Help with fMRI experiment

Support
1

Hi Chris,

I would like to create a paradigm in MWORKS for an fMRI experiment in macaques, that involves monitoring the monkey’s gaze while presenting stimuli, to deliver increasing amounts of reward as monkey’s time of fixation increases. The presentation of stimuli are independent of the monkey’s behaviour.
Could you guide me on how should I go about to accomplish this?

Thanks a lot for your help.

Best,

Samy

2

Hi Samy,

I can write an example protocol for you, based on your specifications, which can serve as a starting point for your design. Can you provide some more information about how the protocol should work? For example:

  • What kind of stimuli will you present?
  • How should the stimuli be presented (e.g. how many stimuli, displayed for how long, with how much time in between)?
  • How often is the reward dispensed, and what is the range of reward amounts?

Any details you can provide will be helpful.

Thanks,
Chris

3

Hi Chris,
Thanks a lot for your reply. I prepared a powerpoint slide that should give all the information you need.

Best Samy

4

Hi Samy,

Thanks for the details. I’m working on this now, and I have a few questions:

  • Do you want to add another flickering disc every 10 seconds, or is there always just one disc, which changes position every 10 seconds?
  • Is the position of the flickering disc random?
  • Does the full protocol consist of 10s fixation only, followed by 10 10s disc presentations, followed by a final 10s fixation only?
  • When the full cycle is complete, does the reward go back to the original base amount?

Thanks,
Chris

5

Hello Christopher,
There is another flickering disc appearing for 10s, 10s after the first one.
The position of the discs are fixed.
A block is : 10s fixation dot, 10s fixation dot + first disc, 10s fixation dot + first disc +second disc. With 10 blocks in total, amounting to 300s, and ending with a fixation dot only for 10s.
The reward remains independent from the stimuli, and can continue increasing until an upper threshold, and remain there while the monkey is fixating.

Many thanks for your help.

Best,

Samy

6

Hi Samy,

I’ve attached an implementation of the protocol you described.

The flickering discs are implemented using a slightly simpler method than what I suggested previously. For testing purposes, the experiment uses the mouse pointer to simulate eye movement. Also, it omits the actual dispensation of the reward, as this depends on the specific I/O hardware you’ll be using.

The experiment is written in MWEL, so you’ll need a recent nightly build to run it. If you have any questions, please let me know.

Cheers,
Chris

7

Attachment: fMRI.zip (1.45 KB)

8

Hello Chris,
Thank you so much for this, I will test it and get back to you.
So this kind of experiment cannot be programmed in the standard MWorks editor?

Best,

Samy

9

Hi Samy,

So this kind of experiment cannot be programmed in the standard MWorks editor?

No, you definitely could create it in MWEditor/XML. However, it would be more difficult. In particular, MWEL’s macros simplify the implementation and eliminate many redundant definitions that would be present in an XML version of the experiment.

Chris