Have you ever tried to imagine life without your limbs? We tend to take many things such as our arms, fingers, legs, etc., for granted. But there are many people who, either through genetic defects or accidents, have lost the ability to use their limbs for simple, daily mundane tasks like tying shoelaces, or brushing teeth. Scientific discoveries however are being made everyday to overcome such challenges. For instance studies conducted by neurobiologist, Dr Andrew Schwartz and his group at the University of Pittsburgh, have shown that monkeys are capable of controlling a robotic arm by simply thinking about it.
To start at the beginning, we need to understand an integral part of our nervous system, the neurons. Neurons or nerve cells are considered to be the basic elements of the nervous system. Neurons are essential for normal functioning due to their capability to transmit critical information through our entire body. Information is transferred both chemically as well as electrically. The neurons break up into sub-specialised groups to carry out different tasks. For instance, there are sensory neurons that carry the information from the sensory receptors throughout the body to the brain.
Because the neurons can send out electric messages, scientists can record the electrical activity for each neuron. With many years of careful recording, it was noticed that neurons are very sensitive to changes in body movement. In fact neurons fire their electric signals in specific directions based on the type of movement. So scientists recorded which direction each neuron fires in and were able to combine the responses from the cells to get an accurate representation of what say, the arm was doing.
The next layer of complexity was applying this system to a test animal, the monkey. The scientists began with simply recording the monkey’s neurons for any task it performed. The next big step was to teach the monkey to recognise a certain task and perform it while its brain’s neurons were being recorded. Eventually the monkey learned to use the recording device to perform the task it wanted to perform. So the monkey learned to have specific thoughts, its thoughts were translated into electric signals, these signals from its neurons were read through electrodes and converted into actual motion in a robotic prosthetic arm to covert the monkey’s thought into action. This was no easy task, since first the monkey had to be familiarised with the concept of controlling its actions. Scientists used a joystick, which the monkey used to move food towards it. The joystick was linked to the robotic arm. Next the robotic arm electrodes were implanted into the monkey’s brain and the monkey was shown the food and simply by thinking about moving the arm the neurons in its brain fired signals in specific directions. So step by step scientists developed a robotic arm that read signals from the monkey’s brain to move the food to its mouth.
The implications of this research are limitless. Already several human patients have been implanted with electrodes where they can control a cursor on a computer screen. And advances are being made to allow humans to use robotic prostheses by using their thoughts to carry out simple activities. So what may have seemed like something from a sci-fi movie not too long ago has very much become a reality.
The writer is a Ph.D. in Molecular Genetics and Genomics and is working on skin cancer at Novartis