I thought I might use this space to do some preliminary exploration of concepts that I find interesting and related to all drug-modified sensory and perception. If I find that I've enough to say on any of these topics, I'll go ahead and thread-up. Yes, basically mental masturbation.
1. How awareness seems to work: sensory prediction
Despite a little over a half-century of dedicated research, consciousness and awareness remain somewhat nebulous concepts. When stated in conversation, we all know what's being referred to; we all accept that every healthy human, when conscious, is accurately aware of its surroundings. Despite such central roles played in our day-to-day lives, neither are intuitive in the least - and have required a bevy of clever tricks to slowly develop a fundamental understanding of what's meant by the word awareness.
Among the various exercises used to probe the characteristics of awareness, there are a few that I find particularly neat. Think: were you just aware of the sensations generated by the chair you're sitting upon, your feet on the ground, or the sound of your air conditioner and/or refrigerator whirring? While there are a handful of cognitive disorders that render individuals constantly distracted by, and painfully aware of, such sensory input - the majority of humans give little-to-no thought to such stimulation. In fact, it'd be disadvantageous to do so. This is because such stimulation is quickly integrated into what you expect to sense given past experiences - and take for granted as fundamental characteristics of a given environment. This system applies to every single sensory system - and extends even to our perceptions of the passage of time.
Thus, we're constantly comparing sensory inputs to our own, internally-generated, sensory predictions. Given that, it seems awareness of your surroundings occurs predominantly when sensory inputs are incongruent with those your brain has learned to predict. In other words, you become aware of features of your environment when they puncture your internal model of your surroundings. Is it too quiet - perhaps your air-conditioner/refrigerator is broken? Are you currently thinking about how many humans are outside your home? Would you if you suddenly heard the sounds of a riotous crowd just outside your door?
I would argue that many drugs distort this experience- and pattern-based sensory prediction system that guides awareness. It's unfortunate that researchers of consciousness have been bridled by drug-laws, as the experiences they generate almost certainly offer unique insights into how the cogs in this system interact. Consider an individual in the throes of a profound stimulant addiction. Such individuals tend to be overly-paranoid, and will perceive inappropriate patterns in their environments; uniformed men staking-out their home, conspiracy theories, hypochonriasis, etc. are all symptoms of this dysfunctional sensitivity to environmental stimuli. Another way to state this, in the context of this short snippet: such individuals' system of prediction is simply inaccurate, and awareness is incapable of deciphering discrepancies between what's predicted and what's occurring. Effects of stimulants are, of course, just one example of this system modified.
2. What's the difference between waking-consciousness and sleeping-consciousness? sensory anchoring & weighting
Anyone familiar with research of brain activity during sleep knows that such activity during dream-sleep strongly resembles waking-brain activity. How is this possible, and why can't we, therefore, live in a dream?
The answer is, some individuals DO have trouble distinguishing between dream and waking realities. This is due to the fact that awareness is modulated by the quality of sensory inputs - and in some cases, this system is dysfunctional; data coming in from our sensory systems 'anchors' perception. Intact visual systems prevent the majority of us from believing there are things present that aren't actually there - prevent delusions from guiding behavior.
Can you tickle yourself? - and I mean really give yourself uncontrollable fits of giggles and spasms? For the majority of us, the answer is no. When someone else is doing the tickling, however, we tend to experience silly sensations along a spectrum of severity - occasionally being so severe as to induce powerfully negative emotional responses. Something quite interesting concerning some schizophrenic patients, however, is that many ARE capable of tickling themselves. Research suggests a distortion in such individuals' integration of their own motor activity and resulting sensory activity - their brains' prediction system, anchored by their own motor activity - causes them to respond similarly to how a non-schizophrenic individual would to someone else tickling them. They respond like you'd respond to someone else surprising you with a tickle fit.
So, in other words, your awareness is anchored by what your senses tell you is occurring. Some find it surprising that about 1/3 of our brains are dedicated to vision alone. While you're sleeping, your eyes aren't notifying you that you aren't soaring through distant nebulae or dancing in a lush masquerade ball - so such experiences become tangibly real and immersive; they become believable, as the rest of your brain is un-anchored and free to run wild.
Vision isn't a simple system. Take the case of an individual born with sight, rendered blind by a chemical explosion - who endured blindness throughout adolescence and adulthood for 43 years, attaining considerable success in business and downhill speed-skiing. He learned to adapt to the absence of sight. After these 43 years, however - he underwent a new surgical procedure that promised to restore his vision. The day the bandages were removed, everyone was baffled; he indeed had visual experiences, but they were completely alien and utterly incongruent with those he'd once known as a child, prior to his injury. After weeks and weeks of recovery, his brain slowly re-learned how to integrate the stimuli from his eyes to the rest of his sensory experience - and now enjoys completely functional sight. In other words, by comparing visual stimulation with tactile, motor, and auditory experiences - the brain was able to appropriately weigh visual stimulation to decipher an accurate depiction of events. All this to say: vision is a profoundly complex process, and the brain performs a feat of computation to render visual stimuli useful and not overwhelming.
Psychedelics, dissociatives, and deliriants are prized for their unique cognitive and sensory effects - and for many, their visual effects are their most attractive. We're capable of literally seeing in completely new ways under the influence of such compounds, becoming sensitive to nuances we never before considered - as well as observing the effects of various facets of visual experiences functioning in distorted ways. Sensations of floating or flying tied to transient absence of depth perception induced by Salvinorin A, dancing shadows-turned to interact-able humanoids induced by diphenhydramine, and awareness of molecular similarity & unity with all matter in the universe triggered by breathing and melting walls induced by LSD and psilocin are all examples of such vision-based changes in cognition. I would argue that, largely due to this modification of our visual experience, cognition is permitted to get a little more creative with conceptual association; our brains aren't anchored by visual experiences in the same way under the influence of psychedelics as sober, permitting us to experience and learn about the universe in novel and unique ways.