Computer Circuits Built from Brain Cells
The human brain is currently the
most sophisticated computing device we know of. It uses a massive
network of interconnected cells to to redundantly transmit and
receive coded messages. Because of it's redundancy the brain can
have multiple errors happen at the same time and still be able to
work properly. This way the entire system never goes down, like your
computer at home or at the office does. Humans have created system
that is very similar. You may of heard of it, it's called the internet.
The internet has millions of miles of connections that connect to
millions of servers across the entire planet. Each sever acts an
independent part of the internet system, if one goes down, traffic
can simply be redirected to another, through a different set of
cables. This makes it so that entire system never completely goes
down.
Engineers and scientists want to use this reliable system along
with the aments power of the human brain to create complex,
reliable, super powerful, yet small computers. Well just recently a
group of researchers from the Weizmann Institute of Science in
Rehovot Isreal have found a way to do this by controlling the growth
pattern of neurons. I believe that in a decade or so this technology
combined with a few other nano-technologies will revolutionize the
entire computer industry. This technology will also help to bridge
the gap between technological interfaces and biological interfaces.
Such as wiring cybernetic limbs to your brain as if it were your own
natural limb. Can you imagine the possibilities? Consider the
possibilities of having electronic components installed directly
into your body. Like a robotic eye perhaps, that can enhance your
sight by %100.
-Below is an article I found tat NewScientist.com that talks about
this.
- From NewScientist.com news service, Colin Barras
For all its
sophistication and power, your brain is built from unreliable
components – one neuron can successfully provoke a signal in another
only 40% of the time. This lack of efficiency frustrates
neuroengineers trying to build networks of brain cells to interface
with electronics or repair damaged nervous systems. Our brains
combine neurons into heavily connected groups to unite their 40%
reliability into a much more reliable whole.
Now human engineers working with neurons in the lab have achieved the same
trick: building reliable digital logic gates that perform like those
inside electronics.
Built from scratch
Elisha Moses at the Weizmann Institute of Science in Rehovot, Israel, and
his students Ofer Feinerman and Assaf Rotem have developed a way to
control the growth pattern of neurons to build reliable circuits
that use neurons rather than wires.
The starting point is a glass plate coated with cell-repellent material.
The desired circuit pattern is scratched into this coating and then
coated with a cell-friendly adhesive. Unable to gain purchase on
most of the plate, the cells are forced to grow in the scratched
areas.
The scratched paths are thin enough to force the neurons to grow along
them in one direction only, forming straight wire-like connections
around the circuit. Using this method the researchers built a device
that acts like an AND logic gate, producing an output only when it
receives two inputs. The gate is made from a network of neurons in a
square shape approximately 900 micrometres on a side. Three of the
sides form a "horseshoe" 150-micrometres wide, and packed with
neurons.
Neurons send their wire-like extensions that carry signals – axons –
across those narrow bridges to the neuron island. When stimulated
with a small dose of a drug, the neurons send signals around the
circuit. An ion blocker is used in the centre of the horseshoe to
electrically isolate one side from the other. By changing the width
of the bridges, the researchers are able to control how many axons
link to the neuron island, and tune their device to behave like an
AND gate.
The neurons on the island only produce an output after receiving signals
through both of the thin bridges. Like a natural system, the device
transcends the performance of individual neurons – achieving 95%
reliability from a collection of 40% reliable components.
Rotem thinks that this provides a useful model for real brain function.
"The existence of a threshold level for activation plays a central
role in neuronal computation," he says. In his logic gates and real
brains alike, many neurons contribute to generate a signal strong
enough to excite another group of neurons, he says.