Hello experts,
Could anyone explain how to interpret the results of mrclusterstats and vectorstats? How to get the numerical values in pvalues from output files. How could we visualize the outputs?
Thank you in advance.
Ram
Hi Ram,
Visualisation of the results of vectorstats would depend very much on the nature of the data that you provided to it. vectorstats treats it as structure-less data, and assumes there is no correlation between the inputs, so the fact that that command was utilized isn’t enough information for me to suggest anything fancy. All you can do is look at the raw text files output by the command. I assume of particular interest will be the file with the name “*_fwe_pvalue.csv”. Note however that this file contains the values (1-p); so any entry with a value of greater than 0.95 is significant at p<0.05.
For mrclusterstats, there’s a wide range of ways in which you could visualise the results. The simplest is to use the mrview Overlay tool, load the image “*fwe_pvalue.mif” within that tool, and apply a lower threshold of 0.95. The result of this is that the overlay image ("*fwe_pvalue.mif") will only be drawn for voxels where the value is 0.95 or greater; i.e. voxels significant at p<=0.05. From there you can play with opacity, colours, background image, whatever. The important thing to understand is that there isn’t a single button to click to “show my results”: you get to choose what input / output data from your statistical analysis are to be used to determine what visual features of the display.
Rob