Sometimes, scientists do things that kinda seem impossible.
Like, in a paper that came out on Monday, they took memories from one group of sea slugs
and stuck them in other sea slugs — so that the second group seemed to remember something
that had never happened to them.
It’s an amazing feat of science, and it could someday help us understand human memory…
but it’s also a little spooky.
This experiment, which was published the journal eNeuro, was part of our decades-long search
for an engram: a physical thing in our brains that contains our memories.
For the record, we haven’t found one.
The most common idea says that long-term memories are probably housed in the connections between neurons.
But some researchers believe they’re stored in your non-coding RNA somehow.
RNA is best known for helping your cells create proteins.
It’s kind of like a recipe created from the information in DNA.
But non-coding RNA isn’t involved in making proteins.
There are lots of different types, and we’re still figuring out everything those molecules
can do.
And with this new paper, we have more evidence that one of their jobs could involve memory.
In this study, scientists repeatedly prodded the tails of 34 sea slugs, called California
sea hares.
Each poke triggered a defense reflex where they suck their tails inside their bodies.
Normally, they probably do this to protect their sensitive, squishy parts from predators.
But y’know, it’s good for science, too.
The more the researchers poked, the longer that reflex lasted.
And after two days of this, the sea slugs had been trained to keep their tails in about
60 seconds longer than they had at the start.
Then, the scientists took samples of RNA from the sea slugs’ nervous systems and injected
them into the circulatory systems of another group of sea slugs — ones who didn’t get
any tail prods.
And after the injection, these new sea slugs also performed the tail reflex about 40 seconds
longer than normal.
It wasn’t quite as long as the trained group, but the change was big enough to suggest that
the sea slugs had basically been injected with the memories of the first group.
Or at least, something in their nervous systems changed and made their tail reflexes last longer.
After follow-up experiments, the researchers believed this happened because that non-coding
RNA somehow triggered DNA methylation.
This is when methyl groups get attached to specific parts of DNA, and it usually stops
the production of certain proteins.
So maybe that, in turn, altered something in the sea slugs’ neurons.
There’s still a lot to figure out — like how non-coding RNAs cause methylation, and
how methylation changes sea slug neurons and, ultimately, memories.
And we can’t say for sure that this works the same way in humans.
But if it did, it would put us one step closer to understanding where our memories live inside
our heads, and how we might even be able to alter them.
Which is all kinds of weird.
If you need a breather after all that, well, we’ve got the study for you.
For years, scientists have noticed that controlled breathing — like from certain meditation
practices — can provide all kinds of cognitive benefits, including improved focus.
And according to a paper published last Thursday in the journal Psychophysiology, we might’ve
figured out why.
It all has to do with a little structure in your brainstem called the locus coeruleus,
or the LC.
And the LC affects a lot of things, including your respiratory system.
It’s linked to nerves that remind your body to keep breathing even when you’re not thinking
about it.
As a result, the activity of this region is influenced by how much carbon dioxide is in
your body.
When there’s more CO2, like when you inhale, your LC fires more often.
And the opposite is true when you exhale and your CO2 levels drop.
Now, the LC has another job too: It’s your brain’s main producer of a neurotransmitter
called noradrenaline or norepinephrine, which is a major player in your ability to focus.
The tricky thing is, your brain has kind of a sweet spot for noradrenaline levels.
If there’s not enough of it, you don’t feel stimulated, so it’s hard to focus.
But if there’s too much, you feel overstimulated or anxious, so you still can’t focus.
According to this study, controlled breathing could help.
See, as you inhale and your LC fires faster, it also produces slightly more noradrenaline.
And it produces slightly less as you exhale.
So by controlling your breathing, the authors suggest that you can actually optimize those
noradrenaline levels — and your focus.
In their study, they tracked the locus coeruleus activity of 14 participants during two phases:
an 8-minute rest, and a 20-minute listening task.
In the task, they had to pay attention and respond as fast as possible to mostly random
tones, which could pop up anywhere between 2.5 and 3.5 seconds apart.
To monitor their brain activity, the team used fMRI scans and also tracked participants’
pupil dilation, since previous work has shown that’s a good indicator of locus coeruleus
activity.
They found that participants who were better at the listening activity had more synchronization
between their breathing and the task.
Their inhales and exhales were more in phase with those 2-3 second intervals.
And they probably weren’t trying to do that.
Instead, the scientists thought that their focus levels were actually changing their
breathing — to have the right amount of CO2 for the amount of LC activity.
The researchers suggested this wasn’t a one-way street, either — that controlling
your breathing can influence noradrenaline production and how focused you are.
This was the first study to find a biological link between breathing and cognition in humans,
so we need more papers to know anything for sure.
But the next time you’re struggling to pay attention in class or a meeting, maybe try
taking a deep breath or two.
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