Which epochs are averaged?

[trinsma]

Hi,

I have a basic question about how the P3TemporalFilter selects the epochs. If you set EpochsToAverage lower than the NumberOfSequences, which epochs will be averaged together? Will it be the first or last epochs, or perhaps the ones with the biggest P300 amplitude, or a random sample? The P3TemporalFilter reference page says that EpochsToAverage is the number of epochs that are accumulated, suggesting that the first epochs are used, but it could still mean that the epochs with the largest P300 are accumulated.

Thank you in advance!

Cheers,

Thijs Rinsma

[mellinger]

Hi Thijs,

thanks for this question. I will clarify the point in the P3TemporalFilter documentation.

As you suggest, the P3TemporalFilter uses the first EpochsToAverage epochs to compute an averaged epoch, then outputs that average and sets the StimulusCodeRes and StimulusTypeRes states accordingly. After that, epochs up to NumberOfSequences will be ignored, and averaging will start over on the first epoch of the next character sequence.

Regards,
Juergen Mellinger