> On 20 Aug 2015, at 10:59, Vadim Axel <[email protected]> wrote: > > 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?
It would indicate that *something* is similar (at a pattern level) between the two tasks. You may possibly interpret this as cognitive processing, but cognitive processing is a rather broad concept. Pattern similarity can arise through a variety of different mechanisms, including trivial ones. > 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. This may be considered as shameless self-promotion, but I have done some work on executing versus observing different manual actions [1], and imagery and execution/observation of such actions [2]. [1] Oosterhof, N. N., Wiggett, A. J., Diedrichsen, J., tipper, S. P. & Downing, P. E. Surface-based information mapping reveals crossmodal vision-action representations in human parietal and occipitotemporal cortex. J. Neurophysiol. 104, 1077–1089 (2010). [2] Oosterhof, N. N., Tipper, S. P. & Downing, P. E. Visuo-motor imagery of specific manual actions: A multi-variate pattern analysis fMRI study. Neuroimage 63, 262–271 (2012). _______________________________________________ Pkg-ExpPsy-PyMVPA mailing list [email protected] http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-exppsy-pymvpa
