Scientists create LIVING artificial nerve networks

"They're made out of meat!"

No, (with all due apologies to Terry Bisson), not the humans. Their computers. Soon.

Because in the future, the interface between brain and artificial system will be based on nerve cells grown for that purpose. As recently featured on the cover of Nature Physics, Prof. Elisha Moses of the Physics of Complex Systems Department at the Weizmann Institute of Science in Rehovot, Israel, and his former research students Drs. Ofer Feinerman and Assaf Rotem, have taken the first step in this direction by creating circuits and logic gates made of live nerves grown in the lab.

Here's a summary what they did, according to their published results "Reliable neuronal logic devices from patterned hippocampal culture" Nat Phys 4, 12 (Dec 2008) Ofer Feinerman, Assaf Rotem, and Elisha Mose

The researchers grew a model one-dimensional nerve network – by getting the neurons to grow along a groove etched in a glass plate. They found they could stimulate these nerve cells using a magnetic field (as opposed to other systems of lab-grown neurons that only react to electricity), and that varying the width of the neuron stripe affected how well it would send signals.

The scientists took two thin stripes of around 100 axons each and created a logic gate similar to one in an electronic computer. Both of these “wires” were connected to a small number of nerve cells. When the cells received a signal along just one of the “wires,” the outcome was uncertain; but a signal sent along both “wires” simultaneously was assured of a response. This type of structure is known as an AND gate.

The next structure the team created was slightly more complex: Triangles fashioned from the neuron stripes were lined up in a row, point to rib, in a way that forced the axons to develop and send signals in one direction only. Several of these segmented shapes were then attached together in a loop to create a closed circuit. The regular relay of nerve signals around the circuit turned it into a sort of biological clock or pacemaker. Full article here

Image source: Nature Physics magazine.