They then record the spikes of voltage produced at points within the culture when signals from the sensor are sent to it. When they find an area that fires consistently when the sensor input reaches it, those signals can be picked up by an electrode and used to, say, make the robot avoid an obstruction.
It seems as though the neurons don't really parse the input at all. They simply 'fire' whenever they are fed a certain signal from the ultrasound input.
For example, if the ultrasound sensor indicates "wall dead ahead" with a 1 volt signal, and a certain knot of neurons in the culture always generates a 100-microvolt action potential when that happens, the latter signal can be used to make the robot steer right or left to avoid the wall.
So the robot then interprets the neurons' firing as an indication that it is close to a wall, and changes direction accordingly.
In all, it appears that only a tiny bit of "processing" is actually being done by the neurons, and it may be misleading to imply that they are really "controlling" the direction of the robot. All they do is fire in response to a voltage generated by the ultrasound input; it is the robot which interprets this firing as "a wall is close, time to change direction."
Slashdot Mirror
From TFA:
They then record the spikes of voltage produced at points within the culture when signals from the sensor are sent to it. When they find an area that fires consistently when the sensor input reaches it, those signals can be picked up by an electrode and used to, say, make the robot avoid an obstruction.
It seems as though the neurons don't really parse the input at all. They simply 'fire' whenever they are fed a certain signal from the ultrasound input.
For example, if the ultrasound sensor indicates "wall dead ahead" with a 1 volt signal, and a certain knot of neurons in the culture always generates a 100-microvolt action potential when that happens, the latter signal can be used to make the robot steer right or left to avoid the wall.
So the robot then interprets the neurons' firing as an indication that it is close to a wall, and changes direction accordingly.
In all, it appears that only a tiny bit of "processing" is actually being done by the neurons, and it may be misleading to imply that they are really "controlling" the direction of the robot. All they do is fire in response to a voltage generated by the ultrasound input; it is the robot which interprets this firing as "a wall is close, time to change direction."
Still quite an impressive breakthrough, though.