From: tolman@asylum.cs.utah.edu (Kenneth Tolman)
Newsgroups: sci.virtual-worlds
Subject: Re: SCI: Direct Neural-Electronic Interfacing
Date: 14 Nov 92 04:40:27 GMT
Article-I.D.: u.1992Nov16.030501.21532
Organization: University of Utah, CompSci Dept
Originator: hlab@stein.u.washington.edu



>****** DIRECT NEURAL - ELECTRONIC INTERFACING *****************************

>Can someone tell me if there's any work being done at the moment on direct
>hardware - wetware interfacing techniques? By this I mean methods by which 
>VR environments may be manipulated directly by, say, an EEG interpreter
>converting stimuli received from skull electrodes; or more surgically
>invasive equipment a la Known Space-like 'drouds' or 'jacks'. 

Here at the University of Utah there is a bioengineering project which
involves direct implantation of stimulating electrodes in the visual
cortex.  I went to a lecture on it, and surprisingly the researchers
have little or no awareness of virtual reality, they are interested in
providing sight to the blind.

The implantation device consists of a small (1 cm) silicon board with
around 100 tiny 150 micron spikes with a metallic point.  This board
is literally shot into the brain on the visual cortex, on one of the
"ridges".  It needs to be injected with high velocity or it does not
get pushed into the brain, it merely crushes the brain down and causes
cell damage. (like pushing on cheese with a blunt knife, push fast and
hard)

They provided results that demonstrated the functionality of the board
6 months after implantation into a cat, with no apparent brain injury.

This board directly stimulates the active visual cortex, which lies
just beneath the surface of the brain.  Alternatively, it can record
electrical activity.  The device at present is pretty weak.. it only
has 100 pixels resolution, and takes up a very small area of the visual
field.  The amount of the visual field is equivalent to a thumb nail
held at arms length, that is TINY!

They hope to have functional systems for humans in the early 2000's, which 
will only be for blind people (perhaps deaf people) and will not provide
extensive vision.  It is not likely this system will allow for full
immersion for a number of reasons:

  1) The whole visual field is directly mapped onto the cortex surface,
which undulates up and down, most of which is inaccessible for this type
of implantation.  Thus, these boards could be placed all along the
ridges which would provide a form of patchwork vision.

  2) The devices are pretty crude, and a single board has caused no
rejection problems or brain damage but it is likely that many boards would
have a multiplied risk factor.

  3) Our ignorance of brain signal integration is embarressing.. these
boards eliminate all of the preprocessing in the retina, and multiple
signal crossovers and so forth.  We will need to understand much more
to build even adequate direct neural interfaces.

  I predict that full direct neural immersion will not be available for
200 years, and that it will require biosynthetic wiring which provides
an interface from the neuron to the computer.  External hardware devices
may remain much in vogue until all the glitches are out of direct
interfacing, which would require another 50 years on the above figure.
Newsgroups: sci.virtual-worlds