THE BRAIN COMPUTER INTERFACE

A brain computer interface (BCI) is a technology which allows a human to control a computer, peripheral or other electronic device with thought. It does so by using sensing electrodes to detect electric signals (generated by thought activities in the brain) remotely, in contact or implanted inside the brain. These signals collected from the brain are then sent to a computer linked with the brain interface to interpret them, based on previous known signal behavior in the data base and thereby outputting the necessary commands to a connected machine to execute the desired action accordingly.

There are three types of brain computer interface methods; these are non-invasive, semi invasive and invasive. The non-invasive method uses sensors in the form of a headgear placed on the scrap to measure the electric signals or central nervous activity of the brain. Whereas, in the semi invasive method, the electrodes are placed on the exposed surface of the brain. Though it is called semi invasive, it still requires minor surgery to implant the electrodes. However, in the invasive method, the electrodes are implanted directly into the brain during major neurosurgery. The micro electrodes are placed directly into the cortex, to measure the activity of the central nervous system. Invasive devices produces the highest quality signals of all the three brain computer interface  methods, but are prone to scar tissue buildup causing the signals to become weaker over time as the body reacts to foreign object in the brain.

The function of the central nervous system is to respond to events in the outside world or the body by producing outputs that serve the need of the human body. All the natural outputs of the central nervous system are neuromuscular or hormonal. Thus, a brain computer interface central nervous system in this regard, is a system that measures central nervous system activity and converts it into artificial output that replaces, restores, enhances, supplements or improves natural central nervous system output and thereby changes the ongoing interaction between the central nervous system host and its external or internal environments.

The central nervous system activity, consist of the electrophysiological, neurochemical and metabolic phenomena that occur continually in the brain. These phenomena can be quantified by monitoring the central nervous signals using sensors on the scalp, on the surface or within the brain. Thus a brain computer interface records these signals, extracts specific measures or features from them and converts or translates these features into artificial outputs that act on the outside world or on the body itself.

There are five types of applications that a brain computer interface might control and they are;

A brain computer interface output might replace natural output that has been lost as a result of injury or disease. For example, a person who can no longer speak might use a brain computer interface to type words that are then spoken by a speech synthesizer or a person who has lost a limb control might use a brain computer interface to operate a motorized wheel chair. In these examples the brain computer interface output replaces lost natural output.

A brain computer interface output might restore lost natural output. For example, a person with spinal cord injury whose arms and hands are paralyzed might use a brain computer interface to stimulate the paralyzed muscles via implanted electrodes, so that the muscles move the limbs or a person who has lost bladder function due to multiple sclerosis might use a brain computer interface  to stimulate the peripheral nerves that control the bladder, thus enabling urination. In these examples, the brain computer interface output restores the natural outputs.

A brain computer interface output might enhance natural central nervous system output. For example, a person performing a task that requires continuous attention over a prolonged period, for example driving a vehicle or serving as a sentry, might use a brain computer interface  that detects lapses in attention and then provides an output e.g. sound that alerts the person and restores attention. By preventing the attention lapses that periodically impair natural central nervous system output and might cause traffic accidents, the brain computer interface enhances the natural output.

A brain computer interface output might supplement natural central nervous system output. For example, a person who is controlling the position of a computer cursor with a hand operated joystick might use a brain computer interface to select items that the cursor reaches or a person might use a brain computer interface to control a third robotic arm and hand. In these cases, the brain computer interface supplements natural neuromuscular output with an additional artificial output.

Finally a brain computer interface output might conceivably improve natural central nervous system output. For example, a person whose arm movements have been impaired by a stroke involving the sensor motor cortex might use a brain computer interface  that measures signals from the damaged critical areas and the stimulates muscles or control an orthic device so as to improve arm movements. Because this brain computer interface application enables more normal movements, its repeated use may induce activity dependent central nervous system plasticity that improves the natural central nervous system output and thereby helps the person to regain more normal arm control.

It is noteworthy to mention that in the year 2019, researchers at the University of California, san Francisco, developed a brain computer interface that allowed a paralyzed woman to type at a rate of eight words per minute, utilizing only her thoughts. Also another notable example is the Brain-gate system developed by researchers at brown university and Masschusset general hospital. The Brain-gate system they developed employed an array of sensors implanted in the motor cortex to record neural signals linked to the intention for movement. These signals were subsequently translated into commands, enabling users to control computer cursors, robotic arms or even their own wheel chairs with remarkable precision.

There is a growing list of brain computer interface non-invasive headgear and wearable in the market offering products by companies like; emotive, neurosky and starlab. Other Similar product launches are planned for the year that point to a bionic future for humans. Where do we go from here? Robocop? Terminator? Or Darth Vader? The truth is out there begging to be told, the human race is slowly evolving into a race of cyborg.

 

Sources

• An introduction to the brain computer interface and companies working on it. Compiled by Howie Baum.
• Brain computer interface principles and practice (2012) edited by Jonathan Woolpaw MD and Elizabeth winter Woolpaw PhD. Oxford university press.
• Bir Baumer . Brain computer interface research coming of age (2006) clinical neurophysiology.
• Gilbert G. cyborgs and moral identity. Journal of medical ethics(2006)