Damage to the spinal cord can block the electrical signals produced by nerve cells in the brain from reaching the muscles required for limb movement. The result is paralysis - the loss of voluntary muscle function. Neuroscientific research by Chet Moritz and his colleagues at Washington University, USA, offers hope for people with paralysing spinal cord and similar debilitating nerve pathway injuries.
In the study, monkeys were trained to control the electrical activity of individual nerve cells in the motor cortex, an area of the brain responsible for voluntary movement whilst they manipulated a cursor on a computer screen during a video game. When the animals had learned to control the cursor, their wrist muscles were temporarily paralysed with anaesthetic which blocked the nerves supplying the wrist. The experimenters subsequently by-passed the nerve block using a brain-computer device, called a ‘neurochip’, to transfer electrical activity directly from nerve cells in the monkeys’ motor cortex to the previously paralysed wrist muscles. As a result, the animals regained control of wrist movement and could continue to successfully guide the cursor in the video game.
These exciting studies pave the way for the future development of brain implants allowing people with paralysed limbs to regain voluntary control of muscle movement. However, as the scientists acknowledge, there is much research to be done before such devices are available in the clinic.
Find out more
Episode 5 of Breaking Science.
‘Direct control of paralysed muscles by cortical neurons’
by Chet Moritz, Steve Perlmutter & Eberhard Fetz