Exploring long-term memory storage
By Malavika Eby
Walking through the school hallways, I see everyone. Laughing in geometry with me three years ago, walking at lunch together, ranting about essays to one another, I remember all of it. Eighth grade. Freshman year. Sophomore year. Now. You all were always there.
The people that stayed with me as a part of my life gave me countless memories, some that I hope to never let go of and some I can’t wait to leave behind. Seeing someone rather than looking through them when they sit across from me, the distinction comes from whether they spark in me a certain twinge of excitement, surprise, regret or merely a complete void of feeling. The almost indifferent, “Oh, right, it’s you.”
Why is it that people tell us that what’ll really matter at the end of these four years is the people in our life and the time we spent with them rather than the quizzes or letter grades? Why do the people matter so much?
Thing is, memories are a tricky thing. Our experiences, they’re sensed, carried, encoded, stored and communicated back as a response. As straightforward as this sequence appears, the intricacies of our neurological and psychological mechanisms keep the process anything but.
Right now, while I couldn’t be farther from understanding truly how memory works, I’d say this story was my first real lesson anyway.
In November of eighth grade, Mr. Kampp began a new lesson, introducing an upcoming history project about the Declaration of Independence.
Sensory neurons within the inner ear hair cells send electrical signals, action potentials, darting to the central nervous system. These signals pass neuron to neuron, promoting the release of neurotransmitters, received at dendrites (the branches of the neuron) and transmitted through synapses, the opposite end.
Auditory processing of Mr. Kampp’s words was taking place.
Having reached the spinal cord, interneurons mediate between the arriving sensory neurons and the motor neurons preparing to react. The incoming chemical information is coded into an outgoing chemical response, sent back to our muscles and limbs to produce a physical reaction.
My ears perked up with the mention of the new assignment. I leaned forward in interest. Apparently, we could decide how to present the information we’d research for this project. What if I made a song like our group did last year? Yes, I decided, let’s do it.
The time I spend working, the lyrics I edit to be about the Declaration of Independence, the iMovie lyric video I make at the end of the project — they’re all now encoded into the working, short-term memory of the brain.
Through active maintenance of the experience by thinking about it for the next few weeks, my experiences are kept at the surface, now repeatedly processed while still temporary.
In the July before my junior year, we started talking again. About school, about our lives that’d lately been so disconnected from one another, about the middle school memories we still kept — because while we weren’t close, we’d always at least existed in the backs of each other’s minds as background characters.
“Hey, remember when you sang Mercy by Shawn Mendes in our eighth grade history class?”
Experiences that’d once been encoded — but now scattered throughout the complex web of experiences that’d built up in my brain since then — are reprocessed. Brought back up again, the active process of retrieval and rehearsal of stored memories through this conversation are bringing them back to consciousness.
I hadn’t thought of the project in years, forgetting much of that time, much less which songs I’d recorded. But yes, now I remembered because the memories weren’t deleted, but rather stored inaccessibly, until they were retrieved by an active effort to remember.
“I remember coming up to you after and asking which song it was. I listened to it on repeat for weeks afterward when I couldn’t get it out of my head.”
Oh, wow. I had no idea.
Reprocessing of old memories comes through something we understand as connectionism in parallel processing, forming connections with new memories, understandings, experiences that web together to build the complex interwoven neural networks that form the structure of our minds.
Neural pathways are changed and strengthened, my perspective on the project renewed and the memory now shifted from the temporary shelf of working memory to one of more permanence.
Last week, shuffling through old voice memos, I found the recordings I took of myself singing Mercy, the lyrics changed to express struggles of living under the control of King George III.
Chuckling in amusement, I told my mom about how I asked to stand outside my classroom as my whole class listened to the song, watching the lyric video projected onto the white screen. I’d been that nervous.
How could I remember that minor a detail of an experience I could barely recall just a few months ago?
And that’s why memory is a funny thing. The person who’d brought memories of that project back to me had taken a rather significant role in my life, influencing even the song they treasured to take value in my own mind.
The energy I’d invested into actively remembering the experience was retrieving parts of the memory that I did not even recall existed, a process sparked over and over again when I see that person in the halls sometimes.
When we wonder why the memories that last are those of our friends and not grades — this is why. People are not like objects, numbers or words, but rather entire collections of every experience that’s been shared between you and them, accumulated into the relationship you hold today.
With every reminder of this relationship, a role that could be taken on by certain songs, places or pieces of clothing, neural pathways are strengthened once again, shifting the memories closer to long-term storage.
As I had remembered a minor middle school project after years just by reprocessing them with new connections I unexpectedly built, the next time you wonder why you always hear that people are most important, remember the neurons that make it so.