[Eeglablist] Error when plotting study ERPs after clustering

Malte Anders malteanders at gmail.com
Thu Jun 13 06:53:38 PDT 2019

Hi all,

I have followed the EEGLAB tutorial and Makoto's preprocessing timeline in
the past weeks in every single detail possible and I am stuck at the
following process:
I have ~30 subjects with 2 groups (~15 healthy subjects & ~15 ill
subjects), 4 conditions (4 different temperatures while measuring) and 1
session per subject. Each subject has four .set files (one file per
condition) that was measured during the same session (without taking off
the cap).

I have used preprocessing guideline according to Makoto. I have then
grouped the subjects using the Study-options in EEGLAB and ran ICA with the
option "Concenate datasets for the same subject and session (check=yes)?".
Dipoles were calculated with DIPFIT before grouping the subjects in the
study for each file/condition individually.

When clustering components I only check "dipole locations" and "dipole
orient" to avoid statistical double dipping.

After clustering, I get my clusters (17 in my case). When I try to Plot
ERPs, ERSPs, spectra or ITCs for the components in each cluster, I get the
following error:
"Cannot handle conditions with different number of components,
(Error occured in function std_readdata() at line 288)".

I can't make heads and tails of this. Plotting dipoles or scalp maps works
flawlessly. The eeglab wiki says: "If you do not wish to use some of the
measures in clustering but still want to be able to visualize it, select it
and enter 0 for the PCA dimension." so I checked ERP, spectra... in the
clustering process and entered "0" for PCA (and 10 for weight) which is
producing the same error.

Maybe I have a hard time understanding the process, but I can't help myself
even with google. Can somebody spare a minute?

Thank you!

Malte Anders
PHD student
Fraunhofer IME, Frankfurt, Germany

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