Thanks for the answer. Suppose, I can similarity between two tasks a) only in specific region, but not other regions and b) do not get similarity in this region when I use some control task. Do you see a trivial, non-cognitive explanation to this?
Thanks for refs. So, you show that vision and action have similar neural representation. Representation is obviously the straightforward interpretation, whereas cognitive processing is a next step. In my case, I have also baseline because I check similarity between A > baseline1 is similar and B > baseline2. But conceptually, I think it is all the same. On Thu, Aug 20, 2015 at 2:18 PM, Nick Oosterhof < [email protected]> wrote: > > > 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
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