The Wikipedia page that was referenced to you contains, at the bottom, precisely what you are looking for: a list of non-wikipedia, academic references, on cannabis usage for meditation purposes.
Such as:
"The earliest known reports regarding the sacred status of cannabis in India and Nepal come from the Atharva Veda estimated to have been written sometime around 2000 - 1400 BC,[1] which mentions cannabis as one of the "five sacred plants".[2]"
"scholars associated Chinese wu (shamans) with the entheogenic use of cannabis in Central Asian shamanism.[11]"
Where [1], [2] and [11] are:
[1] Courtwright, David (2001). Forces of Habit: Drugs and the Making of the Modern World. Harvard Univ. Press. p. 39. ISBN 0-674-00458-2.
[2] Touw, Mia. "The religious and medicinal uses of Cannabis in China, India and Tibet". J Psychoactive Drugs 13 (1).
[11] "Before the Christian Era" from Zuardi AW (June 2006). "History of cannabis as a medicine: a review". Rev. Bras. Psiquiatr. vol.28 no.2 São Paulo. Retrieved 2009-12-10.
And in China:
[13] Compare "if taken in excess will produce visions of devils … over a long term, it makes one communicate with spirits and lightens one's body", Li Hui-Lin (1978). "Hallucinogenic plants in Chinese herbals". J Psychedelic Drugs 10 (1): 17–26.
I have no personal opinion on the topic, I am not an history scholar or a meditator, but those references certainly indicate a use of cannabis for meditation purposes, at least certains forms of meditation. Don't you agree?
Neuro
