From: Robin Hanson (rhanson@gmu.edu)
Date: Mon May 08 2000 - 14:50:14 MDT
>NATURE NEWS UPDATE
>Tuesday 21 March 2000
>
>Does not compute
>
>JOHN WHITFIELD
>
>Old people tend to have worse eyesight. But, as Audie Leventhal and
>co-workers, of the University of Utah, have discovered, this isn't
>necessarily because they have worse eyes. It could be because their brains'
>image-analysis software has gone awry.
>
>A brain region called the 'primary visual cortex' pieces together nerve
>impulses from the eyes into a basic picture of the world, which it passes on
>to other bits of the brain that give meaning to what we see.
>
>The primary visual cortex employs specialists to get the job done. Some nerve
>cells, for example, are particularly sensitive to vertical lines, while
>others respond to horizontal lines. This is called 'orientation bias', and
>allows the brain to assess the shape of objects. Other neurons act as motion
>detectors, firing in response to objects moving left, or right, say, due to
>their 'direction bias'.
>
>Full text:
>http://helix.nature.com/nsu/000323/000323-4.html
This is disturbing; it suggests that ordinary brains get worse as
they get older. It's not that they stay fine and the body they
run gets worse.
Robin Hanson rhanson@gmu.edu http://hanson.gmu.edu
Asst. Prof. Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030
703-993-2326 FAX: 703-993-2323
This archive was generated by hypermail 2.1.5 : Fri Nov 01 2002 - 15:28:30 MST