[Eeglablist] ICA backtranformation

[Tarik S Bel-Bahar]

Hello, hoping this response is useful to you.

One can edit file information using the gui, and apply the ica info from one
dataset to another.

One can also do this.from.command line, filling the current file's ica
weights and.ica.sphere with weights and sphering matrices from another file.

This usually works if you have the same number of.channels, and thus, ICs,
across the two files.
On Jun 28, 2011 10:48 AM, "Dagfinn Matre" <Dagfinn.Matre at stami.no> wrote:
> Hi
>
> In the EEGLAB tutorial on artifact rejection
http://sccn.ucsd.edu/wiki/Chapter_01:_Rejecting_Artifacts, this list appear
at the bottom:
>
> 1. Visually reject unsuitable (e.g. paroxysmal) portions of the continuous
data.
> 2. Separate the data into suitable short data epochs.
> 3. Perform ICA on these epochs to derive their independent components.
> 4. Perform semi-automated and visual-inspection based rejection on the
derived components.*
> 5. Visually inspect and select data epochs for rejection.
> 6. Reject the selected components and data epochs.
> 7. Perform ICA a second time on the pruned collection of short data epochs
-- This may improve the quality of the ICA decomposition, revealing more
independent components accounting for neural, as opposed to mixed
artifactual activity. If desired, the ICA unmixing and sphere matrices may
then be applied to (longer) data epochs from the same continuous data.
Longer data epochs are useful for time/frequency analysis, and may be
desirable for tracking other slow dynamic features.
>
> Under step 7, it says "... the ICA unmixing and sphere matrices may then
be applied to (longer) data epochs from the same continuous data..."
>
> How is this done in practice?
>
> Best,
> Dagfinn
>
>
>
> Dagfinn Matre, PhD
> Forsker/Research scientist
> Statens arbeidsmiljøinstitutt/Nat Inst of Occupational Health
> P.O. Box 8149 Dep.
> N-0033 Oslo, Norway
> T: +47 23 19 52 15/F: +47 23 19 52 04/M: +47 47 23 60 47
> E: dagfinn at stami.no
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