Brain–computer interface (BCI)

The Brain Computer Interface, also known as the Brain Machine Interface (BMI), is a direct line of that exists communication between the electrical activity of the brain and external devices, most commonly the limbs fitted to the human body which are robotic. BCI is often aimed at mapping, investigating, expanding, supporting or repairing sensory motor or human cognitive functions.

History of BCI

Hans Berger’s discovery of electrical activity in the human brain which was followed by the development of electroencephalography (EEG) is said to be the beginning of Brain Computer Interface. In the year 1924, he was the first person to record human brain activity using EEG. By analyzing brain wave traces, he was able to identify oscillatory activity such as alpha waves and Berger waves. In his EEG chart, Berger analyzed the correlation between changes and brain disease. EEG has opened up entirely new possibilities for studying the activity of the human brain.

Professor Jacques Vidal coined the term “BCI” as well as created the first publication which was peer-reviewed on this subject. Vidal is widely recognized in the BCI community as the inventor of BCI. The experiment described by Vidal in the year 1977 was the first application of BCI after the 1973 BCI Challenge. This was a non-invasive EEG control of a graphic object.

Difference with neuroprosthetics

It is a field of neuroscience dealing with neuroprostheses and use artificial devices that replace impaired nervous system or brain-related problems, or the function of the sensory organs or the organs themselves such as diaphragm, bladder etc.

These terms are often used interchangeably. BCI as well as Neuroprosthetics aim to achieve the same goals of auditory, visual, communication skills, motor and even recovery of cognitive function. Both of these use similar surgical as well as experimental techniques.

About animal research of BCI

Few laboratories succeeded in recording signals from the rats and monkeys cerebral cortex to generate movement by manipulating BCI. The monkey moved a computer cursor across the screen and directed the robot’s hand to do a simple task just by thinking and observed visual feedback, but there was no motor activity.

In the year 2020, Elon Musk successfully transplanted Neuralink into pigs, as announced in an extensive webcast. In the year 2021, Elon Musk announced that monkeys are now able to play video games using Neuralink devices.

Limitations and other uses of BCI

BCI has been developed to predict electrical activity of primate muscles, in addition to predicting kinematic parameters of limb movement. Such BCI can be used to restore mobility to limbs paralyzed by electrical stimulation of muscles. Current BCI technology lacks sensory models that can provide accurate, reliable as well as safe access to brain signals.

About BCI research in Humans

Invasive BCI: This requires surgery so as to implant electrodes under the scalp to send brain signals. The main advantage is that it allows for more accurate readings. However, its drawbacks include the side effects of surgery. After surgery, scar tissue may form and the signals in the brain may weaken. The body may not be able to accept the implanted electrodes, which can lead to illness. Invasive BCI is used for the recovery of vision, communication as well as movement.

About Partially Invasive BCI: In the skull, this device is implanted but not in the grey matter and is implanted outside the brain. They emit signals with better resolution than non-invasive BCI as the cranial bones deflect and deform the signal, and the risk of formation of scar tissue in the brain is lower than that of fully invasive BCI.

Electrocorticography: measures the electrical activity of the brain under the skull and the electrodes are embedded in a thin plastic pad and are placed under the dura just above the cortex. Until recently, it had not been fully investigated due to restricted access to subjects. Currently, the only way to get a signal for examination is to use it in patients who need invasive monitoring to find and resection the focus of epilepsy development. The ECoG is highly promising due to its higher spatial resolution, better signal-to-noise ratio, wider frequency range, lower training requirements, and lower technical difficulty than EEG recorded on the scalp.

About Non Invasive BCI: Experiments on humans are also being performed using non-invasive neuroimaging technology. The EEG-based interface is easy to wear and does not require surgical intervention, but the skull attenuates the signal and diffuses and blurs the electromagnetic waves generated by the neurons, resulting in relatively low spatial resolution and cannot be used for effective high frequency signals. EEG-based interfaces require some time and effort before each usage session, while non-EEG-based and invasive interfaces do not require prior training. Overall, the optimal BCI for each user depends on a variety of factors. One of the difficulties of reading EEG is its high sensitivity to motion.

Issue with BCI

Issues related to BCI are that little is known about its long-term impact on users. It’s difficult to obtain informed constrain from the people who have problems communicating before administrating a BCI device. The impact of BCI technology on patients the quality of life as well as on their families. Health-related side effects of BCI are also there.  Accountability and Responsibility Issues which claims that the effects of BCI nullify free will and control sensorimotor activity, claim that cognitive intent was incorrectly translated due to BCI dysfunction. Also, Deep brain stimulation may change personality.

Future of BCI

A key challenge is to make it work more user-friendly by providing motivational feedback in a style that users find useful. Both software and hardware should be easy to use for both caregivers as well as patients, fuelling enthusiasm for technology. Tasks should not be static and repetitive, but should be adaptive in nature so that one can clearly see the progress through milestones as one increase their productivity.

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