Hi,
No, you should only see activation within the mask - I just tested
this and that's what I get. Note that in FEAT pre-threshold masking,
the mask needs to be in the space of the native FMRI data - is your
mask transformed into original FMRI space (and re-thresholded if
necessary)?
Cheers.
On 4 Dec 2007, at 22:06, Lucina Uddin wrote:
> Thank you for the clarification. One more question: I have entered a
> mask of the inferior frontal gyrus as my pre-threshold mask, yet in
> the activation maps I still see other additional areas outside that
> mask (e.g. V1). Does this mean there is an error occurring
> somewhere? Thanks again,
>
> Lucina
>
>
>
>
>
> On Oct 5, 2007, at 4:43 AM, Steve Smith wrote:
>
>> Hi - FEAT only ever passes up raw unmasked COPEs anyway - so
>> anything you do in post-stats at the first-level has no effect on
>> the higher-level analysis.
>>
>> Cheers.
>>
>>
>>
>> On 5 Oct 2007, at 00:00, Lucina Uddin wrote:
>>
>>> Hi, I have a question regarding the Pre-threshold masking option
>>> in FEAT. As I understand it, this is an option when one wants to
>>> constrain one's search for activation within a specified ROI. Is
>>> it appropriate to apply an ROI mask at the individual subject
>>> level (i.e. in a first-level analysis) and carry through the
>>> results to a higher level analysis, or should the masking only be
>>> done at the highest-level when looking for group differences
>>> within that mask? Thanks in advance for your help,
>>>
>>> Lucina
>>>
>>>
>>> Lucina Q. Uddin, Ph.D.
>>> New York University
>>> Child Study Center
>>> 215 Lexington Avenue
>>> 14th Floor
>>> New York, NY 10016
>>> (212) 263-4673
>>> [log in to unmask]
>>>
>>>
>>>
>>>
>>
>>
>> ---------------------------------------------------------------------------
>> 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
>> ---------------------------------------------------------------------------
>>
>
> Lucina Q. Uddin, Ph.D.
> New York University
> Child Study Center
> 215 Lexington Avenue
> 14th Floor
> New York, NY 10016
> Phone: (212) 263-4673
> Fax: (212) 263-4675
> [log in to unmask]
>
>
>
>
>
---------------------------------------------------------------------------
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
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