Mu waves- motor imagery

Comments

• chipaudette

  January 2015

  I did some trials back with the pre-Kickstarter OpenBCI hardware.  I'm pretty sure that I saw Mu waves, but I'm no expert in this area.  Unlike eyes-closed Alpha, it was indeed challenging to see the Mu waves.

  
  

  Here are some posts describing what I found...

  
  

  http://eeghacker.blogspot.com/search/label/Mu Waves
  

  
  

  Chip
• meagmohit

  January 2015

  Hi,

  
  

  I read all of your blog posts.

  I was reading about mu-waves and its amplitude should be decreased when imagining/moving hand/feet.

  In your case its amplitude increases, which I think is due to may be movement related frequencies?

  
  

  Mohit
• chipaudette

  January 2015

  I think that you might be misinterpreting my figures....the Mu waves only appear when I'm relaxed and they disappear when I move my hands.  I think that this confirms your expectation.
• meagmohit

  February 2015

  Ohh yes, you are right. I am sorry for my wrong interpretations.

  
  

  Just for the clarification purposes, did you measure the potential difference between  C3 and Cz?

  And what did you use as BIAS? or turned the BIAS off?

  
  

  I did several experiments to get the mu waves, hence I want to reproduce the results you got.

  
  

  Thanks,

  Mohit
• chipaudette

  February 2015

  Hello Mohit,

  
  

  For the Mu wave work that I described at:

  
  

  http://eeghacker.blogspot.com/2013/11/waveforms-from-homemade-electrodes.html
  

  
  

  It looks like I did C3 vs Cz as you said.  It looks like I did not use any bias connection at all.  If I were to do this over, I might try using an earlobe as the bias connection.  Ideally, it wouldn't really matter where you put the bias.

  
  

  Also, given that my results were pretty weak, I hope that you don't reproduce my results...I hope that you get BETTER results!  Then you can show me how to do it correctly!

  
  

  Chip
• jfrey

  March 2015

  Hello,

  
  

  An update: last WE I tried motor imagery with OpenBCI for the first time. As I was more focused on taking notes for my tutorial, on checking the behavior of the soon-to-be-released driver within OpenViBE  -- and on making nice videos, let's be honest -- I am not 100% positive that all I saw was actual EEG data (and not muscle artifacts), but during my tests I did observe "beta rebounds" associated with feet movements. If you want to have a try, you may take a look at http://blog.jfrey.info/2015/03/03/openbci-motor-imagery/

  
  

  In the OpenViBE scenarios that I used only the beta frequency band is used, but it should be easy to add another feature and use the classifier with mu frequencies as well. Hope it helps
• user93

  March 2015

  till my openbci hardware arrives i am using test data to learn . The mu waves data set  here given in EEGhacker github page is in .mat how do i use it in openbci GUI.
• chipaudette

  March 2015

  
  

  Hi...EEGHacker here...

  
  

  I converted the MAT files over to OpenBCI formatted CSV files.  I pushed them up to the EEGHacker GitHub, so you should be able to get them.

  
  

  Be aware that the data that was in the MAT files had been normalized, so I didn't know what the correct scale factor should be to convert them into OpenBCI format.  I took a guess by scaling them by 1x10^5, which kinda put them in the right range.  But, if you're looking to do any detailed analysis of the amplitude of these waveforms, I would be very cautious, since the amplitude that I assigned to the data was just a guess.

  
  

  Chip