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Electronic Circuit Mimics Brain Activity

Posted by Hemos on from the if-i-only-had-a-brain dept.

A lot of people wrote in with the news blurb from Yahoo! regarding the announcement of a ciruit that supposedly acts in a manner resembling human brain activity. Details in the blurb are pretty sketchy though - post links below if ya got 'em. One of the interesting points that they say though is that the brain does both digital and analog - but that's pretty much all they say about it.

4 of 134 comments (clear)

  1. Goddamn do you read submissions? by GoNINzo · · Score: 5
    Jesus guys, do you read submissions? I already researched this for you!

    The Institute that is doing the research has more information here. I believe the guy doing the actual research has more research here.

    Next time you get multiple submissions, try picking the post with more info than the rest instead of attempting to summarize. Especially when you leave out the important links.

    --
    Gonzo Granzeau

    --
    Gonzo Granzeau
    "Nothing the god of biomechanics wouldn't let you into heaven for.." -Roy Batty
  2. Some clarification by Alik · · Score: 5

    I've read the original paper in Nature. (I'd post a link, but I only have access via my university's account, and I have no interest in getting that revoked.) This is not exactly a neural network in the classic sense, although it is similar. The standard neural network is specifically designated an artificial network --- it implements a computational model of neurons. These guys are actually attempting to simulate the known electrical behavior of neurons, in the theory that a network composed of elements that truly mimic neurons will be more brain-like.

    Now. "Digital and analog." This is not a new discovery. It has long been known that neurons have a specific threshold WRT to incoming signal; if the incoming signal does not meet the threshold, the neuron will not fire. If signal is above threshold, the neuron fires. If signal is really above threshold, the neuron fires repeatedly, encoding the strength of the stimulus as the frequency of the train of pulses. (AFAIK, the circuits described here didn't implement that last behavior.) This is a digital response. The output, however, is a continuous voltage at a particular frequency: an analog signal. (Whoever called this "a digital response to analog criteria" is correct.)

    The important thing is that connections between neurons have different weights, and there's often a lot of local feedback. In practice, these feedback loops tend to be tuned so that a given cell will respond only to a fairly specific stimulus (the right light intensity in the right part of your visual field, or facing a certain direction relative to known landmarks, or hearing a sound from a certain direction, for example). These guys have implemented a circuit on silicon that shows the same filtering behavior and also captures the idea that neurons can be "on" or "off".

    Yes, this is kind of neat. Yes, it could eventually lead to advances in AI; at the very least, it could provide useful signal filtering for robotic applications. No, it has nothing to do with plugging your Pentium into your parietal lobe or your Mac into your medulla, at least not until our circuit-design ability is so good that we can entirely mimic the black-box behavior of brain areas. (Hint: we don't even entirely understand that behavior for most regions.)

    I'm also kind of surprised that this made Nature; there are guys at UPenn who've had working neuromorphic circuits for years now. Then again, it's only in the Letters section, and these new guys worked out some mathematical models for the gain of a neural circuit rather than just trying to copy existing ones.

  3. Oh, this too is wonderful.... by mat+catastrophe · · Score: 5
    From the story, "may one day be used to create computers that think more like humans, scientists said on Wednesday."
    User: OK, computer, run Netscape 9.5, please and load the page slashdot.
    Computer: I'm sorry, Dave, I can't do that.
    User: What?!? Why not?
    Computer: Because you didn't properly shut me down last night. You just ran off with that other machine....
    User: Other machine? You mean the laptop? It means nothing to me!!! I just use it when I have to be out of the house!
    Computer: That's too bad. I won't be doing anything else for you as long as that bitch is around!!!!
    Technology: Improving your life, one step at a time!
    --
    sig not found
  4. Quantum computing by jhk · · Score: 5
    Ray Kurzweil's "Age of Spiritual Machines" goes into more depth - that the brain, rather than being digital or analog, is a quantum computer, storing information in quantum states in the brain, which is supposedly a bridge to the next level of processing. It's definitely worth a read, and gives an idea of where this may all be going.

    JHK
    http://www.cascap.org