Electrode vs. channel

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Perdu
Posts: 2
Joined: Thu May 16, 2013 10:26 pm

Electrode vs. channel

Post by Perdu »

Hello,

I'm considering the list of devices posted previously on this forum, and I'm wondering whether there is a difference between electrodes and what's called "channels" (I can't figure out what it is exactly). On the previous list, the openEEG device is presented as having only 2 channels, whereas on the linked resource, it is advised to buy 5 electrodes. So, as the post is a-year-and-a-half old, I am considering the possibility that openEEG has been greatly improved since then! Is it the case, or are electrode and channels two different things?

I haven't found the information on this forum with a quick research, so I thought it was worth creating a thread about it.

Thanks,
Perdu - a student considering to experiment BCI

fabien.lotte
Posts: 112
Joined: Sun Mar 14, 2010 12:58 pm

Re: Electrode vs. channel

Post by fabien.lotte »

Dear Perdu,

In case of what is called a monopolar montage, channels and electrodes are the same thing: each electrode gives you one signal. But it can be different if you use a different electrode montage, e.g., a bipolar montage. In such a montage, the signal you get is the difference between two electrodes. As such, you have one bipolar channel from 2 electrodes. You also need a ground electrode for EEG experiments. I don't know the OpenEEG system, but if it provides 2 bipolar channels, then you indeed need 5 electrodes : 2 electrodes for each of the 2 bipolar montages plus 1 ground electrode. I hope this helps,

Best regards,
Fabien

Perdu
Posts: 2
Joined: Thu May 16, 2013 10:26 pm

Re: Electrode vs. channel

Post by Perdu »

Hello,

Thanks for your answer, I understand better now!

Regards,
Perdu

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