Scientists install living eel brain in small robot to call the shots
2001-04-23 04:00:00 PDT Chicago -- The cyborg aims for the light and wheels forward. Another light flashes and the cyborg turns. Again and again, like a bull in a ring, the cyborg charges, sometimes veering right, sometimes left, sometimes moving straight ahead, always looking for the light.
The cyborg is no "RoboCop," but it is a revolutionary experiment in combining a mechanical device with living tissue. The robot is controlled by an immature lamprey eel brain that was removed, kept alive in a special solution and attached to the hockey-puck-sized robot by wires so it can receive signals from the device's electronic eyes and send commands to move the machine's wheels.
"Until the recent past, people were using biological nervous systems to inspire technology," said physiologist Sandro Mussa-Ivaldi of Northwestern University's Rehabilitation Institute of Chicago. "Now we've gone one step beyond, to tap into the nervous system itself."
Mussa-Ivaldi's lamprey larvae are one of a large number of creatures whose supple sensory resources are being put to work in a new generation of animal/machine hybrids.
Mussa-Ivaldi is testing the lamprey brain's ability to control a robot, but the long-term possibilities could be much more spectacular: Learning more about how brains work so electronic microprocessors can be developed to help compensate for damage from strokes and other types of nerve trauma.
A variety of other similar experiments are unfolding in labs across the country, where rapid advances in electronics and other fields have enabled scientists to integrate animals and microelectronics. These experiments envision a range of applications - using bacteria attached to computer chips to map pollutants; insects as part of sensors to detect land mines, chemical weapons and narcotics; and rodent brains to help identify new medicines.
"There's a couple of things making this happen," said electrical engineer Michael Simpson of the Oak Ridge National Laboratory. "Even before the mapping of the human genome was completed, there was an explosion in our understanding of genomics and neural pathways in other animals.
"At the same time, (microelectronic) devices keep getting smaller and denser," Simpson added. "Single chips are beginning to get complex enough so that they can begin to work with biological systems."
In Tennessee, Simpson and colleague Gary Sayler have genetically engineered bacteria to glow in the presence of chemical agents and affixed them to microchips. The Rockville, Md., company Dynamac is licensing their "critters on a chip" for applications that could include highlighting the boundaries of toxic waste plumes, monitoring air quality or analyzing body fluids to test for signs of disease.
In Iowa, entomologist Tom Baker has built a device for finding land mines using tiny moth antennae that emit signals to microprocessors, which transform them into different tones. The signals drop in pitch when the antennae encounter the odor of high explosives used in mines or unexploded ordnance.
In Los Angeles, neuroscientist Michel Baudry is using brain slices from mice and rabbits to develop a system for warning soldiers about the presence of chemical or biological weapons. The system creates an electronic blueprint for a normal environment, so that when the balance is upset, an alarm will tell soldiers to don gas masks.
Formidable barriers remain before scientists will fully benefit from "critter science." Animals must be trained and maintained. Shelf life of natural tissue is a problem.
And so is size. University of Montana entomologist Jerry Bromenshenk has trained bees to find explosives, and the Agricultural Research Service's Joe Lewis has done the same in Georgia with parasitic wasps, but there is not yet a practical method for tracking such tiny sentinels when they are flying free.
And at Iowa State University in Ames, Baker can read the reactions of his moth antennae on an oscilloscope, but he doesn't yet have the electronics that a soldier needs to discriminate between the signal he wants and other odor sources.
"We are getting the engineering tools that allow us to plug into living systems," said Alan Rudolph of the federal government's Defense Advanced Research Projects Agency, which has funded a number of critter projects. "We are asking the question: 'Can we make machines with living components and make them work?' "
A cyborg sees the light By using a lamprey eel's brain to steer a wheeled robot, scientists have taken a step toward mating human brains and computer chips.
1. Light is picked up by detectors on the robot.
2. A micro-processor converts the light into electrical signals.
3. The signals are sent through wires attached to the left and right sides of the eel's brain stem.
4. The brain reacts to the signals by emitting spikes of activity.
5. Wires on the eel's spinal cord pick up the activity and forward it to a microprocessor.
6. The micro-processor reads the signals and tells the wheels to move toward where the eel brain perceived the light. Source: Northwestern University Washington Post Graphic