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I liked the decorative placards for each of the offices… as seen at their San Franscisco HQ today.

I also saw Soft Wired, a pre-print of the founder’s new book on brain plasticity and how to proactively sculpt the sensory cortex to be a better learner

I was reminded of an interesting article I read recently in the MIT Tech Review on Daniela Schiller’s research on memory consolidation and fear training:

“memories are reshaped and rewritten every time we recall an event. And, the research suggested, if mitigating information about a traumatic or unhappy event is introduced within a narrow window of opportunity after its recall—during the few hours it takes for the brain to rebuild the memory in the biological brick and mortar of molecules—the emotional experience of the memory can essentially be rewritten.”

In animal studies, a Pavlovian response can be erased with one ECT timed to occur right after the trigger event. And by interfering with protein synthesis in the amygdala, memories could be erased after their recall.

The biochemical work suggested that “memories essentially had to be neurally rewritten every time they were recalled.”

And “intervening during the brief window when the brain was rewriting its memory offered a chance to revise the initial memory itself while diminishing the emotion (fear) that came with it. By mastering the timing, the NYU group had essentially created a scenario in which humans could rewrite a fearsome memory and give it an unfrightening ending. And this new ending was robust: when Schiller and her colleagues called their subjects back into the lab a year later, they were able to show that the fear associated with the memory was still blocked.”

And the enigmatic conclusion: “if we are all rewriting our memories every time we recall an event, the memory exists not as a file in our brain but only as the most recent rewrite of a scenario. Every memoir is fabricated, and the past is nothing more than our last retelling of it. Archival memory data is mixed with whatever new information helps shape the way we think—and feel—about it. “My conclusion,” says Schiller, “is that memory is what you are now. Not in pictures, not in recordings. Your memory is who you are now.”

“The safest memories are those you never remember.”

And that, well, that blew my mind.

7 responses to “Posit Science”

  1. js.brain Avatar
    js.brain

    Fascinating! So we have to recall nice memories and we have to keep them now!

    Reply
  2. jurvetson Avatar
    jurvetson

    [http://www.flickr.com/photos/jsbrain] — Yes… and the part that really challenges my notions of perception and reality is the rewriting of memories with each recall. Hawkins started to lift the veil of free will and the sanctity of “self” with his memory-prediction model of the brain, where our perceived world is internally generated from our memory constructs with new sensory input registering only when it differs from the internal prediction.

    Now Schiller is saying that those internal models are being rewritten with each recall, not just for current “reality” but for our long term memories of the past. So not only is perceived reality mainly a simulation, but also our memories of the past can be reshaped without our perceiving it.

    It’s like discovering reentrant code in our recursive reality.

    When I first read Hawkins (as a former chip designer), I kept seeing comparisons between the different “memories” – those in our head and those in our computers. It seems that the developmental trajectory of electronics is recapitulating the evolutionary history of the brain. Specifically, both are saturating with a memory-centric architecture.

    Hawkins argues that “the brain does not ‘compute’ the answers to problems; it retrieves the answers from memory… The entire cortex is a memory system. It isn’t a computer at all.”

    Rather than a behavioral or computation-centric model, Hawkins presents a memory-prediction framework for intelligence. The 30 billion neurons in the neocortex provide a vast amount of memory that learns a model of the world. These memory-based models continuously make low-level predictions in parallel across all of our senses. We only notice them when a prediction is incorrect. Higher in the hierarchy, we make predictions at higher levels of abstraction (the crux of intelligence, creativity and all that we consider being human), but the structures are fundamentally the same.

    More specifically, Hawkins argues that the cortex stores a temporal sequence of patterns in a repeating hierarchy of invariant forms and recalls them auto-associatively. The framework elegantly explains the importance of the broad synaptic connectivity and nested feedback loops seen in the cortex.

    The cortex is relatively new development by evolutionary time scales. After a long period of simple reflexes and reptilian instincts, only mammals evolved a neocortex, and in humans it usurped some functionality (e.g., motor control) from older regions of the brain.

    Thinking of the reptilian brain as a “logic”-centric era in our development that then migrated to a memory-centric model is analogous to the history of electronics, where we started with speedy processors and logic, and today, over 96% of transistors are for memory not logic, even inside an Intel processor. Is this a fundamental attractor in computation and cognition? Might a conceptual focus on speedy computation be blinding us to a memory-centric approach to artificial intelligence?

    The Brainstorm Wall

    Reply
  3. jurvetson Avatar
    jurvetson

    Oh, and lest anyone think we are drifting off topic with this thread, it is, in fact, intimately related to rockets!
    At least in my mind…

    HBR List: Launching a Better Brain

    Reply
  4. seatonsnet Avatar
    seatonsnet

    As long as we rewrite our memories ourselves, this is very good news, but how long will it be before others appear and organize to rewrite our memories to their benefit?

    Reply
  5. js.brain Avatar
    js.brain

    Thinking of memory as our logic would like to learn more about positive emotional memories:
    "It is known that emotional memories of both a positive and a negative kind are stored by our brain in a particularly robust way.
    Consequently they have a very large effect on our behaviour and, in the case of adverse memories, they can place considerable restrictions on the way we go about our lives. As a result, we avoid places, smells or objects that remind us of the traumatic experience, because they may trigger severe anxieties."
    Another studies: "Sights, sounds and smells can all evoke emotionally charged memories. A new study in rats suggests why: The same part of the brain that’s in charge of processing our senses is also responsible, at least in part, for storing emotional memories."
    Here Schiller is saying: "By mastering the timing, the NYU group had essentially created a scenario in which humans could rewrite a fearsome memory and give it an unfrightening ending. And this new ending was robust: when Schiller and her colleagues called their subjects back into the lab a year later, they were able to show that the fear associated with the memory was still blocked."

    Reply
  6. js.brain Avatar
    js.brain

    And Steve Jobs is a great example of reshaping his memories and give them an unfrightening ending: He said:
    "So at 30 I was out. And very publicly out. What had been the focus of my entire adult life was gone, and it was devastating." ..""But something slowly began to dawn on me — I still loved what I did. The turn of events at Apple had not changed that one bit. I had been rejected, but I was still in love. And so I decided to start over.
    I didn’t see it then, but it turned out that getting fired from Apple was the best thing that could have ever happened to me. "

    Reply
  7. ukweli Avatar
    ukweli

    Our mind is a physical thing!

    Reply

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