Snail neuron cultured on a silicon chip and surrounded by polyimide pickets. © 2000 National Academy of Science, USA.

The idea of developing neuroelectronic systems to use as neuroprosthetics has been around for a long while ... in science-fiction books. Few neuroscientists have focused their attention on this very real challenge, despite the fact that it is becoming increasingly approachable. A recent study by Zeck and Fromherz should stimulate progress in this field, as they provide evidence that it is possible to transmit signals through a silicon–neuron–neuron–silicon circuit.

The authors cultured individual snail neurons on top of a stimulator and a transistor in a silicon chip. As these neurons form electrical synapses with neighbouring cells, the authors could trigger presynaptic action potentials by delivering voltage pulses to the stimulator, and record a spike in the postsynaptic neuron and a concomitant voltage change in the transistor under this cell. It is therefore feasible to form 'synaptic contacts' between electronic circuits and nerve cells. Although there are still many technological limitations to the development of more complex and efficient circuits, this proof-of-principle experiment is a fundamental step in a neglected field.