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Re: [Indo-Eurasia] Middle Paleolithic footwear

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  • VictorM
    Hmm, Steve. Are you saying there are no localized functional areas in the brain? What do studies about **brain damage** tell us in regard to your claim?
    Message 1 of 13 , Feb 1, 2008
      Hmm, Steve. Are you saying there are no localized functional areas in
      the brain? What do studies about **brain damage** tell us in regard to
      your claim? Aphasia? Neurocognitive deficits and disorders linked to
      physical changes in *particular parts* of the brain? My former
      colleague, Jerry Packard, did extensive studies on the different effects
      regarding linguistic ability that resulted from damage to particular
      areas of the brain. He based some of his work on the research of Michel
      Paradis.

      Are you saying that brain functions are distributed indiscriminately
      throughout all parts of the brain? Why would brain scientists even use
      a term like Broca's AREA if there weren't some sort of localization
      going on?

      Are you saying that as much cognition takes place in the medulla
      oblongata as in the cerebrum, and that as many autonomous functions are
      controlled by the cerebrum as by the medulla oblongata? That there is
      no distinction between the overall function of the cerebrum and the
      overall function of the medulla oblongata? That balance and movement
      are controlled just as much outside of the cerebellum as inside of it?

      There's a LOT more I could write about this, but I doubt that it would
      be of any use.

      Best,

      Victor




      Steve Farmer wrote:
      >
      > Victor writes:
      > No one doing any serious work in the neurosciences
      > has accepted localization theories like this for a long time.
      >
    • Steve Farmer
      Dear Victor, ... There are no localized brain areas in the simple way that you were describing them ( cognition being localized in frontal regions). That is
      Message 2 of 13 , Feb 1, 2008
        Dear Victor,

        You wrote:

        > Are you saying there are no localized functional areas in
        > the brain?

        There are no localized brain areas in the simple way that you were
        describing them ("cognition" being localized in frontal regions).
        That is well known, Victor. It isn't at all controversial.

        > What do studies about **brain damage** tell us in regard to
        > your claim? Aphasia? Neurocognitive deficits and disorders linked to
        > physical changes in *particular parts* of the brain?

        It's not my claim, Victor. It's a fact, well confirmed in non-
        invasive imaging studies, and accepted by everyone doing serious work
        in the field. What neuropsychological studies (studies of brain-
        damaged subjects) tell us is that in a heavily distributed network
        system that if you take out key hubs you can damage a function
        more than if the damage occurs elsewhere. But that doesn't mean that
        the function is localized in that region. Language is a good example.
        If you have lesions in (say) Broca's area or Wernicke's area (what
        older textbooks call "language areas"), you'll get particular kinds
        of language deficits, or aphasias. But that doesn't mean, as they
        claimed in the heyday of module theories (e.g. Fodor 1983) that
        language is "localized" there. Sensitive neuropsychological measures
        will in fact show that you will get linguistic dysfunctions if you
        damage just about any cortical or subcortical region in the brain,
        e.g. the basal ganglia. There are thousands of papers (that
        is no exaggeration) and hundreds of books that cover this. I think
        the best overview (of hundreds) is presented in Friedemann
        Pulvermuller's studies, e.g., _The Neuroscience of Language. On Brain
        Circuits of Words and Serial Order_, Cambridge U. Press 2003. But the
        choice is almost arbitrary. Here's a link to that book:

        http://tinyurl.com/3bcata

        It is a very fine study, and every chapter deals in part with this
        question. But again, this is not controversial. Even Lieberman's
        book, that I mentioned yesterday, will do. He spends a great deal of
        his time dealing with this specific issue, and pounds away (a bit
        redundantly) on the issue of models of language based on Broca's area
        and Wernicke's area being wrong. Here's a link to a 2002 paper of his
        in the Yearbook of Physical Anthropology ("On the Nature and
        Evolution of the Neural Bases of Human Language"), which is much
        better than his recent book, that covers this issue in depth.

        The first lines: "The traditional theory equating the brain bases of
        language with Broca's and Wernicke's neocortical areas is wrong".
        Link to the full paper:

        http://tinyurl.com/ydqy5q

        > My former colleague, Jerry Packard, did extensive studies on the different
        > effects regarding linguistic ability that resulted from damage to particular
        > areas of the brain. He based some of his work on the research of
        > Michel Paradis.

        Studies of brain damage until neuroimaging techniques came around
        were the bread and butter of the field, Victor. Their limitation, as
        pointed out long ago by classical neuropsychologists like Luria, was
        that lesions are rarely truly focal: the bullet that hits you in the brain
        or granny's stroke causes diffuse damage. But, in any event, last year
        there were 35,000 papers published in neurobiology, and that number
        is expected to go up by 30% this year. Old views (like localized
        cognitive functions) are long gone. Mahesh Jayachandra (on our
        List), who is both a neurologist (MD) and neurophysiologist (PhD)
        exchange published papers on this and similar topics daily, and
        discuss them, nearly without fail. You have to read those technical
        papers to follow the field. Keeping up is quite difficult, as Mahesh
        could tell you.

        > Are you saying that brain functions are distributed indiscriminately
        > throughout all parts of the brain?

        They are not distributed "Indiscriminately" -- we're not back in Karl
        Lashley's day (d. 1958!), who spoke of the "equipotentiality" of the
        neural networks. But they are widely distributed in many areas, and
        were certain things are encoded varies quite widely even in single
        individuals.

        Let's take language as an example, since you've brought it up and
        I've recently written a section of this in my book. To pick just one
        example of the complexities of distributed processing:
        the processing of individual words has been shown to occur in
        different parts of the brain depending on the language being spoken
        (Valaki et al. 2004), on whether the speaker is literate or
        illiterate (Peterson et al. 2000; Li et al. 2006), on the class of
        words being processed (e.g., verbs or nouns) (Damasio et al. 1996;
        Martin et al. 1996), and even on whether the meanings of the words
        are known from first-hand experience (for example, from milking a
        cow) or second-hand (just from reading or hearing about a cow or
        seeing its picture) (cf. Pulvermuller 2002, 2003). Locations of
        encoding can also change as a language user’s experience with the
        meanings of a word change over time (you finally milk that cow!).
        Many of these findings, which depend in part on non-invasive imaging
        studies, show how far we’ve come from the simply “language module”
        theories of the past.

        > Why would brain scientists even use
        > a term like Broca's AREA if there weren't some sort of localization
        > going on?

        See above, e.g., the discussion in Lieberman's 2002 paper.

        > There's a LOT more I could write about this, but I doubt that it would
        > be of any use.

        Best,
        Steve
      • mahesh_jayachandra
        ... Dear Victor and the List, I concur with Steve about localization and distributed functions in the brain. His point of view is common knowledge and not
        Message 3 of 13 , Feb 1, 2008
          Victor Mair wrote to Steve:

          >Hmm, Steve. Are you saying there are no localized functional areas in the brain?

          Dear Victor and the List,

          I concur with Steve about localization and distributed functions in
          the brain. His point of view is common knowledge and not
          controversial in cognitive neuroscience.

          Steve has a good view of progress and new research in the field and
          knows as much neurobiology (actually more, sometimes) than most of the
          people I have worked with.

          For sometime now, we've had a practically daily interaction on
          integrating history with the brain. This integration is important and
          fortunately, we seem have enough data and software tools to begin.

          There are few generalists (foxes as opposed to porcupines) in
          neuroscience. Francis Crick was a famous exception - and he was an
          "outsider".

          Cheers!
          Mahesh
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