EEG.event is empty after calling clean_artifact with channels_ignore

[leima1]

Description

[EEG.event returns empty when calling clean_artifacts() with channels_ignore]

On line 225 (+/- 1) of clean_artifacts function, EEG.event is emptied (EEG.event = []).

It appears that Events get added back only if EEG = oriEEG gets called on line 345. However, line 345 only gets called if line 322 ~isempty(EEG.event) && isfield(EEG.event, 'type') && isstr(EEG.event(1).type) is true. In situations where there is no event added to EEG between line 225 and line 322, then the original events never get added back.

#### Steps to Reproduce

1. [Set Highpass, BurstCriterion, WindowCriterion, and BurstRejection off, while passing a channel to ignore]
   EEG = pop_clean_rawdata(EEG, ...
   'FlatlineCriterion',5,'ChannelCriterion',0.7, ...
   'LineNoiseCriterion',4,'Highpass','off', ...
   'BurstCriterion','off','WindowCriterion','off', ...
   'BurstRejection','off','Distance','Euclidian', ...
   'channels_ignore',{'5Z'},'fusechanrej',1)

#### Expected behavior:

EEG.event should be the same as what was passed into pop_clean_rawdata. I assume the ignored channel will also be placed back.

#### Actual behavior:

EEG.event is empty and the channel that was ignored never got placed back.

#### Versions

OS version	[Windows 10 Enterprise]
Matlab version	[2023b]
EEGLAB version	[eeglab2023.1]
clean_rawdata version	[2.91]

[arnodelorme]

Apologies for the late response. I do not see the same code on the lines you mentioned.

https://github.com/sccn/clean_rawdata/blob/master/clean_artifacts.m

I am having a hard time understanding the issue. Is your issue that your events are numerical and this section of the code is not called?

[leima1]

Hi Arnaud!

Thanks for looking into this.

Say I have an EEG structure with events, and the online reference channel is labeled as '5Z.' I want to remove noisy channels using the following line of code while making sure that '5Z' is ignored (i.e., not get removed).

EEG = pop_clean_rawdata(EEG, ...
    'FlatlineCriterion', 5, 'ChannelCriterion', 0.7, ...
    'LineNoiseCriterion', 4, 'Highpass', 'off', ...
    'BurstCriterion', 'off', 'WindowCriterion', 'off', ...
    'BurstRejection', 'off', 'Distance', 'Euclidian', ...
    'channels_ignore', {'5Z'}, 'fusechanrej', 1);

However, when I run this code, the returned EEG structure has an empty EEG.event field, and the channel '5Z' is removed. I would have expected that including 'channels_ignore', {'5Z'} was to retain that channel.

If I call the function without including 'channels_ignore', {'5Z'} as an input, the EEG.event struct keeps its initial events. ‘5Z’ gets removed regardless.

EEG = pop_clean_rawdata(EEG, ...
    'FlatlineCriterion', 5, 'ChannelCriterion', 0.7, ...
    'LineNoiseCriterion', 4, 'Highpass', 'off', ...
    'BurstCriterion', 'off', 'WindowCriterion', 'off', ...
    'BurstRejection', 'off', 'Distance', 'Euclidian', ...
    'fusechanrej', 1);

I will send you an example .set file where this issue occurs.

[arnodelorme]

OK, that makes sense. Let me look into that.

[arnodelorme]

Note for self: data downloaded in bug837 folder.