Numerous studies have found that 5-HT2A receptors are localized on cortical pyramidal cells. This is supported by electrophysiological data that suggests hallucinogens have excitatory effects on neurons in the neocortex (Nichols, 2004). The thalamus is probably the second most important site of action for hallucinogens. In rat brains significant levels of 5-HT2A are concentrated in parts of the thalamus. The thalamus, along with the amygdala, represent the major source of glutamate afferents within the neocortex. It processes somatosensory
inputs and receives afferents from the raphe nuclei and the locus coeruleus (Nichols, 2004).

the LC is often referred to as the "novelty detector" for salient external stimuli. One would predict that sensory events that may not ordinarily seem remarkable may be perceived as having "increased novelty". This is indeed one of the effects commonly reported by
users of hallucinogens (Nichols, 2004).
http://www.123helpme.com/view.asp?id=33297

Though think about this, as your thalamus filtering mechanism is "switched off", and as serotonin temporarily looses its rather repressive control over the conscious state, you would technically be far more receptive to novel information from the outside...like I said, you are bombarded with billions of signals, billions of kinds of them as well, every second, now all of these, except for smell, enter your brain through the thalamus, which filters them before they are sent to the cortex regions, on psychedelics the thalamus eases up on its filtering, so I suppose you are getting information from the outside that you would not otherwise.

I also feel that in accordance with The many-worlds interpretation of quantum mechanics that there could be infinite alternate "lines"...





Multiverse theory also makes some interesting claims...

Perhaps we do encounter entities from these other dimensions, perhaps when the conscious-being leaves it's physical body it's migrates into one of these other dimentions... it appears that physical objects can not cross the barrier, but consciousness and information can, and all consciousness traversing these dimensions are apparently using the same "highways" so extra-terrestrials, dead people, Gods and deities, and conscious-beings from other dimensional plains may all collide in these spaces...
-eg

In sheer numbers, these microbes and their genes dwarf us. It turns out that we are only 10 percent human: for every human cell that is intrinsic to our body, there are about 10 resident microbes — including commensals (generally harmless freeloaders) and mutualists (favor traders) and, in only a tiny number of cases, pathogens. To the extent that we are bearers of genetic information, more than 99 percent of it is microbial. And it appears increasingly likely that this “second genome,” as it is sometimes called, exerts an influence on our health as great and possibly even greater than the genes we inherit from our parents. But while your inherited genes are more or less fixed, it may be possible to reshape, even cultivate, your second genome.