My 2 cents though is that if a voxel is really not activated even at a
modest uncorrected level such as 0.001 or 0.01 by the aspect of your
task that you are interested in, then it probably should not be
selected for a PPI (or other secondary type of analysis such as DCM),
since the activity in that voxel would appear to be unrelated to your
task.
Darren
On Tue, Jan 4, 2011 at 8:20 PM, MCLAREN, Donald
<[log in to unmask]> wrote:
> You need to do each session separately.
> If you set the p-value to .999, then you select voxels that are not
> activated.
>
> Best Regards, Donald McLaren
> =================
> D.G. McLaren, Ph.D.
> Postdoctoral Research Fellow, GRECC, Bedford VA
> Research Fellow, Department of Neurology, Massachusetts General Hospital and
> Harvard Medical School
> Office: (773) 406-2464
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> On Tue, Jan 4, 2011 at 9:15 PM, junhai xu <[log in to unmask]> wrote:
>>
>> Dear SPMers,
>> SPM5 asks me which session should be chosen when the first eigenvariate
>> was extracted in doing PPI analysis. Our design contains 6 sessions.
>> I want to get the first eigenvariate from the whole 6 sessions. So which
>> one should be chosen?
>>
>> Another problem: for each subject , can I extract the first eigenvariate
>> from the point that isn't activated.
>>
>> Thanks.
>>
>> Best wishes,
>>
>> Junhai
>> --
>> Junhai Xu
>> Research Center for Sectional and Imaging Anatomy
>> Shandong University School of Medicine
>> No. 44, West Wenhua Road, Jinan, Shandong
>> 250012 P.R. CHINA
>>
>> Tel: +86-531-8838 2093
>>
>
>
--
Darren Gitelman, MD
Northwestern University
710 N. Lake Shore Dr., 1122
Chicago, IL 60611
Ph: (312) 908-8614
Fax: (312) 908-5073
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