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 spontaneously—in mice it’s a spike every minute or so—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.

summer breeze
chipmunks forage
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 1728—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 bar—
wobbly moon

cr: Andrew Johnson via Unsplash

In a study out of Yale this week, researchers explored the neurological pathways governing a fly’s choice in what to eat—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 decisions—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 problems—and are kind of the opposite of chemotherapy, when you think about it, feeding tumor growth. But don’t expect to lose weight.

fruit flies
descending
on fallen fruit