That makes alot of sense. Thank you very much!
Mona
On Sun, Jun 28, 2009 at 2:26 AM, Jesper Andersson<[log in to unmask]> wrote:
> Dear Mona,
>
>> I have some fMRI scans that i need to register to the subjects' t1 brain
>> and
>> the standard brain. In some cases, the T1 brain was obtained from a
>> different
>> scan session than the functional data. How many degrees of freedom should
>> I
>> use, 6 or 7 DOFs? I tried both options, and did not see any visible
>> difference in
>> the registration.
>
> I am assuming we are talking about the EPI->T1 registration here. I would
> say that in principle the 6DOF registration should be the "correct" one. The
> "theoretical" reason for why one would want to use the 7DOF registration
> would be if one of the sequences were geometrically miscalibrated so that
> the actual voxel size was different from the tentative one.
>
> However, if you have a reasonable brain coverage in both scans the results
> will be very similar in the 2 cases (provided the geometry is correct in
> both scans) and both options would give valid results.
>
> Good luck Jesper
>
--
Mona Lisa Chanda
Northwestern University
Department of Physiology
303 E. Chicago
Morton 5-660
Chicago, IL 60611
Cell: (312) 972-3173
Office: (312) 503-1703
Fax:(312) 503-5101
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