Well, basically, MELODIC can be used to make sure that the experiment
worked in general terms. If there is only noise or the subject did not
move the right when he/she should, there should be no respective
component. In block designs there should be components with a
timecourse similar to the experimental setup (motor, visual, resting
and so on). In your case this does not add much information - SPM gave
meaningful results, so the experiment obviously ran alright. I am not
proficient in SPM, however, so I cannot advise on what went wrong in
the comparison.
Best wishes,
Cornelius
On Tue, May 10, 2011 at 5:53 PM, Carolina Valencia
<[log in to unmask]> wrote:
>
> Dear Cornelius,
> what do you mean with this, in the example I was talking about a motor task
> "If there is language related activation in the data, one component (or
> more) will pick it up, along with a nice 30s-timecourse. So, if you
> see that (and FEAT or SPM won't give you anything reasonable), then
> it's most likely misspecified onset value"
> Thanks,
> Carolina
> 2011/5/9 Carolina Valencia <[log in to unmask]>
>>
>> I did, for example a hand tapping task (30sec on 30sec off) during the
>> 3sec*105scans.
>> Another task of foot movement with the same settings. Other task of
>> listening a tale and so on.
>> The onset time chosen in SPM was 10:20:100 with units scans
>> I also use the 3 column file option with the txt file:
>> 23 30 1
>> 83 30 1
>> 143 30 1
>> 203 30 1
>> 263 30 1
>> and I run Melodic and the 6th component is similar to the spm result. (I
>> can not attach the images)
>> But I'm still want to run Melodic to run the other tasks and compare,
>> because sometimes is difficult to find the correct component that correspond
>> to the task in MELODIC
>> Thanks,
>> Best
>> Carolina
>> 2011/5/9 Cornelius Werner <[log in to unmask]>
>>>
>>> Hi Carolina
>>>
>>> On Mon, May 9, 2011 at 4:00 PM, Carolina Valencia
>>> <[log in to unmask]> wrote:
>>> > Dear FSL users,
>>> > (...)
>>> > different motor and languages tasks examinated in independent cycles.
>>>
>>> What do you mean by this? How many separate tasks were involved?
>>>
>>>
>>> The steps in SPM were:
>>> > - Reorient the images according to the AC
>>> > - Realign the functional data
>>> > - Coregister the structural with the mean functional data as a
>>> > reference
>>> > - Segmentation of the structural image
>>> > - normalise the realigned and the bias corrected data
>>> > - smoothing the normalise, realign functional data
>>>
>>> Did you make sure that onset times in your regressor file or .mat
>>> reflect that you discarded 5 timepoints? This is one of the most
>>> frequent mistakes (at least in my experience).
>>>
>>> > The steps in FSL FEAT were:
>>> > - Using BET in the structural Data for brain extraction
>>> > - In data tab choosing the functional data, using a high pass filter of
>>> > 90 (calculated with cut off calc) and delete 5 scans
>>> > - Pre stats all defaults, bet extraction on, FWHM of 6
>>> > - stats tab I use the model setup wizard with rArA with r of 30 seg and
>>> > A of 30 seg
>>> > - Post stat I left defaults
>>> > - registration tab I used the result from Bet extraction in the main
>>> > structural image
>>>
>>> If you have separate tasks (see above) then you shouldn't use the
>>> wizard. Actually, I recommend using the "full model setup" with a
>>> 3-column-file in all but the most simple settings. If you want to
>>> compare output from two packages, you certainly should use the same
>>> onset files.
>>> Another way to find out if there is meaningful signal in the data is
>>> running MELODIC. Here, you do not need to know about onset times. If
>>> there is language related activation in the data, one component (or
>>> more) will pick it up, along with a nice 30s-timecourse. So, if you
>>> see that (and FEAT or SPM won't give you anything reasonable), then
>>> it's most likely misspecified onset values.
>>>
>>> >
>>> > Thanks in advance,
>>>
>>> You're welcome
>>> Cornelius
>>>
>>> --
>>> Dr. med. Cornelius J. Werner
>>> Department of Neurology
>>> RWTH Aachen University
>>> Pauwelsstr. 30
>>> 52074 Aachen
>>> Germany
>>
>>
>>
>
>
>
>
>
--
Dr. med. Cornelius J. Werner
Department of Neurology
RWTH Aachen University
Pauwelsstr. 30
52074 Aachen
Germany
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