3dLME GLT coding

Hi,

I would like to ask about 3dLME GLT coding.
I just bring the ‘example 3’ from ‘3dLME’ instruction on the web as following.

3dLME -prefix Example3 -jobs 24
-model "condgroup"
-ranEff ‘~1’
-SS_type 3
-num_glt 6
-gltLabel 1 ‘pos-neu’ -gltCode 1 'cond : 1
pos -1neu’
-gltLabel 2 ‘neg’ -gltCode 2 'cond : 1
neg ’
-gltLabel 3 ‘pos+nue-neg’ -gltCode 3 ‘cond : 1pos +1neu -1neg’
-gltLabel 4 ‘pat_pos-neu’ -gltCode 4 'cond : 1
pos -1neu group : 1pat’
-gltLabel 5 ‘pat_neg-neu’ -gltCode 5 ‘cond : 1neg -1neu group : 1pat’
-gltLabel 6 ‘pat_pos-neg’ -gltCode 6 'cond : 1
pos -1neg group : 1pat’
-num_glf 1
-glfLabel 1 ‘pos-neu’ -glfCode 1 ‘Group : 1ctr & 1pat cond : 1pos -1neu & 1pos -1neg’
-dataTable
Subj cond group InputFile
s1 pos ctr s1+tlrc’[pos#0_Coef]’
s1 neg ctr s1+tlrc’[neg#0_Coef]’
s1 neu ctr s1+tlrc’[neu#0_Coef]’

s21 pos pat s21+tlrc’[pos#0_Coef]’
s21 neg pat s21+tlrc’[neg#0_Coef]’
s21 neu pat s21+tlrc’[neu#0_Coef]’ \

My question is if these following GLT coding would provide the identical t-test result.

  1. -gltLabel 1 ‘pos-neu’ -gltCode 1 ‘cond : 1pos -1neu’ \

  2. -gltLabel 7 ‘pos+nue-neg+neg’ -gltCode 7 'cond : 1pos +1neu -1neg -1neu ’ \

I assumed that in the second case condition ‘neu’ should be cancelled out.
I have tried this way with my data, but these two gave me the different result.
Could you let me know what happen in this coding?

Thanks

Jung

Are they slightly or dramatically different?

It gave totally different result.

Jung

Jung,

The coding

  1. -gltLabel 7 ‘pos+nue-neg+neg’ -gltCode 7 'cond : 1pos +1neu -1neg -1neu ’ \

is not interpreted correctly by the program. So, use the following

  1. -gltLabel 1 ‘pos-neu’ -gltCode 1 ‘cond : 1pos -1neu’ \

Thanks.

In this case, if I use contrast image, for example ’ pos_neu = pos -neu’ and ’ nag_neu= neg- neu’
and apply them to 3dLME,

a) -gltLabel 1 ‘pos-neu’ -gltCode 1 ‘cond : 1pos -1neu’ \

b) -gltLabel 8 ‘pos-neg_contrast’ -gltCode 8 ‘cond : 1pos_neu -1neg_neu’ \

I expected the similar result, but it also gave totally different result.

Can I get some idea about this?

Jung

f I use contrast image, for example ’ pos_neu = pos -neu’ and ’ nag_neu= neg- neu’ and apply them to 3dLME

It’s hard for me to understand how exactly you’re implementing this in 3dLME. Could you provide the 3dLME scripts to show the details?