The similarities between the psychedelic effects of psilocybin and the reported sensations and fMRI data are well documented. But as far as I know, this is the first study where psilocybin has been given to experienced Zen meditators. There’s a rather gentle film about is called ‘Descending the Mountain’ (I watched it on Prime) with not too much scientific information (not enough), it’s worth a look at. The conclusion is that experienced meditators don’t seen to experience the potentially negative effects of psychedelic substances (quite the opposite in fact) and it appears to deepen the experience of meditation.