During body-scan ('sweeping') meditation, what does brain-imaging (e.g. fMRI) look like? I do not know how extensive body scans have been studied with brain-imaging techniques, e.g. fMRI.

Body scan is a meditation technique developed by Jon Kabat-Zinn. It was derived from a meditation practice ('sweeping') of the Burmese U Ba Khin tradition. 


  "It involves systematically sweeping through the body with the mind,
  bringing an affectionate, openhearted, interested attention to its
  various regions, customarily starting from the toes of the left foot
  and then moving through the entirety of the foot [...] From there, the
  focus moves into, successively, and slowly, the entirety of the pelvic
  region, including the buttocks and the genitals [...] and finally, to
  the face and head."
  
  "We are systematically and intentionally moving our attention through
  the body, attending to the various sensations in the different
  regions. That we can attend to these body sensations at all is quite
  remarkable. That we can do it at will, either impulsively or in a more
  disciplined systematic way, is even more so."
  
  "We might describe what we are doing during a body scan as tuning in
  or opening to those sensations, allowing ourselves to become aware of
  what is already unfolding."


I found it quite easy to practice and had interesting and unusual experiences (mostly pleasant).

My question is: Would any brain and brain-imaging expert - given this description - dare to guess roughly how a body scan may look like in a "brain scanner", e.g. recorded with fMRI?

I am not such an expert, nevertheless I dare to guess.

Presumably, a body scan will - mainly but not solely - take place in the areas of the cortical homunculus in the primary motor and sensory cortices.  

I would guess that it is here that most of body scan related neural activity will occur. But in which manner: how will activity evolve and literally move around, how will it look like in the "brain scanner"?

Five possibilities come to my mind:


Experts and laymen will see nothing but a generally increased, enigmatically billowing activity of the cortical homunculus.
An expert would see some significant patterns, but only vague and hard to communicate.
Even the layman could see something:


an overall increased activity of the cortical homunculus with somehow changing peaks of activity (highlights, representing the body region the attentional focus is currently on)
a mostly "dark" cortical homunculus with a wandering spotlight of activity 
a mostly dark cortical homunculus with a fading-in/fading-out spotlight every now and then



Which of these possibilities do you - as a brain and/or brain-imaging expert - consider the most probable one? Other possibilities are welcome!

And of course hints to studies where this question has been experimentally attacked.

(I found one study but didn't delve deeper into it: there are too few images in it.)
The Mind of the Meditator may be what you are looking for:
https://www.nature.com/scientificamerican/journal/v311/n5/full/scientificamerican1114-38.html

The image taken from the article gives some good explanation: