Photo: Fruit flies (Drosophila melanogaster) enjoying a piece of fruit, courtesy Jack Dykinga, USDA Agricultural Research Service.
I remember the days when you could buy a road map, covering a particular local geographical region, at pretty much any service station and truck stop. Unfolding the map, you found, on one side, a map covering maybe 200 miles by 200 miles, and on the other side a less-detailed map covering maybe the entire state. The main highways were usually red, and the secondary roads blue, or black.
But progress continues, in the world of mapping.
I haven’t learned to use the map app on my phone yet, but I gather that it covers pretty much the entire planet. And you can still zoom down to details as small as a city block. Maybe, as small as a single building?
Not yet as small as a single bedroom, but I’m sure that’s under development. I’m looking forward to the day when I can find my missing blue sock.
But speaking of maps — as you may have heard — scientists hoping to make the world a better place have been spending a lot of time and money mapping animal brains.
They started by mapping a worm brain, which turned out to have about 300 neurons, and then moved on to a fruit fly larvae brain, with about 3,000 neurons.
A neuron is an excitable cell that fires electric signals — called ‘action potentials’ — across an excitable network in the nervous system.
I think of a neuron as similar to an excitable person who constantly posts warnings about border security on social media. But the neuron is less worrisome.
The human brain is also composed of neurons — although, in the case of certain people, you wouldn’t know it.
A neuron looks a little bit like a tiny octopus-like extraterrestrial, with tendrils extending in various directions with every intention of exciting the tendrils attached to nearby neurons. Those connections between the neurons are called ‘synapses’ and that’s where the exciting electric signals happen. So when a person says, “Your excitement is all in your head,” they’re not far from the truth.
Scientists haven’t yet tackled the mapping of the neurons and synapses in a human brain. They did, however, recently map an adult fruit fly’s brain. In 3D, no less. And in living color.
Researchers mapped all 139,255 neurons in the fruit fly’s brain, which are linked by more than 54 million synapses. It’s not immediately clear to me if the fly’s brain continued to function normally after the mapping was complete, but I’m kind of guessing the fruit fly in question was an organ donor.
I personally find fruit flies to be mildly annoying, whenever I have rotting fruit in my kitchen (which is fairly often.) But viewed up close, as in the photo at the top of this article, they actually look kind of cute. I can see why scientists might want to map their brain.
This recently-completed mapping process took five years, and involved hundreds of scientists (and amateur scientists) who were part of a consortium called FlyWire.ai. You can see a list of the people involved on their website.
We should note, however, that this was the brain of one particular fruit fly. (In this case, an adult female.) There’s no evidence that I can find that the next fruit fly’s brain would look anything like the one these scientists spent five years mapping. In fact, I’m willing to bet, if the consortium decided to map the brain of another adult female Drosophila melanogaster, they will be totally surprised by how different it looks.
My personal experience with females is, you never know what they are thinking, until it’s too late.
The obvious prediction — as offered in media reports of this scientific achievement — is that a fruit fly brain map is just the beginning, and we will someday have maps of other animal brains, including (perhaps) a mouse brain, a cat brain, a dog brain, a monkey brain, and ultimately, a human brain. The next step would be to have a phone app where we can zoom into a particular neighborhood in someone’s brain, and find that missing blue sock. (Somewhere in my brain, I know where that sock is.)
This human brain map is not going to become available in the near future, however. It took five years to map a fruit fly’s brain, with 140,000 neurons. A human brain reportedly has 86 billion neurons, many of which are, at any given moment, waiting around for something to do.
If it took five years to map 140,000 neurons, then, according to my pocket calculator, it will take over 600,000 years to map 86 billion neurons.
I will close by saying, my uncertainty about whether the female fruit fly involved in the FlyWire project was a willing volunteer or a reluctant organ donor, causes me to wonder if I would want my own brain mapped.
I’m actually pretty comfortable without the map. It’s a guy thing.