Monday, May 10, 2010

Neuroethology Chromakey

What do bats and electric fish have in common? They both are case studies of Neuroethology, which is the study of brain habits in animals, where they come from, and what they become in humans.

Bats make and receive ultrasound to see around the room, with echolocation. Electric fishes likewise see with their electrical fields. They have something called an "anti-jamming response" which is basically an hysterical phase locked loop- instead of locking onto the frequency of nearby fish, they will move away in frequency, so that each individual fish has its own vibration to "see" with.

This is called "jamming avoidance response" and is seated in the mesencephelon, where it is calculated by differencing two types of neurons, one following the fish's own vibration, the other a differential of the other fish's. This is in "weakly electrical fish" such as the Eigenmania, not strong guys like the eels.

I have been thinking about frequency diversity in the new Deerhorn circuit. It actually uses a PLL to lock onto a radio oscillator, and create a CV from the error signal. But each separate circuit board should not lock onto each other. For now, I am using discretely different inductors to span a range of frequencies, but I wonder if a hysteric PLL can be designed like the electric fishes'?

The phenomena of Neuroethology are best documented by a combination of live video of the organism plus graphs of various functions such as voltage or frequency. That is where chromakeying came in, how I came across "Neuroethology" today. Many scientists use chromakey to squeeze all their data into one video stream, also subjecting the electric fishes to an electric blue background.

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