9 Jun 2007 15:55
Re: EEG guidance
Anish Mittal <mittal.anish@...>
2007-06-09 13:55:27 GMT
2007-06-09 13:55:27 GMT
Dear Prof Bernhard Griamann
I thank you for your valuable information.
I would like to ask you a few more things.I hope you will accept my humble request and help me a little more
do you want to detect these movements or do you also want to
discriminate between these movements?
I want to detect them as well as discriminate them as i want five type of different signals for cursor control
1) You have to be very careful that you will not actually use myographic
activity instead of brain activity (I assume you want to use brain
activity only). Especially with movements that require muscle activity
of muscle groups close to the EEG electrodes.
How can i differentiate whether the signals are myographic or brain ones??
2) The SNR of the brain patterns associated with movements is usually
very well correlated with the size of the corresponding cortical area.
That is, finger movements or tongue movements produce better (easier to
detect or discriminate) patterns than shoulder or elbow movements, since
the latter two have much smaller cortical representations in the motor
3) Because of the previous two points I suggest you should focus on
discriminating the following tasks: (right finger(s), left finger(s),
foot movement (both at the same time). For electrode locations, I
suggest to cover the motor-sensory area as good as it is possible with
your number of electrodes and your electrode caps available - including
the positions C3, C4, and Cz.
---------When i placed the electrodes on the motor cortex the was unable to figure out the difference between the left and right movements.They were coming in the same manner at same electrodes with out any change
One more problem is to select the reference electrode??
Where should i place it
I placed it between eyebrows
--------And my EEG machines measure biploar EEG like between 2 electrodes like Cz-Pz,Fp2-F4.
I am not able to measure the EEG of single electrode with respect to reference.
---------Which type of signals i will get by placing electrodes on C3-C4.Is it that of fingers??
-------My machine software is giving visual (which can taken as print) or .eeg file as output.How i process the .eeg file.Are there some standard softwares available for this??
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