Reaction time problem

[Paul Groot]

Why do you use two separate systems? (Hope I understand your setup)

E-Prime should be able to collect the start/stop responses as well. But if
that is not an option, I would use EPrime on both computers and synchronize
them both with the trigger pulse of the scanner. However, you must be very
careful when syncing two separate devices if you only use a single sync
event at the start of the experiment. This will only work reliable when
both internal clocks run exactly at the same speed. A possible workaround
for this is to record repeating trigger pulses of the scanner (i.e. a
trigger at each EPI onset) and correct for differences offline. Another,
method would be to use a digital link between both computers and let the
experiment script send event markers at specific times. The receiving
computer should record those events along with the start/stop responses.

best
paul

2012/9/28 Mukesh Vaidya <vaidyamukesh5 at gmail.com>

> No response..??
>
>
> On Thursday, 27 September 2012 15:36:27 UTC+5:30, Mukesh Vaidya wrote:
>>
>> Hi All,
>>
>>
>> > We need to extract Reaction Time data [usually in milliseconds] from our
>> participants' in-scanner experiment data.> The E-Prime data files [e-dat files] are generated by a separate system
>> which runs the experiment script [or "paradigm"], and the participant's
>> vocal responses are recorded using a separate computer.> The vocal responses are recorded by manual 'start' and 'stop' button
>> presses, whereas the e-dat files are generated automatically by the
>> computer that is running the experiment, and it is synchronized with the
>> MRI scanner.> If we can figure out what auditory signal, i.e., sound feature that is
>> part of the sound file is synchronized perfectly with any specific
>> time-stamp in the e-dat files, we can then use that time-stamp as our
>> "zero" point, and measure Reaction Time accordingly.
>>
>>
>> I am attaching experiment file as well.
>>
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