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One quick follow-up: Should I use the automatic dim estimate when running
melodic on the group-wise concatenated data, or will that give me hundreds
of components? Thanks

-Pete

> Hi
>
> yes, this is what I' expect - data sets with increased amount of head
> motion will typically have an increased model order. Estimating more
> components in those data sets is useful as these additional
> components soak up variability due to uninteresting but existing head
> motion effects. As such fixing the number of components to 30 does
> sound sub-optimal.
> cheers
> christian
>
>
>
> On 12 Jul 2007, at 14:31, Peter Fried wrote:
>
>> I've noticed that letting MELODIC estimate the number of components
>> somewhat decreases the amount of noise found in resting-state
>> networks.
>> It also seems to break some RSNs into multiple components. We had been
>> selecting 30 components but with the automatic dim estimate the
>> numbers
>> are in the 40-50 range (depending ususally on how much motion there
>> is).
>> Thanks.
>>
>> -Pete
>>
>>> Hi,
>>>
>>> no, it does not matter if some inputs have different number of
>>> components. I always think that the automatic dim estimate is what
>>> should be used - are numbers very much hgher than 30?
>>> cheers
>>> c
>>>
>>>
>>> On 11 Jul 2007, at 21:05, Peter Fried wrote:
>>>
>>>> Hi All,
>>>>
>>>> If I am merging the Melodic outputs for multiple subjects in
>>>> order to
>>>> rerun Melodic, do all the inputs have to have the same number of
>>>> components?
>>>>
>>>> I am trying to decide between choosing 30 components for each
>>>> subject (180
>>>> volumes, TR=2.0) or letting Melodic estimate the number.
>>>>
>>>> Thanks.
>>>>
>>>> -Pete
>>>
>>> ____
>>> 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
>>>
>
> ____
> 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
>