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Mind over Computer 13

[Image: Brain Scan]

Brain Image of Fish Hunting Prey

widely distributed in the brain than was first thought. Conscious seeing
is based in the visual cortex, but there are older pathways still active in
the brain that facilitate this unconscious seeing.

The brain is very plastic. Lose your sight through damage to the eye
or optic nerve, and the brain can repurpose the visual cortex to other
uses such as processing sound or touch. Daniel Kish has developed this
to such a high level that he can ride a bicycle despite being blind. He
clicks his tongue against the roof of his mouth and uses echolocation
to form an auditory model of the world around him. Using a similar
approach, Amir Amedi from the Hebrew University of Jerusalem has
built an audio imager that turns pictures of the world into musical sound
patterns. CAT scans of people using this system show they use the visual
cortex to convert these sound images into models of the world in similar
parts of the brain to a sighted person.

We now know roughly what each part of the brain does, but we
have no idea how it does it. The scale of an individual thought is too
small to see in a brain scan. All we can do is observe large-scale electrical
activity associated with those thoughts. A video, from a group at Tokyo
University, shows an example of electrical activity filmed in real time
as a fish hunts for its prey. Fish have transparent bodies and thin skulls
facilitating this sort of imaging. Humans are much harder subjects to
work with!

The most popular theory to explain how brains work is as some form
of computer. Computers are easy to study because we manufacture them.
They tend to crash quite frequently – usually at the most inconvenient

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