14 January 2019

How to fix a lab fail

I did my fair share of physiological experiments with neurons when I was a trainee.

The experiment was an attempt to get a handle on whether a particular pathway between sensory neurons A and interneurons B had few neurons (maybe even only a single connection; monosynaptic) or many neurons (polysynaptic).

One way you can test whether you have few connections or many is by messing with the physiological saline the neurons are sitting in. Physiological saline is a solution that mimics the inside of the animal they are normally found in. Different species have different mixes of salts and other chemicals that keep the neurons alive and firing. There is usually a lot of gold ol’ sodium chloride (table salt), potassium chloride (salt substitute for some people), and so on.

Normally, that physiological saline contains some calcium, because calcium causes neurons to release neurotransmitters. If you change with the amount of calcium in your saline, you make each connection between neurons more and more likely to fail. Using some ions that mimic calcium (like magnesium) make this plan even more effective.

Pathways with single connections between will often keep working with this altered saline: hen you stimulate A neurons, you still see the response in B neurons.

Pathways with many connections usually stop working with this altered saline. When you stimulate A neurons, you are unlikely to see activity in B neurons.

I was doing this experiment, and the results kept being... disappointing. I couldn’t understand the results. And the neurons seemed to keep dying faster than usual. I talked to my supervisor about these experiments. We went back and forth a bit, and at one point, my supervisor asked,

“What did you mix the solution in?”

I replied, “I mixed it in...”

Freeze frame. Record scratch.

It was at that precise, exact instant – after that exact word but before I said the next – that I simultaneously recognized and solved the problem that had been vexing me in the lab. If I was a cartoon, a lightbulb would have clicked on above my head. If I was in a modern movie, I would have had a high speed montage run in front of my eyes showing the key moments I went wrong.

All of this happened in pause that lasted about a second.

But I couldn’t stop myself from finishing the sentence, even though I knew that I was about to reveal myself as having made a dumb, amateur, “I should damn well have known better” mistake.

“...distilled water.”

My supervisor laughed. Not loudly. A chuckle, I think would be the appropriate description. I think the laugh was not only because he knew the solution as soon as I said it, but because he saw the look on my face that revealed I’d experienced “Aha!” and “D’oh!” moments simultaneously.

I’ d put the calcium substitutes in pure water. Not saline with all the other salts that were needed. No wonder the neurons kept dying.

I fixed the saline and went back to trying the experiment. The neurons were much happier, although it turned out the results of the experiment were so muddy and hard to interpret them that we never published that data in a paper. (It appeared on a couple of conference posters.)

And the moral of the story is: Whenever you have a problem in the lab, make sure to tell someone else. Because sometimes, you might just solve your own problem.

P.S.—I told this story on video as part of the SICB lab fail contest in 2018. I did not win. I wonder if the video is kicking around someplace...

P.P.S.—I didn’t know it until years later, but I was using a technique “Rubber duck problem solving.

P.P.P.S.—In the original account, the duck was stuffed (as in, a hunting trophy, not plush fur), not rubber.

P.P.P.P.S.—When I was deep into CCGs like Legend of the Five Rings, I talked a game company staffer who answered the phone. Her name was Mindy. Mindy would get players calling in with rules questions all the time. If you know CCGs at all, you know there are many complex rules questions that arise, because there were a lot of possible interactions between cards. Mindy said she would often get people really wanting to ask detailed questions about the Ninja Shapeshifter or something. But because Mindy was customer service and events, not game design, she didn’t have all the cards memorized. She’d ask the person on the phone to read the card out loud to her.

She said she lost track of the number of times the person would start reading the card to her, pause, and then say, “Oh.”

They answered their own question just by reading the card out loud.

Say stuff out loud, people. I’m telling you. It works.

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