17
votes
Accepted
Are brain waves electromagnetic waves?
Short answer
Brain waves are not electromagnetic waves.
Long answer
Measured brain activity, as you already mentioned, is the result of individual neurons firing. The activity exists, in fact, of two ...
- 3,172
12
votes
Accepted
Is there a way to make a DIY EEG?
The OpenEEG project has some information for building your own EEG system. Instructables has a "simple" EEG circuit you can build. Note that this is going to be somewhat costly and time consuming ...
- 981
11
votes
Are brain waves electromagnetic waves?
Short answer
Brainwaves are typically associated with the electroencephalogram, which is a signal mainly composed of potential differences generated in the superficial layers of the brain. Potential ...
- 20.5k
8
votes
Are brain waves electromagnetic waves?
If "brain waves" produce a time-varying electric potential as shown on the EEG, then as far as I know electromagnetic waves are present. I was taught that you cannot have a time varying electric ...
- 97
6
votes
Accepted
What is the role of (why )universal gas constant in Nernst equation?
As in the ideal gas law, the universal gas constant allows for calculation of amount of energy associated with a certain group of molecules (see https://en.wikipedia.org/wiki/Gas_constant). As the ...
- 1,855
6
votes
Membrane resistance of a neuron
If there is literature that you are building off of or comparing your approach to, I would look in their papers to see what values they used and use the same. This is the standard approach, as it ...
- 181
6
votes
Voltage sensitive dyes technique: 2-photons microscopy vs confocal microscopy
Confocal Fluorescence Microscopy and 2-photon Fluorescence Microscopy are two techniques commonly used in neuroscience to image only one plane of the sample and thus increase resolution. However, how ...
- 121
5
votes
Can I read what the person thinking through electrodes or something similar?
I take it you want to use eye movements for data input (rather than reading people's thoughts, which would be silly to consider). It's not the greatest idea, efficiency wise, but may have its ...
- 10.2k
5
votes
Accepted
Parallel arrangement of capacitor and resistor in leaky integrate-and-fire model
I see your confusion is caused by $u_{rest}$. Indeed that diagram is somewhat confusing because $u_{rest}$ is not the main source relative to which to consider the topology of the circuit. The main ...
- 10.2k
5
votes
Voltage sensitive dyes technique: What is the underlying measure?
I found that dF/F0 stands for the relative difference in fluorescence at a certain wavelength.
- 131
5
votes
How do I obtain recordings of the P300 wave of the event-related potential in the EEG?
The P300 wave is a positive deflection in the human event-related potential (ERP). A common experiment in which it is analyzed is the "oddball" paradigm, where a subject detects an occasional target ...
- 20.5k
4
votes
Why is Potassium(K) important to neurology & the brain?
The main cell of the brain is the neuron. The neuron has a semipermeable membrane that under specific circumstances lets potassium through. Another common cell is the glia cell, which only has ...
- 618
4
votes
Accepted
What does "diffuse slowing" mean in the context of EEG and Alzheimer's?
Medscape defines diffuse as generalized, in the context of EEG. Generalized means activity recorded across large portions of the cortex. This opposes focal patterns, that occur locally. In turn this ...
- 20.5k
4
votes
What is the meaning of the peak polarity in EEG data?
Short answer
The peak polarity of an EEG is arbitrary.
Background
Positive and negative in an EEG measure is arbitrary. If you measure the EEG between two electrodes and you flip the wires, the ...
- 20.5k
3
votes
Simultaneous extracellular recording from different distant sites (in rodents)
I wouldn't know why multi-site cortical extracellular recordings would not be feasible? What would the practical experimental or technical limitation be in your opinion?
As long as you have a ...
- 20.5k
3
votes
How do you form a rationale to justify choice of time windows in ERP analysis?
Short answer
Electrophysiological responses in general often come in waveforms. These are characterized by a number of peaks and troughs. Dependent on the specific response, arbitrary naming ...
- 20.5k
3
votes
What is input resistance and how to interpret its values?
Ohm's law famously states V=IR, the voltage change (V) across a resistor generated by a current (I) equals the current multiplied by the resistance (R).
The resistor in this case is the cell ...
- 1,855
3
votes
Accepted
How fast can stimuli be administered for evoked potentials?
For auditory brain stem responses (ABRs) the click rate can be really high, as the auditory system is exceptionally fast, in the order of tens of stimuli per second (e.g., Rodriguez et al (2010. This ...
- 20.5k
3
votes
Accepted
Sources on P1/N1 modulation with checkerboard probe
For the fundamentals, I always go back to the more dated literature that is heavily cited (in this field of research, which is pretty big given it uses visual evoked potentials, say >1k times). I ...
- 20.5k
3
votes
Accepted
What are the differences between bipolar channels and monopolar channels for EEG?
In general, closely situated electrodes work well to eliminate environmental noise, at least when a differential amplifier is used. Environmental noise is a major problem in case of scalp-recorded ...
- 20.5k
3
votes
Why does EOG (eye EEG) spike and fall back down when you look to one direction?
If you had an EOG signal in a perfect world, it would show constant deflections based on how far the eyes are directed left/right.
In the real world, measuring any electrical signal is quite difficult;...
- 7,172
2
votes
Accepted
Is it possible to imitate two way communication between a brain and a limb?
Short answer
Mimicking action potentials is possible, but not the most practical approach.
Background
In general, stimulation of neural tissues occurs through placing electrodes in the vicinity of ...
- 20.5k
2
votes
Where should I place a reference electrode?
Short answer
In general, a reference electrode should be placed in a well-conducting medium close, or some distance away from the recording electrode.
Background
The idea of a reference electrode is ...
- 20.5k
2
votes
What is the voltage that an intracortical electrode is expected to receive?
The Utah array is a multi-electrode array for intracortical recordings. In one of many publications on this device, the authors show some sample traces that reveal amplitudes generally between 5 and ...
- 20.5k
2
votes
At what impedances should one gold plate 12.5-µm diameter nichrome wire tetrodes for targeting different brain areas?
The ideal impedance of any electrode aimed at recording low-amplitude neural signals (barred suction glass-pipette electrodes for patch clamping) is simply: as low as possible.
In case of tetrodes, i....
- 20.5k
2
votes
Can brain zaps be demonstrated by EEG?
Short answer
I haven't been able to find studies on EEG correlates of antidepressant discontinuation syndrome.
Background
'Brain zap' is a colloquial term for antidepressant discontinuation syndrome....
- 20.5k
2
votes
Parallel arrangement of capacitor and resistor in leaky integrate-and-fire model
The resistor is the conductance of the ion channels in the membrane. The capacitor is the membrane itself, which acts as a capacitor (a non-conductive center sandwiched between electrically active ...
- 1,855
2
votes
Reference signal when measuring EEG
For the unipolar configuration, why can't we just use Earth ground as
our reference instead of having a reference electrode or performing an
average of measurements on all the electrodes?
The ...
- 20.5k
2
votes
How to determine nerve conduction velocity?
I think there are many ways to accomplish this in terms of technical detail, but they will all boil down to measuring the arrival of an action potential along the axon on at least two points with ...
- 20.5k
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