TechFocusBrain Computer Interface
Hi-tech to overcome disability
Imagine a machine, which receives signals from your brain and helps you control your body organs. Yes, it is not a science fiction anymore, but a real innovation that has created a landmark in the history of mankind. This technology is called brain-computer interface (BCI), which is a promising solution that integrates both medical science and information technology. BCI is particularly helpful for those people who are unable to control body organs with the brain. BCI research was first initiated in 1970 but the technology came in limelight in the mid-1990s. BCI resembles Neuroprosthetics but they slightly differ with each other. Neuroprosthetics typically connect the nervous system, to a device whereas BCI usually connects the brain with a computer system. BCI and Neuroprosthetic came into reality with the vision to restoring sight, hearing, movement, ability to communicate, and even cognitive function. Both use similar experimental methods and surgical techniques. Before we go any further, we need to understand the basic functionality of human brain. The brain is a very complicated part of the human body, which actually controls our activities. Brain is composed of nerve cells called neurons. They are the core component of a brain. Individual neuron is connected with others by dendrites and axons. When we think, move, feel or remember something, our neurons come into action. Neurons generate electrical pulse to send information. The signals are generated by differences in electric potential carried by ions on the membrane of each neuron. Signals spread through the paths, which are insulated by something called myelin. But some signals escapes and scientists concentrate on this occurrence. Scientists have developed BCI systems to detect those signals. There are three kinds of BCI systems such as invasive BCI, partially invasive BCI and non-invasive BCI. Scientists implement invasive BCI system directly into the gray matter of the brain during neurosurgery. As a result, this system can pick up better quality signals. Because it requires invasive surgery to set the electrodes and on the other hand this change in the brain cause the formulation of scar tissue in the gray matter. This scar tissue eventually interrupts the signal reception. Invasive BCI system is utilised to repair damaged sight and providing new functionality to paralysed people. As the name implies, some portion of partially invasive BCI system is implemented inside the skull and the remaining part outside the brain rather than touching the grey matter. This system produces better resolution signals than non-invasive BCIs where the bone tissue of the cranium deflects and deforms signals and have a lower risk of forming scar-tissue in the brain than fully-invasive BCIs. To implement non-invasive BCI system scientists install electrodes on the surface of the head. This set-up is easy to handle and requires no surgery. However, it generates low quality results as the skull blocks a lot of the electrical signal and it distorts what get through. Basically electrodes measures minute voltage difference between neurons. Then it requires some modifications. In modern BCI systems, computer program interprets the signal. Researchers use magnetic resonance imaging (MRI) to select the exact place on the brain to install electrodes. For instance, if researchers need to set electrodes that will enable a person to control a robotic arm, they first identify the pacific portion of the brain for this activity through MRI. The MRI will show which area of the brain is active during arm movement, giving them a clearer target for electrode placement. But in practice the robotic arm movement is not that much easy. Special software is used to coordinate the entire process. But the software requires several trails to understand the signal associated with particular brain activity. Software connected to a robotic hand is programmed to receive the "close hand" signal and interpret it to mean that the robotic hand should close. At that point, when the subject thinks about closing the hand, the signals are sent and the robotic hand closes. Controlling robotic arm creates limitless potential for BCI implementation. Physically challenged people could have braces attached to their own limbs, allowing them to move and directly interact with the surroundings. Cochlear implant is the oldest metaphor of BCI implementation. When people listen to any sound, the sound waves enter the ear and pass through several tiny organs that eventually pass the vibrations on to the auditory nerves in the form of electric signals. If this natural process of hearing become dysfunctional people basically is not able to respond to any sound. However, the auditory nerves may be functioning perfectly well. They just aren't receiving any signals. A cochlear implant solve this problem by bypassing the defected part of the ear and process the sound waves into electric signals and passes them via electrodes right to the auditory nerves. Although this tactic not perfectly allow a deaf person to hear but he or she can conduct conversation. In principle the process to resolve hearing problem is equally applicable for the visually impaired person. But in practice the brain functions more critically to process visual information. On the contrary, the artificial eye development does not perfectly support this system. In the installation process electrodes are implanted in or near the visual cortex, the area of the brain that processes visual information from the retinas. A pair of glasses holding small cameras is connected to a computer and, in turn, to the implants. Several companies are now engrossed in research in order to come up with more advanced BCI system. Neural signal is now developing a technology to restore speech for disabled people. In this regard, an implant picks up signals from the area of the brain associated with speech then transmits the signals to a computer and a speaker. The system systematically recognises each of the 39 phonemes in the English language and redevelops speech through the computer and speaker. Nasa is working on a similar system which actually reads electric signals from the nerves in the mouth and throat area instead directly from the brain. Cyberkinetics Neurotechnology Systems is marketing the BrainGate, a neural interface system that allows disabled people to control a wheelchair, robotic prosthesis or computer cursor. Japanese researchers have developed a preliminary BCI that allows the user to control their avatar in the online world 'Second Life'.
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