[Eeglablist] ASR – include EOG/ECG channels, apply before referencing?

[Makoto Miyakoshi]

Dear Kevin,

> I'm wondering whether to include EOG and ECG channels in ASR like in
traditional ICA? Also, whether to apply ASR before referencing?

Yes, for the purpose of consistency. If I understand correctly (I say this
because the main algorithm is totally Christian's, and I just wrote a
wrapper) ASR computes correlation matrix of the channels. You may want to
include all channels rather than separate some of them (unless you reject
them permanently). Applying it before rereferencing makes sense, since you
want to clean the data (i.e. exclude noisy channels) before referencing.

Your pipeline looks fine to me. Good luck!

Makoto

On Fri, May 1, 2015 at 1:36 PM, Kevin Tan <kevintan at cmu.edu> wrote:

> Hello Dr. Miyakoshi & EEGlab list members,
>
> I'm exploring artifact subspace reconstruction (clean_rawdata plugin) as
> an alternative to threshold-based artifact rejection.
>
> I'm wondering whether to include EOG and ECG channels in ASR like in
> traditional ICA? Also, whether to apply ASR before referencing?
>
> I am using a 128-channel BioSemi ActiveTwo with 8 external channels: M1,
> M2, bipolar hEOG, bipolar left vEOG, bottom right vEOG, and ECG.
>
> BioSemi always records unreferenced. I recorded at 512hz for the sake of
> comp resources.
>
> Here's my preliminary preproc pipeline:
>
>    1. Import data using BDF plugin (unreferenced)
>    2. Add channel location info
>    3. CleanLine
>    4. ASR (including EOG/ECG?)
>    5. Reference to 128ch scalp average
>    6. ERPlab:
>    1. Create Eventlist
>       2. Extract event-based epochs
>       3. Create averaged ERPs
>       4. Lo-pass @ 30hz
>
> Any advice would be appreciated :-)
>
> Many thanks,
> Kevin
> --
> Kevin Alastair M. Tan
> Lab Manager/Research Assistant
> Department of Psychology & Center for the Neural Basis of Cognition
> Carnegie Mellon University
>
> Baker Hall 434
> <https://www.google.com/maps/place/40%C2%B026%2729.5%22N+79%C2%B056%2744.0%22W/@40.4414869,-79.9455701,61m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0>
>  | kevintan at cmu.edu | tarrlab.org/kevintan
> <http://tarrlabwiki.cnbc.cmu.edu/index.php/KevinTan>
>



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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