Cultured Neural Nets?

[Christof Koch]

Yes, there exists a number of groups out there trying to
grow neurons onto silicon  studded with various electrodes and
other sensors: Jerry Pine at Caltech and David Tank at AT & T are
both doing this sort of work.
For a recent reference check the May or June issues of Science
magazine. A german researcher, Fromherz from Ulm, had a paper
discussing his way of interfacing silicon circuits with single
neurons.
 
Christof