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Questions tagged [electrophysiology]

For questions about the study and measurement of the electrical activity of neurons

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Methods for comparing extracellular neural response structure to auditory stimulus structure

I have two arrays, one representing an auditory stimulus and the other representing neural activity from auditory cortex. The auditory stimulus has known temporal and spectral structure. The neural ...
user90664's user avatar
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Literature reviews on nerve conduction velocity?

The Wikipedia article for nerve conduction velocity is frustrating because it lacks citations. What is a good survey or overview of the research on nerve conduction velocity? I'm particularly ...
jskattt797's user avatar
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1 answer
51 views

What is the difference between "electrode" and "pad" on extracellular probes?

Some authors seem to use these terms interchangeably, others distinctly. What is a pad? How is it different from an electrode? Is a pad where stimulation can happen? Can recording also happen at a pad?...
user90664's user avatar
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Can disease, drugs, or other physiological conditions violate the all-or-none rule for action potential?

We are taught that the amplitude of a neuron's spike is always the same (within a negligibly small range)--all or none. But it seems that anomalous physiological conditions like certain diseases or ...
Anasker's user avatar
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2 answers
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Why does EOG (eye EEG) spike and fall back down when you look to one direction?

Why does EOG (eye EEG) first spike and then immediately fall back down when you look to one direction instead of staying spiked and only falling back down when your eyes go back to neutral? From what ...
Dashiell Rose Bark-Huss's user avatar
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What is the "reverse-averaging" technique used in Electroencephalography (EEG)?

Im reading about the Bereitschaftspotential or Readiness-potential "discovery" and I see it was done by "reverse-averaging" the ressults of using EEG to measure certain voltage ...
Metadani's user avatar
1 vote
1 answer
42 views

Measuring spike activity with an electrode: using the principles present in galvanic cells, can one explain how current flows in the electrode system?

Thank you for reading this. In a galvanic cell setup and around each electrode in that setup, we have species that either undergo oxidation or reduction—resulting in the literal flow of electrons ...
orjün's user avatar
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3 votes
1 answer
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Are brainwaves from an EEG meaningful measurements?

I realized that research describing the different stages of sleep all rely on the assumption that we can accurately determine the stage of sleep using an EEG. I wondered if brainwaves are anything ...
Clearvision's user avatar
2 votes
1 answer
494 views

How to calculate Fano Factor for spike train data?

I've heard this used many times but never had to do it myself. How does one calculate Fano Factor (FF) for spike train data? Let's say that you have for some neuron the spike count in a certain time ...
Alex's user avatar
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1 answer
2k views

What are the differences between bipolar channels and monopolar channels for EEG?

In EEG, each electrode records a biopotential which must be compared to a reference biopotential in order to obtain a channel of measurement. Two types of channels are the so-called bipolar channels ...
David Cian's user avatar
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1 answer
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Electric communication between single neurons

It is believed that neurons communicate through neurotransmitters, released from multiple synapses and flow to the axon of the next neuron. But has it been shown if a single neuron communicate with a ...
Leo B Neo's user avatar
3 votes
1 answer
56 views

where is the second electrode in case of electrostimulation

With electrostimulation or functional electrostimulation, a response from the neuron is generated by electrical impulses. But I always read, for example, that a stimulating electrode is above position ...
CB95's user avatar
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1 answer
76 views

What are the advantages of biphasic nerve stimulation?

One can stimulate nerves or muscle cells in different ways - with single-phase or multiphase pulses, cathodic or anodic, and via surface electrodes or implanted ones. What exactly is the advantage of ...
fullspeed's user avatar
3 votes
1 answer
97 views

Why are flat line EEG recordings not perfectly zero microvolt?

I just look at several flat line EEG brain waves and all of them are not exactly at zero microvolt, in the sense there seems to be always a small signal or irregularities to be seen, as well as ...
SnoopyKid's user avatar
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5 votes
2 answers
976 views

Why is it only positive charge that gets injected into a neuron when we inject a current into it?

Learning about the basics of theoretical neuroscience from the youtube lectures from Michale Fee's introduction to neural computation course. We're considering a very simplified model of a neuron, ...
stochasticmrfox's user avatar
2 votes
1 answer
40 views

What do current-clamp pipettes inject in neuronal recordings?

I am news to the field of computational neuroscience, and I constantly see equations involving an "input current", which can be tested experimentally by injecting "currents" into ...
Johncowk's user avatar
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2 votes
1 answer
70 views

Sources on P1/N1 modulation with checkerboard probe

I have been able to find a lot of papers that modulate the P1/N1 component with a visual probe, usually a checkerboard presented parafoveally. I understand the basics of what I am reading, but I would ...
HernanLG's user avatar
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1 answer
126 views

Difference in MEG and EEG readings

Reading the excellent clear answer from @RobinKramer to Are brain waves electromagnetic waves? I have become very interested in the mechanisms behind the measurement techniques using EEG and MEG. From ...
Chris Rogers's user avatar
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1 answer
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How to determine nerve conduction velocity?

Can anyone suggest good sources or papers to understand about experimental setup and procedure for measuring nerve conduction velocity for various types of neurons? I wish to learn how such ...
pavan sai's user avatar
1 vote
2 answers
213 views

Why do we use relative signals and not absolute signals with EEG?

Most EEG machines use a system based upon differential amplifiers to enhance the signal, a basic differential amplifier has 2 inputs and one output. the device takes 2 signals and outputs the ...
RhinoPak's user avatar
1 vote
1 answer
66 views

How to handle single trial ERP (P300)

I am learning to work with EEG data in young and elderly subjects. The goal is to find differences in P300 (amplitude & latency) between both age groups during learning. I analyzed the data based ...
Dawid Archibald's user avatar
1 vote
1 answer
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Is there a mechanical/vibrational communication method between pre- and post-synaptic terminals in addition to chemical and electrical synapses?

I recall hearing something about there being a mechanical way that two neurons can communicate with each other in addition to the chemical and electrical synapse methods. Something about a certain ...
Otherness's user avatar
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1 answer
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Definitions of the alpha wave in the revised glossary by Clinical Neurophysiology Practice?

I am a novice in EEG, and also not a native speaker of English. I am reading through the article A revised glossary of terms most commonly used by clinical electroencephalographers and updated ...
Yosh's user avatar
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-2 votes
1 answer
57 views

to electrophysiologists, where is your electrode?

how do you know where is your electrode in the brain? Whether you're in the soma, axon, its terminal, dendrites - wouldn't it change your signal (and how)? What happens if you are recording from a ...
user25887's user avatar
3 votes
1 answer
350 views

Unable to run AxoGraph v1.7.6 on macOS 10.15 Catalina

After a recent MacOS update, I am no longer able to run the (latest) AxoGraph software for electrophysiology data analysis on my computer, as I get the following error message: ...
Brunox13's user avatar
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2 votes
1 answer
41 views

How fast can stimuli be administered for evoked potentials?

I'm looking for a reference about the ability for sensory stimuli to generate separate evoked potentials in the brain. What is the maximum repetition rate for sensory evoked potentials?
Dadep's user avatar
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0 votes
1 answer
165 views

Is there a region of the brain that mediates pain in a manner reminiscent of the mesolimbic pathway?

The mesolimbic dopamine pathway is a common neural pathway upon which rewards converge AKA the pleasure pathway. So I am trying to find a comparable pathway in the brain for pain -- is there such a ...
faustus's user avatar
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2 votes
1 answer
263 views

Reference signal when measuring EEG

When performing EEG, a number of electrodes are placed on the scalp to measure the electric potential difference between those locations and a reference. In the unipolar configuration, the reference ...
Vivek Subramanian's user avatar
6 votes
2 answers
410 views

Parallel arrangement of capacitor and resistor in leaky integrate-and-fire model

I have read from several sources that in the leaky integrate-and-fire model of a single neuron resistor (leakage) and capacitor (membrane potential) are arranged in parallel. Look at the following RC ...
m.taheri's user avatar
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4 votes
1 answer
4k views

What does "diffuse slowing" mean in the context of EEG and Alzheimer's?

Horvath et al. (2018) mention that: The disappearance of posterior dominant alpha rhythm and the diffuse slowing in AD (alzheimer disease) are easily detectable EEG signs for the experienced ...
MattSt's user avatar
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1 vote
0 answers
26 views

Somatosensory evoked potentials

I am wondering what the best EEG recording montage is to use for recording of electrically evoked somatosensory evoked potentials after median nerve stimulation?
anna's user avatar
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3 votes
0 answers
88 views

Statistic analysis on EEG data - how to deal with it properly?

Let's assume that I have a datasheet looking like that: ...
Mary's user avatar
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4 votes
1 answer
179 views

Can I read what the person thinking through electrodes or something similar?

First of all I'm not a medical student so I may miss some points here. I know that EOG (electro-oculography) works on the corneo-retinal dipole. The cornea (front of eye) is slightly positively ...
Ibrahim's user avatar
  • 141
3 votes
1 answer
686 views

Can a bipolar EEG signal be converted to a monopolar (unipolar) one?

I have bipolar EEG signal of Fpz-Cz of EEG sleep data which I have downloaded from physionet. I would like to have Fpz signal for my sleep study. Is there any way I could convert a bipolar EEG signal ...
maia's user avatar
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4 votes
0 answers
54 views

Splitting EEG signal by marker using BrainVisionAnalyser

I have recorded a long EEG experiment with BrainVision equipment and I want to split it into smaller chunks based on marker numbers. For example, I want to have the chunk of recording between markers ...
MarieZ's user avatar
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4 votes
1 answer
61 views

Simultaneous extracellular recording from different distant sites (in rodents)

I wonder whether it is technically possible today to have simultaneous extracellular recording in awake rodents (e.g., mice) from different non-proximate sites (e.g., V1 and frontal cortex). I mean to ...
student's user avatar
  • 191
2 votes
1 answer
3k views

Can brain zaps be demonstrated by EEG?

Brain zaps are explained as an electrical buzz in the head and the symptoms occur while withdrawing slowly from an SSRI antidepressant medication. Is it possible to detect brain zaps by placing EEG ...
OhBeeHive's user avatar
4 votes
2 answers
194 views

Does the peripheral nervous system processes information like central neurons do?

Neural coding deals with the problem on how neurons or a network of neurons processes a stimulus and creates a response in form of electrical action potentials. Information then might be encoded in ...
Eser's user avatar
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4 votes
1 answer
130 views

Latency between actual neurons firing and muscles response in open and close fist experiment

I'm trying to analyze the electrocorticograms (ECoG) of opening and closing the fist. I have the data of a glove to capture when the hand moves. I'm struggling with finding the best epoch or segment ...
hbak's user avatar
  • 185
3 votes
1 answer
3k views

Where should I place a reference electrode?

This site gives basics of how to place electrodes for action potential recording. What I understand is that in order to get better signal, the reference electrode must be placed where there is minimum ...
ert's user avatar
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1 vote
0 answers
47 views

How close an electrode should be to the target neural tissue? [closed]

Intracortical electrodes are used to record neural signals. How close an electrode should be to the target neural tissue to obtain sufficiently clean / usable or hi-fidelity signal?
lyg's user avatar
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1 vote
0 answers
20 views

Human trials for stentrode neural recordings

Neural recording via a stentrode seems to be next big thing in neuroscience. It can be used to treat disabilities, brain disorders and enable brain to brain communications. Are human trials being done ...
uil's user avatar
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2 votes
1 answer
60 views

What is the voltage that an intracortical electrode is expected to receive?

When a neuron fires, an action potential of about 100 mV is generated. An electrode measuring brain activity will record several hundreds neurons at a time. How much voltage an electrode directly in ...
pybtyh's user avatar
  • 21
4 votes
1 answer
984 views

What is the meaning of the peak polarity in EEG data?

I wish to define neuronal activities by analyzing the peaks of each channel in EEG signals. Some papers use the negative peaks as a measure of neuronal activity and others deploy the positive peaks. ...
Mostafa Jannesari's user avatar
5 votes
1 answer
362 views

How do you form a rationale to justify choice of time windows in ERP analysis?

Event-related potentials (ERPs) can reflect the electrophysiological phenomena behind perception & attention. Often, certain time windows are applied for the analysis of ERP peaks (components). I ...
LennaKB's user avatar
  • 349
4 votes
1 answer
585 views

At what impedances should one gold plate 12.5-µm diameter nichrome wire tetrodes for targeting different brain areas?

Extracellular electrophysiological recordings of rodent brains using tetrodes requires plating them with gold solution in order to achieve appropriate impedances. How does the ideal plating ...
nachosan's user avatar
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2 votes
0 answers
229 views

Is there a reasonably easy way to get emotions from EEG?

I am building a project to visualise brain data from EEG, specifically emotions. I have found a significant numbers of papers that describe methods that include pre-processing, feature extraction and ...
Tom's user avatar
  • 140
1 vote
2 answers
288 views

Why is Potassium(K) important to neurology & the brain?

When researching the pharmacological mechanisms of action and interactions that various psychotropic drugs, poisons, neurotoxins, etc. have on the brain: I frequently see off-hand references to the ...
voices's user avatar
  • 119
5 votes
1 answer
2k views

What is the role of (why )universal gas constant in Nernst equation?

The Nernst equation is an equation that relates the the total voltage, i.e. the electromotive force, of the full cell at any point in time to the standard electrode potential, temperature, activity, ...
Saranraj Nambusubramaniyan's user avatar
4 votes
1 answer
129 views

Membrane resistance of a neuron

I am about to simulate a neuron activity with the "Leaky Integrate and Fire" neuron model. But for that I need the membrane resistance. I was really looking a lot online, but I just cant find a value. ...
Luca Thiede's user avatar