Text 449, 298 rader
Skriven 2004-10-21 09:48:00 av Michael Ragland (1:278/230)
Ärende: Re: Interview with Mayr
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Michael Ragland <ragland66@webtv.net> wrote or quoted: 
Hawking touts engineered humans 
Published: September 4, 2001, 12:20 PM PDT 
By CNET News.com Staff 
 
Renowned scientist Stephen Hawking claims that humans should be
genetically engineered if they are to compete with the phenomenal growth
of artificial intelligence. In an interview in the German magazine
Focus, Hawking said the increasing sophistication of computer technology
is likely to outstrip human intelligence in the future. He said
scientific modification of human genes could increase the complexity of
DNA and "improve" human beings. 

"In contrast with our intellect, computers double their performance
every 18 months," Hawking said. "So the danger is real that they could
develop intelligence and take over the world." Hawking predicted last
year that genetic engineers would be able to create superhumans with
larger brains and increased IQs. He now calls for the development of
technologies that will allow human brains to be linked to computers. 
[...] 

Tim Tyler:
Hawkins calls for development of exactly the same technology he is
dependent on for communicating with the outside world? 
Not a particularly suprising event, IMO.

Michael Ragland:
Hawking was interviewed by the German magazine Focus. It may be
coincidental but the cutting edge research done on linking human brains
to computers is by German scientists. I don't think Hawkings is calling
for exactly the same technology he is dependent on for communicating
with the outside world which is a special computer voice synthesizer
which translates his written words into audible language. I could be
mistaken but I don't think Hawking has nerve cells and silicon chips
interacting directly or such a chip implanted in his brain. In fact,
Hawking's voice synthesizer while remarkable is incredibly slow and when
he appears for interviews he has to have the questions written out to
him beforehand. Otherwise, there is a long delay in his answer. 
I think Hawking realizes the potential advantages and applications of
"plugging the computer into the brain" have numerous possible benefits
which exceed those with crippling conditions such as he has and that
indeed as Fromherz has stated, "Fromherz sees that 'the real dreams
would be the realisation of the brain-in-computer and chip-in-brain'
arrangements. Will that be the point where the boundaries between
biology and technology disappear? 'It's not a matter of technology or
biology,' says Fromherz. 'You take everything on your shelf to create
something technologically useful, be it minerals, polymers, colloids,
proteins, cells, or even tissues. It is a kind of super-chemistry." This
is the kind of technology which would generally benefit everyone. It's
in its infancy, using leech neurons and slices of rat's brains and it
will be quite awhile before it can be practically applied to humans with
advantageous results. 

Yes, one of the applications of this technology would be prosthetics and
restoring eye, limb, etc, use. Hawking is 60 years old almost and often
in poor health. He is not going to see any future applications of
plugging the computer into the brain restore the use of his limbs,
voice, etc. He will be dead long before that happens. But he may realize
there will be similar individuals with conditions which impair their
mobility and he may see advances in "plugging the computer into the
brain" which will restore partial or full function of their eyes, limbs,
etc.



In short

Electrical signals are responsible for communication in both the brain
and computers. Current research is hoping to use this similarity to get
nerve cells and silicon chips interacting directly

Two-way transmission of electrical signals between chips and neurons can
already be achieved on a small scale without invasive connections or
damage to either transmitter
Combining technology and biology could lead to devices to restore
vision, hearing and limb control and equipment for many applications in
the computer industry

This summer, the ubiquitous Microsoft corporation announced that it had
secured a US patent covering the use of the human body as a conductor in
connection with electronic appliances. Newspaper readers were quick to
respond with suggestions of possible consequences ('A fatal error
occurred. Your body will be shut down. All unsaved blood may be lost'),
but in reality it is far from clear what device exactly is to be plugged
directly into its buyer, as the corporation acknowledges that it doesn't
have a specific product relating to that patent.

>From cartoon to reality

One researcher who has been studying possible connections between
silicon electronics and biological cells for over two decades is Peter
Fromherz, a director at the Max Planck institute for biochemistry at
Martinsried near Munich, Germany. In 1985 he drew a cartoon showing an
unhappy computer user interfacing with the machine via a keyboard on one
side, and a much happier user with the wires from the computer plugged
directly into his head on the other. The question inspiring this cartoon
and Fromherz's research is simple, almost naive: as both computers and
brains communicate with electrical signals, why should it not be
possible to create a direct interface between them, without the need for
eyes and monitors, ears and speakers, hands and keyboards? If that
computer is so clever, why can't it just read my mind?

To address this challenge, Fromherz, who was then at the University of
Ulm, set out to grow neurons from the medicinal leech (Hirudo
medicinalis) on silicon chips and persuade the two parties to talk to
each other. Transmission of a signal from the neuron to the chip first
succeeded in 1991, the reverse process four years later. Essentially,
the recording of the neuron signal by the chip relies on a field effect
transistor, while the electronic stimulation of the neuron arises from a
voltage pulse applied to a capacitor, so both processes are absolutely
non-invasive and don't affect the survival of the cell in any way.

At the Max Planck institute, which Fromherz joined in 1994, he built on
that pioneering research with the goals to establish the precise nature
of the chip/neuron interface, expand the work to cells from other
sources, and to build more complex systems consisting of neurons and
semiconductors.

Regarding the mechanisms of the contact between chip and cell, Fromherz
and his coworkers established that an ordinary silicon chip, with the
outermost 15 nm oxidised, is an ideal substrate to cultivate neurons on.
The silicon oxide layer insulates the two sides and stops any
electrochemical charge transfer, which might damage the chip or the
cell. Instead, there is only a capacitative connection, established by a
so-called planar core-coat conductor. Proteins sticking out of the lipid
membrane ensure that there is a thin (50-100 nm) conducting layer
between lipid and silicon oxide, which constitutes the core of the
conductor.

The whole arrangement can be represented by a simplified electrical
circuit, where both the membrane and the silicon oxide have a defined
capacitance, and the electrolyte layer between them (which is part of
the medium surrounding the whole cell) has a given ohm resistance. The
dynamic properties of the system are dominated by the ion channels
within the cell membrane, which determine the ohmic conductance of the
membrane and thus the propagation of the electrical action potential,
which are the typical neuronal signals.

In the neuron-to-chip experiment, the current generated by the neuron
has to flow through the thin electrolyte layer between cell and chip.
This layer's resistance creates a voltage, which a transistor inside the
chip can pick up as a gate voltage that will modify the transistor
current. In the reverse signal transfer, a capacitative current pulse is
transmitted from the semiconductor through to the cell membrane, where
it decays quickly, but activates voltage-gated ion channels that create
an action potential.

Investigating the neuron-chip interface in more detail, Fromherz and his
team established that the gap of up to 100 nm between the two is a
natural consequence of the cell adhesion mechanisms mediated by membrane
proteins. Using the interference patterns of light reflected by the
silicon oxide/silicon layer, they showed that a naked lipid membrane
glued onto a chip leaves only about 1 nm space, but living cells grown
on this substrate will always leave a gap of at least 50 nm, so a more
direct contact is not possible if the biological function of the
membrane is to stay intact. On the other hand, neurons growing on chips
may favour the researchers' interest in placing their ion channels
preferentially in the contact area. In a set of experiments involving
the highly conductive maxi-K channel, they found that the density of
channels per membrane area was one order of magnitude higher in the
contact area than in the free membrane.

Building and imaging networks
The next challenge was to move upwards from one neuron communicating
with one stimulator or sensor to more complex neuro-electronic
architectures, with the distant goal of getting entire neuronal networks
plugged into electronics in a way that would allow their function to be
studied in detail or use them for computational devices. As a first,
elementary step from one neuron to networks, Fromherz and his team
implemented a simple signalling pathway including information transfer
from a chip to a neuron, and then onwards to a second neuron and back to
the chip.

For this first hybrid circuit, they followed the lead of neurology
pioneers such as Eric Kandel and used neurons from snails. These
unappealing invertebrates are popular among neuroscientists, because
their neurons are an order of magnitude larger than ours, and because
circuits consisting of only a few cells can already display a measurable
biological function. As a substrate to grow the cells on, the
researchers designed a specific chip with 14 two-way junctions (ie areas
that can both send signals to neurons and receive signals back) arranged
in a circle of about 200 &mu;m diameter. Typically, they planted five to
seven snail neurons onto such junctions and cultivated them for a few
days, hoping that at least some would form electrical synapses with
others.

The experiment succeeded in producing a few such pairs of linked neurons
that could build a bridge between a signal emitter and receiver in the
silicon chip. Earlier this year, the equivalent achievement was also
reported with a chemical instead of an electrical synapse. However, the
process was much too inefficient and random to enable the construction
of well-defined larger networks.

If a complex and well-defined neuronal network cannot be generated on
the chip directly, maybe the chip can be interfaced with a pre-existing
network, for instance a brain? Following this line of research, Fromherz
and Michael Hutzler have recently presented the first successful
connection between a chip of the kind described above, containing
capacitors to stimulate and transistors to sense nerve action, and a
brain slice containing well-characterised neuronal connections.

Specifically, the researchers turned their attention to the rat
hippocampus, a brain region associated with long-term memory. It is
known that in this part of the rat brain, a region known as CA3
stimulates the CA1 to which it is connected by extensive wiring. Brain
slices can be prepared such that the cut runs alongside the CA3 to CA1
connection and makes this entire communications channel accessible to
experiments. Using such slices, Hutzler and Fromherz demonstrated that
their chip can (via its capacitor) stimulate the CA3 region such that
these brain cells pass on the signal to CA1, where it can be recorded
with the chip's transistors.

While similar stimulation and recording is possible with metal
electrodes, the silicon chip method is the least invasive method
available. In the first experiments with a relatively simple chip
device, the spatial resolution remained low, but in principle, it can be
improved to the size of features on commercial microchips, currently
standing somewhere near 100 nm.

A significant step in this direction is the recent development of a CMOS
(complementary metal-oxide-semiconductor) chip with an array of 128 ×
128 sensors for neural recording packed into one square millimetre. This
was achieved by researchers at the Munich-based company Infineon
Technologies, in collaboration with Fromherz's group. The chip can
practically generate a movie of neurons in action: it delivers 16
kilopixels at 2000 frames per second. The pitch (ie the distance from
one sensor to the corresponding part of the next one) is 7.8 &mu;m,
which is very close to the typical width of a vertebrate neuron.

Applications on the horizon
The involvement of chip maker Infineon with Fromherz's sensor work shows
that there are hopes for commercially valuable spin-off products,
although at this point it is far from clear what they will look like.
Probably, says Fromherz, 'the first applications will be in brain
research and diagnostics.' Sensors like the 16 kilopixel CMOS chip will
enable researchers to fill the gap between studies involving only a few
cells and those operating at larger scales like magnetic resonance
imaging. Processes like associative memory, which have been broadly
localised, could be studied in detail using similar non-invasive
devices.

Prosthetic devices to restore vision, hearing or limb control might be
the next step. On a crude level, artificial retinae with just a few
pixels have already been demonstrated to create visible images. Further
in the future, Fromherz sees that 'the real dreams would be the
realisation of the brain-in-computer and chip-in-brain' arrangements.
Will that be the point where the boundaries between biology and
technology disappear? 'It's not a matter of technology or biology,' says
Fromherz. 'You take everything on your shelf to create something
technologically useful, be it minerals, polymers, colloids, proteins,
cells, or even tissues. It is a kind of super-chemistry.'

Computer makers may be the first who want a piece of this
super-chemistry. 'The microelectronics community becomes interested in
our work because they hope neurons may be a solution to the end of
Moore's law that is visible in about 10 years,' says Fromherz, referring
to the exponential growth of chip performance upheld over the last three
decades. At the moment, it is far from clear what will happen when this
trend hits the physical limits of what is possible with silicon chips.
Alternative methods including quantum, molecular, and biological
computers may allow computer development to go beyond this limit, so at
the moment all these options have to be explored.

Recognising that Fromherz's work may be the basis for crucial
technologies of the future, the Philip Morris Foundation bestowed upon
him its prestigious Research award for 2004, which also resulted in
widespread press coverage. 

With that much attention, it can only be a matter of time before
Microsoft discovers his bio-electronic hybrid systems and starts
developing operating systems for them.

Michael Gross is a science writer in residence at the school of
crystallography, Birkbeck College, University of London. He can be
contacted via his web page at www.proseandpassion.com
References
M Jenkner et al, Biol. Cybern., 2001, 84, 239
R A Kaul et al, Phys. Rev. Lett., 2004, 92, 038102
M Hutzler, P Fromherz, Eur. J. Neurosci. 2004, 19, 2231.
B Eversmann et al, IEEE J. Solid State Circuits, 2003, 38, 2306
  
 
 

"It's uncertain whether intelligence has any long term survival value.
Bacteria do quite well with it."

Stephen Hawking
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