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Krnt2007's avatar

What in the brain/body or the Universe around it helps determine which memories to retain long-term and which to let 'evaporate' with time?

Asked by Krnt2007 (14points) December 25th, 2008

The aim of this question is practical : I am learning languages etc. and want to learn tricks to help me remember learned elements much longer and reliably.

As someone with their ear to the ground about this sort of thing, and an ex-ESL teacher who’s read what’s regarded as the best research, I am aware of some language-specific and non-language-specific factors that can help.


***It appears that…

(a) ...except in maybe autistic persons, at a certain stage of development the brain naturally starts to discard detail and generalise;
(b) ...the brain operates as it does, letting most experience-data fade, in the interests of operating efficiency : though the brain has the storage capacity to store EVERYTHING we experience in our lives, accessing what we want in all that data would be prohibitively slow if we went this route (so the recent theory goes.)

(One theory also contends this is why normal adult brains generalise instead of being open to every iota of detail like Asberger’s / autistic people who can remember and reproduce unusual amounts of data, Rain Man-style.)

***The brain stores in long-term memory things perceived to be related personally to one’s self because the part of the brain that deals with “personal stuff” also deals with long-term memories.

***Memories can be associated with and triggered by sense stimuli esp. I think smell.

Scientists have discovered our favourite dishes are not determined so much by taste but rather associations with positive events i.e. when we were feeling happy etc.

***Attaching a story or what I would call an other “meaningful” mnemonic hook interconnecting elements of data to be memorized is how the world memory champs do their thing.

***Finally, these are just my pet theories, but I think some memories must be written more indelibly in one’s brain/body neural system if…

(a) ...they are perceived as high-priority “important”
(b) ...they are associated with high-priority “important” events, stimuli etc.

For example, unusually “positive” and “negative” experiences seem to be held on longer.

A strong emotion associated with some experience-data
seems to ensure
it will not necessarily always be in the forefront of operating memory,
but can be recalled, whether one wishes to or no,
years down the track.

One wonders if this evolved in us and was retained
because it helped our forerunners survive by :

(i) remembering and thus avoiding
“conflict” or “danger” events or situations
associated with high feelings etc. of
anger, fear, hate, stress etc.
(consider maybe Vietnam vet flashbacks of traumatic events); well as, perhaps…
(ii) remembering and thus seeking

actions or situations
associated with high feelings etc. of
“comfort”, love, pleasure, relaxation, “safety” and “security” –
a sense of “wellbeing”
(think, say, of your most pleasurable memories
of time spent with partner, children, friends and family
in pleasant activities).

Note that my theories (a) and (b) above may be related to the principles of perceived personal connection or relevance and senses e.g. smell being associated with and triggering a memory, which suggests they are correct.



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3 Answers

asmonet's avatar

No need to yell. :)

nikipedia's avatar

Hi. I am a graduate student in neuroscience and I know a little bit about learning and memory. This was sort of a long question and I’m not sure I followed it entirely, but I am happy to answer your title question, which I read as: what determines which memories are retained as long-term memories, and which are discarded?

The easy answer is that memories follow a “use it or lose it” rule. Memories that are accessed repeatedly are physically woven into your neural fabric more tightly and are therefore less likely to be discarded.

More precisely, long-term memory encoding begins in an area of the brain called the hippocampus. When an event causes one cell in the hippocampus—which we’ll call the “presynaptic cell”—to talk to a second cell, which we’ll call the “postsynaptic cell”—the postsynaptic cell becomes filled with calcium ions. If this signal is strong enough, and calcium fills the cell quickly enough, it triggers a cascade of proteins that are signaled by calcium (important proteins in this cascade include calcium/calmodulin kinase II, protein kinase C, protein kinase A, and mitogen activated kinase).

These proteins are then activated by a process called “phosophorylation”, which basically means little “on” switches are flipped and the proteins can do their thing. For the most part, they activate transcription factors (like extracellular signal-regulated kinase) that can initiate gene expression and protein synthesis. The end result of this protein synthesis is that the postsynaptic cell physically changes. It grows more dendritic spines and builds more receptors so that it becomes more sensitive to the presynaptic cell.

You are absolutely correct to point out that this process is linked to smells. The hippocampus is located next to the smell center in your brain and has many connections both to it and from it.

You are also correct that emotional salience can cause a memory to become more strongly encoded. Stress hormones like epinephrine and cortisol can modulate the cellular processes outlined above, but for more detail on this I would like to turn you over to the granddaddy of emotional memory research, James McGaugh:

If you can’t access that article I would be happy to email it to you. It’s a very lovely and thorough review of memory consolidation.

Hope this answered your question, or at least began to. Let me know if I can clarify anything.

cookieman's avatar

h e a d h u r t s

need cannoli

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