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  Hi Maria:

 I am reading the  Fox paper .I can not understand  some details in your paper , although  I have discuss with my colleague. I hope you can help me.

 1) In the section Preprocessing of Functional Data of the paper, what does the sentence 'Each fMRI run was intensity scaled (one
multiplicative constant over all voxels and frames) to yield a whole brain mode value of 1,000 (not counting the first four frames )' mean?  Can you explain to me  how to scale  the data  in details?

 2)In the  section Correlation Techniques of the paper,   what does the sentence '(ii) the whole-brain signal averaged over a fixed region in atlas space' mean? what does the whole-brain signal mean ? How to select the fixed regions? Whole brain signal does not mean all brain voxel averaged,does it ?

 

 

Looking forward to your response.

Sincerely yours

LeiNa

On 10/14/05, Maria Densmore <[log in to unmask]> wrote:

Hello ,

Thanks for your feedback.
I still need clarification of my two concerns.

1) I don't quite understand how to set my design matrix since there is no
baseline condition to subtract the task from.  What I do have is, one task
(eyes closed)that continues throughout the entire 110 volumes acquired.

2) I'm also not sure if this TRUELY translates to a PPI analysis in SPM or if
it's something I won't be able to replicate using SPM.


Comments on the VALIDITY of a resting state analysis are greatly appreciated.

Thanks for you time,
Maria



> Dear spm group,
>
> I've been asked to analyze a data set that was scanned with the same
> parameters
> as the paper:  Fox et al "The human brain is intrisically organized into
> dynamic, anticorrelated functional networks", PNAS July5,2005
>
> This data set was not analyzed using SPM but seems to correlate time
> series data
> for the voxels or regions of interest during a resting state.
>