Dear Alfonso,

I am currently finalizing the results for my PhD thesis, so I would be extremely grateful if you could help clarify this point.

I am running a seed-to-voxel paired analysis comparing V1 vs V3, with age and sex included as second-level covariates.

For three significant clusters, I opened the REX Results window, then the plot window and exported both:

• Export raw data


• Export effect sizes

From the exported rawdata.mat file, I obtained a 46 × 3 matrix (23 subjects × 2 conditions, 3 significant clusters). The first 23 rows correspond to V1 and the last 23 rows correspond to V3.

For the first cluster, the average raw connectivity values are:

• V1: 0.1904


• V3: 0.1802

Thus, the raw functional connectivity appears to decrease slightly from V1 to V3.

However, the exported effectsize.mat file contains:

effectsize.data =



          Cluster1   Cluster2   Cluster3

V1        -0.1256    -0.1184     0.1258

V3         0.6076     0.6259     0.7745

For the same cluster, the "Display effects" plot therefore shows a large increase from V1 to V3, which seems inconsistent with the raw connectivity values.

My question is:

What exactly do the two bars in the "Display effects" plot represent?

I initially thought that the bars represented the average functional connectivity for each condition, but the exported raw data suggest that this is not the case.

Thank you very much for your time !

Best regards,

Adele