[pymvpa] Interpreting representation similarity results

[Vadim Axel]

Hi,

Very simple question: to what extent representation similarity can be
interpreted as similarity of cognitive processing?

Consider a toy sample, where I have two experiments. In Exp.1 there is task
A and baseline1. In Exp.2 there there is task B  and baseline2. For
each experiment, I generate t-contrasts:  A > baseline1 and  B > baseline2.
To check for similarity between tasks A and B, I can run conjunction
analysis (spatial overlap). For stronger evidence, I can for each
experiment, extract t-values for some predefined ROIs. Then, I run Pearson
correlation across voxels within a ROI. Using across subjects statistics I
can show that in some ROIs the correlation between experiments is above 0.
Can this result be interpreted, as having similarity of cognitive
processing during two tasks?

Also, does someone know about papers that examined similarity between
experiments using a contrast (and not Haxby_2001_like_style of patterns of
single faces vs cats). In my case, Exps 1 and 2 have very different
designs, so A and B cannot be compared directly. In general, good
references for citing are highly appreciated.

Thanks a lot,
Vadim
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