[FieldTrip] plotting events from ft_read_event in ft_databrowser

[Schoffelen, J.M. (Jan Mathijs)]

Hi Roy,

A warning is not an error, so that in itself shouldn’t be the issue.

What is the issue, though, is that one of the following will work:

put your my_events in the cfg, rather than the data, i.e. cfg.event = my_events, and supply this cfg to ft_databrowser(cfg,data);

put your my_events in data.cfg, rather than in data, i.e. data.cfg.event = my_events

Best wishes,
Jan-Mathijs

On 21 Mar 2025, at 12:44, Roy Cox via fieldtrip <fieldtrip at science.ru.nl> wrote:

hi all,

Likely I'm missing something obvious, but I'm trying to figure out how to pass an event structure read in by ft_read_event on to ft_databrowser in order to visualize events.

Reading in a Brainvision file using ft_preprocessing, followed by explicitly reading in the events and adding them to the dataset, like so:

%read continuous (single-trial) data
cfg=[];
cfg.dataset='some_path';
cfg.readbids = 'no';
data=ft_preprocessing(cfg);

%read the events
my_events=ft_read_event(cfg.dataset,'eventformat','brainvision_vhdr','readbids','no');

%add to data
data.event=my_events;

 %looks ok:
struct2table(data.event)

ans =

  6×5 table

         type                           value                       sample      duration       offset
    _______________    _______________________________________    __________    ________    ____________

    {'Time 0'     }    {0×0 double                           }             1         0      {0×0 double}
    {'Stimulus'   }    {'recordingtime: 10-Mar-2025 22:49:30'}             1         0      {0×0 double}
    {'Time 0'     }    {0×0 double                           }             1         0      {0×0 double}
    {'New Segment'}    {0×0 double                           }             1         0      {0×0 double}
    {'Stimulus'   }    {'sync_Amp time'                      }           265     5e+05      {0×0 double}
    {'Stimulus'   }    {'LOFF_Lights off'                    }    2.1014e+05     5e+05      {0×0 double}
ans =

When I call ft_databrowser on this data strcuture, I get multiple instances of the following warning and no event markers are plotted:

Warning: could not determine dimord of "event" in:

           hdr: [1×1 struct]
         label: {264×1 cell}
          time: {[0 0.0040 0.0080 0.0120 0.0160 0.0200 0.0240 0.0280 0.0320 0.0360 0.0400 0.0440 0.0480 0.0520 0.0560 0.0600 0.0640 0.0680 0.0720 … ]}
         trial: {[264×1571182 double]}
       fsample: 250
    sampleinfo: [1 1571182]
           cfg: [1×1 struct]
         event: [1×6 struct]

Dove in a bit, and it looks like getdimord is called on data.event, which is probably not what should happen.

Any suggestions? Thanks!

Roy
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