Date: Thu, 7 Sep 95 14:25:49 -0700
From: Peter Langston <psl>
Subject: Nervous Silicon
[And you thought the ProctoSwitch on your GameBoy was high tech... -psl]
From: Science News, 8/26/95, Vol 148, P.137
A Silicon Chip with a Lot of Nerve
The science fantasy of computers that send signals straight to a brain has
taken a small step toward reality.
Peter Fromherz and Alfred Stett, physicists at the Max Planck Institute of
Biochemistry in Munich, have made a silicon chip that can directly stimulate a
nerve cell. Their so-called silicon-to-neuron junction, reported in the Aug.
21 Physical Review Letters, triggers a single nerve cell in a leech without
killing the cell.
"It is possible now to interface individual neurons with silicon
microstructures in both directions," they say, "from silicon to neuron, by
stimulation of a [membrane] spot, and from neuron to silicon, using a
metalfree field effect transistor."
In previous artificial nerve stimulators, metal leads tended to corrode
and shed toxic by-products. In contrast, the silicon chip propagates a voltage
pulse from a tiny spot on the cell membrane. This causes a buildup of positive
charge that trips a neuronal impulse.
The new chip complements "neuron transistors" that receive ionic nerve
impulses, transforming them into an electric impulse on a silicon chip.
Together, the two microstructures offer the possibility of direct, two-way
communication between a nervous system and machinery.
Still, employing the device for medical purposes -- to control an
artificial limb, for example -- lies far in the distance, the scientists
conclude. Exactly how practical it will prove, they say, "remains to be seen."
© 1995 Peter Langston