[Eeglablist] LIMO design - conditions within and across sessions

[Dr Cyril, Pernet]

Hi Lee,

I'm replying on the discussion list as this is of greater interest to 
all (and github issues are more for code than how to analyse something).

 From your post on 
https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_LIMO-2DEEG-2DToolbox_limo-5Ftools_issues_105&d=DwICaQ&c=-35OiAkTchMrZOngvJPOeA&r=kB5f6DjXkuOQpM1bq5OFA9kKiQyNm1p6x6e36h3EglE&m=acPf8ijO6hJ0XqdS4_tO2ABMvQthfGXSfG5NvgIfQAl46bQoFwlq3fh8qXZ_U-E0&s=I8y_TbbMgBIDOQwV4jlsyeRFq8gExYo_OI-oE9M1OU0&e= :

'The actual experiment is a drug study with three different drug 
sessions (placebo, low dose, high dose) each done by each subject 1 week 
apart. While there are two conditions in each drug session (angry faces/ 
neutral faces), I am wondering if I need to concatenate the three drug 
sessions into a single file. I didn't want to do that because they are 
three separate sessions, and I though if I ever wanted to do work with 
components this would not make much sense.'

 From an analysis perspective, it is better IMO to leave sessions 
separated. In LIMO EEG, sessions are analysed separately allowing to 
have their own mean activity and variance. While in some designs it 
won't make a difference, in a case like yours this is likely relevant as 
you may have overall differences between sessions reflecting the drug 
effect. Concretely this means that in STUDY, you have to input 3 set 
files per subject, indicating the session. Then you create a design with 
your 2 conditions leading to estimate the face effect for each session. 
Finally at the group level you can run a repeated measure 3*2 ANOVA 
using beta parameters from all sessions.

Best wishes

Cyril