Questions tagged [neuron]

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Axonal guidance in neuroplasticity

There have been many questions on this SE regarding the "core" of neuroplasticity. It seems to me that it is mainly caused by axonal guidance. For example, a group of neurons of the post ...
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How does a neuron change its function, without changing its synaptic connections?

How does a neuron change its characteristics in order to change its function, without changing its connections with the neural networks? Basically, do any organelles change their properties and are ...
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To what extent are microtubule-filaments present in astrocyte leaflets?

I have been trying to find information about whether microtubule filaments are present in the leaflets of astrocytes. A astrocyte can have quite varied morphology but many at least, have a star-like ...
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Neurons: how does the brain reduce electromagnetic interference?

I read that the frequency of signal over neural ion channels in the brain can range from .19 Hz - 30 Hz at low voltage. For an interference example, AC electricity is 60 Hz at high voltage and ...
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Vision System: neural activity is modulated using FSK?

I’m learning about the human vision system and signaling. Does anyone know if the signaling used by the vision system is modulated at the neuron using amplitude frequency shift keying? I present my ...
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Vision and signal through the nervous system? [closed]

I have questions regarding the signal path between the retina and other parts of the brain. An understanding and then questions in bold follow. Wikipedia states: Retinal ganglion cells spontaneously ...
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The role of PCA (Principal Component Analysis) in recording neurons

I am reviewing the recording methods from an experiment that tracked neuronal activity on the prefrontal cortex of a monkey. From the method description in Nieder, Andreas, David J. Freedman, and Earl ...
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Is the nervous message sent by an eyelash being flexed sent all the way to the brain?

Since the reflex to close the eyelid once an eyelash is touched seems very fast, does the signal from the neuron detecting the touching travel all the way to the brain, get processed then back to the ...
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Why are nerves blocked even though potassium channels are not blocked?

One could read "Local anesthetics produce a very slight, virtually insignificant, decrease in potassium (K+) conductance through the nerve membrane." At Handbook of Local Anesthesia 7th ...
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Illustrating Action Potential Conduction and Ion-Gated Channels

I can separately illustrate action potential and ion-gated channels along an axon. However, I am not sure if I did the right thing on the picture below. What I'm trying to show are the simultaneous ...
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4 votes
1 answer
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Are living cells electrically neutral?

I found random scientific table which had a comment attached: the cells must be electrically neutral. Per my knowledge whole intracellular solution contains more electrons than protons (definition ...
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1 answer
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How many signals can one neuron send and/or receive simultaneously?

I've been researching this question online and finding opposing answers. Some articles say that one neuron can only send one signal at a time while others says that one neuron can send more than one ...
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3 votes
3 answers
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Is there a difference between human neuron cells compared to those of other animals?

Thanks for looking. Firstly, I am nowhere near biologist, just a student, so my apologies if this isn't a "good" question. Background: So I was searching about intelligence, brains and ...
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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 ...
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Connectivity Relation between axon terminal synapses and dendrites

With regards to the synapses between axon terminals and dendrites, what is the relation between a given neuron's axon terminals and its neighbouring neurons' dendrites? Does each axon synapse on only ...
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How are thoughts biologicaly generated?

I want to know how thoughts are biologicaly generated. I know that electrical impulses can trigger formed memories in the brain but what I want to know is how the electrical impulse is generated in ...
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What are "inactive" cells during Ca2+ imaging of neurons?

I am reading this paper, and have found the following Figure (Extended Data Figure 5) where they show maps of active cells in the amygdala as imaged with a miniscope and GCaMP6m: Legend: Using the ...
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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 ...
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What is meant by the term synaptic targeting?

I am studying whether a protein interacts with the mitochondria in the synapses of neurons and I have come across the term "synaptic targeting". I am reading this paper and I have come ...
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Are sensory mechanoreceptors and mechanical nociceptors the same type of neurons or are they different?

I always supposed the neurons / receptors which transmitted touch and pain were the same, since they react to stimulus which are the same but with different intensity, and they just sent a stronger ...
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Why is neuronal firing rate proportional to axonal diameter?

I know that a larger axonal diameter results in faster speed of action potentials due to reduced resistance. However this doesn't explain why the firing rate of neurons is proportional to neuronal ...
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1 vote
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Using coefficient of variation (CV) for GCaMP6 'synchronised episode' spikes, good idea or not?

Using GCaMP6 we have recorded fluorescence activity of kisspeptin neurons that exhibit synchronised pulsatile firing activity. I measured the intervals between each episode, which are quite variable. ...
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Are axons of neurosecretory cells in neurohypophysis myelinated?

According to the pictures that I found in textbooks and Google here these neurons are not myelinated. I just wanted to be sure. They are not myelinated, are they?
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How are neurons selective towards specific stimuli?

I've read several papers that mention that there are specific neurons that are activated for specific things (e.g. neuron A activate only when horizontal lines appear, neuron B activate when certain ...
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Can potassium ions depolarise neuron membranes?

I am reading a journal paper about the cell adhesion molecule NCAM2 and I have come across the following statement: To confirm the functionality of the reporters, neurons were time-lapse recorded ...
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Do neurons with dopamine inside only send signals to another neuron with dopamine?

A nerve cell with dopamine receptors gets an action potential and releases dopamine to other neurons. Does this nerve cell only release to cells with dopamine inside? Because what if a neuron has a ...
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1 vote
1 answer
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Do voltage-gated channels in a neuron use ATP

I have a question about action potentials in a neuron. Do voltage-gated sodium and potassium channels use ATP? I mean when they are closed or when they want to open the gate, do they use ATP?
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Why do ion leak channels exist?

I've recently learned about ion leak channels in the context of membrane potential and action potentials. Neurons have ion pumps that require energy in order to maintain the resting membrane potential ...
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Na+ / K+ ATPase: How does it restore resting membrane potential? [duplicate]

Could not find any sources talking about this (in a clear manner). If the Na+ / K+ ATPase pumps 3 Na+ out for every 2 K+ it pumps in, thus making the cell more negative, why is the Na+ / K+ ATPase ...
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Why does exposure to a smell for some time reduce the electrical response of receptor neurons in the olfactory system?

In what way does exposure to a certain smell for some time causes them to loose sensitivity and have a lesser electrical response
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1 vote
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Biophysically, how to change from a tonically firing neuron to an occasionally firing one?

In terms of membrane properties, size and neuronal biophysics (assuming no change in incoming excitation), how can a tonically firing neuron become (say during development) an occasionally bursting ...
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1 answer
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What is a neuronal loop?

Stanford Medicine's OCD page says that Many investigators have contributed to the hypothesis that OCD involves dysfunction in a neuronal loop running from the orbital frontal cortex to the ...
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How would blocking Na/K ATPase affect the ability of a neuron to exhibit a series of action potentials?

Neural firing usually occurs in the form of spike series. Several action potentials are happening in a quick succession. Whereas Na/K pumps (and other pumps) restore ion gradients to allow processes ...
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Typical firing patterns of neurons in the default mode network in resting state

Inspired by the Wikipedia article on the default mode network where I read: Hans Berger, the inventor of the electroencephalogram, was the first to propose the idea that the brain is constantly ...
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Where do the Ca ions that causes neurotransmitter release from synaptic bouton, come from?

I hope the information you share will help clarify the following doubts and gaps in my knowledge: Where do the Calcium ions in the influx (which then triggers the neurotransmitter vesicles) come from?...
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Functional unit

What is meant by functional unit of a system? like when we say that the neuron is the basic unit of neural system do we mean that all those things that are performed by neural system can be performed ...
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1 answer
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Why didn't the human Cerebrum evolve to have granule cells like the Cerebellum does?

The Cerebellum is much smaller compared to the Cerebrum yet it contains more than half of the total neurons contained in the brain. That's mainly due to the granule cells in the Cerebellum which ...
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Effect of myelination on inteligence in cephalopods

Cephalopods are known for their unique intelligence compared to other invertebrates. The number of neurons of cephalopods is of the order $5*10^8$, similar to dogs. Humans have about $10^{11}$ ...
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Myelination and time constant

In textbooks, it says that myelination doesn't really affect the time constant as tau=RC where R is the membrane resistance and C is the membrane capacitance. Myelin increases membrane resistance ...
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What causes sodium channels to open?

What triggers the opening of sodium channels in a neuronal membrane? Is it acetylcholine that activates sodium channels in the postsynaptic membrane? Are sodium channels like receptors that have to ...
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3 votes
1 answer
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Understanding presynaptic and postsynaptic inhibition

One way to classify neural inhibition is based on the inhibition being "presynaptic" or "postsynaptic". As far as I understand, the two different types of inhibition refer to the following: ...
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Relationship between membrane current and voltage in neurons

Depolarization of neurons leads currents of different magnitudes flow in or out of the cell, and the Sodium and Potassium currents can be separately plotted (Purves): Caption: Relationship between ...
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How long does it take the neurotransmitters to diffuse accross the synaptic cleft?

Neurotransmitters get from the pre-synaptic neuron to the receptors on the post-synaptic neuron by diffusion across the gap between these two (the synaptic cleft). My question is, how much time does ...
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1 vote
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When do the first neurons appear in humans?

According to this Neural Plate The neural plate appears in day 18 in humans (very specific). and according to this Neural Plate (wiki) The progenitor cells that make up the precursors to neural ...
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