Hi Thalia,

There seem to be 2 symbols in your expression that are not defined.
The 'b' you use should probably be defined by the "mean" dataset
that you have. So "-subjname.mean+orig" should most likely be
"-b subjname.mean+orig", defining b.

The warning refers to the symbol 'c', which is from 'cliplevel'. You
should put a numeric value in there, to cut out any mean that is
below a threshold (i.e. if the mean is too low, you assume there is
no activation there, otherwise, low-valued voxels (outside the brain,
say) will obscure the voxels that you really care about).

I hope this helps,

- rick