[FieldTrip] Append/Average same conditions over sessions

[Ellen Schuessler]

Dear all,

Here a short description of the issue:
My data was conducted in 2 sessions (a week in between), both sessions contain all conditions (e.g. A B C D).
For each session I will have a bit more than 400 trials to run ICA on.
After ICA and after I redefine trials I will have separate files per condition (trials x time) for each session. Then, I want to concatenate conditions over sessions. That is, condition A session 2 should be appended to condition A of session 1 before I average.

Now here is my question:
I understand that ft_appenddata is mainly used to append different conditions. Additionally I read that files of different days might confuse in the sampleinfo (cf. http://fieldtrip.fcdonders.nl/faq/i_used_to_work_with_trl-matrices_that_have_more_than_3_columns._why_is_this_not_supported_anymore - middle part of the text).
This might be true in may case as well? If not, can I just add the two matrices (sessions) horizontally (which sounds a bit too simple in my ears)? Anyway, what would be the best way to average my conditions over sessions and at which operational step? 

Thank you all very much in advance! 
If you have any further question please do not hesitate to contact me!
Your help is very much appreciated.
Ellen

-- 
Ellen Schüßler, Dipl.-Psych.
PhD Student

Max Planck Institute for Human Cognitive and Brain Sciences
Research Group "Subcortical Contributions to Comprehension"
Department of Neuropsychology
Stephanstraße 1a
D-04103 Leipzig
Germany

Phone: +49 (0) 341 / 99 40 - 2474
Fax:   +49 (0) 341 / 99 40 - 2260
Email: schuessler at cbs.mpg.de
Web:   www.cbs.mpg.de/~schuessler