I had just been thinking about this question and came across a sentence in a novel by my favorite SF author, John Brunner, titled The Stone that Never Came Down. He wrote that hallucinogens “destroy perceptual sets and make things we’ve seen a thousand times fresh and novel.” What is the science on this?
Well, see, it’s like this. Neurologists have discovered that there are receptors in the human brain that seem specifically adapted to accept THC, which suggests…
Ooo, Funyuns!
…What were we talking about again?
Mmmmmmm Funyuns.
http://www.geocities.com/hollywood/set/2403/bigjimpic.jpg
Biopsychiatry.com will give you hours and hours of reading fun of this matter. It’s a refreshing change from most medical writing on psychoactive agents, anyway … I like their take that it’s ok for an antidepressant to be fun.
To respond to the question, I doubt THC and LSD and other “destroy” perceptual sets, whatever that means, although they do radically change your perceptions and thought patterns while you’re under their effects. So does alcohol, for that matter.
Here’s a sample from Biopsychiatry:
The effects of cannabinoids on the brain
by Ameri A
Pharmacol Biochem Behav 1999 Oct; 64(2):257-60
ABSTRACT
Cannabinoids have a long history of consumption for recreational and medical reasons. The primary active constituent of the hemp plant Cannabis sativa is delta9-tetrahydrocannabinol (delta9-THC). In humans, psychoactive cannabinoids produce euphoria, enhancement of sensory perception, tachycardia, antinociception, difficulties in concentration and impairment of memory.
…
The acute effects of cannabinoids as well as the development of tolerance are mediated by G protein-coupled cannabinoid receptors. The CB1 receptor and its splice variant CB1A, are found predominantly in the brain with highest densities in the hippocampus, cerebellum and striatum. … The discovery of endogenous cannabinoid receptor ligands, anandamide (N-arachidonylethanolamine) and 2-arachidonylglycerol made the notion of a central cannabinoid neuromodulatory system plausible. Anandamide is released from neurons upon depolarization through a mechanism that requires calcium-dependent cleavage from a phospholipid precursor in neuronal membranes. The release of anandamide is followed by rapid uptake into the plasma and hydrolysis by fatty-acid amidohydrolase. The psychoactive cannabinoids increase the activity of dopaminergic neurons in the ventral tegmental area-mesolimbic pathway. Since these dopaminergic circuits are known to play a pivotal role in mediating the reinforcing (rewarding) effects of the most drugs of abuse, the enhanced dopaminergic drive elicited by the cannabinoids is thought to underlie the reinforcing and abuse properties of marijuana. Thus, cannabinoids share a final common neuronal action with other major drugs of abuse such as morphine, ethanol and nicotine in producing facilitation of the mesolimbic dopamine system.
The above paragraph is best enjoyed while consuming Funyuns.
Different neural activity is elicited by the same stimuli since the drugs significantly alter the brain ‘setting’, by modulating activity throughout the cortex. If same stimuli leads to same physical brain state which leads to same mental state, then same stimuli --(drugs)-> different physical brain state → different mental state a.k.a. novelty.
Our brains come with cannabinoid receptors. In other words, our brains are structured specifically to allow them to get high on pot. Anandamine is also present in chocolate.
Dark chocolate almond biscotti for me.
No, our brains are structured specifically to allow messages to be transmitted by means of neurotransmitters. Our endocannabinoid receptors exist so the brain can regulate its function with endocannabinoids, and it happens that cannabis contains a chemical that can activate the same pathways, just as Papaver somniferum contains chemicals that activate our endorphin receptors. That doesn’t mean we’re designed to be able to use plants to get high - it just sorta happened that way.
Has anandamine actually been shown to have any particular effect when eaten? If it has, I seem to be a bit behind the times.
It’s not known why the brain acquired a cannabinoid pathway. Coincidental co-evolution or perhaps adaptation.
Morphine & codeine are endogenous as well.
Yeah, is the matchup purely an accident? Please show how the concept of coevolution explains it. Or do I have to get Stewart Brand in here?
THC, for whatever neurochemical reason, increases activity in the amygdala, the part of the brain associated with judging the “significance” of sensory input (or of “thoughts”, ie. combinations of memories of sensory input). What would normally be mundane thus yields a bigger “significance hit” due to the lowered threshold required to trigger activity.