Hi John,
Both images are informative (colored by significance or
by correlation magnitude), but showing both may not be
good use of publication space. So authors choose what
they want to focus on.
The significance map makes the details of significance
much more clear, which may be desirable. When perusing
someone else's results, the significance maps are what
I first look at.
However in publication, magnitude images seem to be more
efficient, since the images already show significance to
a degree, based on thresholding. And one would expect
reviewers and readers to want details of the correlation
magnitudes anyway.
But there is no rule.
- rick