LAB LEAKS

Beauty and the Brain 🌼

Here’s to the greatest boy band of the 2010's

In this issue:

• How a popular instagram filter tapped into a theory about natural selection.
• No, we won’t be downloading our memories any time soon.
• Yes, “pregnant brain” is a real thing.
• Organs on chips, why HIV-AIDS is so hard to treat, and other recent developments for your next coffee break.

What do scientists and One Direction have in commmon?

They’re both asking "What Makes You Beautiful". One trait that is commonly believed to contribute to attractiveness is bilateral symmetry. You might have seen TikTok/Instagram filters that can show you a perfectly balanced version of your face (if not, check out #symmetricalface).

Where does this notion come from?
The fact that nearly every animal is somewhat symmetrical along their midline has led some to theorize that perhaps evolution selected for this trait. As the theory goes, asymmetrical features might serve as an indicator of poor genetic health, which could in turn create evolutionary pressure for selection of symmetrical mates.

Sounds intriguing.
In a recent study, researchers used fruit flies to put the symmetric = attractive idea to the test. Female fruit flies select their sexual partners based on a male’s ability to sing a “courtship song” by rubbing/vibrating their wings (if only human courtship were that easy.) So what happens when a male fly with asymmetric wings sings his love ballad?

The experiment: First, male flies were subjected to a variety of genetic and environmental interventions to influence the symmetry of their wings. These males were then allowed to hang out with a female fly and compete for her affections by singing to her (just imagine being serenaded by the entire One Direction crew). The female picked a “winner”, and the remaining “loser flies” were ushered aside (we’d pick Harry, tbh).

That seems harsh.
Don’t worry, we’re sure nobody got their feelings hurt. But back to the science — the researchers found that on average, the “loser” males had much higher degree of wing asymmetry than the winners. In other words, the females could tell that the courtship songs coming from lopsided wings were a bit off, and they ended up picking the most symmetrical males they could find.

The Leak: If you think that symmetrical individuals are more attractive, you now have something in common with fruit flies. According to a new study, male flies with asymmetric wings are less likely to be selected as mates by females, probably because of differences in the quality of the courtship songs that these males produce. But don’t worry, here at Lab Leaks we think you’re beautiful just the way you are.

Wish you could channel your inner Dumbledore and pull individual memories out of your brain?

It might help to know how your memories are actually stored. Is the brain like a hard drive in which specific neurons store specific memories? Elon Musk might think so, but that’s simply not how it works. According to a new study, memories are not stored in a single brain area, but are widely distributed across your entire brain.

How did they figure this out?
To see where memories are stored, the researchers first imparted a scary memory to a group of mice by placing them in a box and giving them a mild electrical zap to the foot (sorry, mice). At the same time, they measured neural activity in the entire brain to see which neurons were active during formation of the memory.

What did they find?
Neurons related to memory formation were found in 117 different brain regions (for context, that’s a lot). When the mice were placed back in the same box a few days later (this time with no zap), these same neurons became active once again, suggesting that the mice were able to recall the scary memories of the last time they had been there (the same way you might feel at your high school reunion).

The Leak: For a long time, neuroscientists believed that memories were mainly formed and stored in one area of the brain — the hippocampus. A new study challenges this belief by showing the memory formation is way more complex than that, involving 100+ brain regions. Needless to say, we probably won’t be “downloading” any memories any time soon (sorry Elon and Dumbledore).

Think pregnancy cravings are just a cultural stereotype?

Think again. You’ve probably heard pregnant women describe intense cravings for all sorts of food. No, they’re not just making it up. A new study shows that pregnancy cravings have observable neural correlates in the brain.

You’re allowed to do studies on pregnant women?
In this case, it was pregnant mice. In the study, the researchers observed that pregnant mice also experienced food cravings for sweet food, and increased their overall food intake when exposed to highly palatable foods (they’re eating for two, after all). Using a tiny mouse MRI machine, the scientists also found that areas of the brain that process rewards were more active in these pregnant mice, which might explain why they were more likely to hanker after sweet treats.

The Leak: When it comes to food cravings, “pregnancy brain” is a real and verified phenomenon. So if you know someone going through pregnancy right now, bring them a box of chocolates — we’re sure they’d appreciate it.

Wouldn’t it be useful to know beforehand how certain medications might affect you?

Scientists agree. “Organ-on-a-chip” techniques (the lab kind, not the nacho kind) can be used to take cell samples from a patient and test various drugs on them before ever writing a prescription. A new study describes a way to maintain these cultured cells with their in-body properties for maximum realism (for example, having lung cells that artificially “breathe”).

What’s the best way to avoid trouble with the law?

Just become the law. At least that’s what HIV does, protecting itself from the human immune system by hiding INSIDE immune cells. Talk about a bold strategy.

If you’re a mouse looking to bulk up on some muscle…

Might we recommend probiotic supplements using bacteria derived from the tummies of Olympic athletes.

In case you missed it:

• Scientists show how we pick up on red flags faster than positive cues.
• Scared of snakes? You’re hardwired for it.
• This week’s Covid update: breathalyzer tests.
• After 123,984 human MRI scans, we’re a tiny bit closer to understanding human brain development.
• “Forests have more than one trick up their trees,” especially when it comes to global warming.

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