Paralyzed (瘫痪的）people can now control artificial limbs（假肢） by thought alone. This is possible because of the development of technologies which involve（涉及） connecting the brain to a computer or other electronic devices. One well-known use of such technology enables deaf people to hear. The device has several parts. One part is surgically（通过外科手术般的） implanted in to the inner ear. There it stimulates（刺激） nerves to cause the sensation（感觉） of sound. The other part sits behind the ear and works like a miniature（微型） microphone.
Another new device allows those who have lost an arm or a leg to control their artificial limb just by thinking. The first human volunteer to try this out was Matt Nagel. Matt was paralyzed from the neck down due to a vicious(凶狠的） knife attack.
The process of implanting the device into Matt was quite involved(复杂的）. First, a circular（圆形的） piece of his skull was removed. Then a tiny plate with hair-thin electrodes（电极） was inserted into his brain. It was placed in the motor cortex（运动皮质）, the brain region that controls movement. This plate detects the electrical signals in the brain that usually control hand movement. From the plate, thin cables(电缆） were connected to a small computer which decodes the signals from the plate and converts them into commands. Hopefully, these commands would control the artificial hand attached to Matt's arm.
Shortly after the operation, Matt was surrounded by the surgeons as he stared at his artificial hand with hope. To the delight of the crowd, the hand started moving, and the fingers closed, becoming a fist. At that moment Matt made history. He became the first person to control an artificial limb by using a device surgically instead into his brain.
Since the operation, Nagel has continued to test the technology and further investigate(调查） its capabilities. Using thought alone, he can now perform a variety of tasks. He can control a TV and even open emails. Such uses of technology are inspiring and bring joy to our hearts. It is powerful evidence that technological advancements will improve our lives.
