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

learn more… | top users | synonyms

3
votes
1answer
43 views

What are tail currents?

This is a voltage clamp on an ion channel. When the voltage is stopped there is a still a current at the end (the tail current). I understand that the gates aren't completely closed because of which ...
2
votes
1answer
29 views

Minimal viable EEG equipment for dissertation research on BCI / BMI

I am planning out a dissertation study of Brain-computer Interface (a.k.a. Brain-machine Interface, BCI, BMI, etc) applications. One of the 3 papers in that dissertation will involve collecting ...
5
votes
1answer
49 views

What physical or mental actions can be picked up by EEGs?

There certainly seem to be a lot of gadgets and gizmos leveraging EEG technologies to the control of devices. This makes me wonder: what intentions/thoughts can be captured by EEG technology, and ...
6
votes
2answers
142 views

What signal processors comprise an Event-Related Potential system for EEG?

So my 30,000 ft. understanding of the EEG signal processing data flow is: Capture raw EEG data ("raw waveforms") Run these raw waveforms through a Signal Processing Framework that consists of 1+ "...
1
vote
0answers
16 views

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 ...
4
votes
2answers
196 views

Are Gram negative bacteria classified as such because of their negative membrane potential?

Does the membrane potential usually quoted for Gram negative bacteria (e.g., E. coli) refer to the potential across both membranes? - If yes, then does the potential fall more over the inner or outer ...
1
vote
1answer
19 views

What will happen to a neuron if I suddenly remove the pump but not the leaky Na+ and K+ channels?

K+ is more abundant inside the cell and thus has a propensity to move outwards. It has an equilibrium potential of -80 mV. Na+ is more abundant extracellularly and thus has a propensity to move ...
3
votes
0answers
7 views

At which voltage will the conductance decrease due to the narrow pore in a voltage-gated potassium channel?

If you have a voltage-gated potassium channel that do not inactivate, at which voltage would you see decrease in ion conductance related to the narrow path in the pore? With that said I know that in ...
3
votes
0answers
18 views

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 ...
3
votes
1answer
50 views

Understanding the configuration of channels in the 10-20 EEG montage

In a typical 10-20 system there are 21 electrodes placed on the scalp. However, this does not mean there are 21 distinct "channels" or voltage sources. I've heard that some of these electrodes are "...
1
vote
1answer
29 views

Analysing the ERP (Event-Related Potential from EEG recordings) in terms of the P-300 wave

I am trying to understand how to analyze ERP (Event-Related Potentials) from EEG recordings in focus on P-300 waves. I have come up with a few questions which I hope you might be able to help with: ...
8
votes
2answers
1k views

Why is Fast Fourier Transform applied to raw EEG data?

I am trying to understand why Fast Fourier Transform (FFT) is used in the analysis of raw EEG channel data. My understanding (at the 30,000 ft view) is that FFT decomposes linear differential ...
1
vote
1answer
44 views

Why is active transport needed in repolarization?

During the repolarization phase of an action potential, the potassium ions diffuse out of the cell, and active transport begins. What I do not understand is why active transport is needed when the ...
6
votes
1answer
104 views

Software recommendation for protein in electric field modeling? [closed]

I'd appreciate a suggestion for software to compare models of two proteins in an alternating electric field. The more detail, or perhaps direction towards an existing and similar paper, the better. ...
1
vote
0answers
35 views

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 ...
0
votes
0answers
31 views

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 ...
7
votes
2answers
145 views

Why does the intensity of an action potential once generated at the trigger zone remain undistured throught the axon?

What causes this consistency? I read the previously asked questions on this site none of them carry an answer to this question.
1
vote
1answer
17 views

Why are local field potentials generally band-pass filtered?

I was wondering what the rationale was behind low-pass or band-pass filtering in local field potential measurements? It seems to me that we could potentially filter out potentially valuable ...
3
votes
1answer
111 views

What is the direction of current flow in myelinated nerve cells?

Is it correct to say electric current flows through the extracellular space, or cytosol of a nerve fiber during impulse conduction? I know that an impulse is actually a change of membrane potential ...
4
votes
1answer
188 views

How's the membrane potential restored to resting state after hyper polarisation?

I have known for so long that Na+/ K+ pump restores the membrane potential. But as it pumps in 2 K+ for every 3+ Na+ moving out how can it make the membrane potential less negative when the net result ...
7
votes
1answer
309 views

What keeps the resting potential of neurons constant at -70 mV?

I know the sodium-potassium pump pumps out 3 Na+ ions and pumps in 2 K+ ions per reaction so the negative charge in the axon increases. However, once the voltage (difference of charge inside and ...
2
votes
1answer
49 views

How are physiological reversal potentials (or ion concentrations) of neurons measured?

Patch clamp electrophysiology experiments typically use an intracellular solution that mimics the ionic concentrations of neuronal cytosol. At the same time, the extracellular solution is meant to ...
2
votes
1answer
111 views

What are the highest and lowest amplitude values in ECG for humans?

I'm currently trying to parse the records captured from an ECG device and display them on a mobile application. I am wondering what the highest and lowest possible amplitude values for ECGs are in ...
4
votes
1answer
72 views

Do repetitive movements on EEGs show up as discernible patterns?

Here is a typical EEG reading: If I am connected to an EEG, and am sitting perfectly still, and then begin doing some repetitive motion, say, 10,000 times, will we see discernible patterns emerge ...
3
votes
1answer
2k views

What is the difference between rheobase and threshold?

Neuronal tissues can be excited by electrical stimulation. Two commonly encountered characteristics for electrically stimulating nerve cells is the threshold and the rheobase. My question is what the ...
5
votes
1answer
113 views

Criteria for compound action potential thresholds

As opposed to action potential thresholds (which are binary yes/no events), electrophysiological thresholds of compound action potentials are arbitrary. Mostly a certain noise level is picked and when ...
2
votes
1answer
179 views

What are wave frequencies in the EEG?

Here is a typical EEG reading: I understand that each row corresponds to the signal read between two sensors on a standard 10-20 (or 10-5) distribution setup (e.g. ...
3
votes
1answer
64 views
3
votes
1answer
40 views

Efficacy of the 10-20 montage for EEG

I am trying to better understand the relationship between the placement of EEG electrodes and the quality of the "brainwave" signals they produce. There is the standard 10-20 system which has me ...
2
votes
1answer
61 views

Why is stimulation of nerve tissue with a negative pulse called “cathodic” stimulation?

By definition, the cathode is defined as the terminal through which current exits a polarized device. But in the context of neuromodulation, such as spinal cord stimulation, deep brain stimulation, ...
1
vote
0answers
29 views

Effects of pH vs membrane potential within a cell? [closed]

How are these two concepts related? Does changing each result in the same effects? As in: what kind of reactions/processes would be affected if we changed the pH within a cell? Would the results ...
1
vote
0answers
29 views

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 ...
9
votes
2answers
7k views

Why is saltatory conduction faster than continuous conduction?

How does spacing apart sodium and potassium channels allow the action potential to travel faster down the axon? This is the reason always cited for saltatory conduction and myelination, but my mental ...
2
votes
1answer
5k views

How do inward rectifier potassium channels work in the heart?

Apparently in cardiomyocytes, there is an inward rectifying potassium channel that operates during phase 4 of the cardiomyocyte action potential. I have heard that despite this potassium channel ...
5
votes
2answers
322 views

Why does depolarisation by high intracellular K+ trigger calcium channels opening?

I have learnt that in pancreatic beta cells, glucose being metabolised in the cell causes a high ATP level, which triggers ATP-dependent potassium channels to close. This means that potassium can't ...
2
votes
1answer
36 views

How are cardiac cells stimulated by an action potential?

Why, and how, does the action potential of one cell in the heart stimulate an action potential in the next cell? I'm interested in an answer with citation.
0
votes
0answers
17 views

EMG recording and muscular contraction

In many form of peripheral neuropathies the excitability of some neurons is changed and their conduction velocities are consequently altered.What are the effects that this might have on an EMG ...
0
votes
0answers
11 views

ECG cardiac monitoring

How is the signal observed from electrode and electrode impedance is affected if we clean one of the pair of Ag/AgCl cardiac electrode by scraping it with steel wool until it was shiny and bright
3
votes
1answer
38 views

classical conditioning paradigm for hippocampal learning

I wanted to know what a suitable classical conditioning experiment would be to analyze learning and memory capabilities in rodent models with respect to hippocampal long-term potentiation. For ...
14
votes
1answer
271 views

Effect of pupil responses on the electroretinogram

The electroretinogram (ERG) is a measure of electrical activity of the retina. It is typically recorded from the cornea with a wire electrode or gold-foil electrode. Generally, the the ERG is ...
2
votes
1answer
24 views

How can I interface cAMP signal or membrane potential from slime mold to an electrode?

I am very much interested in measuring cAMP (cyclic adenosine mono phosphate) signal and membrane potential from amoeba. Since I want to try this as a hobby, what are the basic steps I must do to view ...
3
votes
1answer
144 views

Can an electrocardiogram be recorded with a single electrode?

Is it possible to do an electrocardiogram with one electrode? Or is it neccesary to have multiple electrodes? I do not understand much about EKG, so I am sorry if this question sounds naive.
4
votes
1answer
298 views

Doubling the concentration of extracellular calcium hyperpolarizes a neuron. Why?

I was doing some back of the envelope calculations to try to answer this question in more mathematical terms. Essentially the question states: Why does increasing the extracellular potassium ...
4
votes
1answer
145 views

If the average resting potential of a neuron is -70 mV, why is there such a high ratio of potassium ions inside relative to out?

My bio teacher was discussing the ratios of different ions inside versus outside the cell. $$\text{OUT:IN}$$ $$\text{K}^+ (1:20)$$ $$\text{Cl}^- (11.5:1)$$ $$\text{Ca}^{2+} (10000:1)$$ $$\text{Na}^+...
31
votes
5answers
2k views

Why did life not evolve to use radio?

We use electromagnetic communication everywhere these days. Cell phones, wifi, old-school radio transmissions, television, deep space communication, etc. I'm curious about some of the possible ...
3
votes
1answer
167 views

Explanation of ECG in MI using an electrostatic model

I found a paper presenting an electrostatic model to explain the ECG recorded in various leads. This model essentially calls for considering the depolarization wavefront to be the major contributing ...
6
votes
2answers
4k views

How is membrane capacitance related to the increased speed of saltatory conduction?

Here is the original question which inspired my question. As explained by the answers there, the reason saltatory conduction in myelinated neurons is faster than non-myelinated conduction is because ...
1
vote
0answers
215 views

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? ...
1
vote
1answer
634 views

Why is Electrical Cardioversion contraindicated in AF and Digitalis Poisoning?

I am thinking why electrical cardioversion is contraindicated in atrial fibrillation with digitalis toxicity/poisoning. Cardiac digitalis is also called digoxin and cardiac glycoside. It is ...
4
votes
2answers
446 views

Mechanism behind negative conductance of ion channels

I am struggling to understand negative conductance shown on I-V curves on ion channels. Mechanistically, negative conductance means that inward (or outward) current increases when voltage across ...