Error in function run_HEP() in EEGLAB when running plug in BrainBeats for HEP extraction

I am using the BrainBeats plug in feature of EEGLAB, hoping to use this for extracting and analysing Heartbeat Evoked Potentials from my EEG data. It's quite a new plugin, so I'm using the only version (BrainBeats1.1) which can be downloaded here:

I have loaded my biosemi .bdf EEG data into EEGLab on Matlab and saved as a .set file after assigning channel locations and rereferencing to mastoids. I have then opened .set file in Brainbeats1.1 and tried to extract Heartbeat Evoked Potentials.

Download EEGLAB plug ins including BrainBeats

Brainbeats paper contains instructions

Cannard, C., Wahbeh, H., & Delorme, A. (2023). BrainBeats: an open-source EEGLAB plugin to jointly analyze EEG and cardiovascular ( ECG / PPG ) signals. 0–26.

BrainBeats paper

I can run the script (method 1) until receiving error message.

1. Saved my .bdf file as a .set file in EEGLAB
2. Load data into EEGLAB: File > Load existing dataset >MGpractice231123_1524.set
3. Tools>Brainbeats>process file at subject level
4. Select "Heartbeat-evoked potentials HEP" as analysis to run, "ECG" as heart data type, select the ECG channels labeled > 'EKGl' is my heart beat channel
5. All other ticks in boxes are left as automated
6. Select Ok

It runs for a while and produces some graphs (after I'd installed plug ins to solve previous error messages). Now I get an EEGLAB error message stating: "EEGLAB error in function run_HEP() at line 41: Assigning to 2 elements using a simple assignment statement is not supported. Consider using comma-separated list assignment." I didn't want to fiddle with code of built in functions in EEGLAB?

So line41 of run_HEP function relates to: EEG.event(shortTrials).type = [];

See context below:

% Remove trials with IBI<550 ms. see Candia-Rivera et al. (2021)  and Park & Blanke (2019)
shortTrials = find(IBI<550);
if ~isempty(shortTrials)
    warning('Removing %g trials with interbeat intervals (IBI) < 550 ms', length(shortTrials))
    IBI(shortTrials) = [];
    EEG.event(shortTrials).type = [];
else
    fprintf('All trial have an interbeat interval (IBI) above 550 ms (minimum recommended). \n')
end

The warning I get in command window before the error message is relevant:

Warning: Removing 2 trials with interbeat intervals (IBI) < 550 ms

Here is the .set data file I am working with

.set data file

I also have two run_HEP file paths, however removing one at a time doesn't help.

C:\Program Files\MATLAB\R2023b\toolbox\BrainBeats-eeglab_v1\functions

C:\Program Files\MATLAB\R2023b\toolbox\eeglab2023.1\plugins\BrainBeats1.1\functions

Can anyone please tell me how I might rectify this? Advice much appreciated

[Taylor]

I would recommend reaching out to the EEGLAB discussion board. It is such a complicated third-party toolbox, people on Answers generally don't want to dig through all of their source code to find the root cause.

Answer 1

[Walter Roberson]

Change

EEG.event(shortTrials).type = [];

to

for ST = shortTrials(:).'
    EEG.event(ST).type = [];
end