bci2000.org BBS

Hi Gerv,
When running the initial session with neuroscan I'm getting the following error.

Warning: StimulusPresentationTask::Preflight: Due to a sample block duration of 40ms, the actual value of the ISIMaxDuration for stimulus 1 will be 1480ms rather than 1500ms.
Warning: StimulusPresentationTask::Preflight: Due to a sample block duration of 40ms, the actual value of the ISIMaxDuration for stimulus 2 will be 1480ms rather than 1500ms.
Warning: StimulusPresentationTask::Preflight: Due to a sample block duration of 40ms, the actual value of the ISIMaxDuration for stimulus 3 will be 1480ms rather than 1500ms.
Warning: StimulusPresentationTask::Preflight: Due to a sample block duration of 40ms, the actual value of the ISIMaxDuration for stimulus 4 will be 1480ms rather than 1500ms.

Any idea how to fix this?

Thanks,
Emily

Emily,

Simply set the ISIMin/MaxDurations to 1480ms.

This warning is because the Neuroscan system (and thus BCI2000) is set to a fixed SampleBlockSize of 40 at 1 kHz (40 ms). Thus, the timing in BCI2000 is driven by a 40 ms clock, and 1500 ms is not a multiple of 40ms.

Gerv

Hi Gerv,
Thanks for getting back to me so quickly. I can't find an ISI field under any of the configuration tabs. Is it known by any other name?
thanks,
Emily

Emily,

These parameters are named ISIMinDuration and ISIMaxDuration in BCI2000 v2.0. They are in the Application tab and are described on http://www.bci2000.org/wiki/index.php/U ... tationTask

Gerv