Dear Steve,
Please forgive my lack of understanding on this subject, but how will
Featquery know that i have modeled the rest period, and how will it know
which EV corresponds to the rest trials? If i use the %signal change in
Featquery, then the baseline will be the time average of
filtered_func_data, which will include all the conditions that i do not
want to model.
thank you very much,
paymon
On 12/7/2007 5:22 AM, Steve Smith wrote:
> Hi,
>
> You can just use Featquery to get the % signal change as it will take
> care of all of these issues for you.
>
> Cheers.
>
>
>
> On 5 Dec 2007, at 17:47, Paymon Hosseini wrote:
>
>> Hello,
>>
>> I have an event related study that has 6 experimental conditions a
>> lot of control conditions. For analyzing it, i just modeled the 6
>> experimental conditions and the rest period (i.e fixation) and
>> ignored the control conditions (for now).
>>
>> My question is about calculating %signal change for the 6
>> experimental copes (each cope is one experimental condition minus
>> fixation). Specifically, i am wondering how i should calculate the
>> baseline to get the %signal change relative to fixation. I suspect
>> that I cannot use filtered_func_data as baseline, because it includes
>> all the control conditions that i have not modeled. A possible
>> solution may be to concatenate all the fixation periods of a subject
>> into one volume, and then divide the copes by this new volume and
>> then multiply by 100 to get the %signal change. Is this correct?
>>
>> thank you very much for any help,
>> paymon
>
>
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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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