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

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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 ...
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2answers
55 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 ...
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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 ...
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28 views

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

Why is the first phase of the pulse from a pacemaker cathodic?
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18 views

Criteria for electrophysiological threshold

As opposed to action potential thresholds (which are yes/no events), electrophysiological thresholds of compound action potentials are arbitrary. Mostly a certain noise level is picked and when the ...
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0answers
72 views

effect of pupil responses on the electroretinogram

The electroretinogram is generally considered to reflect the retinal processing of a light stimulus, typically a photoreceptor response followed by secondary neuronal activity. However, I am wondering ...
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75 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 ...
4
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1answer
53 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 ...
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36 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 ...
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2answers
35 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 ...
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42 views

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

I want to make a project for EEG signal processing, and in my research I found the concept of SSVEP, which means that if you have a stimulus with low frequency applied to the eye, the electrical ...
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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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1answer
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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? ...
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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 ...
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2answers
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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 ...
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2answers
83 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 ...
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1answer
2k 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 ...
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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 ...
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2answers
104 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 ...
2
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1answer
727 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 ...
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49 views

Patch-Clamping Neurons Resources

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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1answer
127 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 ...
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3answers
280 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 ...
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1answer
91 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.
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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 ...
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1answer
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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 ...
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2answers
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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, ...