Monday, July 29, 2019

Brain Computer Interface

Modifying the human body or enhancing our cognitive abilities using technology has been a long-time dream for many people. An increasing amount of research tries to link the human brain with machines allowing humans to control their environment through their thoughts. Research on BCIs began in the 1970s, but it wasnt until the mid-1990s that the first working experimental implants in humans appeared. Following years of animal experimentation, early working implants in humans now exist, designed to restore damaged hearing, sight and movement. The common thread throughout the research is the remarkable cortical plasticity of the brain, which often adapts to BCIs, treating prostheses controlled by implants as natural limbs. With recent advances in technology and knowledge, pioneering researchers could now conceivably attempt to produce BCIs that augment human functions rather than simply restoring them, previously only the realm of science fiction. 2. Brain Machine Interface (Brain Computer Interface): In this definition, the word â€Å"brain† means the brain or nervous system of an organic life form rather than the mind. Computer† means any processing or computational device, from simple circuits to silicon chips (including hypothetical future technologies such as quantum computing). A Brain Machine Interface (BMI), sometimes called a Direct Neural Interface or a Brain Computer Interface, is a direct communication pathway between a human or animal brain (or brain cell culture) and an external device. In one-way BCIs, computers either accept commands from the brain or send signals to it (for example, to restore vision) but not both. Two-way BCIs would allow brains and external devices to exchange information in both directions but have yet to be successfully implanted in animals or human. Brain-computer interface (BCI) is collaboration between a brain and a device that enables signals from the brain to direct some external activity, such as control of a cursor or a prosthetic limb. The interface enables a direct communications pathway between the brain and the object to be controlled. In the case of cursor control, for example, the signal is transmitted directly from the brain to the mechanism directing the cursor, rather than taking the normal route through the bodys neuromuscular system from the brain to the finger on a mouse. By reading signals from an array of neurons and using computer chips and programs to translate the signals into action, BCI can enable a person suffering from paralysis to write a book or control a motorized wheelchair or prosthetic limb through thought alone. Current brain-interface devices require deliberate conscious thought; some future applications, such as prosthetic control, are likely to work effortlessly. One of the biggest challenges in developing BCI technology has been the development of electrode devices and/or surgical methods that are minimally invasive. In the traditional BCI model, the brain accepts an implanted mechanical device and controls the device as a natural part of its representation of the body. Much current research is focused on the potential on non-invasive BCI. At the European Research and Innovation Exhibition in Paris in June 2006, American scientist Peter Brunner composed a message simply by concentrating on a display. Brunner wore a close-fitting (but completely external) cap fitted with a number of electrodes as shown in fig. Electroencephalographic (EEG) activity from Brunners brain was picked up by the caps electrodes and the information used, along with software, to identify specific letters or characters for the message. The BCI Brunner demonstrated is based on a method called the Wadsworth system. Like other EEG-based BCI technologies, the Wadsworth system uses adaptive algorithms and Pattern-matching techniques to facilitate communication. Both user and software are expected to adapt and learn, making the process more efficient with practice. During the presentation, a message was displayed from an American neurobiologist who uses the system to continue working, despite suffering from amyotrophic lateral sclerosis (Lou Gehrigs disease). He was able to send the following e-mail message: I am a neuroscientist who (sic) couldnt work without BCI. I am writing this with my EEG courtesy of the Wadsworth Center Brain-Computer Interface Research Program. EEG Pattern Recognition This project aims to improve performance of NASA missions by developing brain-computer interface (BCI) technologies for augmented human-system interaction. BCI technologies will add completely new modes of interaction, which operate in parallel with keyboards, speech, or other manual controls, thereby increasing the bandwidth of human-system interaction. The research will extend recent feasibility demonstrations of electromyographic (EMG) methods for neurocontrol to the domain of electroencephalographic (EEG) methods of neurocontrol. These methods will bypass muscle activity and draw control signals directly from the human brain. BCI technologies will provide powerful and intuitive modes of interaction with 2-D and 3-D data, particularly for visualization and searching in complex data structures, such as geographical maps, satellite images, and terrain databases. . Model train control via brain interface machine: Hitachi has successfully tested a brain-machine interface that allows users to turn power switches on and off with their mind. Relying on optical topography, a neuroimaging technique that uses near-infrared light to map blood concentration in the brain, the system can recognize the changes in brain blood flow associated with mental activity and translate those changes into voltage signals for controlling external devices. In the experiments, test subjects were able to activate the power switch of a model train by performing mental arithmetic and reciting items from memory. The prototype brain-machine interface allows only simple control of switches, but with a better understanding of the subtle variations in blood concentrations associated with various brain activities, the signals can be refined and used to control more complex mechanical operations. In the long term, brain-machine interface technology may help paralyzed patients become independent by empowering them to carry out actions with their minds. In the short term, Hitachi sees potential applications for this brain-machine interface in the field of cognitive rehabilitation, where it can be used as an entertaining tool for demonstrating a patient’s progress. NOTE: The earliest interfaces developed in this breakthrough field of research require scientists to insert electrodes into the skull in order to physically tap directly into the brain, and researchers are currently trying to develop technologies that will enable them to access neurological activity through minimally invasive techniques. It is hoped that some day brain machine interfaces will be able to read neural signals non-invasively, from outside the skull, and that devices will be operated involuntarily, without deliberate conscious thought. Thus, for example, fighter pilots wearing specialized helmets may be able to operate some controls automatically, just by thinking. 4. Neuroprosthetics: Neuroprosthetics (also called Neural Prosthetics) is a discipline related to neuroscience and biomedical engineering concerned with developing neural prostheses, artificial devices to replace or improve the function of an impaired nervous system. The neuroprosthetic seeing the most widespread use is the cochlear implant, with approximately 100,000 in use worldwide as of 2006. There are several types of neuroprosthetic as follows: I. Sensory Prosthetics: i. Visual prosthetics: One of the prominent goals in neuroprosthetics is a visual supplement, noting roughly 95% of all people considered blind suffer significant impairment but have some capability (for example, seeing some sort of blur) only about 5% of blind people are totally blind. By the 1940s, researchers had established the concept of artificial electrical stimulation of the visual cortex, and in the late 1960s, British scientist Giles Brindley produced breakthrough findings with a system for placing electrodes on the brains surface. When specific areas of the brain were stimulated in blind volunteers, all reported seeing phosphenes that corresponded to where they would have appeared in space. However, experiments were discontinued because of the uncomfortably high currents required for stimulation on the surface of the brain. Encouraged by this work, the National Institutes of Health undertook a project to develop and deploy an interface based on ultra fine wire (25 to 50 micrometers) densely populated with electrode sites that could be implanted deep into the visual cortex, thus requiring less current than Brindleys original design. This work led to new electrode technology—finer than the width of human hair—that could be safely implanted in animals to electrically stimulate, and passively record, electrical activity in the brain. The efforts produced significant advances in neurophysiology, with publication of hundreds of papers in which researchers attempted to develop an electronic interface to the brain. ii. Auditory prosthetics (cochlear implant): A cochlear implant (or bionic ear) is a surgically implanted device that can help provide a sense of sound to a person who is profoundly deaf or severely hard of hearing. Unlike hearing aids, the cochlear implant does not amplify sound, but works by directly stimulating any functioning auditory nerves inside the cochlea with electrical impulses. External components of the cochlear implant include a microphone, speech processor and transmitter. iii. Prosthetics for pain relief (Spinal Cord Stimulator): The Spinal Cord Stimulator or (Dorsal Column Stimulator) is used to treat chronic neurological pain. It is implanted near the dorsal surface of the spinal cord and an electric impulse generated by the device provides a tingling sensation that alters the perception of pain by the patient. A pulse generator or RF receiver is implanted in the abdomen or buttocks. A wire harness connects the lead to the pulse generator. II. Motor prosthetics: . Bladder control implants (Sacral anterior root stimulator): Where a spinal cord lesion leads to paraplegia, patients have difficulty emptying their bladders and this can cause infection. From 1969 onwards Brindley developed the sacral anterior root stimulator, with successful human trials from the early 1980s onwards. This device is implanted over the sacral anterior root ganglia of the spin al cord; controlled by an external transmitter, it delivers intermittent stimulation which improves bladder emptying. It also assists in defecation and enables male patients to have a sustained full erection. The related procedure of sacral nerve stimulation is for the control of incontinence in able-bodied patients. ii. Sensory/Motor prosthetics: In 2002 an implant was interfaced directly into the median nerve fibres of the scientist Kevin Warwick. The electrode array inserted contained 100 electrodes, of which 25 could be accessed at any one time. The signals produced were detailed enough that a robot arm developed by Warwicks colleague, Peter Kyberd, was able to mimic the actions of Warwicks own arm and provide a form of touch feedback via the implant. Fig: Electrode array Fig: Robot arm iii. Cognitive prosthetics: Sensory and motor prostheses deliver input to and output from the nervous system respectively. Theodore Berger at the University of Southern California defines a third class of prostheses aimed at restoring cognitive function by replacing circuits within the brain damaged by stroke, trauma or disease. Work has begun on a proof-of-concept device a hippocampal prosthesis which can mimic the function of a region of the hippocampus a part of the brain responsible for the formation of memories. . BMI versus Neuroprosthetics: Neuroprosthetics is an area of neuroscience concerned with neural prostheses — using artificial devices to replace the function of impaired nervous systems or sensory organs. The most widely used neuroprosthetic device is the cochlear implant, which was implanted in approximately 100,000 people worldwide as of 2006. [2] There are also several neuroprosthetic devices that aim to restore vision, in cluding retinal implants, although this article only discusses implants directly into the brain. The differences between BCIs and neuroprosthetics are mostly in the ways the terms are used: neuroprosthetics typically connect the nervous system, to a device, whereas the term â€Å"BCIs† usually connects the brain (or nervous system) with a computer system. Practical neuroprosthetics can be linked to any part of the nervous system, for example peripheral nerves, while the term BCI usually designates a narrower class of systems which interface with the central nervous system. The terms are sometimes used interchangeably and for good reason. Neuroprosthetics and BCI seek to achieve the same aims, such as restoring sight, hearing, movement, ability to communicate, and even cognitive function. Both use similar experimental methods and surgical techniques. 6. Future Trends and Scopes: Recent advances in cortically controlled brain-machine interfaces (BMIs) have demonstrated that goal-directed movement of external devices is possible in real-time using multi-electrode recordings from cortex. A number of challenges are currently being confronted to further advance BMI research to the next level. These include choosing the optimal decoding algorithm for the type of control to be performed, localizing the optimal cortical site for reliable control, and focusing on the most suitable electrophysiological signal for practical use in a BMI. We present results that attempt to address these challenges based on multi-electrode recording from multiple motor cortical areas in behaving monkeys. . Conclusion: Although brain–machine interfaces are often talked about in relation to disabled people, we can expect they will also be used by the non-disabled as a means to control their environment especially if the devices are non-invasive and no implants are needed. To date there has not been much public discussion of the implications of brain machine interfaces, the amount of public RD funding they receive, and control, distribution and access to these devices.

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