Dear Saul,
> We have a block design where one of our conditions across a run has different
> block lengths. For example, one block is 18 seconds, while another block of the
> same condition is 30 seconds. These blocks are the same stimuli and condition,
> so we would not like to make separate regressors. However, we are not sure how
> to specify different lengths of blocks for the same condition.
you can simply specify the length (duration) for each onset separatly, e.g.
SOA for trial 1: 0 50 100 180
Duration : 18 30 32 18
etc.
Karsten
--
-------------------------------------------------------------
Karsten Specht, PhD
Department of Biological and Medical Psychology
& National Competence Centre for functional MRI
University of Bergen
Jonas Lies vei 91
5009 Bergen
Norway
Tel.: +47-555-86279
Fax: +47-555-89872
[log in to unmask]
http://fmri.uib.no/
|