Excuse such a basic email, but I'm wanting to run a contrast like that below –
cong_pre mot_pre incong_pre cong_post mot_post incong_post
1 0 -1 -1 0 1
But I have accidentally specified it as two separate contrasts at the first level; i,e
A: 1 0 -1 0 0 0
B: 0 0 0 -1 0 1
I was wondering - i should get the same results if, at a higher level analysis, I simply run
a two-sample t-test, carrying up the two copes from the first level analysis shouldn't I? T
The only problem I have then is that I want to use A as an exclusive mask, and I can't
see how I can easily do this?
Thanks, Alex
On Tue, 14 Jul 2009 17:55:26 +0100, Joe Galea <[log in to unmask]> wrote:
>For each subject I have 6 scans:
>
>[cong_pre] [mot_pre] [incong_pre] [cong_post] [mot_post] [incong_post]
>
>I wanted to look at pre(cong-incong) - post(cong-incong), so I for each
>subject I created a contrast of:
>
>cong_pre mot_pre incong_pre cong_post mot_post incong_post
>1 0 -1 -1 0 1
>
>This has created a contrast file for each subject. I now want to run a
>random effects analysis on those contrast files across subjects. I have
>entered the cope image that I want to compare for each subject and have set
>EV1 to 1 across all subjects. I then have one contrast which is my group
>mean effect.
>
>However when I run the analysis I get this error message in the log file:
>
>/usr/local/fsl/bin/fslmaths mean_func -Tmean mean_func
>syntax error in expression "2.000000e+00 *
>
>": premature end of expression
> while executing
>"expr $mean_lcon_incr * [ exec sh -c "cat $feat_files($session)/design.lcon" ] "
> (procedure "feat5:proc_gfeatprep" line 270)
> invoked from within
>"feat5:proc_gfeatprep "
> ("-gfeatprep" arm line 2)
> invoked from within
>"switch -- [ lindex $argv $argindex ] {
>
> -I {
> incr argindex 1
> set session [ lindex $argv $argindex ]
> }
>
> -D {
> incr argindex 1
> set..."
> ("for" body line 2)
> invoked from within
>"for { set argindex 1 } { $argindex < $argc } { incr argindex 1 } {
> switch -- [ lindex $argv $argindex ] {
>
> -I {
> incr argindex 1
> set ses..."
> (file "/usr/local/fsl/bin/feat" line 137)
>
>
>I am not sure what this error message means. Any help would be much appreciated.
>
>Joe
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