Can I generate stimuli and capture data in Psycho-physiological experiments to 1mSec resolution?

[CHRISM]

I am trying to assess the feasibility of using LabView for psycho-physiological experiments. This would require on-screen stimulus presentation of images, video, and/or sound with simultaneous acquisition of analogue physiological signals and digital I/O for reaction times. Resolution must be in the order of 1mSec in most cases to test subliminal presentations or measure fast reaction times (video not quite so important). Is LabView capable? Has anybody written such software already?

[Doug (CapeFl)]

Labview can easily present images and record data (as you mentioned) simultaneously. 1msec rate is very feasible as long as you have any decent PC (e.g.: 64Mram/500MHZ+). As for data input, there are many workable options, from simple serial to parallel, to specialized I/O boards, including handling multiple lines of input. One of the greatest benefits with labview is the quickness of coding, and the numerous options for processing, displaying, and managing your data. I haven't written software to capture Psycho-physiological experiments, but as far as Labview is concerned with data in and out, I believe any Labview programmer will tell you, its a good choice.

Check out the PDF on Labview and Subject Monitoring:
http://zone.ni.com/devzone/devzoneweb.nsf/opendoc?o
penagent&1CC5B9DED24D46A686256934004EE292&cat=321B275A902C5088862569390077DD3E

[Labviewguru]

LabVIEW should be quite capable. However, I would suggest the real-time version, if that is what you are looking for.

Be careful though, realtime is not a matter of being fast, it is a matter of code executing based on exact timing.

You should contact a consultant with considerable experience with timing, real-time, and LabVIEW to find out exactly how to solve this issue. The benefit of using LabVIEW is the speed of development, and flexibility of the final product. The only question then is how your specific application needs can be met.

I know of someone who wrote code to test reaction times several years (and versions of LabVIEW) ago.

[CHRISM]

Thanks for the info. LabVIEW RT is not an option for us for various reasons. I will construct a detailed Statement of Requirements and submit it to our local NI office for comments. It could be that the achievable resolution will limit the application to teaching purposes only. I would still like to know if LabVIEW in it's basic form (No IMAQ) can present previously digitized video clips as an on-screen stimulus.

[Ben]

Hi CHRISM,

Yes it can be done in LabVIEW. I have written applications using NI hardware and LabVIEW with 0.25 usec resolution.

Data Science Automation (www.DSAutomation.com) has done an an application similar to what you have described. It presented a TV comercial to a subject while monitoring their engagement factor (NASA developed technology that analyzes brain waves) in order to evaluate how effective the commercial was in capturing and holding the subject's attention.

I was not personally involved in this project, so I can't give many more details off the top of my head. If you are intersted, give us a call at (724) 745-8400 and ask for Karl Szymanski.

We are capable of supporting you in any manner you choose. Everything from teaching the basics of LabVIEW, Data Acq
uisition, and image acquisition and processing, through full system development.

I can be reached at the number above or at

bar@DSAutomation.com if you would like to talk to me.

Ben

[Ed Bogart]

Ben wrote:

> Hi CHRISM,
>
> Yes it can be done in LabVIEW. I have written applications using NI
> hardware and LabVIEW with 0.25 usec resolution.
>
> Data Science Automation (www.DSAutomation.com) has done an an
> application similar to what you have described. It presented a TV
> comercial to a subject while monitoring their engagement factor (NASA
> developed technology that analyzes brain waves) in order to evaluate
> how effective the commercial was in capturing and holding the
> subject's attention.
>

CHRISM,

It has been a few years since I developed the technology above (as a
consultant to NASA) but based on my experience at that time, I would say
that the answer is yes and no. Yes, using LabVIEW you can create an
application that will generate
stimuli, collect response data, display
stimulus and response in near real-time and do the analysis. The hitch
is that it is near real-time.

When I tried to do Auditory Evoked Potential averaging for instance, I
found that there was no way to prevent the processor from stealing
cycles from the timing loops. The net result was a non deterministic
time error that with an s.d. of several microseconds smearing the
averaged curves.

The problem may not exist now with faster computer, operating system and
LabVIEW.

You can email me for more information ar bogart@exis.net