BrainStreamEventFields

Fields of the Event Structure

Every incoming marker instatiates a new [[BrainStreamImportantConcepts#SecEvents|event]. The event structure contains a number of fixed fields:

event.name                   : name of the marker
event.time                   : time [s] referred to number of acquired samples
event.brainstreamversion     : current version of [[BrainStream|Brain Stream]] 

If a DATA timepoint is specified for the event, the event structure also contains the following fields:

event.BRAINSTREAM            : contains information required for internal [[BrainStream|Brain Stream]] processing

    .data.raw               : raw data [channels x data]
    .trial.time             : start of data segment [s]
          .samp             : always set to 1
          .offset           : start of data [#samples] 
          .duration         : number of samples
    .hdr.Fs                 : sample frequency      
        .channels.*         : see remarks below 
        .labels.*           : see remarks below
        .Cal                : raw data calibration matrix
        .nChans             : number of channels
        .label              : all channel labels (compatible with fieldtrip)
        .orig               : always original header information
        .usedcap            : name of cap used in current block (user should take care of further handling) 
    .trial                  : same as event.data.trial 

 

• channel and label information can be grouped together based on settings specified for corresponding hardware device topic in the blocksettings. It uses fieldrips ft_channelselection function to match channels that belong to certain groups, like 'EEG' or 'EOG'. The data for the selected channels appears in a separate field. For example, if you defined a group of eeg electrodes, the data for these electrodes shows up in event.data.eeg. See [channel selection] on the FieldTrip website for more options.

Depending on the utilized data source, additional fields might be present inside the hdr structure.

In addition, requested copies of global variables appear as separate fields of the event structure (for more information see the [[BrainStreamImportantConcepts#SecVariables|Global Variables] section).