How Memory Works

How happy is the blameless vestal’s lot!
The world forgetting, by the world forgot.
Eternal sunshine of the spotless mind!
Each pray’r accepted, and each wish resign’d...
From Alexander Pope’s Eloisa to
Abelard
 
In screenwriter Charlie Kaufman’s 2004 romantic fantasy whose title was inspired by the above poem, two lovers choose to erase their memories to free themselves of one another. They undergo targeted memory erasure by a fictitious company, Lacuna Inc. “Don’t forget, with Lacuna, you can forget.” The film — Eternal Sunshine of the Spotless Mind — was critically acclaimed.

I still would have written it differently.  In my version, Lacuna’s mind-blowing technology would be able to strengthen, not erase memories.

I have dissected the human body, read Plato’s Republic, studied French for five years, and squandered hours learning how to dive (what can I say, I have buoyancy issues). I would like the power to recall those memories on demand. Instead, I can barely remember where I put my reams of notes and my PADI card.

It would be nice to remember what club I hit when I blasted it from behind the trees off the 7th fairway to win the hole. Or what line I said that had my audience smile. I could go on, but I think I’ve made my point. We preach a lot each day, usually (hopefully) learn much more, and recall very little of it all. Can we dream of a day when we can instill permanency to some memories that matter? Basic principles first.  
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There are three steps to consolidating a memory: Encoding, storage and retrieval. Let’s examine what happens when you read this article. Your brain, knowing no better, perceives it as a novel sensory stimulus, worthy of being retained. This triggers molecular cascades in the brain complex enough to give us both headaches. Your memory’s CEO — the hippocampus — will probably filter out those details as not being important, so I will just save me the retrieval and you the filtering and omit them here. Your brain processes the colour and texture of this page, the sounds around you, and other sensory cues, and integrates these into a single memory. As you pay more attention to what you read, you stop hearing the sound of the fan; the growls of your stomach become less noticeable. The greater your attention, the stronger and more specific your memories become. You move from simply encoding that you are reading, to that you are reading about memory, to the specific details in this piece. It is no wonder that memory athletes (yes, such people exist) compete with dark glasses and noise-cancelling headsets. The more the brain can focus on a particular stimulus, the greater its encoding and eventual retrieval will be.  

Congratulations or consolations, you have just encoded a memory with me! This memory exists as a series of connections or synapses between brain cells. Synapses may be created for the first time, for example, when you learn something new, taste my friend Ramzi’s mixer-made green chicken curry surprise, or experience the initial thrill of the aurora borealis. Advertisers are not crazy when they invest millions of dollars to present you something so novel that it generates an entirely unique neural network that they can own, repeatedly reinforce, and recall upon simple visual or auditory cues. Do co mo, do co mo, do co mo…. so where are you moving your mobile phone connection?  

The neural connections of a memory may crisscross the brain. When you remember a friend who owes you money, you may visualise his face and access the visual cortex at the back of your head. The picture of his face may fire your amygdala in the centre of your brain that regulates the anger that starts rising. A memory is not a discrete physical unit in the brain. It is an expansive network of connections, like the plot to a James Joyce novel that requires frequent access to a number of sections of the book to keep things in order. It is no wonder that with the disruption of these delicate networks, one of the greatest side-effects of traumatic brain injury is memory loss. Luckily, due to something called neural plasticity, new networks can form.  

Once Information has been encoded, it is ready to be stored. This happens through three stages. The first stage happens as sensory memory and lasts a fraction of a second, just long enough for the brain to perceive it. As you touch the paper, your sense of feeling is happening at this ephemeral stage.   

9810158895. This number will stay in the second stage of your memory store — your short-term memory — for about 30 seconds. Repeat the number and it will stay as long as you continue. Consider your short-term memory to be like your computer’s cache RAM. On average, you can store seven items in your short-term memory without using any memory tricks. Try it. Pen, 15, factory, moonlight, dentist, railroad, purple. Without referring back to the list, now write those items down. Not a lot up there is there?  
 
Clive Wearing is a British music conductor who lives imprisoned by his short-term memory. Due to an illness that damaged his hippocampus, he can form no new memories that last longer than 20 to 30 seconds.  Wearing has lost the ability to move memories from his short-term memory to his long-term memory and, like Guy Pearce in Memento, he suffers from anterograde and retrograde amnesia. Every time you meet him, he will introduce himself to you. What he does retain are components of his long-term memory, such as the ability to play music. Just don’t ask him what he has played when he is finished.  

Long-term memory is how you want important information to be stored. Unlike your computer, your brain does not have a single place or hard drive where it stores its permanent data. Memories will go to different parts of the brain depending on the type of memory. Your muscle memory on how to hit a backhand or a winning serve is consolidated across your basal ganglia, cerebellum and motor cortex. It is a kind of procedural memory and is the memory that Wearing relies on to play the piano. Declarative memory is the other type of memory and includes all else. The headline of this article, the name of its writer, and your first impressions of the topic all fit here. That assumes any of those made it past your hippocampus for long-term storage!

Now, how do you move things from short- to long-term memory? Aha, you have identified the Holy Grail!  How can I read something once and never need to refer to it again? What smart food will pipe information into my long-term memory with ease? Why did it take me 10 years to become a doctor? Damn, where is my PADI card again?  

Luckily, we know a couple things about forming long-term memories. Rehearsal works. Simple recitation, for example, Li Be B C N O F Ne, Li Be B C N O F Ne, Li Be B C N O F Ne, is one way to commit the periodic table of elements to memory. Another way, called elaborative rehearsal, applies an understanding to the rehearsal. As we move across the periodic table from Lithium to Neon, the atomic number and number of valence electrons increase. This is a more robust way to form long-term memories.  

At the molecular level, as two neurons fire together, their synapses become stronger. This process, called long-term potentiation, holds the key to understanding memory. Each time you listen to your favourite song, the network of neurons that encodes its memory lights up. The same neurons in the network may be active as a part of other networks or have random activity. But they fire synchronously when you remember or hear your song. How well you recall that tune depends on the strength of the synapses between these neurons.

Now that you know how to store memories, all that remains is to learn the final step to consolidating a memory — its retrieval. While studies have shown that attention is critical for the proper encoding of a memory (what did you just say?), you do not need to be attentive to be able to retrieve your memories. If I quiz you while you’re multi-tasking and distracted, you may take longer to give me responses, but your accuracy will not decrease. That is pretty good support to the belief that memory recall is automatic in nature.  Once something gets encoded and robustly stored, recall follows naturally.  
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Now that you passed the reading comprehension part of this treatise on memory, let’s head back to Hollywood and its eternal sunshine. Unfortunately, there are no devices, drugs, or magic spells I can share that will help you encode and permanently store the latest trivia you wish to commit to memory. But I do have some findings that you may be happy to hear.  

Unequivocally, sleep helps in the formation of memories. You may have already known that, or assumed it to be such. As the renowned sleep researcher Allan Rechtschaffen once said, “If sleep doesn’t serve an absolutely vital function, it is the greatest mistake evolution ever made.”

Dr. Jan Born is a neuroscientist who may have found a trick that could facilitate your memory consolidation.  “There was some evidence that slow oscillations (in slow wave sleep) are involved in declarative memory consolidation,” explained Born as the motivation for an insightful experiment he conducted. Born and his colleagues at the University of Lübeck, Germany, had young medical students learn 46 word pairs before they slept. On average, the students remembered about 36 words before sleeping. As they slept, their sleep was monitored and, once in deep or slow wave sleep, their brains were stimulated with a weak electric field. The results the next morning were exceptional. The students remembered about 41 words, significantly more than a group of untreated medical students could recall.   

In 25 years, if his memory starts to fade, would Born deploy some zapping technology to boost his memories? He says no. “I would take care of good sleep.”   

What if you are not interested in simple measures like better sleep? You can stay up playing with the online games, exercises and programmes of companies such as Luminosity, CogniFit, Cogmed and PositScience that say they improve brain fitness, a concept that is widely debated. Dr. Adrian Owen of the University of Western Ontario, Canada, put brain training to the test. He had 11,430 participants use online brain training games, and complete neuropsychological tests to determine if they became smarter. His results showed that the games did not improve general cognitive function.   

In our multi-tasking world, what you can do is pay attention while learning. As mentioned above, you can task away and execute on multiple projects without much problem. However, you cannot effectively form memories in the same way. Encoding doesn’t happen properly when you are distracted at the formation of a memory. Can’t recall when you scheduled your next conference call? It isn’t your retrieval that is to blame. You were most probably distracted when you scheduled the call. Another thing to keep in mind is that if you take interest in what you’re learning, attention and memory both improve.

Computer tools such as scheduling calendars have an obvious utility in our worlds. I don’t believe they are making us dumb; they are saving our time from memorising names, numbers, and dates that some silicon can do better. We make ourselves dumb if we don’t use the time technology saves us to expand our minds and enrich our lives. For example, a study by researchers in Luxembourg has shown that seniors who speak four or more languages are five times less likely to have cognitive issues than those who speak only two languages. Merde, I knew I should have paid more attention in French class!

For those who want really quick memory fixes, is there anything on the chemist’s shelf? Yes, there are medications such as modafinil and methylphenidate that can improve attention and, possibly, memory. Dr. Anurag Trivedi is a neurologist who has had young students come to him asking for these medicines for memory enhancement. “I think that non-pharmacological interventions are better,” he says. “I recommend a healthy lifestyle, regular and balanced meals, exercise, good sleep and making time for hobbies.” He stresses that meditation and deep sleep improve encoding and storage of memories. He recommends that pure vegetarians add vitamin B12 to their diet as it has an important role in the brain. Finally, while neurodegenerative conditions that cause memory loss cannot be reversed, the treatable causes of memory loss should be diagnosed and treated. Vitamin B12 and thyroid hormone should be measured in all patients with memory dysfunction.  

I am convinced we will soon have a memory contraption based on Born’s brain stimulation work, and I will use it when it’s available.

Until then, I will pay a little more attention while learning, elaboratively rehearse what needs to be remembered, use sleep to store a recent memory I want to keep, and continue to pop my multi-vitamins for good measure.  Eternal sunshine of the elephant’s mind is what I seek, without needing to grow tusks or an unsightly bottom.