If you're following the first of my suggestions below (steps 1&2) then
the pain-correlation contrast would be [0 1].
Steve
On 3 Feb 2009, at 05:45, David Shirinyan wrote:
> Quick followup.
> Would the appropriate Contrast (the contrast looking for voxels
> correlated
> with the pain ratings) then be
> 1 1
> or
> 0 1
>
> Thank you
>
On 1 Feb 2009, at 10:56, Steve Smith wrote:
> 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
>>
>
>
> ---------------------------------------------------------------------------
> 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)
> [log in to unmask] http://www.fmrib.ox.ac.uk/~steve
> ---------------------------------------------------------------------------
>
---------------------------------------------------------------------------
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)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
---------------------------------------------------------------------------
|