[Eeglablist] Is it safe to apply ICA weights to data at different sampling rates?

Makoto Miyakoshi mmiyakoshi at ucsd.edu
Mon Jun 16 11:14:49 PDT 2014


Dear Jeff,

Should be fine.

Makoto


On Mon, Jun 2, 2014 at 1:22 PM, Iman M.Rezazadeh <irezazadeh at ucdavis.edu>
wrote:

> Hi,
>
> I am trying to explain my opinion using the microstates approach
>  “Spatiotemporal Analysis of Multichannel EEG: CARTOOL;  Denis Brunet,
> MicahM. Murray and Christoph M.Michel”
>
>
>
> Each brain’s microstate corresponds to a period of coherent synchronized
> activation of a large scale neuronal network. It does not change
> instantaneously (like by every msec).  This corresponds well to the
> proposal that neurocognitive networks evolve through a sequence of
> quasi-stable coordination states, rather than a continuous flow of neuronal
> activity. It has been shown that microstates and ICA components reveal
> similar neural activation maps[Reference: the paper I mentioned above].
>
>
>
> Now, suppose you the sampling rate for one experiment is 1000Hz (1msec
> time difference between two consecutive samples) and you want to
> down-sample it to 500Hz (2 msec time difference…) .  there is not much
> difference btw the microstates maps since 1 or 2 msec time period is not
> that much the brain could switch btw one microstate to another (which leads
> to changing of ICA maps). But if you down-sample the signal by 10 time(
> like 100Hz) then one might be skeptical about the changes in the
> microstates maps/ICA maps.
>
>  Best
>
> Iman
>
>
>
> *-------------------------------------------------------------*
>
> *Iman M.Rezazadeh, Ph.D, M.Sc, B.Sc.*
>
>
>
> Research Associate II
>
> Semel Intitute, UCLA , Los Angeles
>
> & Center for Mind and Brain, UC DAVIS, Davis
>
>
>
>
>
>
>
> *From:* eeglablist-bounces at sccn.ucsd.edu [mailto:
> eeglablist-bounces at sccn.ucsd.edu] *On Behalf Of *Cockburn, Jeffrey
> *Sent:* Monday, June 2, 2014 10:21 AM
> *To:* eeglablist at sccn.ucsd.edu
> *Subject:* [Eeglablist] Is it safe to apply ICA weights to data at
> different sampling rates?
>
>
>
> Greetings.
>
>
>
> A while back I computed and exported ICA weights for data that was
> down-sampled to 250Hz. I'd like to do revisit that data at its original
> 500Hz sampling rate. Is it safe to apply the 250Hz ICA weights to the 500Hz
> data? Is it safe to apply ICA weights to data with a different sampling
> rate in general?
>
>
>
> Thanks.
>
>
>
> -- Jeff
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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