• Booze, Weed and the Human Brain

    A study by Rachel Thayer and colleagues from the Universities of Boulder, Colorado and Portland, Oregon, published recently in the journal Addiction revealed some fascinating differences between the impact of recreational alcohol and cannabis use on the structure of the human brain.

    It was known from previous research that the more alcohol an adult regularly drinks the greater the degree of shrinkage of the brain’s grey matter. The grey matter is the folded outer surface of the brain that makes it look a bit like a walnut. This is where neurons interface with each other by means of synaptic connections at which one neuron can exert an influence on another. It is the networks of neurons bringing information together within the grey matter that allows computations to be performed so that we can perceive the world via the senses, feel emotions based on our interactions with other people and execute purposeful behaviours like decision making, problem solving and voluntary movements. So, as a rule of thumb, the lower the volume of space occupied by a person’s grey matter, the greater the reduction in computational power.

    This new study looked at not just the link between boozing and grey matter but also investigated whether it had any impact on the white matter too. White matter is the neuronal cabling along which electrical messages are ferried to and from different patches of grey matter in different parts of the brain’s cortex. Grey matter in the occipital lobe at the back of the brain, which crunches sensory information coming in through our eyes, can send messages to the prefrontal cortex via white matter pathways, and vice versa. Grey matter in the left side of the brain can send information to and receive information from right hemisphere cortical areas via white matter connections that run through the corpus callosum (this is a thick bundle of white matter connecting the left and right halves of the brain).

    These white matter pathways contain the neuronal axons, which is the cabling through which electrical pulses (called action potentials) are passed between neurons. These axons are wrapped in electrically insulating myelin fibre which speeds up the transmission of action potentials. Damage to this insulating layer can be detected with a certain type of MRI scan and is formally described as ‘reduced white matter integrity’. Thayer and colleagues’ findings showed that the more alcohol people routinely drank the greater the impact on grey and white matter. High alcohol consumption is associated with reduced grey matter volume AND white matter integrity.

    That’s not all. They also looked at the differences between adult brains (20-55 years old) and adolescent brains (14-19). While high alcohol intake way associated with reduced grey matter volume in the adolescent brains, they didn’t find any evidence of reductions in white matter integrity. Presumably if those teens carried on their high alcohol intake, they would end up damaging their white matter like their older counterparts.

    Perhaps the most surprising thing about this study is that, across over 400 teens and more than 800 adults, they found no evidence of any link between the amount of cannabis consumed in the 30 days prior to brain scanning and the grey matter volume or white matter integrity. This suggests that despite alcohol being legal in the UK and cannabis being illegal, from the perspective of the impact of these commonly used recreational drugs on two different important aspects of brain structure, the relevant laws may well be working in direct opposition to the degree of harm caused, both to the individual and society as a whole.

    If you enjoy these blogs then you’ll love my 2 series of Secrets of the Brain in Ultra High Definition (www.insight.tv / Sky Channel 564). This story was covered on episode 90 of my fortnightly Geek Chic’s Weird Science podcast available on iTunes, Acast, Libsyn and Podbay. I dig around on the internet on a daily basis for articles on the very latest breakthroughs in neuroscience research and, when I find something interesting, well-written and relevant, I post it on Twitter (@drjacklewis). Most excitingly of all, from the 12th July 2018, my new book – The Science of Sin: Why We Do The Things We Know We Shouldn’t – will be available in all good bookshops.

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  • Review: High Society at the Wellcome Trust Collection by Dr Jack Lewis

    Henry Solomon Wellcome was well ahead of the game when it came to the “Mo-vember” look for a charitable soul

    With just one week to go before it closes (Sun 27th Feb 2011) I visited the “High Society” exhibition at the Wellcome Collection in London yesterday so that I could review it here in case you were curious.

    I would like to state for the record that I LOVE THE WELLCOME TRUST and would rate Henry Wellcome in my top 5 heroes of all time. His enormously generous philanthropic endowment has turned into a fantastic instution built on sound priniciples that have withstood the tests of time.

    Not only does the WT fund an enormous amount of British scientific research (my PhD included – during which my scientific approach was gradually sculpted under the influence of many extraordinary neuroscientists; most of whom were also Wellcome Trust funded), but it also takes it’s role in public engagement with science, a subject very close to my heart, extremely seriously.

    This commitment to spreading the good word of scientific innovation old and new is, I believe, deliciously exemplified by the special exhibitions that rotate through their space on the Euston Road a few times per year to showcase an interesting area of scientific enquiry. These exhibitions beautifully complement the tone set by the permanent collection upstairs: ancient medical tools, scientific relics and other treasures from the history of medicine; not to mention some outstanding fashion photography modelled by good old Henry himself.

    In late 2010/early 2011 the show space addressed the issue of mind-altering substances. From the outset the visitor couldn’t help but be impressed upon that these chemicals have been popping up throughout history everywhere, for millenia. Drugs of various description have been consumed in one form or another across ALL cultures of the world. And the vehicle for explaining this was a lovely collection of drug paraphernalia from all over the globe and a whole bunch of amazing facts about the drug trade both medical, illicit and sometimes both.

    Psilocybin is a hallucinogenic substance found in certain species of mushrooms

    The free exhibition included a 6th century BC embossed tablets from the Middle East describing some of the medical uses of Cannabis sativa, ornately decorated tobacco pipes, ancient betel nut cutters, indian and chinese opium pipes right up to the modern day DIY crackpipe (comprising a small water bottle, a biro casing and some perforated tin foil).

    These drug taking curiosities, collected from all corners of the earth, may well have encouraged spectators to consider why human beings everywhere are so keen to experiment with mind-stimulating (or mind-depressing) substances in spite of the potential dangers, for instance, picking the wrong mushroom and popping your clogs.

    People expecting an exhilarating experience may have been disappointed. I personally believe it is always important to arrive at an event free of the burden of overly-high expectations. And it worked just fine for me as there were some real treasures within.

    Shockingly heroin was once sold by Bayer pharmaceuticals as an everyday medicine

    Highlights for me included some of the black and white footage documenting Andean Indians drinking the potently hallucinogenic ayahuasca extract (which immediately makes a person vomit and is deemed to be a good thing… helping to purify body and soul prior to entry into the “other” world) provided a fanastic account of how, why and where these indigenous tribespeople enter into this ritual.

    Also the footage of a 1950’s experiment in which a “terribly posh” doctor tests a volunteer before and after consumption of the hallucinogenic drug mescaline. I thought it was very amusing that he was considerably better at counting down from 100 to zero in blocks of 7 (i.e. 100, 93, 86, 79 etc) when he was tripping compared to before he had taken any drug. Also amusing (to me at least) was the way he answered all questions from the battery of cognitive tests directly in a very authoritative manner, yet failed absolutely to find suitable words to describe the gorgous array colours that were hallucinogenically tinting his vision and no doubt also inducing his huge grin.

    Scandalous: when our plentiful supplies of silver and gold were no longer worth what they were the British Empire got China hooked on opium so that we could trade that instead!

    It was also very interesting to get an insight into some of the details of the Opium Wars in which the British used Afghani opium to get the whole of East Asia hooked on smack as a solution to plummeting gold and silver prices leaving them with no barganing chips with which to trade. An absolute scandal of which I had no prior knowledge. There was also an ingenious installation involving various projectors and light filters beaming amorphous colours and shapes onto a large screen that I could have watched for hours – very relaxing.

    The sillhouettes are spectators standing in front of the projectors, not part of the trippy art installation – or are they?

    And on the way out I found the large graphical representations of the relative yearly global turnover elicited from trading legal versus illegal drugs of recreation very interesting – as the relative size of the cannabis versus cocaine versus opiate markets are not as you might expect, particularly when compared to the computer game or pornography markets. Another large graph that effortlessly conveyed a lot of information in a very straightforward, user-friendly manner depicted the gradually declining purity and increasing costs of cocaine as goes from being picked and processed at source, moved from Andean regions to the Carribean, imported into the UK and then sold to the end consumer. It seems that the biggest jump in the cost per kilo occurs, not surprisingly if you think about it, when it enters the country in which it is to be sold, the suprise comes when it is revealed that the hike in cost from before to after is a whopping 600%.

    This ball of opium is the size of my fist!!

    In conclusion it was an eye-opening and fascinating excursion into the world of illicit drugs through the ages showing how our interest in them across all cultures has always been there and will probably always remain.

    Remember you can follow Dr Jack to catch his daily #braintweets.

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