[Eeglablist] SIFT seems to be stuck using a single data point, not whole epoch - help!

James Jones-Rounds jj324 at cornell.edu
Tue Aug 5 15:39:57 PDT 2014


Hello all,

While using the newer versions of SIFT (1.33), EEGLAB (13.3.2b), and MATLAB
(2014a) with our data, we're noticing strange behavior that seems to
suggest the SIFT processing steps are only using a single data point
instead of the entire epoch.

The preprocessing steps appear to work, although rather quickly, and do not
give the typical status update indicating which window is being analyzed at
that moment (status update just says "checking whiteness, Condition: "
instead of "checking whiteness, Condition: , windows 6/105", etc.). These
steps complete much more quickly than usual. Our concern is that a single
data point is being used as opposed to the whole epoch. Additionally, when
using the model order selection step, the model order selection assistant
does not give a resulting line plot indicating how many windows exceed or
don't exceed the thresholds for whiteness or consistency. There's just a
single bar graph for one of the whiteness evaluating algorithms, and the
rest are blank. The visualization of connectivity also produces a familiar
component vs. component matrix of graphs, but all of them are empty.
Finally, when we go to use the BrainMovie feature, only a single time-point
seems to be available in the bottom time-scroll bar (i.e. the "start" time
point and the "end" time point are the same time point, in our case, -1.88
seconds).

This appears to be the case for other datasets we're trying, and we're also
using the recommended steps found in the SIFT manual. How would we go about
verifying whether a single data point in the epoch is being used, and has
anyone else noticed this issue? Is it a MATLAB-EEGLAB-SIFT version
compatibility issue?

Thank you all for your attention!

James
-- 
James Jones-Rounds
Laboratory Manager
Human Development EEG and Psychophysiology (HEP) Laboratory,
Department of Human Development,
--------------------------------------------
Cornell University | Ithaca, NY
607-255-9883
eeg at cornell.edu
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