Professor Penny and others,
For a procedure like the one mentioned below, are there any guidelines for
incorporating subjects with multiple sessions?
For example, BMS results favored one model across this group, how then
would I average to acquire parameter strengths and probabilities across
this group with multiple sessions?
Best,
Drew
On 9/18/13 5:05 AM, "Penny, William" <[log in to unmask]> wrote:
>Dear Kushal Kapse,
>
>Here I would advise using Bayesian Model Averaging to first average over
>model space.
>
>This will produce a single vector of model parameters for each subject:
>
>w=BMS.DCM.rfx.bma.mEp
>
>You can then do t-tests, F-tests or multivariate tests to look for
>consistency of
>effects over a group of patients or eg. two-sample t-tests to look for
>differences between patients and controls.
>
>Best wishes,
>
>Will.
>
>> -----Original Message-----
>> From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]
>> On Behalf Of Kushal Kapse
>> Sent: 05 September 2013 17:16
>> To: [log in to unmask]
>> Subject: [SPM] BPA, BMA v/s FFX, RFX
>>
>> Hi Peter and SPM users,
>>
>> Two months ago we had email conversation about my doubts on DCM. I
>> finished the analysis and now working on interpretation. I went through
>> the DCM tutorial and BMA paper to get understanding on what way to
>> interpret my datasets. I read the book section
>> http://www.fil.ion.ucl.ac.uk/~wpenny/publications/spm-
>> book/selection.pdf to understand BMA and BPA. But i have following
>> question:
>>
>> 1- We are specifically looking to understand connectivity in brain
>> across treatment. This makes us incline to use parameter estimates over
>> model estimates (BPA over BMA). BUt seems we can only do BPA if we
>> select FFX and BMA if we select RFX. Why is this? Can I do RFX and then
>> perform BPA? The reason to use RFX is that we are expecting different
>> cognitive network for each patient. But we want to do Bayesian
>> Parameter Averaging to interpret how patients connectivity changes as a
>> measure of treatment across two scans.
>>
>> SO my question is , can i do BPA using RFX.
>>
>> Your advice will be really helpful again.
>>
>> THanks
>>
>>
>
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