EEG Pulse Duration with Onsetsignal

[Nate]

So to close this- the pulse duration was the duration of the stimulus
in this instance.  This was actually not a problem, as Brain Vision
only looks at the onset of the pulse, not the duration of the pulse.
So, all is well!

On Nov 16, 11:50 pm, Nate <nateaschrei... at gmail.com> wrote:
> Yes it's ridiculous.  It's even more ridiculous that our lab paid for
> one...but we don't really have a dedicated tech staff.  (Have you seen
> how much the electrode caps cost?! I would be willing to quit my job
> and sit at home and make them myself for that price.)
>
> Thanks for the help on the pin placement- I'll check this out.  If
> anything it is a good lesson in parallel port communication.
>
> On Nov 16, 4:41 pm, David McFarlane <mcfar... at msu.edu> wrote:
>
> > Wow, BioSemi wants $100 for a simple 25-pin D-sub to 37-pin D-sub
> > cable?  I could build one from parts for a lot less than that, and
> > then I would know exactly what it does.  But anyway...  I would just
> > work on the 25-pin connector on the E-Prime end (and in fact I would
> > add a straight-through 25-pin cable just to make my work
> > easier).  That pinout remains the same for Presentation and EP.  Then
> > yes, your negative lead goes to ground (pin 25; you can Google to get
> > several pinout diagrams, pay attention to gender).  Then you have to
> > know how to translate decimal to binary, and be aware that we count
> > bits from low to high.  The value 9 comes to binary 00001001, which
> > means that it would raise a signal on pins 2 and 5.  So put the
> > positive lead of the meter on either of these (you will of course try
> > both those pins plus a few others just to complete the exercise and
> > to see if I really know what I am talking about).  If you then still
> > wanted to see how the signal makes it through the BioSemi cable, then
> > it looks like you put leads from pin 37 to pins 1 or 4 at the end of
> > the BioSemi cable.
>
> > Sorry, I can't help at all with the Brain Vision issues.
>
> > -- David McFarlane, Profesional Faultfinder
>
> > >This is indeed VERY helpful.  If I was to measure the duration of the
> > >pulse (the trigger sent is actually '9') using a voltmeter, I would
> > >then connect the negative wire to the incoming PCI-DIO cable ground
> > >hole (which one is this?) and the positive lead would then connect
> > >to...hmm the chart below does not show 9....
>
> > >This shows the pin mapping for this, but there is an error on the page
> > >and I also can't tell which chart is actually for eprime.
> > >http://www.biosemi.com/faq/presentation.htm
>
> > >Onto the other method/explanation: in this example then, I do not have
> > >a prerelease for this particular slide, so the pulse duration is
> > >probably1500ms.  Other triggers/slides are of different durations and
> > >are hopefully not relevant....
>
> > >However, now comes the potential problem of analysis in Brain Vision
> > >analyzer, though I am not sure this is the correct forum for this (but
> > >then again, I have not found a BV forum anywhere).  Anyways, if anyone
> > >is familiar with this, I would really appreciate some input, as I am
> > >kind of lost:
>
> > >I have been told that the triggers/markers (or only the one marker of
> > >interest?) need to be moved based on the length of the pulse.    So
> > >in  this example the 5 (or 9 in my instance) marker would need to be
> > >moved with an offset of 1500 ms. Anyone know if this is true?

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