Hi
On 15 Aug 2007, at 17:20, Vitaly Napadow wrote:
> hi all
>
> firstly, thanks for finally pushing this out. i think we were all
> chomping
> at the bit looking forward to the new release and it feels great to
> finally
> play with the new tools.
>
> i had completed an analysis of resting state data but want to go
> back and
> try the new tools now. i have 15 subjects and two separate rest
> runs that i
> am comparing from each subject. i assume i want to use Multi-session
> temporal concatenation to contrast the two rest runs.
Yes, temporal concatenation is probably what you want, though you
still will need to decide on what exactly you want to compare between
runs, e.g. the amount of variance in the associated time course (as a
measure of volatility) or any other quantity you could come up with
such as mean level
> so as not to compare
> apples to oranges, i want to contrast specific resting state
> networks. my
> question is, if i specify and 2nd level design.mat and design.con
> file with
> a 1 -1 contrast how will i know which resting state networks
> (evident on
> group maps) are associated with or correspond to which 2nd level
> output
> components?
Don't quite understand the question. In the new release version you
have the option of testing (in the GLM sense) each associated time
course and each associated session/subject mode using design and
contrast matrices. The GLm fit will be performed separately for each
time course and/or subject session mode vector.
>
> alternatievly, if i already did single-subject analyses and have
> mixing
> matrices etc with components corresponding to known resting
> networks and
> which can be pulled out to input into a 2nd level group analysis,
> are my
> options to contrast on a 2nd level the same as before?
fundamentally yes, the main difference being that in the case of
separate analyses you're bound to have differences in e.g. the
default-mode network between subjects. In the case of temporal
concatenation or full TICA you effectively fix the spatial maps to be
identical and only allow the time courses to be different.
hope this helps
Christian
> thanks
>
> vitaly
>
____
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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