8 Jul
2008
8 Jul
'08
3:20 p.m.
Hi Andre,
We are doing this at the moment with FSL. Our design has 10 subjects
who each do 2 sessions (however, the number of sessions each subject
does could vary). We do a first level analysis on the 20 (10 * 2)
scans. We then do a second higher-level analysis in which we combine
the two sessions from each subject. This is followed by a 3rd
higher-level analysis in which we look at the activation across subjects
for each contrast.
Cheers,
Tim
andre(a)ynic.york.ac.uk wrote:
Dear Users,
Concatenation or higher level stats?
We would value the input of any users who have experience of 'combining'
fMRI data across multiple runs for more robust averaging.
The issue arises when trials of an experient are acquired in different
data blocks due to technical limitations of scan scquisition protocols or
often to reduce the strain on participants in a single session.
I have searched many available resources. There are well documented
routines for (1) analysinng the sessions individually and then compring
them with a higher level analysis or (2) demeaning the two timeseries and
combining them into a single one .. then following the standard analysis
individual subject routine.
Comments would be appreciated (especially from anyone has first hand
experience of doing this).
Thanks
Andre'
--
Dr Tim Andrews
Department of Psychology
University of York
York, YO10 5DD
UK
Tel: 44-1904-434356
Fax: 44-1904-433181
http://www-users.york.ac.uk/~ta505/
http://www.york.ac.uk/depts/psych/www/admissions/cns/