18-12-2012, 01:41 PM
Seminar Report on Brain Gate System
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INTRODUCTION
BrainGate is a brain implant system developed by the bio-tech company Cyberkinetics in 2003 in conjunction with the Department of Neuroscience at Brown University. The device was designed to help those who have lost control of their limbs, or other bodily functions, such as patients with amyotrophic lateral sclerosis (ALS) or spinal cord injury. The computer chip, which is implanted into the brain, monitors brain activity in the patient and converts the intention of the user into computer commands. Cyberkinetics describes that "such applications may include novel communications interfaces for motor impaired patients, as well as the monitoring and treatment of certain diseases which manifest themselves in patterns of brain activity, such as epilepsy and depression."
Currently the chip uses 100 hair-thin electrodes that sense the electro-magnetic signature of neurons firing in specific areas of the brain, for example, the area that controls arm movement. The activities are translated into electrically charged signals and are then sent and decoded using a program, which can move either a robotic arm or a computer cursor. According to the Cyberkinetics' website, three patients have been implanted with the BrainGate system. The company has confirmed that one patient (Matt Nagle) has a spinal cord injury, while another has advanced ALS.
HISTORY
After 10 years of study and research, Cyberkinetics, a biotech company in Foxboro, Massachusetts, has developed BrainGate in 2003. Dr. John Donaghue, director of the brain science program at Brown University, Rhode Island, and chief scientific officer of Cyberkinetics, the company behind the brain implant, lead the team to research and develop this brain implant system.
BRAINGATE NEURAL INTERFACE SYSTEM
The BrainGate Neural Interface System is currently the subject of a pilot clinical trial being conducted under an Investigational Device Exemption (IDE) from the FDA. The system is designed to restore functionality for a limited, immobile group of severely motor-impaired individuals. It is expected that people using the BrainGate System will employ a personal computer as the gateway to a range of self-directed activities. These activities may extend beyond typical computer functions (e.g., communication) to include the control of objects in the environment such as a telephone, a television and lights.
The BrainGate System is based on Cyberkinetics' platform technology to sense, transmit, analyze and apply the language of neurons. The System consists of a sensor that is implanted on the motor cortex of the brain and a device that analyzes brain signals. The principle of operation behind the BrainGate System is that with intact brain function, brain signals are generated even though they are not sent to the arms, hands and legs. The signals are interpreted and translated into cursor movements, offering the user an alternate "BrainGate pathway" to control a computer with thought, just as individuals who have the ability to move their hands use a mouse.
PLATFORM TECHNOLOGY
Neurons are cells that use a language of electrical impulses to communicate messages from the brain to the rest of the body. At Cyberkinetics, we have the technology to sense, transmit, analyze and apply the language of neurons. We are developing products to restore function, as well as to monitor, detect, and respond to a variety of neurological diseases and disorders.
Cyberkinetics offers a systems approach with a core technology to sense, transmit, analyze and apply the language of neurons in both short and long-term settings. Our platform technology is based on the results of several years of research and development at premier academic institutions such as Brown University, the Massachusetts Institute of Technology, Emory University, and the University of Utah.
SENSE
Cyberkinetics' unique technology is able to simultaneously sense the electrical activity of many individual neurons. Our sensor consists of a silicon array about the size of a baby aspirin that contains one hundred electrodes, each thinner than a human hair. The array is implanted on the surface of the brain. In the BrainGate™ Neural Interface System, the array is implanted in the area of the brain responsible for limb movement. In other applications the array may be implanted in areas of the brain responsible for other body processes.
TRANSMIT AND ANALYZE
The human brain is a super computer with the ability to instantaneously process vast amounts of information. Cyberkinetics' technology allows for an extensive amount of electrical activity data to be transmitted from neurons in the brain to computers for analysis. In the current BrainGate™ System, a bundle consisting of one hundred gold wires connects the array to a pedestal which extends through the scalp. The pedestal is connected by an external cable to a set of computers in which the data can be stored for off-line analysis or analyzed in real-time. Signal processing software algorithms analyze the electrical activity of neurons and translate it into control signals for use in various computer-based applications.
APPLY
Cyberkinetics' ability to generate control signals and develop computer application interfaces provides us with a platform to develop multiple clinical products. For example, using the BrainGate™ Neural Interface System, a person may be able to use his thoughts to control cursor motion and/or replicate keystrokes on a computer screen. In another example, a doctor may study patterns of brain electrical activity in patients with epilepsy before, during and after seizures.
IMPLANTING THE CHIP
There will be two surgeries, one to implant the BrainGate and one to remove it. Before surgery, there will be several precautionary measures in order to prevent infection; patients will have daily baths with antimicrobial soap and take antibiotics. In addition, MRI scans will be done to find the best place on the brain for the sensor. Under sterile conditions and general anesthesia, Doctor will drill a small hole into the skull and implant the sensor using the same methods as in the monkey studies. Patients will receive post-surgical care including a CT scan, some blood tests, and wound care in the hospital for 1 to 5 days after surgery. After surgery, one of the study doctors will see the patients at least once a week for six weeks, then monthly and as needed. A nurse will also check the patients regularly and will always carry a 24-hour pager. The skin around the pedestal will need to be carefully monitored during the study. Detailed instructions will be provided so that the patient’s daily care provider can help with skin care.
BRAIN-COMPUTER INTERFACE
A brain-computer interface (BCI), sometimes called a direct neural interface or a brain-machine 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 humans.In this definition, the word 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).
Research on BCIs began in the 1970s, but it wasn't 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.
BCI 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. There are also several neuroprosthetic devices that aim to restore vision, including 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 “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.
WORKING
The sensor of the size of a contact lens is implanted in brain’s percental gyrus which control hand and arm movements. A tiny wire connects the chip to a small pedestal secured in the scull. A cable connects the pedestal to a computer. The brain's 100bn neurons fire between 20 and 200 times a second .The sensor implanted in the brain senses these electrical signals and passes to the pedestal through the wire. The pedestal passes this signals to the computer through the cable. The computer translates the signals into a communication output, allowing a person to move a cursor on a computer screen merely by thinking about it.