Cognitive Daily

Chris Chatham has an excellent summary of a talk by University of Chicago neurologist / mathematician Jack Cowan, who has come up with a mathematical explanation of a variety of common hallucinations.

The development of orientation and spatial frequency maps in V1 [a region of the brain which maps images as they are transmitted from the eyes] can be simulated with some fairly “simple” (maybe simple to Jack Cowan, but not to me!) self-organizing functions, such that “orientation and spatial frequency are the zeroth and first order spherical harmonics” and “the coefficient of the first order representation is just the dot product of the vector of feature preferences with the vector of stimulus features, where the vectors have components given by the first order spherical harmonics. Similar representation can be found for directional motion, binocular disparity, and color.”

You can watch a video of Cowan’s presentation here.


  1. #1 Eric Irvine
    May 26, 2006

    ….. hmm hay, glaven.

  2. #2 Dave Munger
    May 26, 2006

    Okay, Eric, you got me — What’s this “glaven” thing all about? All I could find on Google is an aside in The Simpsons.

  3. #3 MtMan900
    May 26, 2006

    Dave- It is a reference to a character in the Simpsons who is based off of Jerry Lewis’s The Nutty Professor.

    So, he makes all of the weird noises and jerks “hay glaven” and whatnot, but then is pretty much the smartest guy in town. (Until Stephen Hawking came in to save the day)

  4. #4 Dave Munger
    May 26, 2006

    Clearly I need to catch up on my Simpsons — I thought I’d seen a lot of those!

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