Questions tagged [electrophysiology]
The study of the electrical properties of biological cells and tissues.
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How to measure Na/K channel activation at the membrane level?
Assume that there are two different signals occurring on the ECG - during depolarization and repolarization in the standard ECG.
I was advised not to use the standard ECG in measuring the exact ...
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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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Why is the resonance frequency of a neuron defined by peak impedance?
I'm relatively new to the field of electrophysiology, so if anything is unclear or incorrect, please let me know.
One thing that continues to confuse me throughout my reading is the property of ...
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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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conduction in unmyelinated axons
(Not a specialist here) Several questions touch the voltage propagation along an unmyelinated axon, but I'd like to focus on the following.
How fast does the voltage of a sub-threshold perturbation ...
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Can high energy photoelectrons damage cell membranes?
I've read that in addition to ionizing radiation causing damage to DNA through direct absorption, but DNA can also be damaged through photoelectrons with enough energy. The thing I was wondering is ...
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How can I simulate heart electrical activity in a 2D plane?
I am not a biologist/medical student, I study software engineering. But I really like when medicine and engineering hold their hands together to achieve great things.
As a side/toy project, I was ...
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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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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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Ion channels affected by gravity
In the literature I have found that action potentials behave differently when gravity is changed (cannot access fully).
Action potential properties are gravity dependent.
http://link.springer.com/...
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Potential homogeneity across cell membrane
During respiration, individual bacteria (and mitocondria) produce a relatively large potential difference (∼100 mV) between the inside and outside, using energy to pump $H^+$ out of the cell to the ...
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Neural correlates of the function of the cardiovascular system?
Are there any known neural correlates of the function of the cardiovascular system? I'm looking for research results that use standard brain imaging techniques (e.g. electroencephalography, ...
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Biology Experiment Data (Hodgkin-Huxley)
I'm doing research into the Hodgkin-Huxley Model from an electronics/mathematics perspective and I'm looking to find actual numerical results from experiments on squid axons. I want to compare the ...
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To define the total Resistance of Systemic Blood Circulation
Some systems are in parallel.
For instance, the resistance of lungs $R_{\text{lungs}}$.
Assume here for simplicity that these parallel systems can be handled linearly.
We also consider only Total ...
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Opening probability of a voltage-dependent ion channel
Does the opening probability of a voltage-dependent ion channel depend on the unitary conductance?
I think so because of the equation:
but I am not sure.
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Electrodes for electroporation of bacterial cells
Wikipedia says
"The process {electroporation} requires direct contact between the electrodes and the suspension."
However I've read the process is an effect of the field strength alone, ...
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Is there a way to derive Bazett's formula to correct QT interval in ECG?
As we know that QT interval in ECG is a function of heart rate (HR) and to comment on the pathology associated with altered QT interval, we must neutralise the effect of HR. For this Bazett's formula ...
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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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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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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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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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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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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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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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State of voltage gated sodium channels in depolarised potentials
Case 1
We learn in Physiology that during the depolarization phase in the membrane, more sodium channels tend to open as the membrane potential increases i.e., less negative. This is a kind of ...
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Measuring, using and analyzing skin resistance in kohms
What are ballpark ranges of skin resistance in Kohms for average men and their significance (for example 500-1000s = stressed vs 1000+ = fairly relaxed)
What do various skin resistances in kohms say ...
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Article or answer to whether "blood volume pressure" and "electrodermal activity" have any correlation to stress and or feelings overall
As the title suggests, I would like some help finding if there is any correlation between between blood volume pressure and electrodermal activity?
The paper I'm writing is about measuring stress and ...
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Is there an equivalent to a refresh rate for the brain and consciousness?
Computers have a clock rate that synchronizes their processors. In spite of tempting analogies, the brain is clearly not simply an organic computer. It is constantly changing, rewiring and pruning its ...
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Relationship between body size and damage done by electricity
We all know that if a person gets stunned by a 2000 volt stun gun, he/she may be knocked unconscious, but he/she is still alive and apparently no damage done on his/her body.
But what could happen if ...
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Measuring a plant's electric activity any instructions where to place electrodes?
I would like to measure a plant's electric activity / voltage, I've looked online to find out where to place the electrodes and what type of electrodes to use but they seem to very wildly. Any ideas?
...
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Why doesn't the Goldman Equation take into account ions that have no permeability?
While I was studying the Hodgkin-Huxley model, I encountered an a phenomena that confused me a lot.
I couldn't find the answer myself, so I wanted to ask here.
While calculating the equilibrium ...
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Confusion regarding the role of the capacitor in the electrical equivalent of a membrane
I am having trouble understanding the electrical equivalent of a cell mebrane as it is shown in this picture taken from Kandel:
What I cannot understand is the capacitor in the specific image. Why is ...
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Using Nerve Conduction Studies to determine nerve regeneration
I was reading a paper investigating using MRI as a way to determine peripheral nerve regeneration: https://sci-hub.do/10.1016/j.expneurol.2009.10.012
They mention that
... nerve conduction studies ...
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How do I stimulate a neuron extracellularly, specifically the sphenopalatine ganglion
Apologies if this is too basic of a question, but I am an electrical engineer, just getting into neuromodulation/neurostimulation.
For my senior project, I am trying to make a device that stimulates ...
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Effect of opposing electric charges on cells
Is the affect on a cell between two negatively charged plates theoretically similar to between a positively and negatively charged plate? In other words, would it induce charges on the inside and ...
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Is there a proton gradient across the cell membrane, just like for the mitochondrial membrane?
Mitochondria have a proton gradient, is there also a proton gradient between cells and the extracellular medium?
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Does the zeta potential of a nanoparticle generally take into account ligand charge?
For example, if I had a quantum dot nanoparticle with conjugated linker peptides capped with polyarginine tracts.
Would the localization of negative charge from arginine change the zeta potential ...
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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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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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What's a cells membrane potential without any leak channels?
Consider the following ion concentrations on either side of a cell membrane (in = inside cell, out = outside cell):
$[\text{Na}^+]_{\text{in}} = 10mM$,
$[\text{Na}^+]_{\text{out}} = 142mM$,
$[\text{K}^...
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