Wednesday, April 28, 2010

Neuron asleep at the switch

Last night I had an exercise in remembering something from my childhood maybe 65 years ago. The overall experience I was remembering was the arrival of the “ice cream man” on our street. Specifically, I recalled (or thought I recalled) a specific product the ice cream man sold. It was a combination bar of frozen juice with ice cream inside. I remembered it as a “Dreamsicle.” I wrote about it in yesterday’s blog.

This morning, in the shower, I had a flash: It wasn’t a “Dreamsicle,” it was a “Creamsicle.” I had remembered the sound of the word but I pulled up an incorrect rhyming version of it from my memory. The minute I got out of the shower I rushed to the computer, pulled up the incorrect blog and corrected it.

This got me to wondering how memories are created, stored and recalled in the brain. I Googled “how memory works” and found Public Broadcasting’s Nova Science Now website. There I was able to view a video of neurosurgeon Itzhak Fried talking about how memories are stored and retrieved.

According to Fried, an experience (say, the arrival of the ice cream man and buying stuff from him) is captured by a single neuron, or a group of neurons firing together. When the call goes out to recall that memory, the same neuron or neuron group fires again.

So let’s say each neuron in the group of neurons that captured the original visit by the ice cream man remembered one part of the experience: one captured the look of the ice cream box, another the sound of the cow bell that signaled the ice cream man’s arrival, and several others the taste of various goodies in the box.

But on further reflection, there must have been one neuron for each quality of each particular product – in this case, the Creamsicle. One neuron got the flavor, one got the temperature, one the location of the ice cream inside the icy blanket around it, one the stick frozen into the Creamsicle to provide a handle and, finally, one got the name.

So let’s dig a little further. Maybe there were several neurons assigned to grab the name. One got that it ended in “… sicle.” Another got that the first syllable sounded like “…eem.” And the one in charge of getting the first letter probably got “C” at the time – but something happened to it along the way.

Now, 65 years later, along comes a memory call: Hey, remember that bar with frozen juice on the outside and ice cream on the inside? What was it? Every frozen-bar-with-ice-cream neuron hustles up to bring its part: Here’s “..sicle,” and here’s “…eem,” and… “Hey, where’s the neuron with the first letter?”

Well, it turns out that neuron was asleep at the switch, as it were. “Duh, I’ve forgotten. Maybe it was ‘D’ for ‘Dreamsicle,’ because they were pretty dreamy-good. So I’ll offer up ‘D.’”

For a few hours, the other neurons accepted the D. But this morning the faulty first-letter neuron snapped awake and said “Hey, wait a minute, it was C, not D. Creamsicle, not Dreamsicle.”

Why did it fail? It came close, but it failed. Has it been doing other things since the ice cream man came by? Remembering algebra, sunsets, the smell of apple pie in the oven, an acquaintance’s name, a dentist’s appointment? Has it been overworked?

Or has it been lying there in the cranial soup, with no responsibilities other than remembering “C?” Did it just go flabby? Use it or lose it, and I didn’t use it?

I’ll probably never know. But I have certainly profited by the experience. I’ve delved deeper into my brain than I thought I would. And I may know a little more about how this amazing organ works – maybe one neuron’s worth.

One thing is for sure. After all this, that dumb neuron better not come up with D again.

1 comment:

Sharon Lippincott said...

Whatever else your brain full of neurons did, it came up with a delightfully entertaining account of that dreamy creamsicle. And your neurons are more powerful than you knew. Mine bought right into the slothfulness of yours, and I was good with Dreamsicle, and ditto the change.