
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What happens in the synapse when cocaine administration occurs in the human brain

As far as i know when you accept cocaine in your blood some cocaine molecules reach some synapses in your brain and fill some Reuptake tunnels preventing the cell to simply "do not know that fired ...
Flux's user avatar
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How fast does activity affect synaptogenesis?

How long does it take for the increased activity due to a novel stimulus to cause an increase in synapse generation? There are many studies which show that the number of synapses in the brain ...
Cort Ammon's user avatar
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Understanding the picture of a synapse

I need help to see exactly what is going on here. According to the textbook here is shown a synapse, but I cannot quite see the things the textbook says are there. From what I understand: (1) At1 and ...
Cure's user avatar
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2 answers
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What material fills the synaptic cleft? Is it water?

The synaptic cleft is the gap between the pre-synaptic and post-synaptic neurons, and neurotransmitters are transferred between the neurons within this region. What substance exits in this space, is ...
Alex L's user avatar
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Why chemical synapses are more common?

Reading into the types of synapses I found out that there are two types of them; electrical and chemical. chemical synapses use neurotransmitters to transmit impulses, are slower than electrical ...
Aditya Kumar Panda's user avatar
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1 answer
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Does tremor frequency generally increase as Parkinson's disease progresses?

I've been trying to research this question, but most if not all the on-line journals require costly subscription, and the studies that are posted look at tremor frequency with regards to other factors....
docscience's user avatar
3 votes
1 answer
93 views

A question concerning the strength of synapses

Synaptic strength can be defined »as the average amount of current or voltage excursion produced in the postsynaptic neuron by an action potential in the presynaptic neuron« Synaptic strengths and ...
Hans-Peter Stricker's user avatar
3 votes
1 answer
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What makes synaptic vesicle release probabilistic?

The fusion of synaptic vesicles (SVs) with the plasma membrane of the active zone (AZ) upon arrival of an action potential (AP) at the presynaptic compartment is a tightly regulated probabilistic ...
Alex L's user avatar
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1 answer
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Are synaptic boutons always located on axons?

I am learning about the protein Synaptophysin and I have read that it is an integral membrane protein localised to synaptic vesicles. I have also read that it is a specific and sensitive marker for ...
ceno980's user avatar
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Can a postsynaptic neuron 'shut itself off?

I am an amateur interested in neuroscience and was curious whether there is a process by which a neuron or group of neurons would close their receptors and stop receiving signals from specific ...
maxg795's user avatar
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3 votes
1 answer
231 views

Deducing synaptic strength from electron micrographs?

There are several promising techniques for connectomics based on iterative sectioning and imaging of tissue with scanning electron microscopes (e.g. FIB-SEM and ATUM) By looking at such micrographs, ...
Josh's user avatar
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Why electrical synapses are more common in invertebrates?

I suppose it's because they live in an environment where there's a constant vulnerability to predators and they need to respond quickly. But it's not really the case for many invertebrates and besides ...
Venkatesh Choudhary's user avatar
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At what rate does synaptogenesis occur in adults?

From many articles, I can find the rate of synaptogenesis at its highest: roughly 580,000/minute (weeks 6-23 after conception). However, I'm having trouble finding the rate with which it occurs in ...
Cort Ammon's user avatar
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3 votes
0 answers
79 views

What prevents neurones from touching at chemical synapses?

The synaptic clefts are really small, but the neurones which they are between do not touch even against forces like gravity. What really prevents them from coming into direct contact at the synapse, ...
Arush Ramteke's user avatar
2 votes
4 answers
396 views

Human brain is superior than till-date computers, yet why we perform poor than computer?

Scientists found storage capacity of synapses by measuring their size. They found, on average, a synapse can hold about 4.7 bits of information. This means that the entire human brain has a capacity ...
Resorcinol's user avatar
2 votes
2 answers
340 views

What determines the influx of calcium ions in the voltage-gated ion channels?

Calcium channels play a crucial role in neuronal signaling by helping the synaptic vesicles to fuse through the synaptic active zone and release their neurotransmitters. My question is, at a given ...
Alex L's user avatar
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2 votes
1 answer
107 views

Why do SRIs help in serotonergic neurotransmission?

Serotonin reuptake inhibitors (SRIs) block the action of the serotonin transporter (SERT) which, according to Wikipedia, leads to an increase in serotonergic neurotransmission. Now this book ...
vauge's user avatar
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2 votes
1 answer
471 views

Synaptic connectivity in the newborn's brain

In my understanding, learning is related to the strengthening and weakening of synaptic connections. Very roughly said: Synaptic connections that are used often are strengthened, those that are used ...
Hans-Peter Stricker's user avatar
2 votes
1 answer
52 views

Why use embryonic neurons to study protein knockouts/mutants in long term potentiation?

Just wondering if anyone had some ideas about the question in the title. I'm just wondering why some papers use embryonic cultures of specific brain regions for neurones to test the effects of ...
user28298's user avatar
2 votes
1 answer
533 views

Dendrodendritic synapse through axodendritic synapse at same dendrite?

Reading Wikipedia's article of dendrodendritic synapse, I find that: Dendrodendritic synapses are activated in a similar fashion to axodendritic synapses in respects to using a chemical synapse. ...
Jean-Paul's user avatar
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2 votes
1 answer
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Cumulative synaptic transmission delay

Assume the following: there are at least 10^11 neurons in the human brain there are approximately 10^14 synaptic connections in the human brain (because on average each neuron gets inputs from ...
JimPanSee's user avatar
2 votes
1 answer
98 views

Plasticity between excitatory and inhibitory neurons?

All that I've learned about synaptic plasticity only concern the synapses between excitatory neurons. For example, all pyramidal neurons (excitatory) in the cortex have plastic synapses between them, ...
sebjwallace's user avatar
2 votes
1 answer
389 views

What is the full name of E. G. Gray?

E. G. Gray is Neuro scientist who found and described first the two major morphologically defined synapse types (Gray Type I (asymmetric) and II (symmetric)) in his work E G Gray (Oct. 1959). “Axo-...
jan-glx's user avatar
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2 votes
1 answer
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What's the difference between Cytoplasmic pool and Granular storage pool?

What's the difference between Cytoplasmic pool and Granular storage pool when speaking about neurotransmitters and synaptic cleft. I encountered this here: Amphetamine’s mechanism of action thus ...
Ehsan88's user avatar
  • 315
2 votes
2 answers
70 views

How are presynaptic burst firing signals transmitted post-synaptically?

Neurons can exhibit burst firing and this presynaptic process basically results in a flurry of action potentials being fired in a short time window. I'm, however, wondering how these signals are ...
Moppentapper's user avatar
2 votes
0 answers
105 views

The human brain in numbers II-A: synaptic connections per structural type [closed]

The overall number of synapses in the human brain is roughly 1,000 trillion, i.e. 10,000 synapses per neuron. I assume that each structural type of neuron (basket, pyramidal, ...) has a somehow ...
Hans-Peter Stricker's user avatar
2 votes
0 answers
40 views

Synapse formation [closed]

I am trying to learn about neuronal synapse formation, but the literature is intimidating to someone with little background knowledge. I am interested in synapse formation in both human adults as ...
vrume21's user avatar
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2 votes
0 answers
435 views

When the mind is highly active, roughly how many neurons become excited in one second?

I'm curios to know how many times neurons send signals in one second when the brain is highly active (Highly active meaning during difficult problem solving, or any task that might bring the brain to ...
J.Todd's user avatar
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1 vote
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What is synaptic clearance?

Please explain what the term synaptic clearance means. For example, what would dopamine synaptic clearance be? It is important to me in context of dopamine signaling variation due to difference in ...
Bogdan's user avatar
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1 vote
1 answer
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Exocytosis of synaptic vesicles

I'm reading the following paper: http://jcs.biologists.org/content/123/6/819 The part I am really confused about is when they say: Exocytosis appears to use two alternative pathways: clathrin-...
user3665690's user avatar