[Eeglablist] Coherence in meditation-seeking kind help from experts in EEGLAB

Hayder Hussein hayder978 at yahoo.com
Sat Jun 5 01:49:43 PDT 2010

Dear Professors,

I really appreciate your help and spending time to reply me.
It is life or death!
I will do my thesis depending on this analysis for huge data (repeating the same as below).

Please I am seeking the help of your experience in using EEGLAB.
It is easy that may be I have a mistake in this, it will cost me too much to analyze a lot of data which may be the way of analysis is wrong from the very beginning, so I am asking your kind advice.

My research interest is to check the significant coherence changes between channels or components during meditation.

I will list the settings of EEGLAB for the analysis of the EEG signals took during rest and during meditation. It is too easy that I have falled in some mistake in this, which you the experts can easily see the flaws so please correct me if I am wrong.
I am not sure especially with the parameters between (((brackets)))

Now as a pilot study, I will analyze just one person's data.

1. EEG readings (20  channels,sampling rate 1000 sample/sec) during rest (mind wandering) for 200 seconds.

2. then EEG readings during meditation for 200 seconds, so the total EEG reading is 400 seconds.

3. (((Let us say that the baseline is the 1st 200 seconds, let us divide the meditation (200 seconds) into 40 epochs, each epoch last for 5 seconds.)))

4. The baseline for all the epochs is the same (the 1st 200seconds) which are the rest state.

5.So the dataset info should looks like:

Channels per frame         20
Frames per epoch           5000
Epochs                     (((40)))
Events                     (((None)))
Sampling rate              1000
Epoch start (sec)          (((200  )))
Epoch End                 ((( 205)))  (means the 1st epoch,((( the second will start    at 205 and ends in 210 ?))))

6. I should specify the pop_newcrossf() as the following:

First channel                          1
Second channel                         2
Epoch time range   [min max] (msec)    ((([200000    205000])))
Wavelet cycles                         3 0.5
Linear coherence or phase coherence   (((?)))
Bootstrap significance                 0.01
optional arguments                 'padratio',2,'baseline',[0 200000]

My understanding that this will make EEGLAB calculating the coherence between ch1 and ch2 for 40 epochs during meditation (each epoch 5 sec.) and using the baseline(1st 200sec. during rest) to normalize the coherence and calculate the significant coherence. Is this correct?

I am relatively new in this area, I apologize if my questions seems naive.

Haider Al-Wasiti, M.D.
M.Sc. student - Biomedical Engineering/UPM
wasiti at mutiara.upm.edu.my
hayder at wasiti.net


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