This week, researchers at Yale monitored retinal waves in the brains of mice to show that they were dreaming visually before birth, practicing the use of sight so they would be prepared for possible predators the moment they open their eyes.
Newborn humans exhibit some of the same behaviors, so this is believed to imply that fetuses dream as well. What’s interesting, though, is the question of what the dreams would be. Some kind of ancestral, epigenetic memory of sight?
an infant dreams
in the womb
Honestly, I can’t quite wrap my head around this week’s sciku article. The role of dopamine in our external rewards system has been studied extensively, but we also have regular passive spikes of the neurotransmitter cycling trough our brains spontaneouslyâ€”in mice it’s a spike every minute or soâ€”and we don’t really understand why.
In a study published this week in Current Biology, researchers demonstrated that mice are not only responding to these regular spikes, but are able to alter them. The suggestion is that it might play a role in the foraging process, with a tiny dopamine hit every minute reminding them to stay alert for some greater reward. The chemical process seems to prod us forward, making sure we’re never quite satisfied. I wonder if it might play a role in ADHD?
At least that was my interpretation. The press release doesn’t quite make sense to me, and the study itself was even more impenetrably written. But I think that’s what it means? Maybe I just need a nap.
under my hammock
Who knew that the moon’s orbit wobbled on an 18.6-year cycle? Well, actually, we’ve known about this since 1728â€”and Bronze Age peoples knew about it thousands of years ago, and tracked it in their megalithic monuments all over the world.
But a paper in Nature Climate Change this week studied the impact it will have on high tide flooding in the coming decades. Right now we’re approaching the major standstill, where tides variation is the lowest, hiding the impacts of sea level rise on coastal flooding. In 2034, we’ll be at the minor standstill, which exacerbate the flooding.
he tells it again
walking home from the barâ€”
In a study out of Yale this week, researchers explored the neurological pathways governing a fly’s choice in what to eatâ€”is it the taste or the calories they’re after?
To explore this, scientists laced a normally sweet, nutritious food with bitter quinine, and watched the flies brains as they decided whether to eat that, or another food that was sweeter, but lower in calories.
In the end, it mattered how hungry they were. If the flies were hungry, they chose the bitter food with more calories, but if they were satiated they chose the sweetness, suggesting even in a fly there are multiple pathways governing these decisionsâ€”the gut’s needs can override the brains dopaminergic reward system.
While it’s not mentioned in the study, I can’t help but think this is the answer to the mystery of why artificial sweeteners don’t help people lose weight. Diet soda satisfies the reward system with a hit of sweetness, but does nothing for the body’s deeper craving for calories. So we drink diet soda, then eat more, and it makes no difference to calorie intake.
This doesn’t mean we aren’t better off drinking diet soda, as simple sugars are inflammatory at these high doses, and lead to diabetes and other health problemsâ€”and are kind of the opposite of chemotherapy, when you think about it, feeding tumor growth. But don’t expect to lose weight.
on fallen fruit
One of several great things about the new mRNA vaccines is that they’re so simple. They’re basically just the lipid membrane, saltwater, and the mRNA, which is so easy to synthesize that I did it myself as an undergrad. Despite all the rumors, there are far fewer opportunities for side-effects and unknowns than with traditional vaccines.
Unknowns like this. For years, flu researchers at the Wilson Lab at the University of Chicago kept seeing antibodies that were reactive to every virus they tested, and they couldn’t figure out why. It turns out the antibodies were binding to glycan, a sugar molecule found in the chicken eggs that the vaccines were being produced in.
The early polio vaccines were grown in monkey kidney cells, and about a quarter of them turned out to be contaminated with Simian Virus 40, which may increase the risk of soft-tissue cancers (still a controversial claim to this day)â€”so we started growing vaccines in chicken eggs instead. Almost 50 years later, we just realized this process leads to the production of antibodies for glycan.
As this is a new discovery, we don’t know what it means, if it means anything, but it’s easy to imagine that this has been making all of our egg-grown vaccines less effective than they would be otherwise, as the immune system wastes resources making antibodies to these meaningless clumps of sugar.
The point is, biology is messy and traditional vaccines are a crude technology. That we’re advancing to mRNA vaccines, with much less junk and much greater precision, is something to celebrate.
lightâ€™s long journey
from the sun into the son