H is for hippocampus


Source: Wikipedia Creative Commons

The word of the day is ‘hippocampus,’ I told C as we drove home from Whole Foods on a late October afternoon.

Why do you say that? she asked.

I came across the word three times today, I said. First listening to the radio: I heard a song by Hippo Campus, that band you’re going to see in a few weeks. Then I got an email from Hippocampus, a magazine that only publishes essays. And last I got a call from an old friend who works at a foundation, asking me to write a press release about four neuroscientists who just received awards for their research on memory. They all study the hippocampus. 

Weird! said C. But fun that you get to talk to neuroscientists.

Yeah, well, it’s a little daunting, actually. I looked over their grant proposals and I can hardly understand what they’re talking about. 

Oh, I can help you! chirped my self-assured eighth grader. I gave her a sideways glance. I didn’t know her knowledge of the hippocampus extended beyond her infatuation with the band that gave us “Suicide Saturday.”


Yeah! she said with enthusiasm. I know about neurons! The synapses connect them to each other. Signals fire along them. I did a presentation on them this fall. She looked lit from within as she said this, her own synapses firing at the thought of helping her simple mother understand the function of the brain.

Okay, you’re on, I said. I’ll show you the project descriptions when we get home. I have to interview each of them next week, and I want to have some idea what they’re researching before I call. 

As soon as we got home I spread the proposals out on the dining room table. Strike while the iron’s hot, I figured, before C’s rare interest in my work submerged to teen indifference. C settled in beside me, opening up the PowerPoint I hadn’t known she’d made for school. 

Here’s an example of what I’m having trouble understanding, I said, reading aloud from one of the researcher’s project descriptions:

We propose to bridge synaptic and systems plasticity by tagging dendritic spines undergoing plasticity in vivo with temporal resolution (hours) sufficient to resolve in a single training session. 

The overload of unfamiliar words made my brain freeze, but somehow C was not daunted. 

I know what dendrites are, she said. They’re part of the neuron. 

She showed me an image of a neuron in her report, and sure enough she had labeled the spiky tendrils shooting out from the end as dendrites.

But what’s plasticity? she asked.

I was hoping you would know, I said. 

So we googled it. 

Changeability, I told her. Ability to adapt to new information. Something like that.

In vivo? she asked slowly. In a living brain, I said – they’re doing studies on live animals. Mice and rats. 

From this and a few more paragraphs we pieced together that this researcher was going to color code the specific neurons that fire in a mouse’s brain as it encounters new objects and forms new memories. And that if her lab’s research succeeds, they will better understand how memories are formed in healthy brains—and that maybe someday that knowledge will help restore memory function in those who lose it. 

Such an abstract idea in itself: that loved ones might lose their memories one by one, synapses ceasing to fire, gray matter going dim.

Why was I tasked with conducting this arcane bit of communications research this fall? I felt plucked from nowhere, tagged like one of those millions of dendritic spines to fulfill a small task I had not imagined existed. 

The assignment gave me the chance to engage with my thirteen-year-old as an equal, untangling a riddle.

It gave me a little extra money to put toward regatta fees next year.

It gave me an image to cling to—of synapses blazing from one neuron to the next—when my sister called to say they found a tumor in dad’s brain, and that mom keeps forgetting things she should remember. 

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