Cell renewal

Oct 31, 2012

Discussion by: Lizzie1
Watching new series with pleasure. The point in the programme where cell renewal was discussed , esp the memory of a memory of a memory left me wondering. I know that some memories get distorted as we age but the number of accurate memories people have from early childhood on must be staggering. Is this just happenstance because certain links/cells don’t renew at the same time or is there a more complicated mechanism involved? (and by that I don’t mean a soul – promise I’m not a god botherer).

13 comments on “Cell renewal

  • 2
    papa lazaru says:

    Yup. Kinda clueless. I know there was a cool CGI documentary on the BBC called the Secret Life Of The Cell couple of weeks ago, but I don’t think you’re referring to that, unless they made it into a mini series? Was a bloody brilliant bit of popular science. 

    Think of this kind of animation made for the general public, an hour long.


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  • While I’m at a loss too as to what programme you may be referring to, I do know something about memory. The first thing to say here is that we don’t really know about this subject with any good measure of certainty. But, as far as we can tell today, when you retrieve a memory you are actually taking it to a “labile” state (it’s believed this helps in updating memories, so, for example, you can update the now “labile” memory if a place that provided food no longer does so), which means that in a way you are “rewriting” the same memory over and over each time you access it, explaining perhaps why some memories may become “corrupted” as time goes on (I’m pretty sure we have all experienced one memory getting mixed up with another, and we are not sure how things actually went *that* time?, that could happen because we were “accesing” – i.e. remembering – memory A, when event B was being “recorded” as memory B).

    Now, where is this “memory” information recorded in the cell? It’s specifically at the synapse (that’s the connection between two neurons), and we have evidence to think these  processes can last years or even decades (which would correlate well with the durations of memories). Also, a single memory is apparently stored in several points of the brain (brain scans show different areas being activated at the same time when recalling a specific memory, so you activate a region related to emotions, anotehr to smells and etc to get the “whole picture”).

    Your question is interesting because one of the major areas involved in memory is the hippocampus, a part of the brain with active cell renewal (cell replication), which would mean the memories would be destroyed before too long once renewal has done it’s thing. I think – but my memories are fuzzy here – that said memories in the hippocampus are later “transferred” from the hippocampus to other parts of the brain for long-term storage, we call this consolidation of long-term memory (since most of the brain doesn’t have cell replication, they can safely be stored for decades in these other areas).

    Now this are all examples of how it *could* be, not necessarily how *it is*. Even if it turns out to be largely true, most probably it won’t hold for all kinds of memories and… stuff. I hope this was somewhat clear, if you are interested in the biology of memory (who isn’t?) you can google for terms like “long-term potentiation” and “long-term depression” which are the processes I said occurr at the synapse in neurons.

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  • I read an excellent pop science book recently: Daniel Coyle – The Talent Code.

    He discusses sports and music performance, and the associated learning processes. The myelenation of neurons is particularly important for laying down prominent neural pathways. And repetition in conjunction with various hormones is an important part of the process. The strongest childhood memories would like be those associated with intense emotion and repetition.

    Another good book on this stuff is Steven Pinker – How the Mind Works.

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  • 8
    Lon Bierma says:

    The great Sigmund Freud, a fellow atheist, taught us that we suffer nearly total amnesia of our early childhood thoughts, especially those that had an emotional impact. Those memories are not totally lost, but repressed to a mental structure which he named the unconcious. They can be be retrieved via hypnosis or psychoanalysis. Any cursory reading of Freud’s works will provide great insight into the mechanics of forgetting. An early physiologist he understood that thoughts had to have physical constructs, but then and I must add now, those processes were ill understood.

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  • 9
    This Is Not A Meme says:

    The new series is Sex, Death, and the Meaning  of Life, yeah?

    I believe you may be referring to confabulation, in terms of memory distortion. Confabulation occurs in any system (memory, number sets, social systems, physical systems, any system) when information is absent or lost. The rest of the information suggests what is missing, and if the system is capable of self-repair to any degree, the restored section may differ from the original. In terms of memory, this can occur from cellular damage, but not necessarily. Confabulation occurs constantly in our minds, filling in gaps through inference.

    One great source of false and altered memories is hypnosis. Age regression hypnosis used to be mistaken for something like time-travel. While a person is under, they know what childhood is and they construct a convincing reality from their imagination. The subject also understands that children have crude handwriting, and while hypnotized they contrive their handwriting, but these samples do not match authentic samples from the subject’s youth. Still, the subject experiences childhood in a way indistinguishable from ‘authentic’ memories.

    Memories can be tinkered with and can reflect things as petty as political beliefs. Imagination is an integral aspect in the creation and recall of memory, and sometimes this corrupts the data to a noteworthy degree.

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  • While it’s true that “we suffer nearly total amnesia of our early childhood thoughts…”, I can’t recall any research supporting the idea that this especially true of “…those [memories] that had an emotional impact.”. Further, the reason why they are not remembered is probably not due to any active repression – it is more likely that permanent memories are not formed because of all the synaptic reshaping and programmed cell death (called synptic pruning) going on at that time – the brain is literally in a constant state of wiring and rewiring itself in response to the masses of stimuli bombarding it. This is a necessary process and a by-product may plausibly be a lack of memory from that time.

    There has, however, been reseach (see Elizabeth Loftus) into whether early childhood memoeies “…can be be retrieved via hypnosis or psychoanalysis.” with the consistant finding that they cannot. In addition, such participants often come to believe that they remeber events which are known not to have occured at all (these are called false memories’).

    Freud had little or no rigorous experimental data to use in developing his thoughts about memory (not to mention the rest of human psychology) and consequently the idea that “Any cursory reading of Freud’s works will provide great insight into the mechanics of forgetting.” is false – that is why freud recieves a couple of lectures in the ‘history of psychology module’ and none in the memory section of a ‘cognitive psychology module’ (at least on the British Psychological Society accredited course I did for my undergraduate).

    I can agree with the last sentence “An early physiologist [Freud] understood that thoughts had to have physical constructs, but then and I must add now, those processes were ill understood.”, but I must add that they are understood much better now than in Freud’s day – and this is thanks to the mass of empirical, quantitative data gained through righourous experiments (e.g. questionnaire, memory recall rates, reation time experiments, neuropsychological and electrophysiological) gathered over the last 60-70 years, and owes very little to Freuds wild speculations.

    (I don’t know how use the quote thing)

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