Not really.....each independent component comprises one spatial map
and one timecourse. If you take the outer product of the two
("multiply" them) you get a 4D dataset which describes how that
component appears in the original data. If you do this separately for
each component and them add them all up you would get back to the
original data (apart from the Gaussian noise removed at the start of
the ICA processing). However, I'm still not sure what your question
is.....
Cheers, Steve.
On 18 Jul 2007, at 20:58, Peter Fried wrote:
> Sorry, I don't think I was being clear.
>
> I've extracted a component and I see that it's timecourse is really
> just
> all the individual timecourses back-to-back. I'm wondering if I can
> split
> the the component into individual maps corresponding to the individual
> timecourses. Does this make more sense?
>
> -Pete
>
>> Hi,
>>
>> if you run avwsplit on melodic_IC you'll get separate 3D maps from
>> the 4D volume.
>> cheers
>> christian
>>
>>
>> On 18 Jul 2007, at 20:09, Peter Fried wrote:
>>
>>> Hi All,
>>>
>>> I seem to remember reading something about this on the list but I
>>> can't
>>> find it.
>>>
>>> If I've run a group-level melodic analysis on merged feat outputs
>>> (as
>>> opposed to melodic outputs) is there anyway to divide up the
>>> group-component into individual components? I know that the
>>> melodic_mix
>>> contains the time-series for each subject, but I don't know how to
>>> recreate a spatial map based on the time-series data. Thanks.
>>>
>>> -Pete Fried
>>> Center for Magnetic Resonance Research
>>> University of Minnesota
>>
>> ____
>> Christian F. Beckmann
>> University Research Lecturer
>> Oxford University Centre for Functional MRI of the Brain (FMRIB)
>> John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK.
>> [log in to unmask] http://www.fmrib.ox.ac.uk/~beckmann
>> tel: +44 1865 222551 fax: +44 1865 222717
>>
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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
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