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15

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 parts. First of all, there are the action potentials (APs). APs are current flow within a neuron from one end to the other. The magnitude of these APs (and the ...


13

Antoine Tremblay has just released an advanced analysis toolbox: http://onlinelibrary.wiley.com/doi/10.1111/psyp.12299/abstract It's missing about half the features on your list, although fundamentally, spectral density is a simple task and LORETA is a stand-alone package anyways (although similar approaches, e.g. general CSD estimation, are implemented in ...


12

This very much depends on what, exactly, you're trying to do. EEG measurements tend to be extremely reliable, but the inferences one may draw on mental state are not necessarily so. EEG-driven BCI overwhelmingly relies on machine learning to correctly classify signals into a finite number of categories and act upon them. Typically, you'll do something ...


12

In short: we know that eye-blinks are reflected frontally in the EEG data and we use that knowledge to identify which components reflect for example eye-blinks. It would not make sense to identify a component related to eye-blinks on the back of the head - there would be something wrong with your data. What ICA does is (data driven) estimate a number of ...


12

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 because you are dealing with tiny voltages and high impedances. OpenBCI has some hardware for sale (still expensive but not as bad as research-grade equipment) and ...


11

The source I have quoted below gives an example of the following stenographic image:- Is this perception a particular trick that my eye performs or is it processing the visual data in an alternative way? Stereograms can be viewed as three-dimensional images by providing two side-by-side views of a three-dimensional scene, rendered from slightly ...


11

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 differences represent electric fields and do not represent electromagnetic (EM) radiation. EM radiation is build up of packets of energy (photons). EM radiation ...


9

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 potential without creating an electromagnetic wave. You can try browsing wiki explanation https://en.wikipedia.org/wiki/Maxwell%27s_equations, but the main idea is ...


8

A study by D’Zmura et al. (2009) in which two syllables were spoken in imagination showed that imagined speech information was present in EEG alpha, beta and theta bands. The beta band (13-18 Hz) proved most informative. The most informative electrodes were located mainly near the top of the head (vertex) where electromyographic artifacts had least influence....


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EEG research all started with Hans Berger, who in 1929 reported that brain activity could be recorded by measuring electrical activity on the scalp. Although the notion of ‘brain waves’ that were found by Berger was controversial, over the years many researchers replicated the results, which led to the acceptance of EEG as a real phenomenon. Neurons Before ...


7

The field of study you should focus on is the one for which you have already identified in your paragraph above which is EEG based "brain-computer interface". EEG signals are compared by their "features". Each of the signal you have provided above have different features. These features can be mean, variance, frequency, kurtosis, skewness ...


7

I'm only going to attempt to answer a small part of your question: how does glial activation affect the blood oxygen level-dependent (BOLD) response measured by fMRI? Schulz et al. (2012) were able to investigate the role of glial signaling on fMRI activity by simultaneously measuring neuronal responses with invasive optical imaging and fMRI. They found ...


7

Based on your comments I interpret your question as: "(1) What is the definition of the signal-to-noise-ratio (SNR) and (2) how do I determine the SNR for event-related potential (ERP) amplitudes in an EEG signal?". (1) Signal-to-noise-ratio (SNR) is a term often encountered in electrophysiology (e.g. EEG) and signal processing and can be loosely defined ...


7

They are ordered based on when they were discovered/named (as pointed about by Ana's comment). Alpha and beta waves were among the first signals observed in EEG data. From Wikipedia: Alpha waves were discovered by German neurologist Hans Berger, most famous for his invention of the EEG. Alpha waves were among the first waves documented by Berger, along ...


7

Yes they do. That is to say, light conditions do not generally affect alpha waves, only the eyelids do (and other factors). This has led to alpha waves being interpreted as reflecting an active inhibitory process in the visual cortex (relaxation) rather than a reduction of stimulus (resting). The following image is from an Israeli study published in 2013 ...


6

Bearing in mind the fact that I can't prove a negative, I'm going to say "No, it's not (yet) possible". Flow is rather loosely defined (e.g. "merging of action and awareness"), so coming up with hard measures is a challenge in and of itself -- even without bringing electrophysiology into the equasion. As a Positive Psychology concept, it belongs to the ...


6

The Emotiv system has been evaluated in a research setting. Badcock et al. (2013) recorded EEG activity with the Emotiv EPOC and a more conventional laboratory system simultaneously, and found that both systems produced similar results for ERPs with a relatively high signal-to-noise ratio, but it was harder to detect less reliable signals with the EPOC than ...


6

You should consider using subject-specific alpha channels and frequency ranges. There are differences between individuals in alpha peak frequency. Also the placement of the EEG cap as well as small differences in orientations of cortex can affect which channels pick up perceptual activity. One way to do this would be to record data from the subject with ...


5

Yes, and no. Biofeedback has been an active field of research since the 70s, but has been a bit "fringified" as a cure for ADHD, etc. It is possible to fine tune the brain activity for specific tasks. To borrow an example from BCI, the Rolandic Mu Rhythm can be used to "train" a user to refine the movement of a cursor or other pointing device. Jonathan ...


5

We were looking for an EEG device few years ago. The commercial offers were between 20,000 EUR for a 32 passive electrode to 50,000 EUR for an 64/128 active electrode. This included everything except the computers - some offers were without off-line data processing software. I never considered the EEG systems that were not mentioned in the method section of ...


5

If you are considering an alternative to matlab that is free I would recommend octave. If you are on linux you might consider the whole neurodebian. In terms of book I did not find Steve Luck's book very helpful, but Todd Handy's one was more suited for me. Also a very good book is van Drongelen's Signal Processing for Neuroscientists (cannot put the link ...


5

Disclaimer: These are my preferences, biased by my own research experience. In general, I am not a fan of block designs. Blocking introduces difficulty in comparing both neural and behavioural activity between blocks due to effects of practice, fatigue, adaptation, learning, boredom, muscle tension and possibly others. It is of course possible to counter-...


5

Michelle Heijblom's (2009) master thesis on Visualising tinnitus with fMRI and EEG mentions the following: Different studies report that tinnitus is characterised by an increase in slow-wave activity (0.5- 4Hz: delta activity) and a decrease in alpha activity (8-12 Hz) at temporal regions. Recently it has been suggested that this loss of alpha power ...


5

How many trials do you have per condition? With a small number of trials in the deviant condition, and a small number of participants, these things can happen. The ISI would not cause this per se, however, have you considered looking at effects of the previous trial? You can analyze the baseline intervals as a function of what type the previous trial was, ...


5

Replicating fMRI signal was first used in the Tower of Hanoi task as seen in section 5.8 of "How to Build a Brain": There is strong evidence that dendritic processing, driven by neurotransmitter usage, underwrites the BOLD signal (Logothetis & Wandell, 2004). It is that BOLD signal that is actually measured by MRI machines. Consequently, MRI ...


5

What you are looking for is Imagined / Silent Speech Classification (my best guess). I'm interested in this for a few years (exactly to work with Vim) now and worked with some of the cheap EEG headsets like Emotiv EPOC and Neurosky MindWave Mobile. A paper on it: http://www.scipublish.com/journals/ABSE/papers/1021 Patent applications: http://www....


5

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 stimulus in a regular train of standard stimuli. The P300 wave only occurs if the subject is actively engaged in the task of detecting the targets and its ...


5

An ERP is an Event Related Potential, making it inherently connected to an event. Having stimulus/response independent ERPs is thus impossible. There do exist potentials that seem to be stimulus independent, or at least vary in timing, but these are often the result of cognitive processes. These potentials are the result of Event Related (De-)Synchronization ...


4

An old question, but there has been some recent developments by third-parties and now cheaper and hopefully just-as-accurate EEGs exist. From Are recent affordable EEG devices any good? we see the Emotiv System and a paper that can attest to its accuracy. We also have OpenBCI, an open-source EEG catered to makers, which has recently been funded ...


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