What is/are the cause/s of becoming "perceiveless", an unconsciouse-being?

Althought as most not desired existence sometimes quoted, there seems to be less information about the cause why one gains the existence of an "not-perceiving-being", Unconscious beings (asaññasatta). [explained as "only body 'no' mind" often] What is the cause, what is the required tendency to gain a asaññasatta-existence, state? Which kind of training should one go after to gain this long lasting state (which causes one to become a "fortuitous-arising-ists" ([DN1](http://zugangzureinsicht.org/html/tipitaka/dn/dn.01.0.than_en.html)) , or a materialist, when falling from there) Maybe some experts or googlyanika (those living dependency of teacher google) here are willing to elaborate about the being and coming into being of such beings. *(Note: this is not given for trade, exchange, stacks or entertaining, but as a tiny emergency-question for a timely exit from this wheel nourishing on delusion)*