Brain Computer Interfaces, a Review

The brain is in many respects the centre of our being, controlling our actions, movements, thoughts and emotions. It is somewhat of a mystery, presenting itself only through the body's exterior façade. It is safeguarded by a thick skull that insulates it from the outside world. Information from the surroundings is relayed to it via the five senses - touch, sight, sound, smell and taste. Its role was underestimated in the past by cardiocentrists who believed that thought, sensation and behaviour originated in the heart and that the brain was there to "make the heat and boiling in the heart well blent and tempered"-Aristotle(384-322BC). Today we can pinpoint the areas of activity in the brain, and localise its functions. We now have an understanding of the physiological processes and signals that occur. We know that neurons in the brain's cortex transmit signals to an efferent nervous system, i.e. from the brain towards motor output pathways, and also from an afferent system, i.e. from the sense organs to the brain. The impulses are both electrical and chemical signals, which can be detected and measured as with any system using specific techniques. As with any system if there are problems we want to solve them, if there are improvements to be made we implement them where possible. Problems can occur in the afferent system, and also in the efferent system, for example causing visual or auditory impediments in the first case and paralysis in the latter. By effectively "bypassing" the nervous system the brain can be connected in a more direct sense to its environment. Brain computer interfaces offer this possibility. Their origins lie in providing alternative communication methods for the disabled, but now offer the possibility of providing people with "different senses". These augmentative channels will allow the brain to directly connect to its environment. Electrical signals originating from the brain can be directly sent to computers, providing it with an additional control output. This can even be connected to the Internet to provide an "extended nervous system" for controlling a robot hundreds of miles away. Conversely new and different senses such as ultrasound or infrared detection could be relayed as sensory information to the brain. In the exciting information age we live in today, integrating technology with our biological systems seems like a natural progression, and obtaining a "silicon nervous system" may by the only way to keep up! The Driving Forc