I have never used Matlab nor PowerPoint for fMRI stimuli presentation.
However, if this is what others at your site are doing, the "trigger"/sinc
pulse is typically MRI scanner specific; your MRI tech (or whoever is
running the MRI scan sessions) should be able to help you set it along with
your other scan parameters.
If no one else is doing fMRI, I would recommend stimuli/task presentation
software such as E-Prime (PC) or Superlab (Mac).
Hope this helps,
On 7/16/09 8:09 AM, "Charmaine Borg" <[log in to unmask]> wrote:
> Dear SPMers,
> I am completely new to fMRI research and I doubt if this is an
> appropriate question here...but I will try... I am soon going to start
> the design of an fMRI task on power point presentation. I have the
> structure organized, but what I am unsure of is the MatLab syntax to
> trigger the presentation. We have 6 conditions Fear, neutral objects,
> neutral bodies, disgust core, disgust animal and sexual
> Exposure of each Stimulus 1.4s
> Inter-Stimulus interval 1s
> 1 Block = 10 stimuli (1.4x10)+(9x1)= 23s
> Inter-Block interval 16s (8s rating + 8s cross fixation)
> 1 Run = 6 blocks (23 x 6) + (16 x 5) = 218s
> (1 condition per block, pseudorandom e.g. D, N1, N2, F, SN, and P.
> There will be 6 repetitions i.e. 60 stimuli of each condition)
> Inter-Run interval (fixation of cross and instructions) 30s
> Experiment = 6 runs (218x6)+(30x5)= 1458s
> I apologize for taking your time but would appreciate your
> guidance/referral immensely.
> Thanks in advance