The idea of teaching the brain to move through thoughts a marker on a computer or a robotic arm was at the center of the annual conference of the "Society for Neuroscience" that took place two weeks ago in Miami
Imagine a situation where a paralyzed person uses his thoughts to activate a robotic arm that puts a cookie in his mouth. It sounds like something out of a science fiction story, but these days research groups around the world are working on developing devices that will translate thoughts into movements that will be performed by robots and computers. These devices will help millions of people who have lost their ability to move to perform actions and communicate with the environment.
The idea of teaching the brain to move through thoughts a marker on a computer or a robotic arm was at the center of the annual conference of the "Society for Neuroscience" that took place two weeks ago in Miami. At the conference, the first generation of devices powered by brain waves was presented. The effectiveness of these devices is being tested these days with the help of people suffering from severe paralysis. The degree of progress in this field can be learned from the words of one of the conference participants, who said that the main problems facing device developers today are not scientific but engineering. An extensive review on this was recently published in the journal "Science".
How does information travel from the brain to the limbs? For example, let's say that we want to pick up a ball from the floor. The visual system sends information to the back of the cerebral cortex. It plans the movement and sends a command to the area of the brain that supervises the movement. From there, precise instructions to perform the task are sent through the spinal cord to the arm muscles. But when the spinal cord is damaged, the passage of information from the brain to the limbs is blocked, and the limbs do not respond to commands.
In recent years, understanding has expanded with regards to the interrelationships between the brain cells and their organization coordinated with the activation of the organs of movement. At the same time, electrodes were developed that are able to receive information from many nerve cells at the same time. All of these prepared the ground for the development of prostheses that would receive information directly from the brain and act in place of the paralyzed organs of movement.
The first step in the development of such devices was made by Philip Kennedy, chief scientist at the "Neural Signals" company in Atlanta, who developed a device that would help those who cannot communicate with the environment to do so. Kennedy built a perforated electrode that is implanted in the brain and releases a mixture of substances that cause the nerve cells to grow extensions. The nerve extensions penetrate into the electrode through the pores, where the signals coming out of the nerve cells are received and the intensity of their activity is recorded. The information picked up by the electrode is transferred to the computer, processed by it and moves the cursor on the screen. With the help of the movement of the cursor it will be possible to find out words, write down messages and have a conversation with the environment.
After receiving approval from the US Food and Drug Administration (FDA) in 1996 to try the device on humans, Kennedy and his team implanted the electrode in three paralyzed patients. The electrode was implanted in the area of the brain involved in movement control.
One of the trial participants died of her illness shortly after the electrode was implanted; The second patient underwent the operation in July and his nerve cells still did not grow enough extensions. The electrode in the third patient, 53 years old, paralyzed in all his body organs after a stroke, was implanted a year ago. In this year, the patient learned to move the cursor on the computer with his thoughts. In the first stage he learned how to concentrate on thinking about moving his hand, and today he is able to move the cursor on the computer while thinking directly about this action.
According to the researchers, the success of the experiment indicates the great flexibility of the brain - a feature that allows it to learn new functions. For example, in cases where a certain area of the brain is damaged, another area sometimes has to fulfill the damaged function. Kennedy says that in this experiment the area that was responsible for the movement adapted itself to the task of moving the cursor on the computer.
The next step is to teach the neurons how to move prostheses. For this, electrodes are required that will receive information from a larger number of nerve cells, and these are being developed by the scientists. Experiments in this regard are currently being conducted in rats and monkeys. The goal is to receive in real time the information transmitted by the nerve cells, and create movement with it. So far, researchers have been able to directly operate a robotic arm by receiving signals from 26 neurons in the brains of monkeys. The neural activity was recorded in the computer and it regulated the movement of the robot - it "decided" which joints to move and to what extent. Thus a natural three-dimensional movement of the arm in space was created. In the next step, the researchers plan to teach the animals to consciously monitor the movement of the robotic arm.
Scientists express optimism regarding the application of the method in the future. However, these experiments are only at the beginning of their journey and it will take another ten years before they can be applied to humans.
Appeared in Haaretz newspaper, 18/11/1999
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