[Eeglablist] Help with ERP study

[ivano triggiani]

Dear Sonia,

I would change the name of your markers to have two levels, based on
stimulus type and instruction type. I'd do something like this:

EEG = pop_loadset('filename', 'dataset_name.set');

% Map your markers
marker_map = containers.Map();
marker_map('S 32') = struct('stim_type', 'A', 'instr_type', '1');
marker_map('S 34') = struct('stim_type', 'A', 'instr_type', '2');
marker_map('S 43’) = struct('stim_type', 'B', 'instr_type', '1');
% etc…

% Add the factors
for i = 1:length(EEG.event)
    factor_info = marker_map(EEG.event(i).type);
    EEG.event(i).stim_type  = factor_info.stim_type;
    EEG.event(i).instr_type = factor_info.instr_type;
end

Then you can create a study with two levels for your 2x2.

Maybe someone has a better solution.

Ivano


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*Antonio Ivano Triggiani, Ph.D.*


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On Sun, Jul 6, 2025 at 10:24 AM Sonia Mariotti via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Hi all,
>
> I created a study in eeglab and wanted to run LIMO, but I run into some
> issues. I'm new to eeglab and to coding as well, so I've mostly used the
> GUI and a little bit of code from chatGPT. You can see in the screenshot
> how I built the study. The data was segmented and pre-processed in Brain
> Vision Analyzer, so I'm not running ICA here - is that fine?
> I have 4 recordings per participants that correspond to the 4 tasks they
> did. I wanted to compare the EEG signal in these tasks to see if there is
> any difference by running a 2x2 design. When I go to Study > Edit study
> design, I don'manage to select the two factors of interest, which are task
> condition and task type. I wonder if it's because of how I organised the
> recording into the study, as I cannot retrieve these two factors in the
> list of options (I only get to select the four conditions or the markers I
> assigned to each trial).
>
> I have managed to pre-compute and plot channel measures, but I wanted to
> run statistical analysis. When I try to run LIMO an error message pops up:
> No results files were found and ask if I want to browse for a .mat file,
> which I don't think I have.
>
> Thanks for your help!
>
>
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