Issue 9

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In this issue:


  • How your brain can adapt to lower energy intake, but not without a cost.

  • Why reporting the retraction of scientific articles is more important than ever.

  • Context matters to the brain...even for fruit flies.


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Feel like you’re drained of all your energy?

You’re not alone – we’re exhausted too. It probably doesn’t help that your brain is a major energy hog, using up 20% of your total caloric intake. But what happens when energy is in short supply? A new paper shows that the brain has built-in mechanisms for saving energy when food is scarce (the OG low power mode).

The experiment: A group of scientists took some mice and restricted the amount of food they could eat. These mice experienced a 15% reduction in their body weight. Next, the scientists measured neural activity from these skinny mice to figure out how their brains might compensate for the lower caloric intake.

What did they find?

Incredibly, the mice reduced consumption of adenosine triphosphate (aka ATP aka the basic molecule for energy in our bodies) in their brains by 29%. Yet at the same time, the neurons themselves didn’t actually become any less active.

Hold on. How do you use less energy without also reducing neural activity?

It turns out the brain accomplishes this by simply lowering the threshold for what it takes to make a neuron active. In other words, even though there was less energy in the system, individual neurons adapted to become more easily excitable, leading to similar overall levels of neural activity in the brain.

Did this affect the mice in any way?

You betcha. In this new energy-deprived mode of operation, the mice were worse at telling visually similar stimuli apart. The scientists concluded that even though the brain still works when forced to give up its precious ATP, it doesn’t function with the same degree of precision.

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The Leak: Your brain is easily the biggest consumer of energy in your body. When mice were forced to eat less food and reduce their energy intake, their brains were able to compensate by reducing energy expenditure. This adaptation was not without consequence, as the mice’s vision appeared to become less precise. So the next time you get blurry-eyed after skipping your morning breakfast, be sure to head over to the nearest café to fuel up on some ATP.  


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What to tell your uncle who believes everything he sees on Facebook.

Science begs to differ. You may have heard claims on social media that Ivermectin — an anti-parasitic drug often prescribed to farm animals — is actually a cure for COVID-19. Believe it or not, this claim originally came from…doctors.

Wait. What?

The debate around Ivermectin can be traced back to a critical care doctor named Dr. Pierre Kory. Dr. Kory has advocated for curing COVID with a treatment regimen that he calls “MATH+”. One of the drugs in this regimen is none other than the infamous Ivermectin.

Does MATH+ actually work?

Dr. Kory sure wants you to think so. Last year, he published a paper using data from a hospital showing that patients treated with MATH+ had a 6% mortality rate. This is far lower than the 15-30% mortality rate reported for other hospitalized patients. Several media outlets (looking at you, Joe Rogan) were eager to shower Dr. Kory with attention for his unorthodox claims. But as it turns out, his “MATH+” didn’t quite add up.

Tell me more.

Upon hearing about the paper, the hospital took a closer look at their records. They soon realized that Dr. Kory had grossly miscalculated the mortality rate. According to the hospital, the actual mortality rate for patients treated with MATH+ was in fact anywhere from 10-28%. That’s off from the originally reported 6% figure by a factor of four.

What now?

The journal has retracted the paper, which is basically their way of disavowing the findings and admitting they were wrong. Retracting a paper is a big step, but a necessary one for preventing the spread of scientific misinformation.

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The Leak: We’d all like to find a miracle cure for COVID, but wishing something were true doesn’t make it so. This latest paper is one of several to have been retracted in the past year for making inaccurate claims. Who knows — maybe one day a well-controlled trial will reveal that Ivermectin is indeed an effective coronavirus treatment. Until then, get vaccinated (seriously) and leave the deworming pills to the horses.


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Ever wonder why you act so differently depending on context?

Of the many incredible things your brain does every day, one that has long fascinated scientists is the sheer breadth of behaviors it can produce. Take dopamine for instance — a neurotransmitter that you’ve probably heard influences feelings of reward and motivation. Did you know that dopamine also plays a major role in helping you control your movements? How can one molecule contribute to such diverse functions? That’s what the researchers in a recent study set out to uncover (courtesy of our good friend, the fruit fly).

The experiment: Fruit flies were placed on top of a ball so that they could walk freely in place (kind of like a fly treadmill). As the flies walked around on their ball, the researchers presented them with two different contexts. In one, the flies were randomly given sugar treats from time to time as they walked around breathing normal clean air. In the other, the scientists exposed the flies to a tempting smell, which the flies naturally gravitated towards (flies are suckers for a good scent). The researchers measured activity in the fly brain from neurons that release dopamine (DANs, for short) during these two contexts.

What did they find?

When the flies walked around in the clean air context, the activity of DANs was related either to the flies’ movement patterns or to receiving sugar. But when the flies pursued a tasty smell in the odor context, the activity of DANs became correlated with the aspects of the flies’ movements relative to the odor, such as the total distance traveled towards the smell. In other words, when the flies had a motivational goal (reaching the source of a tasty scent), the neural activity of the DANs became multifaceted and integrated aspects of movement AND reward.

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The Leak: Dopamine neurons in the fly brain can change their activity to represent relationships between movements and reward, depending on context. This type of information “multiplexing” might very well explain how one organ (your brain, in case that wasn’t clear) can help you navigate so many different scenarios.


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