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The Wisdom of Psychopaths
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Until recently, most scientists believed that neurons were the all-important brain cells controlling mental functions and that the surrounding glial cells were little more than neuron supporters and “glue.” Now research published in March in Cell reveals that astrocytes, a type of glia, have a principal role in working memory. And the scientists made the discovery by getting mice stoned.
Marijuana impairs working memory—the short-term memory we use to hold on to and process thoughts. Think of the classic stoner who, midsentence, forgets the point he was making. Although such stupor might give recreational users the giggles, people using the drug for medical reasons might prefer to maintain their cognitive capacity.
To study how marijuana impairs working memory, Giovanni Marsicano of the University of Bordeaux in France and his colleagues removed cannabinoid receptors—proteins that respond to marijuana's psychoactive ingredient THC—from neurons in mice. These mice, it turned out, were just as forgetful as regular mice when given THC: they were equally poor at memorizing the position of a hidden platform in a water pool. When the receptors were removed from astrocytes, however, the mice could find the platform just fine while on THC.
The results suggest that the role of glia in mental activity has been overlooked. Although research in recent years has revealed that glia are implicated in many unconscious processes and diseases [see “The Hidden Brain,” by R. Douglas Fields; Scientific American Mind, May/June 2011], this is one of the first studies to suggest that glia play a key role in conscious thought. “It's very likely that astrocytes have many more functions than we thought,” Marsicano says. “Certainly their role in cognition is now being revealed.”
Unlike THC's effect on memory, its pain-relieving property appears to work through neurons. In theory, therefore, it might be possible to design THC-type drugs that target neurons—but not glia—and offer pain relief without the forgetfulness.
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21 Comments
Add CommentThis is a potentially useful discovery - potentially leading to the manufacture of drugs that reduce pain without intoxicating the patient but, seriously, the 'forgetfulness' and related effects can also have important therapeutic value...
Reply | Report Abuse | Link to thisHowever, THC is not the same as marijuana, it's just one compound found in marijuana; there's hundreds. It is poor science to link a general use of a substance to a specific result using a single component of that substance. This report is *not* about marijuana, it's about a chemical also found in it that acts completely different in isolation than in concert with its other naturally occurring chemicals. Since marijuana is traditionally smoked to ingest the chemicals, I further suggest that this study had nothing to do with marijuana, as they most likely injected the mice with processed, liquid THC, nothing AT ALL like its natural presence in marijuana. It is simply FALSE and therefore reprehensible that SA would claim that marijuana had anything to do with this study, other than it is one of the natural occurring flora that also contains a somewhat similar drug - but again, what they used has nothing to do with "real" marijuana, so this is just bad reporting. Remember, folks, 99.9% of ALL Heroin users drink MILK! Let's synthesize milk and study its effects on the brain - no, because that would be as stupid as the article's title.
Reply | Report Abuse | Link to thisHello, jtdwyer. Remember the SA article on the brain rewiring that goes on in Arctic gray squirrels during their hibernation? Now we know how they retain their memories!
Reply | Report Abuse | Link to thisAgreed Promytius. This report is not accurate or relevant in any means. It's definitely not my favorite thing when reports like this mislead readers especially when some people don't actually try to find out the truth. But, take it easy. It is a report, not a scientific paper. It serves to catch people's eyes, it did the job pretty well I'd say. Wouldn't you?
Reply | Report Abuse | Link to thisHey Percival, Could you provide us the link to this study about arctic gray squirrels, please? It sounds intriguing. Thanks a lot!
Reply | Report Abuse | Link to thisHi jun1017WANG - It is interesting - I found it at
Reply | Report Abuse | Link to thishttp://www.scientificamerican.com/article.cfm?id=arctic-ground-squirrel-brain
Hi Percival - Human memory is not a recording device! A search for 'Arctic gray squirrels' came up empty, so I tried '... grey ...' & then just 'Arctic squirrels' to get a hit. It was 'Arctic ground squirrels! I don't think this sampling implies anything about chemical use - I take a lot of heart meds...
Whoa. How do you remove receptors from every neuron or astrocyte in the brains of live mice?
Reply | Report Abuse | Link to thisYou make a good point promytius, one shouldn't mistake a single chemical component, of a plant for instance, for the plant itself. However, in research, if I am researching the effects of marijuana (especially in animals), I would likely use THC to emulate its effects, as it is the main psychoactive ingredient of marijuana. Additionally, if I wanted to test you for marijuana use, I would test you for THC levels. So I feel as though it's erroneous to imply that the two are ENTIRELY different and unrelated (and I feel like it is a dangerous assumption for an individual with little understanding of marijuana and THC to adopt, which is why I'm making this post).
Reply | Report Abuse | Link to thisMarijuana is the vehicle used primarily for THC delivery - evidenced through the selective breeding of marijuana for high THC levels for its psychoactive properties.
Also, I feel that it is also false to claim that the article didn't make it clear that THC is a component of Marijuana.
Lastly, I feel like your analogy with Heroin and milk drinking isn't appropriate. If milk contained heroin, then it would be a better analogy. As it stands, milk and heroin are entirely unrelated (i.e., drinking of milk offers no information about heroin use that can be used to make predictions), whereas marijuana and THC are not unrelated. Studying marijuana in order to understand THC or vice versa is of predictive value and thus an idea of merit.
You guys are way off. Tabs of THC was about the best and cleanest of the pot super-highs, outdoing Thai-sticks or nepalese templeballs ... so I've heard.
Reply | Report Abuse | Link to thisOne can use conditional knockout (e.g. cre-loxP system) to do that like in this study.
Reply | Report Abuse | Link to thisThat classic stoner thing is a typical, stale exaggeration though; for someone who uses pot everyday, all day, to forget something mid sentence would be strange. It is with those less familiar with cannabis that we have these forgetting spells. Anyway, poor mice.
Reply | Report Abuse | Link to thisAnd that forgetfulness can be useful in treating PTSD; experienced users don't actually forget things mid sentence, but they do have an increased ability to get over bad events & move on to the next thing with a positive attitude.
Reply | Report Abuse | Link to thisExcellent, a logical reply to a very bad argument.
Reply | Report Abuse | Link to thisAccording to wisegeek.com, milk has casomorphins "which fail to break down completely, may have an effect on the body similar to that of morphine or other opiates."
Reply | Report Abuse | Link to thisUhmm.. I was going to make a very pithy remark here,
Reply | Report Abuse | Link to thisI think, but I sort of forget what, ummm, I'm
doing on this website. Ummmm... bye.
I think you're missing the point of the article, it's not about the effects of THC or marijuana on memory, but rather about the possible role of glial cells in working memory, THC just happens to be the substance used to understand the process.
Reply | Report Abuse | Link to thisVery interesting article. I have to recommend a book by Steven Romer (2003) that gives a comprehensive, multifaceted theory of how glial cells are responsible for consciousness and even memory (as the solution to the retrograde-messenger problem, etc.). Ever since I read that book, all I see are studies directly confirming the models he puts forth in that book having to do with how the brain reflects reality. I have to mention it, because I was so skeptical before I read that book. One thing that struck me is how he said that evolution did not equip us to look at and understand brain matter, and that there are some strange things going on we can see only indirectly through experiments such as this one. One of these is that our time sense is based on neurons and that the glial cells do not have this feature. Anyway, just thought I would mention that and see if anyone else had read it?
Reply | Report Abuse | Link to thisGiovanni Marsicano has done a lot of great studies on CB1 etc but when searching for the effects on memory in FSTs, I didn't find exactly what you are saying he found. I really don't understand why, in this day in age that a scientific publication can't just CITE SOURCES. I don't know now if it's my failed search or your misinterpretation ...and as a scientist, that doubt means this article is currently unreliable information for me. You'll have to excuse me for doubting, but the scientific community has become a little too faith-based in recent years for my liking...
Reply | Report Abuse | Link to thisThere is another interesting aspect to the problem: "stoned memory space". That is, there seemed to be this phenomenon that what you learned straight, you could remember when straight. What you learned while stoned was forgotten when you got straight. But it was there when you got stoned again. Many musicians had trouble playing straight because they couldn't remember all of the practicing and riffs that they learned while stoned.
Reply | Report Abuse | Link to thisAlthough they are a little off on the number involved, I have to agree with the post above where the writer refers to the comparison of THC to marijuana. THC is one of 6 major psycho-active cannabinoids found in the plant. There are 33 altogether (27 are precursors or break-down by-products of those 6). The process by which the drug was administered to the mice and the dosage used probably bears no resemblance to any naturally occurring consumption.
Reply | Report Abuse | Link to thisHowever; the basic biochemical reactions discovered between glia and THC are still valid findings and open the door to much more research. Obviously we still have much to learn about the relationships between glial cells, neurons, their respective functionality and interaction. Already, they have unwittingly uncovered why the memory phenomenon, with chronic marijuana use, seems to be completely reversible (experientially anyway).
It would be interesting to track the population and activity level of glia at different dosages/blood levels. I would love to see such a study conducted long-term across varied daily consumption amounts and after cessation.
10000+ years of documented human consumption pretty well establishes that there are no real harmful effects from using marijuana. It would be nice to see some real research aimed at uncovering its biochemical effects using humans, normal consumption routes and dosages.
Most research to date involves introducing massive amounts of the single compound THC to mice and monkeys. Further, this research is skewed by the abnormal routes of administration. Fear and stress have dramatic effects on cognition. These effects derive from chemical activity in the brain also (probably involving the same glial/neuronal mechanisms).
The current state-of-the-art in MRI technology should make it possible to study human subjects. Differentially labeled neurons and glia along with labeled cannabinoids (preferably all 6) could be visualized in vivo.
http://www.sciencedirect.com/science/article/pii/S0092867412001420
Reply | Report Abuse | Link to thisIf you're interested in reading the actual article do so before you comment. As far as I can tell the article, though not particularly well written or scientifically informative, did indeed have the correct results conveyed.