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

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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 ...
14
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1answer
259 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 ...
9
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2answers
5k 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 ...
9
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1answer
147 views

Is there a biophysical causation from local field potential (LFP) to spikes?

Many experiments showed that neurons tend to fire at some phase (usually trough) of local field potential (LFP) oscillations, such as theta or gamma rhythm. LFP is supposedly generated by a population ...
7
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2answers
231 views

Is “exhaustion” of the Hodgkin-Huxley membrane at constant stimulation a real phenomenon?

I was playing around with a simulation of the Hodgkin-Huxley model using their original parameters for the squid giant axon. By applying a constant stimulation current to the model in resting state, ...
7
votes
2answers
207 views

What does pain look like in wave form?

I am interested in understanding what "pain" and "hot/cold" look like, as far as waves signatures (signal processing) go. My general understanding of how pain (nociceptive pathways) and hot/cold ...
7
votes
1answer
241 views

What is the reason behind high resting membrane potential of pacemaker cells?

Pacemaker cells have high resting membrane potentials of -50 to -40 mV, whereas normal cells have their resting membrane potential around -70 mV. Which ions, and what kind of channels are responsible ...
7
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2answers
166 views

Is there a biological neuron that spikes in response to hyperpolarizing currents?

As some background I've been building Electrophysiological models of neurons, and in the process stumbled upon a model, that in all respects is biologically plausible, but has a bizarre property I ...
6
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2answers
195 views

How to analyse an ECG?

I have a project about extracting features from a homemade ECG. I need the PQRST points from the signal of the heart beat. The ECG I'm using has 3 electrodes that attach to the chest. The problem is ...
6
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1answer
3k views

Why do neurons have a negative resting potential?

Neurons expend the majority of their energy powering ion pumps to maintain the chemical gradients that power their electrical activity. To have a negative resting potential, neurons leak potassium ...
6
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1answer
87 views

How does the frequency of a visual stimulus affect the steady-state visually evoked potential?

I want to design a project for EEG signal processing. In my research I found the concept of SSVEP. SSVEPs represent the electrical activity of the brain as measured via EEG, and are evoked by visual ...
5
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2answers
95 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 ...
5
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2answers
2k 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 ...
5
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1answer
94 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 ...
4
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1answer
99 views

Why isn't there any repulsive force between Na+ and K+ disrupting thier roles in transmembrane voltage/ action potentials

Pretty self explanatory question. I have a basic grasp on the "How" and "Why" of Reversal/Action Potential in and between neurons, but this question lingers.
4
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2answers
122 views

Connect the inner and outer space of cell with a wire, will there be electricity?

There is a potential difference, but ions can not go through wires, right? Though there is a electric field, but there is no electron source, I am thinking the answer is no, or will there be some ...
4
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1answer
85 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. $$\text{OUT:IN}$$ $$\text{K}^+ (1:20)$$ $$\text{Cl}^- (11.5:1)$$ $$\text{Ca}^{2+} (10000:1)$$ ...
4
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1answer
177 views

Mechanisms of extracellular stimulation of neurons

When stimulating a group of neurons with an electrode, let's say we put it in a region that contains axons, what is the mechanism by which the axons are stimulated? I've been told electrodes ...
4
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1answer
158 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
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2answers
324 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 ...
4
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1answer
63 views

Do local field potentials (LFP) create waves on the surfaces of nerve cells?

Are waves created by the LFP on the surfaces of neurons cell bodies? Since the cells have a resting potential, do these waves create harmonic oscillation of the membranes at particular frequencies? ...
4
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0answers
38 views

Why does a pacemaker have a negative pulse? [closed]

Why is the first phase of the pulse from a pacemaker cathodic?
3
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1answer
81 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.
3
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2answers
673 views

Action potential changes in low sodium concentrations but constant osmotic pressure

If I bathe a squid axon in a fluid that has high sodium concentration , why does the duration of action potential decrease compared to a control experiment in low sodium bath but maintained at the ...
3
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1answer
213 views

How does a microelectrode work?

On Wikipedia, the entire microelectrode page states only the following: A microelectrode is an electrode of very small size, used in electrophysiology for either recording of neural signals or ...
3
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1answer
37 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 ...
3
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1answer
135 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 ...
3
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0answers
61 views

Patch-Clamping Neurons Resources [closed]

Are there any lectures available on Patch-Clamping? Were can I find a mathematical model of Patch-Clamp? (that can be easily implemented in matlab). I have found some step-by-step protocols on ...
2
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2answers
131 views

How precise is EEG?

Imagine we want to read impulses within single neurons in the brain. Can we do that now for a single region within the brain? If not, what is the smallest region that can be monitored for an activity ...
2
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2answers
138 views

Breakdown current for human body

If I am not mistaken, during exposure to electricity sources it is the magnitude of the current and not the voltage that kills the human body. If so, what is the order of magnitude of current that ...
2
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1answer
1k views

Why does high-voltage mostly shock a person, and even small current kill?

This may be the wrong forum to ask. For instance several people are known to have survived a direct lightning strike; albeit the number of fatalities are probably far larger. Anyway, I found myself ...
2
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1answer
30 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.
2
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1answer
22 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 ...
2
votes
1answer
56 views

What equipment is needed to perform simple plant electrophysiology?

What is the minimum needed equipment to perform simple plant electrophysiology? I am looking for some simple experiments that I could run at home for learning. Ideally, I would transfer the skills to ...
2
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1answer
1k 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 ...
2
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1answer
4k 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 ...
2
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1answer
164 views

How stable is in vivo whole cell patch clamping?

For a head fixed animal, how stable is the current state-of-the-art whole cell recording from a cortical neuron? The animal's breathing, and heart beat must move the neuron relative to the recording ...
2
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0answers
35 views

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, ...
2
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0answers
72 views

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 ...
1
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1answer
33 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
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3answers
391 views

Do Viruses produce a biomagnetic field?

From wikipedia: Biomagnetism is the phenomenon of magnetic fields produced by living organisms. The present scientific definition took form in the 1970s, when an increasing number of researchers ...
1
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1answer
223 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 ...
1
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0answers
21 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
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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 ...
1
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0answers
166 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
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0answers
92 views

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 ...
0
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1answer
139 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
0
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1answer
31 views

Is missing Q wave characteristic for Wolff-Parkinson-White Syndrome?

No my study books says about that no Q waves in WPW syndrome. They are about wide QRS complex often however. I heard today that the characteristic property of WPW is often a missing Q wave, like here ...
0
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2answers
84 views

Are Purkinje Action Potentials Neuronal and Cardiac?

I first thought that action potentials of His-bundle i.e. Purkinje fibers are Cardiac. However, I started to think that this is not enough. I think now that they are neuronal and cardiac. My ...
0
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2answers
58 views

How is it that ionic diffusion is independent of other ions?

This question arises from the explanation of what the resting potential of a cell membrane is. In the Goldman formula, there is no interaction between different ion types. If diffusion is caused by ...