[Paleopsych] Economist: Modelling the brain: Grey matter, blue matter

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Wed Jun 15 19:46:53 UTC 2005

Modelling the brain: Grey matter, blue matter

    The first serious attempt to build a computer model of the brain has
    just begun

    THE most complex object known to humanity is the human brain--and not
    only is it complex, but it is the seat of one of the few natural
    phenomena that science has no purchase on at all, namely
    consciousness. To try to replicate something that is so poorly
    understood may therefore seem like hubris. But you have to start
    somewhere, and IBM and the Ecole Polytechnique Fédérale de Lausanne
    (EPFL), in Switzerland, propose to start by replicating "in silico",
    as the jargon has it, one of the brain's building blocks.

    In a partnership announced on June 6th, the two organisations said
    they would be working together to build a simulation of a structure
    known as a neocortical column on a type of IBM supercomputer that is
    currently used to study the molecular functioning of genes. If that
    works, they plan to use future, more powerful computers to link such
    simulated columns together into something that mimics a brain.

    In a real brain, a neocortical column is a cylindrical element about a
    third of a millimetre in diameter and three millimetres long,
    containing some 10,000 nerve cells. It is these columns, arranged side
    by side like the cells of a honeycomb, which make up the famous "grey
    matter" that has become a shorthand for human intelligence. The Blue
    Gene/L supercomputer that will be used for the simulation consists of
    enough independent processors for each to be programmed to emulate an
    individual nerve cell in a column.

    The EPFL's contribution to the Blue Brain Project, as it has
    inevitably been dubbed, will be to create a digital description of how
    the columns behave. Its Brain Mind Institute has what is generally
    regarded as the world's most extensive set of data on the machinations
    of the neocortex--the columns' natural habitat and the part of the
    brain responsible for learning, memory, language and complex thought.
    This database will provide the raw material for the simulation.
    Biologists and computer scientists will then collaborate to connect
    the artificial nerve cells up in a way that mimics nature. They will
    do so by assigning electrical properties to them, and telling them how
    to communicate with each other and how they should modify their
    connections with one another depending on their activity.

    That will be no mean feat. Even a single nerve cell is complicated,
    not least because each one has about 10,000 connections with others.
    And nerve cells come in great variety--relying, for example, on
    different chemical transmitters to carry messages across those
    connections. Eventually, however, a digital representation of an
    entire column should emerge.

    This part of the project is expected to take two to three years. From
    then on, things will go in two directions simultaneously. One will be
    to "grow" more columns (the human brain contains about 1m of them) and
    get them to interact with one another. The second will be to work at a
    more elementary level--that is, to simulate the molecular structure of
    the brain, and to look at the influence of gene expression on brain

    Assuming that the growth of computing power continues to follow
    Moore's Law, Charles Peck, the leader of IBM's side of the
    collaboration, reckons it should be feasible to emulate an entire
    human brain in silico this way in ten to 15 years. Such an artificial
    brain would, of course, be a powerful research tool. It would allow
    neurological experiments that currently take days in a "wet lab" to be
    conducted in seconds. The researchers hope, for instance, that their
    simulated brain will reveal the secrets of how certain psychiatric and
    neurological disorders develop. But that is probably not the real
    reason for doing it. The most interesting questions, surely, are
    whether such an artificial brain will be intelligent, or conscious, or

    Rhapsody in blue?

    Some academics, such as Roger Penrose of Oxford University, argue that
    brains do not work in a way comparable with a computer, so any kind of
    simulation that is built on digital architecture and uses traditional
    programming techniques is doomed to failure. Dr Penrose thinks that
    exotic quantum processes are involved in the generation of
    consciousness. The "Blue Brain" project will help to determine whether
    he is right or wrong.

    Henry Markram, the boss of the Brain Mind Institute, and the leader of
    the EPFL's side of the collaboration, stresses that Blue Brain's
    formal goal is not to build an artificial intelligence system, such as
    a neural network. Nor is it to create a conscious machine. The goal is
    merely to build a simulacrum of a biological brain. If the outputs
    produced by the simulation in response to particular inputs are
    identical to those in animal experiments, then that goal will have
    been achieved. On the other hand, he also says, "I believe the
    intelligence that is going to emerge if we succeed in doing that is
    going to be far more than we can even imagine." Watch this space.

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