Hi,
1. create EV1 that models all the pain events
2. create EV2 that looks like EV1, but where the height of each event
is modulated by the pain response. Orthogonalise EV2 wrt EV1.
OR
(for more flexibility in modelling, but possibly modelling overkill)
create EV1,2,3,4 etc after binning the pain responses into separate
bins (e.g. if the response is an integer on scale 0:10, create one EV
for each) and in each EV only include those events of the
corresponding response strength. In this case all events should have
height 1 and you don't need the EV for _all_ events.
Cheers.
On 1 Feb 2009, at 02:07, David Shirinyan wrote:
> We conducted an fMRI study with periodic pain ratings entered by the
> participant. We would like to ask which voxels correlate with a given
> persons pain ratings throughout that persons scan-a within subject
> correlation of a behavioral measure with our signal. How should we
> go about
> doing this? For the sake of the example, lets say we have 10
> subjects with
> 2 runs of 100TR’s each. There were 15 pain ratings per run, per
> subject.
> Thank you
>
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
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