[Eeglablist] Merge Set Problem

[Arnaud Delorme]

Dear Ryan,

For EEGLAB single data epochs cannot be differentiated from continuous data. And continuous data gets processed and merged differently than epoched data. The reason for this is that EEGLAB works at the single trial level. In theory, if you have less than 30 data trials, any measure you compute (ERP, ERSP) is going to be extremely noisy. There is no real reason to have a datasets with a single data trial.

Assuming all you data epochs have the same length, you can merge your datasets from the command line using

EEG = ALLEEG(1);
EEG.data(:,:,end+1:end+ALLEEG(2).trials) = ALLEEG(2).data(:,:,:);
EEG.data(:,:,end+1:end+ALLEEG(3).trials) = ALLEEG(3).data(:,:,:);
EEG.data(:,:,end+1:end+ALLEEG(4).trials) = ALLEEG(4).data(:,:,:);
[ALLEEG EEG CURRENTSET] = eeg_store(ALLEEG, EEG);
eeglab redraw

Arno

> On Oct 3, 2018, at 2:15 PM, David Ryan <ryand1 at goldmail.etsu.edu> wrote:
> 
> Hello,
> 
> I have run into an issue with pop_mergeset.m. I have been trying to append 4 set files and get the error ‘The two epoched datasets must have the same number of points’. Here is some info about the data sets:
> 
> Data set A) 1 epoch
> 
> Data set B) 1 epoch
> 
> Data set C) 1 epoch
> 
> Data set D) 4 epochs
> 
>  
> 
> Data sets A,B, & C will merge with no problem. Data set D will merge with any single data set (A,B, or C) but will not merge with more than one other data set. I have also tried merging data sets A,B, & C, saving it as a new data set and attempting to merge it with Data set D, but I get the same error. Attached is the ALLEEG variable that has the info about each data set.
> 
>  
> 
> Thanks,
> 
> David Ryan
> 
> -- 
> David Ryan, Ph.D.
> Research Health Specialist
> Mountain Home VA Health Care System (621)
> Auditory Vestibular Research Enhancement Award Program (REAP)
> Research Service
> (423)-926-1171 Ext. 7575
> www.avreap.research.va.gov
> 
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