
“Neuristor”: Memristors used to create a neuron-like behavior - evo_9
http://arstechnica.com/science/2012/12/neuristor-memristors-used-to-create-a-neuron-like-behavior/
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soccerniru
I want to point out that people should be wary of this recent wave of press
surrounding "neural" computing. A lot of this involves trying to emulate
biophysical properties of neurons we observe in the brain, but it is not clear
how these properties affect function or if they are even necessary for the
types of computations we are interested in emulating in silicon.

That being said, memristors are a fascinating piece of technology and we need
to make progress on all fronts if neurally-inspired computing is to become a
reality. This latest development (capturing the nonlinear properties of sodium
and potassium channels in a microelectronic device) is quite interesting, as
these properties are crucial for reproducing the spiking behavior of real
neurons. All I'm saying is take these results with a grain of salt, there is
still a lot of work to do!

~~~
drucken
Understatement.

Even if perfect replication of a neuron electronically was possible, there are
86 billion neurons in an average human brain which is well over ten times the
number of transistors present on modern chips.

Of course, functional electronic neuron models and scaling well before that
point is likely to be immensely useful anyway.

~~~
Tuna-Fish
Even if it took a hundred thousand transistors (/transistor-size devices) to
emulate a neuron, that wouldn't actually be a problem. Compared to
electricity-on-copper, the connections between neurons are _slow_. When
operating on electricity, there are no problems whatsoever in making your
brain consist of a million chips that fill a warehouse.

~~~
InclinedPlane
Indeed. So it might actually be possible to emulate a human brain in hardware
rather sooner than we might have thought. Memristors are also memory devices,
with access times on the order of modern RAM, and a small multiple of 86
gigabytes is not a huge amount of storage these days. So imagine a 1 billion
"neuristor" processor backed by a few hundred GB of memristor storage and
operating in a sort of time-shared fashion (load a "brain component" into the
neuristor configuration, interface with the memory for a while, then move on
to the next component and so forth).

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pjin
A search on Wikipedia turned up this 1976 paper [1] (unfortunately, behind a
paywall), which derived a memristor circuit emulating Hodgkin-Huxley dynamics,
a good biophysical model of the membrane potential of a neuron. In particular,
it can show the generation of action potentials.

The relevant part is on p. 210: "In particular, the potassium channel of the
Hodgkin-Huxley model should be identified as a first-order time-invariant
voltage-controlled memristive one-port and the sodium channel should be
identified as a second-order time-invariant voltage-controlled memristive one-
port."

[1]
[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1454361...](http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1454361&tag=1)

