Fun_People Archive
7 Sep
Nervous Silicon

Date: Thu, 7 Sep 95 14:25:49 -0700
From: Peter Langston <psl>
To: Fun_People
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