Wednesday, March 22, 2023
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Teaching an Old Dog New Tricks

Cannabis and Dementia


If you ask some advocates about the benefits of smoking marijuana, they’ll give you an unbelievable list of diseases and health problems that it can supposedly cure. These can range from the fantastic to the banal, and many of the effects seem based on speculation and anecdote. So you can be forgiven if you chose to roll your eyes when you heard someone say that weed can make you smarter and even stave off brain malfunction associated with old age. It was clearly stoner talk. We all know smoking reefer makes you dopey and destroys your memory, right?

(Here comes that “actually” …)

Actually, while cannabis is known to inhibit short-term memory, the effect is only temporary and doesn’t block recall of long-term memories. And new research is suggesting that smoking cannabis can potentially delay the negative cognitive effects of aging. Researchers say it does this by preserving neuroplasticity—the brain’s ability to learn new things.


Learning a new skill seems to just happen on its own, but a whole slew of operations are happening behind the scenes. Neuroplasticity is the term given for the brain’s ability to adapt to new situations. We use our neuroplasticity every day when we talk to new people, learn a new skill or interact with any other novel situation. It’s the mechanism behind learning—and without it, we’d be like the proverbial goldfish.

It used to be believed that the brain stopped adapting sometime in childhood, and people were stuck with the personalities and limitations of their youth. In recent years, however, this has been shown to be completely false. Young brains appear to have the most neuroplasticity of all, and the ability diminishes with age. Nevertheless, our brains will continue to change and adjust throughout our lives.

Imagine that your brain is a set of nodes connected by pathways. These pathways are shallow and undefined, but each time we travel along one, it gets a little more defined and becomes easier to traverse. By traveling the path over and over, we create a groove that becomes easier and easier to fall into.

Developing habits happens in a very similar way. When we repeat the same behaviors, we reinforce the synaptic pathways that form in our brains with those behaviors and make it easier to fall into the groove the next time.

A famous experiment conducted by Ivan Pavlov in the 19th century illustrates the idea perfectly. Pavlov discovered mental conditioning while measuring the amount of saliva dogs produce when being fed. By clicking a metronome during feeding time repeatedly, he was able to initiate a saliva response in the dogs just by clicking the metronome by itself, without any food. By repeating the experiment over and over, he was unwittingly reinforcing the neural pathways in the dogs that made them salivate at the sound.

But neuroplasticity doesn’t just trap us in habits. It also allows us to change those habits by diverting to new pathways. Whenever we try to accomplish a task through a novel means, we create a new pathway that can be traveled. Abandoned pathways, meanwhile, will physically shrink and wither.

This is why habitual behavior—repeating the same actions in the same way, time after time—can theoretically lead to dementia and the loss of basic faculties. The brain comes to rely on only a few synaptic pathways and allows the rest to become useless.

Building Better Brains

Dr. Michael Merzenich, one of the leaders in the field of neuroscience, believes that these dead pathways can be revived and revitalized through active training and exercise. On his blog, he wrote, “Although certain brain machinery tends to decline with age, there are steps people can take to tap into plasticity and reinvigorate that machinery. We just have to ‘exercise’ the brain in the right way. Similarly, people suffering from a variety of cognitive conditions—from schizophrenia to ‘chemobrain’—may be able to retrain their brains to healthier function. The key—and the challenge—lies in identifying what brain mechanisms to target, and how to exercise them effectively.”

The science is still less than a decade old, so there aren’t a lot of proven ways out there to exercise the brain and increase plasticity. But that hasn’t stopped life-hackers from trying. There are now a plethora of apps available to the curious that claim to offer puzzles and games that will increase neuroplasticity when played. Some YouTube videos make the claim that rubbing your tummy while patting your head daily will do the trick.

Cannabis and Brain Health

What’s incredible is that using cannabis can potentially slow the loss of plasticity by physically protecting the brain. In a 2016 study published in the journal Aging and Mechanisms of Disease, Salk Institute scientists found that low doses of THC can reduce the level of plaque-forming proteins that accumulate on nerve cells prior to the onset of Alzheimer’s disease. It also reduced brain inflammation.

By protecting the nerves, THC was shown to prevent the physical deterioration of the brain and preserve neuroplasticity levels. This means that cannabis can play a direct role in extending the life of our meat computers.

Researchers have pointed out that these effects have only been seen to work in a preventative fashion, however, and it’s still not clear if marijuana would be beneficial for those already suffering from dementia.


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