Dear Stephen Smith,
As input I used the results of another higher level analysis
(connectivity resting state for all participants in one image; same for
task).
The only warnings (not errors) I see are the following:
WARNING: The passed in varcope file, var_filtered_func_data, contains
voxels inside the mask with zero (or negative) values. These voxels will
be excluded from the analysis.
WARNING: Extreme smoothness detected in X - possibly biased global
estimate.
WARNING: Extreme smoothness detected in Y - possibly biased global
estimate.
WARNING: Extreme smoothness detected in Z - possibly biased global
estimate.
I assume the last 3 warnings make sense as the data consists of
regression coefficients/standard error from the previous 2nd level
analysis. The question is if the first warning matters.
I would appreciate your suggestions. Thank you.
Best wishes,
Liza
On 2014-07-17 07:56, Stephen Smith wrote:
> Hi - did you feed in standard lower-level FEAT outputs into this
> higher-level FEAT? Did it show any errors in the logs (eg in the log
> page of the web report)?
> Cheers
>
> On 16 Jul 2014, at 20:29, Liza van Eijk <[log in to unmask]> wrote:
>
>> Dear FSL experts,
>>
>> I've run FSL FEAT with 2 files: the connectivity map for all
>> participants during resting state with a seed in the pfc, and the
>> connectivity map for all participants during task with the same seed
>> in the pfc, in order to compare the connectivity maps between
>> resting state and task.
>>
>> However, I received 'nan' as p-values in the cluster lists with
>> z-values >2.3.
>>
>> Set-up model EVs in FEAT:
>> Group EV 1 EV 2
>> input 1 1 1 0
>> input 2 1 0 1
>>
>> Contrasts in FEAT
>> EV 1 EV 2
>> C1 cope 1positive 1 -1
>> C2 cope 1negative -1 1
>>
>> In the report log it says for example: 'zstat1: DLH=nan
>> VOLUME=201561 RESELS=nan'.
>>
>> -What can I do about this nan p-values? Are the results still
>> reliable?
>>
>> -Running the analysis in Camba shows non-significant results (2x1,
>> repeated measures, within group correlations). Any suggestions about
>> this?
>>
>> It would be very helpful if you could share your suggestions. Thank
>> you.
>>
>> Best wishes,
>>
>> Liza
>
> ---------------------------------------------------------------------------
> 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 [1]
>
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