Questions tagged [electrophysiology]

The study of the electrical properties of biological cells and tissues.

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37 views

Difference between Premature Atrial Contraction and Atrial Fibrillation

what is the difference between Premature Atrial Contraction and Atrial Fibrillation. I know that both have irregular heart beat but have normal QRS complex. Both have abnormal or absence P waves but a ...
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33 views

Definition for different arrhythmia

I am wondering if there is an organization, a document or a research that standardize all the rhythms? Such as describing how long should the ECG be flatline to be considered as asystole? The rhythm I ...
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95 views

Where does this equation in the electrophysiology literature form come from?

In my studies I keep coming across the form of an equation that is used in many different mathematical models for voltage gated ion channels. The most general form I have found is in the 1977 paper ...
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23 views

Is the medium which transmits the electrical impulse through the heart different to a nerve?

According to Nerve A nerve is an enclosed, cable-like bundle of nerve fibres called axons Being an Axon An axon (from Greek ἄξων áxōn, axis), or nerve fiber, is a long, slender projection of a ...
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Why do larger diameter myelinated axons have greater conduction velocities than small diameter myelinated axons?

A canonical statement I have frequently read is that "large diameter axons conduct action potentials at faster velocities than small diameter axons". After recently learning the effect of increased ...
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Are large cell bodies of neurons harder to depolarize than small cell bodies of neurons?

In order for the axon to initiate an action potential, we know that the axon initial segment must be brought to threshold. So my question is as follows: Say we have the minimum charge input, "X", ...
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58 views

What is the difference in the electrical excitability between a “large diameter soma” and a “large diameter axon”

There are two stereotyped statements that I have seen during my coursework regarding electric properties of neurons: Large diameter axons propagate action potentials more quickly than small diameter ...
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49 views

At What Rate Do Ions Leak Out of a Plasma Membrane Segment That Has No Ion Channels?

In reading about the purpose of myelin during action potential propagation, I came across a point of confusion. From what I understand, one of the primary "benefits" of myelin is that it aids in ...
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45 views

Assumptions for Nernst Equation

While I am familiar with some of the conditions for the Nernst Equation, for example: 1) "The membrane is only permeable to one ion even if there are several other ions in the system" there is an ...
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27 views

What causes bio electricity? [closed]

When it is said that “electrical impulses sent from the brain” how is this charge flow produced?
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115 views

Living potato clock? [duplicate]

Could a potato stay alive and power a clock while growing in the ground? I know how a potato clock works as a electrochemical cell and involves chemistry, but I am only interested in a growing ...
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37 views

Entropy during neuronal signaling

to begin with: I have some background in cognitive neuroscience, but have not intensely studied the biochemical background of neuronal signalling, so please correct me if my basic understanding is ...
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How do scientists determine the nature of ions passing through a channel/carrier/pump?

The NCE (Sodium Calcium Exchanger) transports 3 Na+ inside the cell for 1 Ca2+ outside. How did we figure this out, and other mechanisms of this sort? If it were a protein, we could tag it with GFP. ...
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137 views

Are there any organisms, extant or extinct, that have only one neuron?

Nervous systems are useful in one way because they allow for integration of complex information. They are also useful because they transmit information very rapidly, over a large distance. However, ...
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58 views

Action potential frequency presynaptic neuron comared with in post-synaptic neuron/ muscle cells

I am a physicist interested in knowing how the action potential frequency in a presynaptic neuron compares with that in a) a post-synaptic neuron and b) membrane depolarisation of muslce cells, ...
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53 views

How is the electrical potential difference distributed between two stimulating electrodes?

Suppose I set the voltage value of an isolated stimulator with a floating ground. I place one electrode above the spinal cord (positive) and the other placed subcutaneously far away from the spinal ...
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96 views

What is the maximum electric potential that can occur in the human body?

Neurons can generate a voltage, if there is an action potential. Also, membranes where an ion concentration gradient is present, generate some membrane potential. What I wish to know is, which ...
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35 views

What is (are) the medium of conduction for an electrical current with an external source in the human body?

I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, ...
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Is it possible to create a biological radio? [closed]

If someone had taken the genome for a basic single or multi-celled organism, and had the understanding of genetic code to write his own program, is it possible on a fundamental level to create the ...
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115 views

What is (roughly) the net charge of the DNA in an average human cell?

I was wondering about what general range for the net charge of DNA in human cells is in Coulombs. I imagine that kind of thing would be hard to measure but could be approximately calculated/estimated....
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117 views

Is the ACh receptor more permeable to sodium ions?

The AChR is permeable to sodium and potassium ions only and has a reversal potential of 0mV. However the Nernst potentials for sodium and potassium ions is ~ +60mV and -88mV respectively. Taking a ...
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64 views

The information carried by nerve signals

Action potentials carry nerve signals in individual neurons and somehow encode information. My question is if it is possible to read that information carried by the nerve signal and feed it into a ...
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How to obtain normalised ECG given ECG readings across lead 1, 2, and 3?

I saw this youtube video on ECG readings and cardiac dipole vector locus of the heart across the three leads. Posting screenshots from it: My question is how to obtain the graph (2nd image) from the ...
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Which kind of electrical brain activity is associated with consciousness and why?

According to this article The ethical brain At the end of the week 5 into the 6 (42-43 days) the first electrical brain activity occurs in a pre-born developing human. And according to the same ...
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177 views

Can the human body utilize electricity? [closed]

In any way could the body store electricity supplied externally?
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109 views

Are resonances the reason receptors work?

From Visual phototransduction - Wikipedia: When struck by a photon, 11-cis retinal undergoes photoisomerization to all-trans retinal which changes the conformation of the opsin GPCR leading to ...
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3k views

Is there any danger in putting a magnet in your ear (next to your brain)

I recently bought some wireless earbuds that fit right in my ear, so they're very small. But the method it uses for charging is magnetic, so it has magnets built into the earbud. I was wondering if ...
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229 views

Why Goldman Equation cannot be used to calculate dynamic changes of membrane potential

I'm reading about Goldman Equation and I've seen in some resources that it calculates the resting potential (not membrane potential in general) and that this equation cannot be used when membrane ...
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89 views

Difference between spiking and firing

In the article "A Topological Paradigm for Hippocampal Spatial Map Formation Using Persistent Homology" by Y. Dabaghian, F. Mémoli, L. Frank, G. Carlsson I read some sentences with huge ...
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Can there be multiple EPSPs with constant current injection to a neuron?

I am performing a current clamp experiment and measuring the change in membrane potential of a neuron with different current injections. A constant current of 50pA is injected to the neuron for 100ms. ...
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142 views

What is the point in the Neuromuscular Junction?

Surely a direct connection (i.e. an electrical synapse) between motor neurone and the sarcolemma would allow for much faster neuromuscular transmission? It is my understanding that chemical synapses ...
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25 views

How much electrical energy is required for intracellular stimulation of a neuron?

How much electrical energy is required for intracellular stimulation (firing) of a human neuron? Electrical energy is measured in joules, and equal to voltage multiplied by current. If you don't know ...
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155 views

Can neurons be inhibited with electric current?

It is well known the electricity can be used to fire neurons. But can it be used to inhibit neuronal firing? This is in the context of extracellular stimulation. In extracellular stimulation, it is ...
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140 views

Mathematical relationship between membrane conductance and conduction velocity?

By what factor would the myelin need to decrease membrane conductance (gm) if you wanted conduction velocity in a 10 μm myelinated mouse axon to be 100 times faster than in a 10 μm unmyelinated mouse ...
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57 views

Why do house geckos take so long to react?

This is the Common house gecko found abundantly where I live. I've been observing this for quite long and I used to ignore it after thinking on it for a short while. Today I decided to write this ...
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91 views

At what point do scientists consider something sentient vs random and/or genetic? [closed]

When I was thinking about sentience from a scientific point of view, I was confused about the bio-electric mental difference between a paramecium, dog, human, and supercomputer. At what point does ...
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53 views

single units vs ensemble recording for signal detection

I would like to know, when looking (in vivo electrophysiology) at response properties (latency, magnitude) in response to sensory stimuli, is there any advantage to looking at single units over ...
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Which ICs can I use to amplify electrical signals from plants?

I wanted to record variation potential and action potential generated in plants due to some stimulus. So which are the ICs that I can use for the amplifying the signals and what kind of experimental ...
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772 views

Why nerve fibre is infatiguable?( is my conjecture correct?)

According to this: A nerve fibre cannot be fatigued, even if it is stimulated for a long time. This property of infatiguability is due to absolute refractory period. How is refractory period ...
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What is the standard electrode potential of human blood?

Healthy humans have a pH of around 7.4 (slightly basic.) But if you hooked up the blood as a battery how much electric voltage would one generate, what is the standard electrode potential? This seems ...
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517 views

Why summation takes place at Initial segment?

I know that many EPSPs summate at initial segment to produce action potential. But I don't understand why if EPSP can travel from dendrite to initial segment, then why it doesn't travel further? ...
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Shouldn't recording electrode have as low resistance as possible?

Following quote is from this wikipedia page on single unit recording. Intracellular single unit recordings require electrodes be inserted through the cell membrane to record from within the cell. ...
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How much current is required to stimulate a neuron?

Extracellular stimulation of neural tissue is done using electrode. Amount of current determines neurons how far from the electrode will be excited. How much current is required to stimulate the ...
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34 views

How the electrons from electrode play a role in stimulating the neuron?

I am trying to understand how a neuron fires action potential after being stimulated via electrode (extracellular stimulation). GHK equation gives the membrane potential,which is -70 mV when neuron is ...
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What is the resistance of a single human cell? [closed]

What is the resistance of a single human cell? I know different cells will have different values, some examples would suffice. I did not find any such information on the internet.
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193 views

How do plants store energy by potassium battery?

Plants have a so-called potassium battery system for energy storage/conversation. Wikipedia only has a reference to a technical article. Can someone explain it in a layman's language (or refer to a ...
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72 views

What voltage damages a neuron or a group of neurons?

Neurons are stimulated for research and therapy purposes. How much voltage (current, duration, etc) can a neuron or a group of neurons, in humans, take without being damaged?
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135 views

Organic battery?

Similar to the Matrix movie where humans were used as a source of electricity but different by using electric eels. Farmed like tuna what would be the electricity exchange to the food they eat?
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233 views

Are Sharks able to detect electromagnetic waves using their Electroreception ability?

I will include some publications and links that may help. I could not concluded an answer with my limited knowledge on the subject. Shark Passive electroreception sensitive to low frequency (below 50 ...
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2k views

Sodium concentration during action potential generation

At the peak of the graph, is the concentration of Na+ outside the cell more than inside? That must be to overcome the electrical force in the opposite direction. When is the concentration of Na+ ...