I do MRI work, and my gut is that none of the claims about dance vs. exercise would replicate. The behavioral data suggests that activity of some type will improve cognitive function (main effects of time). Such beneficial effects of activity on the brain have been shown before, and this is generally accepted. However, the authors' behavioral data doesn't show any difference between the dance vs. exercise groups. This means that the study is overall off to a pretty bad start if their goal is to study dance vs. exercise differences...
The brain data claims to show that the dance vs. exercise groups showed different levels of improvement in various regions. However, the brain effects are tiny and are probably just random noise (I'm referring to those red spots, which are very small and almost certainly don't reflect proper correction for multiple hypotheses given that the authors effectively tested 1000s or 10000s of different areas). The authors' claims about BDNF are supported by a p-value of p = .046, and having main conclusions hinge on p-values of p > .01 usually means the conclusions are rubbish.
In general, my priors on "we can detect subtle changes in brain matter over a 6-week period" are also very low. Perhaps, a study with this sample size could show that activity of some kind influences the brain over such a short length, but I am extremely skeptical that this type of study could detect differences between dance vs. exercise effects.
The brain data claims to show that the dance vs. exercise groups showed different levels of improvement in various regions. However, the brain effects are tiny and are probably just random noise (I'm referring to those red spots, which are very small and almost certainly don't reflect proper correction for multiple hypotheses given that the authors effectively tested 1000s or 10000s of different areas). The authors' claims about BDNF are supported by a p-value of p = .046, and having main conclusions hinge on p-values of p > .01 usually means the conclusions are rubbish.
In general, my priors on "we can detect subtle changes in brain matter over a 6-week period" are also very low. Perhaps, a study with this sample size could show that activity of some kind influences the brain over such a short length, but I am extremely skeptical that this type of study could detect differences between dance vs. exercise effects.