Dear MRtrix devs and community, I see that the -negative option has been eliminated in the latest version of mrclusterstats. Out of curiosity - what gives? Has this been implemented in an alternative framework, or is the intention that users will specify and run these contrasts separately? If the latter, I would kindly request it be included in future releases.
All stats commands used to support only a single contrast (single line in the contrast file), but there was the option to also test the negative contrast.
As the stats commands now support contrast files with multiple lines, the user can now add multiple contrasts, including a negative contrast, so the negative option is no longer necessary.
The best I can offer is the changelog (“Major software changes” → “Statistical inference” → “Multiple hypotheses”), which admittedly failed to explicitly state that the -negative command-line option was correspondingly removed (now added).