I didn't get a chance to read the full paper, so this may be covered, but do they account that the causality may be reversed? Meaning that instead of nasal bre

I didn't get a chance to read the full paper, so this may be covered, but do they account that the causality may be reversed? Meaning that instead of nasal breathing causing more brain activity, instead the subjects had to concentrate more on consciously breathing through their nose and the activity is due to that? I.e., the brain activity is actually "causing" the nasal breathing?