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Feb 03 2014

I always wanted to understand myself

This should be good: Jennifer Ouellette has a new book out, Me, Myself, and Why: Searching for the Science of Self . From her description of the contents, it sounds like it’s a sensible approach to the current state of the science, recognizing that there is a genetic component to human behavior and a large learning component.

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  1. 1
    David Wilford

    This from research on genetically identical mice placed in different environments is interesting:

    Where Does Identity Come From?

    … The most interesting part of the study, however, came when the researchers examined the brain changes that paralleled the changes in exploratory behavior. Before ending the experiment, the mice were injected with a compound that’s selectively incorporated into dividing cells, and hence labels adult-born neurons. While most neurons are fashioned during early development, there are a handful of well-studied brain areas in which new neurons are continuously produced even in adulthood.

    Strikingly, the mice which were the “wanderers” at the end of the study were also those who experienced the greatest proliferation of adult-born neurons. While the usual caution of correlation not implying causation applies here, the result is still intriguing. Even after the genetic die are cast at conception, and after the bulk of the neural scaffolding is laid down in early life, the brain maintains a trickle of raw potential through its ability to grow a limited number of new neurons. The authors conjecture that these neurons are involved in tailoring and tuning our behaviors, applying context-specific corrections and adjustments to the more hard-coded aspects of our behavior. In their words, the ways in which we live our lives may make us who we are.

    http://www.scientificamerican.com/article/where-does-identity-come-from/

    I’m tickled by this because my New Year’s resolution this year was to get out more. So far, so good, despite the brutally cold weather.

  2. 2
    Sastra

    David Wilford #1 quoted:

    In their words, the ways in which we live our lives may make us who we are.

    An interesting excerpt, but this part made me smile because it sounds like the true-but-trivial side of a deepity. It reminds me of those personality tests in magazines aimed at teenagers. “Your favorite color/pet/style of relaxing may reveal who you are.” I can visualize a new article along those lines: “What the way you live your life can tell you about your personality.” Insecure as a teenager, I always took those tests.

    From the article:

    9. When I die, and my brain shuts down for good, my self will cease to exist, because consciousness is emergent. It is a real thing—I think, anyway, although some very smart people disagree—but it is still a product of that constant flow of neural information in the brain.

    Uh oh, there goes the ‘Spirituality’ market. She may have lost a good chunk of the audience which buys and reads books about understanding the Self.

  3. 3
    David Wilford

    Sastra @ 2:

    I don’t think Dan Dennett would characterize new neural development as a mere deepity. I’m currently having fun getting back into playing music after a hiatus of over thirty years since my early college days, and rediscovering how practice still makes for better playing through muscle memory development. I’ve never stopped listening to music, but the act of playing and listening at the same time is also giving my mind’s ear a good workout as well as I try to anticipate what the next note/chord/word should be. I’m basically an introvert, but I’m getting to like performing songs in front of others because it’s about the song, not me. But it’s still me singing, of course. I think Pete Seeger had the right idea when it came to getting everyone to sing and engage with music rather than being only a passive listener, because it activates you. And Pete was absolutely an activist.

  4. 4
    Sastra

    David Wilford #3 wrote:

    I don’t think Dan Dennett would characterize new neural development as a mere deepity.

    Oh, I agree! That was an intersting finding. It’s just that out-of-context it sounded like a deepity, especially when combined with the ‘search for self’ meme of my adolescence.

    Play on!

  5. 5
    Fukuda

    @David Wilford #1

    While the process Jason Castro is describing in that article (hippocampal neurogenesis) is in itself very interesting, it’s far from the most relevant neural process he could’ve used to write about identity, really.

    The birth of new neurons in that specific region (the hippocampus) is a well-known phenomenon related to several important cognitive functions, such as memory and spatial navigation, but it’s not directly related to the self or consciousness. Such aspects of behavior are more high-level phenomena so to speak.

    According to the latest models (see Sahay et al. 2012 ), the role of these newly born cells is directly related to spatial (and temporal, see later) navigation. You can imagine the hippocampus as a brain structure forming a giant lookup table in which the individual neuron’s firing represents the animal’s surrounding space, each cell (place cell) firing when the animal is in a particular place.

    Every time the animal enters a new environment, this map-like table is updated, and this updating is brought upon by the reading of upstream inputs by the place cells. This “upstream” region is where new neurons are born. The birth of these neurons allowing the circuit to be progressively rewired in order to encode new environments, subsequently improving discrimination of new input patterns by downstream place cells.

    Since this birth is highly regulated, we expect from these models a higher neurogenesis (that is, neuron production) in animals having different lifestyles. Mice living in more “enriched” environments (larger cages, more toys to play with, etc) do indeed show higher neurogenesis (Liu, N. et al. (2012)), which isn’t exactly surprising considering the hippocampus’ role in spatial navigation.

    But the hippocampus is not only able to represent spatial landmarks, its cells are also able to laterally self-associate in order to form interconnected “chains” of places and events. This fact allows it to be also involved in memory and novelty detection (known vs unknown environment/situation). As such, this rewiring is also vital to represent new memories. Increased neurogenesis is indeed found for instance in caching birds relying on their memory to find hidden food (Freas, C.A. (2012)).

    As interesting as it is, neurogenesis doesn’t really involve consciousness or the self per se, as the hippocampus is also involved in several unconscious processes, even in humans (Hannula et al, 2012). With this said, it is trivially true that every brain is individual, as the processes rewiring neurons are dependent on environmental changes.

    Take for instance human language. While humans, like songbirds, have an innately restricted diversity of sounds we can produce (phonemes), our brain is largely rewired while learning a language using just a small fraction of all the possible sounds. Two identical twins, with the same genes, will have a radically distinct brain wiring and structure if taught two very distant languages from each other.

    Quite a lot of brain capacities are innate (as spatial navigation for instance), but a lot of them can be either improved by learning or manufactired from scratch like memories. Independently of genetics, no two brains will be identical.

    Freas, C.A. (2012) Elevation-related differences in memory and the hippocampus in mountain chickadees, Poecile gambeli. Animal behaviour

    Hannula, D.E. et al. (2012) The hippocampus reevaluated in unconscious learning and memory: at a tipping point? Front. Hum. Neurosci

    Liu, N. et al. (2012) Early natural stimulation through environmental enrichment accelerates neuronal development in the mouse dentate gyrus. PLoS One

    Sahay, A. et al. (2012) Increasing adult hippocampal neurogenesis is sufficient to improve pattern separation. Nature

  6. 6
    David Wilford

    Fukuda @ 5:

    Thank you very much for the additional details on neurogenesis. I’m not a neurobiologist by training, but by inclination I’m interested in how our brain actually functions to establish the neural connections that enable the mind to exist and also have the flexibility to adjust to its environment. I don’t think my muscle memory gains change my conscious ‘self’ in a significant way, but I think it affects what that self chooses to do and how it does it.

  7. 7
    varady72

    Well, I personally believe there is a native genetic component involved in EVERY conceivable human act and mode of response.

  8. 8
    Akira MacKenzie

    “Know yourself. If you need help, call the FBI.”

    —National Lampoon,
    “Deteriorata”

  9. 9
    David Wilford

    This NYT profile might be of interest to others here:

    http://www.nytimes.com/2014/02/04/science/blazing-trails-in-brain-science.html

  10. 10
    Thumper: Who Presents Boxes Which Are Not Opened

    @varady72

    Do you now? And your evidence for this belief is…?

  11. 11
    David Wilford

    Perhaps varady72 is merely pointing out you need an organism to have a response, and that organism requires a genetic component to exist.

    My thought is that we’re not that far away from having AI’s that effectively mimic human responses.

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