What is a Brain Computer Interface?

Enhancing cognitive capabilities, a brain computer interface (BCI) is a communication system by which the brain does not require nerves to control the body or even the world outside. Providing the disabled user with an alternative method for acting on the world, BCIs are of two kinds: dependent and independent ones.

A BCI is not just a mind reader that reads the electrical signals sent out by individual neurons or even the brain. Dependent BCIs minimally require a partially intact peripheral system. A paralyzed user can then use a dependent BCI to flash letters on a screen by gazing at specific letters. While doing this, an EEG records the particular part of the brain that is active when gazing. But for this to be effective, the EEG relies on the activity of the eyes.

Independent BCIs, on the other hand, work with signals that do not depend on any form of muscle activity. Thus, by merely thinking of a letter, certain electrical patterns that trigger actions of the BCI cause the thought letter to flash on the screen. Independent BCIs require users to be trained in its usage and though dependent BCIs are easier to make, severely handicapped users would benefit only from independent ones.

It is a known fact that an average computer can perform any operation 20,000 times quicker than the human brain. The brain requires several milliseconds to process a bit of information. BCI technologies are also used in advanced thought-controlled computer games. The most fulfilling application of BCIs, howver, is when they are used for patients that are for medical reasons in patients unable to perform even basic movements. Especially true for neurologically hampered patients who suffer from a variety of conditions such as amyotrophic lateral sclerosis, brainstem stroke, cerebral palsy or muscular dystrophies and even accident victims with brain or spinal cord injuries, BCIs help them control their prosthesis by mere thought.

The prevalence of BCIs is evident in Craig Thomas’ novel, “Firefox,” wherein the pilot is able to control the weapon systems of a MiG-31, code-named “Firefox” by thought alone.

However, the pity of it is that at present, even the most sophisticated EEG-based BCIs are hardly fast enough to interpret not more than 25 bits of information per minute. Not only is the speed of communication pitiable but also the signal itself — neither brainwaves nor individual firing rates of nerve cells were meant to drive prosthesis. In order to bring about more powerful BCIs, it is necessary to improve EEG-technology or use other modes of signal transmission.

Source: Brain Tuning