Basically, it compares arousal based practices (Tummo and Yidam) with mindfulness based practices (Sutra mahamudra). What's nice is that Geoffrey Samuel (one of the top 10 buddhologists worldwide) has helped in designing and conducting this study. Apparently more top grade study of this kind are coming ! 

Thanks for sharing. Very cool this was done with Bhutanese meditators. The decrease in gamma power during NDA is interesting and sort of goes against some other findings. I wonder what the takeaway is besides arousal and non-arousal based meditation techniques do different things to the attentional control, which I think has been well-established based on previous research. I do think it's important to develop the taxonomy. There's been a lot of effort to classify different mindfulness-based, Theravadan practices, but perhaps not as many studies looking at Tantric and awareness-based practices. I'll have to read this a bit closer and see what to make of it.

Thanks for posting this, very interesting.

It's very obvious phenomenologically that there's huge differences between all these practices.  The taxonomy of arousal is useful imo and gives us different ways to describe practices other than concentration or insight.  I'd love to read a less technical discussion about how to interpret the quantitative data.