Index TableOfContents

Name

isxavg-re-sess - computes random effects analysis for group data

Synopsis

isxavg-re-sess -analysis (analysisname) -contrast (contrastname) -group (gropuname) -space (spacename) -sf (subjectfilename)

Arguments

Positional Arguments

none

Required Flagged Arguments

-analysis analysisname

session-level functional analysis name

-group groupname

name of group

-space spacename

space in which to average (native, tal, sph, roidef)

-spacedir spacedirname

space in which to average (eg, spm-smooth)

-contrast contrastname

contrast name

-sf sessidfile ...

-df srchdirfile ...

-d srchdir ...

Optional Flagged Arguments

-hemi hemisphere

with sph space <lh rh>

-pctsigch

use percent signal change

-nojackknife

do not use jackknifing

-trunc sign

truncation (pos or neg; neg = set neg vals to 0)

-scriptonly

don't run, just generate a script

-version

print version and exit

Outputs

Description

isxavg-re is a program for intersubject averaging using a random-effects model (see ["isxavg-fe"] for fixed effects model). It actually performs statistical analysis as well. It works by computing one number for each subject (at each voxel) based on the contrast matrix. This yields a set of numbers (at each voxel), one for each subject. The average and standard deviation of the set are computed and used to compute a t-statistic the siginficance of H_0: t=0$ is computed using N-1 degrees of freedom where N is the number of subjects. When jackknifing is turned on, a new set of N numbers is computed by successively averaging N-1 subjects while excluding a different subject each time. This reduces the effects of small sample sizes on the correctness of the siginficance levels. Jackknifing does increase the time to process data. It is highly recommended and the default in '"isxavg-re"'. Note that isxavg-re can be run on any data set, not just the output of ["selxavg-sess"].

Examples

Example 1

Example 2

Bugs

None

See Also

["paint-sess"], ["surf-sess"]

Links

FreeSurfer, FsFast

Methods Description

References

["References/Lastname###"]

Reporting Bugs

Report bugs to <analysis-bugs@nmr.mgh.harvard.edu>

Author/s

Doug Greve, PhD