Monday, August 23, 2010

The Elastic Memory

We remember and in our retelling of the memory we alter it. Memory is elastic. The sounds, smells, sights, textures, flavors you experience as you tell the story may alter the memory itself.

The memory I have of lying on my back in the driveway and looking up into the trees? That’s likely a composite memory. Several instances of taking photographs of leaves and bark, the photographs themselves, of the driveway my father took pride in, of all my time outside, and my own telling and writing about it have created a collective memory of something that brought me joy as a child. I share it often and in many different ways (written, oral, recall in my private universe) and in sharing the memory it is possible that it changes.

For those who cherish memories, the idea of them being not entirely “true” and elastic can be upsetting. But for those who have traumatic memories, this can come as a comfort. It’s an interesting concept.

I read an article last night in the Smithsonian magazine titled, “Making Memories,” published in the May 2010 issue, which focuses on this idea. Karim Nader, a neuroscientist who works at New York University, talks about how he recalled seeing television footage on September 11th of the first plane hitting the north tower of the World Trade Center. He was surprised to learn that this footage aired for the first time the following day.

In order for a long-term memory to be built, neurons need to manufacture new proteins and expand to make the neurotransmitter traffic run more efficiently. Long-term memories have to be built into the brain’s synapses.

We say things like “memory fades,” and think of ink on paper. Over the years, the memory might fade a bit. For an Alzheimer’s patient, the ink becomes invisible. Is it really possible that under any ordinary circumstance, memory stays the same? Nader challenged this idea by experimenting with rats.

From the article:

In 1999 he taught four rats that a high-pitched beep preceded a mild electric shock. The rats froze in place after hearing the beep. Nader waited 24 hours, played the tone to reactivate the memory and injected into the rat’s brain a drug that prevents neurons from making new proteins.

If memories are consolidated just once, when they are first created, he reasoned, the drug would have no effect on the rat’s memory of the tone or the way it would respond to the tone in the future. But if memories have to be at least partially rebuilt every time they are recalled – down to the synthesizing of fresh neuronal proteins – rats given the drug might later respond as if they had never learned to fear the tone and would ignore it. If so, the study would contradict the standard conception of memory. It was, he admits, a long shot. […] It worked.

When Nader tested the rats, they didn’t freeze after hearing the tone. It was as if they had forgotten all about it.

For anyone who has given birth to a child, you recognize the fact that you forget the pain. Your memory focuses more on the joy and less on the pain as time progresses. I’ve always wondered if this was the brain’s trick at getting the body prepared to have more children. If we remember the pain, the likelihood of wanting more children would be slim.

When I think of memory as being plastic, it’s a huge relief. My sister’s memory of a childhood event that we both participated in might be different from my recollection of it because we have led different lives, and told the story in a myriad of unique places which changed it for each. I think seeing photographs of events change the memory of those events too. Photographs remind and can change a memory.

Writers know that the act of writing down a memory can be cathartic. Therapists recommend keeping a journal to patients who need to work through complicated feelings. Is part of this process refashioning the memory so the person can live with it safely?

When I think of writing this essay three years from now, will I only remember the part about the rats and forget the rest?

If memory is plastic, then all memoirs are “lies.” I’m okay with this. I’ve always felt this way. The brain is fascinating, willing to embellish and make connections between all sorts of details that we experience, including those we dream. We are not always aware of our brain’s sleight-of-hand, and it sure is interesting. What colorful scarves are being tossed in the air of my brain as I write this? As you read it?

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