External Email - Use Caution
Hello Freesurfers,
We performed a whole-brain analysis using general linear model analysis with FreeSurfer mri_glmfit for neuropsychiatric symptoms (i.e: depression, etc) to assess their effect on brain’s cortical volume, thickness and area between groups (controls vs mild cognitive impairment, control vs Alzheimer, Alzheimer vs mild cognitive impairment).The severity score (level is either 1,2 or 3) of the neuropsychiatric symptoms was included as fixed factors, while MRI parameters (cortical volume, thickness and areas) were regarded as dependent variables.
Thus, these are two sets of results for group_x_var :
For reference : CN= Control group MCI= Mild cognitive impairment group AD: Alzheimer group NPIDSEV: Depression severity
Contrast
ClusterNo
Max
VtxMax
Size(mm^2)
TalX
TalY
TalZ
CWP
CWPLow
CWPHi
NVtxs
WghtVtx
Annot
Explanation
g2v1_CN_AD_NPIDSEV.area.lh.fwhm10_group-x-var_neg
is there a difference between the group VARiable slopes? contrast 0 0 1 -1. t-test with Group1>Group2 being positive. Note: this is an interaction between group and VARiable
1
-2.0763
158049
2847.57
-19.8
-63.8
12.5
0.0077
0.0066
0.0088
3957
-5537.87
cuneus
2
-2.4711
147091
2469.14
-35.3
-51.9
35
0.0205
0.0187
0.0223
5579
-7317.77
inferiorparietal
g2v1_AD_MCI_NPIDSEV.volume.rh.fwhm10_group-x-var_pos
is there a difference between the group VARiable slopes? contrast 0 0 1 -1. t-test with Group1>Group2 being positive. Note: this is an interaction between group and VARiable
1
2.2852
91120
1748.47
63.7
-39.7
-4.3
0.0054
0.0045
0.0063
3263
4658.91
middletemporal
We would like to have more information on the interpretation of these results. Specifically, we would like to know how to interpret the sign of the max coefficient in relation to the difference between the groups on the severity of depression/NPIDSEV and on the volume/area/thickness of the region of interest. Our interpretation for the first result for example was that the difference between the CN and MCI slopes is negative as depression severity increases, however this does not indicate the direction of the slopes regarding the area of the cuneus or the parietal inferior region. Is this correct?
Thank you very much for your help, Adriana Cannizzaro