Ayahuasca is driven by sound, by song, by whistling. And its ability to transform sound, including vocal sound, into the visual spectrum indicates that some kind of information processing membrane or boundary is being overcome by the pharmacology of this stuff. And things normally experienced as acoustically experienced becomes visibly beheld, and it's quite spectacular.
Terence McKennaThe Truth doesn't need your cooperation to exist. All forms of cult, all forms of hype, all forms of delusion do require your participation in order to exist. I've looked into marginal areas of human experience -historical and otherwise- with a rational mind, and what I've found is that doorways into the miraculous are far fewer than the publicists of the New Age would have us believe. On the other hand, they are not as rare as the proponents of radical reductionism and materialism would have us believe. There are doorways out of the mundane.
Terence McKenna