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Michel Roland-Guill

How Our Brains Make Memories / Greg Miller | Science & Nature | Smithsonian Magazine - 0 views

  • Nader, now a neuroscientist at McGill University in Montreal, says his memory of the World Trade Center attack has played a few tricks on him. He recalled seeing television footage on September 11 of the first plane hitting the north tower of the World Trade Center. But he was surprised to learn that such footage aired for the first time the following day. Apparently he wasn’t alone: a 2003 study of 569 college students found that 73 percent shared this misperception.
  • In short, Nader believes that the very act of remembering can change our memories.
  • Nader was born in Cairo, Egypt. His Coptic Christian family faced persecution at the hands of Arab nationalists and fled to Canada in 1970, when he was 4 years old
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  • Memories surrounding a major event like September 11 might be especially susceptible, he says, because we tend to replay them over and over in our minds and in conversation with others—with each repetition having the potential to alter them.
  • He attended college and graduate school at the University of Toronto, and in 1996 joined the New York University lab of Joseph LeDoux, a distinguished neuroscientist who studies how emotions influence memory.
  • Scientists have long known that recording a memory requires adjusting the connections between neurons. Each memory tweaks some tiny subset of the neurons in the brain (the human brain has 100 billion neurons in all), changing the way they communicate. Neurons send messages to one another across narrow gaps called synapses. A synapse is like a bustling port, complete with machinery for sending and receiving cargo—neurotransmitters, specialized chemicals that convey signals between neurons. All of the shipping machinery is built from proteins, the basic building blocks of cells.
  • In five decades of research, Kandel has shown how short-term memories—those lasting a few minutes—involve relatively quick and simple chemical changes to the synapse that make it work more efficiently. Kandel, who won a share of the 2000 Nobel Prize in Physiology or Medicine, found that to build a memory that lasts hours, days or years, neurons must manufacture new proteins and expand the docks, as it were, to make the neurotransmitter traffic run more efficiently. Long-term memories must literally be built into the brain’s synapses. Kandel and other neuroscientists have generally assumed that once a memory is constructed, it is stable and can’t easily be undone. Or, as they put it, the memory is “consolidated.”
  • under ordinary circumstances the content of the memory stays the same, no matter how many times it’s taken out and read. Nader would challenge this idea.
  • Work with rodents dating back to the 1960s didn’t jibe with the consolidation theory. Researchers had found that a memory could be weakened if they gave an animal an electric shock or a drug that interferes with a particular neurotransmitter just after they prompted the animal to recall the memory. This suggested that memories were vulnerable to disruption even after they had been consolidated.
  • the work suggested that filing an old memory away for long-term storage after it had been recalled was surprisingly similar to creating it the first time
  • In the winter of 1999, he taught four rats that a high-pitched beep preceded a mild electric shock. That was easy—rodents learn such pairings after being exposed to them just once. Afterward, the rat freezes in place when it hears the tone. Nader then 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 on 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.
  • When Nader later tested the rats, they didn’t freeze after hearing the tone: it was as if they’d forgotten all about it
  • After Nader’s initial findings, some neuroscientists pooh-poohed his work in journal articles and gave him the cold shoulder at scientific meetings. But the data struck a more harmonious chord with some psychologists. After all, their experiments had long suggested that memory can easily be distorted without people realizing it.
  • To Nader and his colleagues, the experiment supports the idea that a memory is re-formed in the process of calling it up. “From our perspective, this looks a lot like memory reconsolidation,” says Oliver Hardt, a postdoctoral researcher in Nader’s lab.
  • “When you retell it, the memory becomes plastic, and whatever is present around you in the environment can interfere with the original content of the memory,” Hardt says.
  • The question is whether reconsolidation—which he thinks Nader has demonstrated compellingly in rat experiments—is the reason for the distortions.
  • at the Douglas Mental Health University Institute. Alain Brunet, a psychologist, is running a clinical trial involving people with post-traumatic stress disorder (PTSD). The hope is that caregivers might be able to weaken the hold of traumatic memories that haunt patients during the day and invade their dreams at night.
  • In Brunet’s first study, PTSD patients took a drug intended to interfere with the reconsolidation of fearful memories. The drug, propranolol, has long been used to treat high blood pressure, and some performers take it to combat stage fright. The drug inhibits a neurotransmitter called norepinephrine. One possible side effect of the drug is memory loss.
  • Nine patients took a propranolol pill and read or watched TV for an hour as the drug took effect. Ten were given a placebo pill. Brunet came into the room and made small talk before telling the patient he had a request: he wanted the patient to read a script, based on earlier interviews with the person, describing his or her traumatic experience. The patients, all volunteers, knew that the reading would be part of the experiment. “Some are fine, some start to cry, some need to take a break,” Brunet says. A week later, the PTSD patients listened to the script, this time without taking the drug or a placebo. Compared with the patients who had taken a placebo, those who had taken the propranolol a week earlier were now calmer; they had a smaller uptick in their heart rate and they perspired less.
  • The treatment didn’t erase the patients’ memory of what had happened to them; rather, it seems to have changed the quality of that memory. “Week after week the emotional tone of the memory seems weaker,” Brunet says. “They start to care less about that memory.” Nader says the traumatic memories of PTSD patients may be stored in the brain in much the same way that a memory of a shock-predicting tone is stored in a rat’s brain. In both cases, recalling the memory opens it to manipulation.
  • Nader suggests that reconsolidation may be the brain’s mechanism for recasting old memories in the light of everything that has happened since. In other words, it just might be what keeps us from living in the past.
  • Elizabeth Loftus
  • Karim Nader
  • Eric Kandel
  • Brunet
  •  
    may 2010
Michel Roland-Guill

Your Outboard Brain Knows All - 0 views

  • My point is that the cyborg future is here. Almost without noticing it, we've outsourced important peripheral brain functions to the silicon around us.
  • Of course, it's probably not an either/or proposition. I want both: I want my organic brain to contain vast stores of knowledge and my silicon overmind to contain a stupidly huge amount more.
  • by offloading data onto silicon, we free our own gray matter for more germanely "human" tasks like brainstorming and daydreaming
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  • the surreal and delightful experience of Googling a topic only to unearth an old post that I don't even remember writing
  • it's what author Cory Doctorow refers to as an "outboard brain."
  • There's another type of intelligence that comes not from rapid-fire pattern recognition but from slowly ingesting and retaining a lifetime's worth of facts.
  • You read War and Peace.
  • Then you let it all ferment in the back of your mind for decades, until, bang, it suddenly coalesces into a brilliant insight.
  • We've come to think of human intelligence as being like an Intel processor, able to quickly analyze data and spot patterns. Maybe there's just as much value in the ability to marinate in the seemingly trivial.
Michel Roland-Guill

Rough Type: Nicholas Carr's Blog: Minds like sieves - 2 views

  • we may be entering an era in history in which we will store fewer and fewer memories inside our own brains.
    • Michel Roland-Guill
       
      conclusion un peu rapide: plutôt que moins de mémorisation ce peut être une différente forme de mémorisation, plutôt que mémorisation des faits mémorisation des lieux de stockage des faits.
  • external storage and biological memory are not the same thing
  • When we form, or "consolidate," a personal memory, we also form associations between that memory and other memories that are unique to ourselves and also indispensable to the development of deep, conceptual knowledge. The associations, moreover, continue to change with time, as we learn more and experience more. As Emerson understood, the essence of personal memory is not the discrete facts or experiences we store in our mind but "the cohesion" which ties all those facts and experiences together. What is the self but the unique pattern of that cohesion?
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  • We are becoming symbiotic with our computer tools
  • "when people expect to have future access to information, they have lower rates of recall of the information itself and enhanced recall instead for where to access it."
  • "It seems that when we are faced with a gap in our knowledge, we are primed to turn to the computer to rectify the situation."
  • we seem to have trained our brains to immediately think of using a computer when we're called on to answer a question or otherwise provide some bit of knowledge.
  • people who believed the information would be stored in the computer had a weaker memory of the information than those who assumed that the information would not be available in the computer
  • believing that one won’t have access to the information in the future enhances memory for the information itself, whereas believing the information was saved externally enhances memory for the fact that the information could be accessed, at least in general.
  • when people expect information to remain continuously available (such as we expect with Internet access), we are more likely to remember where to find it than we are to remember the details of the item.
Michel Roland-Guill

Rough Type: Nicholas Carr's Blog: Killing Mnemosyne - 1 views

  • Isidore, the bishop of Seville, remarked how reading “the sayings” of thinkers in books “render[ed] their escape from memory less easy.”
  • Shakespeare has Hamlet call his memory “the book and volume of my brain.”
    • Michel Roland-Guill
       
      Dante: "In quella parte del libro de la mia memoria, dinanzi a la quale poco si potrebbe leggere, si trova una rubrica la quale dice: In quella parte del libro de la mia memoria, dinanzi a la quale poco si potrebbe leggere, si trova una rubrica la quale dice: INCIPIT VITA NOVA."
  • Books provide a supplement to memory, but they also, as Eco puts it, “challenge and improve memory; they do not narcotize it.”
    • Michel Roland-Guill
       
      Voir chez Jack Goody comment la mémoire dite "par coeur" dépend de la textualité.
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  • Erasmus, in his 1512 textbook De Copia, stressed the connection between memory and reading. He urged students to annotate their books
  • He also suggested that every student and teacher keep a notebook, organized by subject, “so that whenever he lights on anything worth noting down, he may write it in the appropriate section.”
    • Michel Roland-Guill
       
      Voir Darnton qui récemment voyait dans les livres d'extraits la preuve que les empans brefs ne dataient pas d'hier...
  • kinds of flowers
    • Michel Roland-Guill
       
      > "anthologie"
  • To him, memorizing was far more than a means of storage
  • Far from being a mechanical, mindless process, Erasmus’s brand of memorization engaged the mind fully
    • Michel Roland-Guill
       
      Il faudrait référer cette thématique érasmienne à la problématique plus large de la mémoire et de l'éducation à la Renaissance. Montaigne, Rabelais, "tête bien faite", vs "bien pleine".
  • “We should imitate bees,” Seneca wrote, “and we should keep in separate compartments whatever we have collected from our diverse reading, for things conserved separately keep better. Then, diligently applying all the resources of our native talent, we should mingle all the various nectars we have tasted, and then turn them into a single sweet substance, in such a way that, even if it is apparent where it originated, it appears quite different from what it was in its original state.”
  • Memory, for Seneca as for Erasmus, was as much a crucible as a container.
  • “commonplace books,”
  • Francis Bacon
  • “a gentleman’s commonplace book” served “both as a vehicle for and a chronicle of his intellectual development.”
  • The arrival of the limitless and easily searchable data banks of the Internet brought a further shift, not just in the way we view memorization but in the way we view memory itself.
  • Clive Thompson, the Wired writer, refers to the Net as an “outboard brain”
  • David Brooks
  • “I had thought that the magic of the information age was that it allowed us to know more,” he writes, “but then I realized the magic of the information age is that it allows us to know less. It provides us with external cognitive servants—silicon memory systems, collaborative online filters, consumer preference algorithms and networked knowledge. We can burden these servants and liberate ourselves.”
  • Peter Suderman
  • “it’s no longer terribly efficient to use our brains to store information.”
  • “Why memorize the content of a single book when you could be using your brain to hold a quick guide to an entire library? Rather than memorize information, we now store it digitally and just remember what we stored.”
  • Don Tapscott, the technology writer, puts it more bluntly. Now that we can look up anything “with a click on Google,” he says, “memorizing long passages or historical facts” is obsolete.
    • Michel Roland-Guill
       
      "Google" > inutilité des outils de mémorisation (signets) eux-mêmes!
  • When, in an 1892 lecture before a group of teachers, William James declared that “the art of remembering is the art of thinking,” he was stating the obvious.
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