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Brain machine-interface


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Brain machine-interface

  2. 2. <ul><li>The bioport </li></ul><ul><li>load new skills into their colleagues' brains </li></ul>
  3. 3. <ul><li>Remember the movie “ The Matrix”, those rebels putting on the computer cords at the back of the neck. </li></ul><ul><li>The bioport (that’s what the technology was called in movie) was a way of giving the Matrix computers full access to the information channels of the brain. </li></ul><ul><li>The rebels use the bioport to load new skills into their colleagues' brains—writing directly into permanent memory. </li></ul>
  4. 4. <ul><li>Imagine all this turning to reality. </li></ul><ul><li>All your exam time problems vanishing. </li></ul><ul><li>You being able to memorize your course books with just a tap of button. </li></ul><ul><li>Futurists and science-fiction writers also speculate about a time when brain activity will merge with computers. </li></ul>
  5. 6. <ul><li>Moving to reality, many researches are actually going on to explore the possibility of the man and machine merger </li></ul><ul><li>Trials for the implanted chip technology have been very successful for monkeys, who have learned to control a computer game with their brains. </li></ul><ul><li>Scientists are finding different ways of receiving senses for people who have lost a sense, such as sight or touch, they are made wear an artificial sensor. </li></ul><ul><li>Scientists at the Max Planck Institute have developed &quot;neuron transistor s&quot; that can detect the firing of a nearby neuron , or alternatively, can cause a nearby neuron to fire, or suppress it from firing </li></ul>
  6. 7. The First Implant <ul><li>Researchers at the University of California, Berkeley, have demonstrated how rhesus monkeys with electrodes implanted in their brains used their thoughts to control a computer cursor. </li></ul><ul><li>Once the animals had mastered the task, they could repeat it proficiently day after day. </li></ul><ul><li>It reflects a major finding by the scientists: A monkey’s brain is able to develop a motor memory for controlling a virtual device in a manner similar to the way it creates such a memory for the animal’s body </li></ul>
  7. 8. <ul><li>The Berkeley researchers implanted arrays of microelectrodes on the primary motor cortex, about 2 to 3 millimeters deep into the brain, tapping 75 to 100 neurons. </li></ul><ul><li>The procedure was similar to that of other groups. The difference was that here the scientists carefully monitored the activity of these neurons using software that analyzed the waveform and timing of the signals . </li></ul>
  8. 9. <ul><li>Monitoring the neurons, the scientists placed the monkey’s right arm inside a robotic exoskeleton that kept track of its movement. </li></ul><ul><li>On a screen, the monkey saw a cursor whose position corresponded to the location of its hand. The task consisted of moving the cursor to the center of the screen, waiting for a signal, and then dragging the cursor onto one of eight targets in the periphery. Correct maneuvers were rewarded with sips of fruit juice. </li></ul><ul><li>While the animal played, the researchers recorded two data sets—the brain signals and corresponding cursor positions. </li></ul>
  9. 10. <ul><li>During manual control [left], the monkey maneuvers the computer cursor while the researchers record the neuronal activity, used to create a decoder. </li></ul><ul><li>Under brain control [right], the researchers feed the neuronal signals into the decoder, which then controls the cursor. </li></ul><ul><li>This determined whether the animal could perform the same task using only its brain. </li></ul><ul><li>a decoder, to translates brain activity into cursor movement. </li></ul><ul><ul><li>decoder is a set of equations , multiply the firing rates of the neurons by certain numbers, or weights. When the weights have the right values, you can plug the neuronal data into the equations and they’ll spill out the cursor position. To determine the right weights, the researchers had only to correlate the two data sets they’d recorded . </li></ul></ul><ul><li>Next the scientists immobilized the monkey’s arm and fed the neuronal signals measured in real time into the decoder. Initially, the cursor moved spastically. But over a week of practice, the monkey’s performance climbed to nearly 100 percent and remained there for the next two weeks. For those later sessions, the monkey didn’t have to undergo any retraining—it promptly recalled how to skillfully maneuver the cursor. </li></ul>
  10. 11. Medical Field <ul><li>Scientists who are finding different ways of receiving senses. People who have lost a sense, such as sight or touch wear an artificial sensor. </li></ul><ul><li>This might be a video camera, or a touch sensitive glove. Then, electrical pulses which encode the sense are sent to brain via a strip on their tongue </li></ul>
  11. 12. <ul><li>REMOTE CONTROL BrainGate technology is designed to read brain signals associated with controlling movement, which a computer could translate into instructions for moving a computer cursor or controlling a variety of assistive devices. </li></ul><ul><ul><ul><ul><li>Plugging a sensor into the human brain's motor cortex could turn the thoughts of paralysis victims into action. Team of Brown University scientists have expanded its efforts to developing technology that reconnects the brain to lifeless limbs . </li></ul></ul></ul></ul>
  12. 13. <ul><li>BrainGate Neural Interface includes a baby aspirin–size brain sensor containing 100 electrodes </li></ul><ul><li>Sensor connects to the surface of the motor cortex (the part of the brain that enables voluntary movement), registers electrical signals from nearby neurons, and transmits them through gold wires to a set of computers, processors and monitors. </li></ul><ul><li>BrainGate can assist those suffering from spinal cord injuries, muscular dystrophy, brain stem stroke, amyotrophic lateral sclerosis (ALS), and other motor neuron diseases </li></ul>
  13. 14. <ul><li>One researcher Peter Fromherz a director at the Max Planck institute for biochemistry in Germany has been studying possible connections between silicon electronics and biological cells. </li></ul><ul><li>Fromherz, first grew neurons from the medicinal leech on silicon chips and persuade the two parties to talk to each other. </li></ul><ul><li>Field effect transistor records the signal from neuron </li></ul><ul><li>The electronic stimulation of the neuron arises from a voltage pulse applied to a capacitor </li></ul>
  14. 15. <ul><li>Fromherz and his coworkers established that an ordinary silicon chip, with the outermost 20 nm oxidized, is an ideal substrate to cultivate neurons on. </li></ul><ul><li>The silicon oxide layer insulates the two sides and stops any electrochemical charge transfer, which might damage the chip or the cell. </li></ul><ul><li>Instead, there is only a capacitative connection, established by a so-called planar core-coat conductor. Proteins sticking out of the lipid membrane ensure that there is a thin (50-100 nm) conducting layer between lipid and silicon oxide, which constitutes the core of the conductor. </li></ul>
  15. 16. <ul><li>In the neuron-to-chip experiment, the current generated by the neuron has to flow through the thin electrolyte layer between cell and chip. </li></ul><ul><li>This layer's resistance creates a voltage, which a transistor inside the chip can pick up as a gate voltage that will modify the transistor current. In the reverse signal transfer, a capacitative current pulse is transmitted from the semiconductor through to the cell membrane, where it decays quickly, but activates voltage-gated ion channels that create an action potential. </li></ul><ul><li>The next challenge was to move upwards from one neuron communicating with one stimulator or sensor to more complex neuro-electronic architectures, with the distant goal of getting entire neuronal networks plugged into electronics in a way that would allow their function to be studied in detail or use them for computational devices. </li></ul>
  16. 17. <ul><li>For this first hybrid circuit, they used neurons from snails. </li></ul><ul><li>As a substrate to grow the cells on, the researchers designed a specific chip with 14 two-way junctions (  ie areas that can both send signals to neurons and receive signals back) arranged in a circle of about 200 &mu;m diameter </li></ul><ul><li>Specifically, then the researchers turned their attention to the rat hippocampus, a brain region associated with long-term memory. </li></ul><ul><li>It is known that in this part of the rat brain, a region known as CA3 stimulates the CA1 to which it is connected by extensive wiring. </li></ul><ul><li>Brain slices can be prepared such that the cut runs alongside the CA3 to CA1 connection and makes this entire communications channel accessible to experiments. </li></ul><ul><li>Using such slices, Hutzler and Fromherz demonstrated that their chip can (via its capacitor) stimulate the CA3 region such that these brain cells pass on the signal to CA1, where it can be recorded with the chip's transistors. </li></ul>
  17. 18. <ul><li>With a relatively simple chip device, the spatial resolution remained low, but in principle, it can be improved to the size of features on commercial microchips, currently standing somewhere near 100 nm. </li></ul><ul><li>A CMOS (complementary metal-oxide-semiconductor) chip with an array of 128 &times; 128 sensors for neural recording packed into one square millimeter. </li></ul><ul><li>The chip can practically generate a movie of neurons in action: it delivers 16 kilo pixels at 2000 frames per second </li></ul>
  18. 19. Applications on the horizon <ul><li>Sensors like the 16 kilopixel CMOS chip will enable researchers to fill the gap between studies involving only a few cells and those operating at larger scales like magnetic resonance imaging. Processes like associative memory, could be studied in detail using similar non-invasive devices. </li></ul><ul><li>Prosthetic devices to restore vision, hearing or limb control might be the next step. </li></ul><ul><li>Further in the future, the real dreams would be the realization of the “brain-in-computer and chip-in-brain” arrangement </li></ul>
  19. 20. Gamers will soon be able to interact with the virtual world using their thoughts and emotions alone. A neuro-headset which interprets the interaction of neurons in the brain will go on sale later this year. It picks up electrical activity from the brain and sends wireless signals to a computer. It allows the user to manipulate a game or virtual environment naturally and intuitively. The brain is made up of about 100 billion nerve cells, or neurons, which emit an electrical impulse when interacting. The headset implements a technology known as non-invasive electroencephalography (EEG) to read the neural activity. It’s a brain computer interface that reads electrical impulses in the brain and translates them into commands that a video game can accept and control the game dynamically.
  20. 21. <ul><li>The headset could detects more than 30 different expressions, emotions and actions. </li></ul><ul><li>Gamers are able to move objects in the world just by thinking of the action </li></ul>
  21. 22. The Challenges and Future Implications <ul><li>Thus the major challenge lies in fact that wiring of the spinal cord is basically unknown. At best, on cats, researchers have been able to hook into their optic nerves, to see what a cat can see. And in blind people, we can stimulate a handful of pixels in their brain, but that's about it. The brain is still a black box. </li></ul><ul><li>A successful BrainGate2 trial could open up a number of new possibilities, Although the technology is similar to what was used in the original testing, the researchers are looking to enlist up to 15 patients this time and gather more information that will help them better understand brain signals as well as &quot;the method by which they decode them. </li></ul><ul><li>Including the use of a second sensor to stimulate both sides of the motor cortex. Researchers thus far have implanted the sensor in the side of the brain that controls a patient's dominant side—the left cortex for righties and the right cortex for lefties. </li></ul>
  22. 23. <ul><li>BrainGate2 is part of a larger mission to help paralysis victims regain control of their bodies. They want to reconnect the brain back to the muscles and eventually back to the entire limb. They are attempting to recreate parts of the nervous system that have been disconnected from the brain. </li></ul><ul><li>Nanobot -based virtual reality is not yet feasible in size and cost(the one using neuron transistors), but researchers have made a good start in understanding the encoding of sensory signals. </li></ul><ul><li>For example, Lloyd Watts and his colleagues have developed a detailed model of the sensory coding and transformations that take place in the auditory processing regions of the human brain . We are at an even earlier stage in understanding the complex feedback loops and neural pathways in the visual system </li></ul>
  23. 24. <ul><li>The brain computer interfacing will become a profoundly transforming technology by 2030. By then, nanobots (robots the size of human blood cells or smaller, built with key features at the multi-nanometer—billionth of a meter—scale made using neuron transistors) will provide fully immersive, totally convincing virtual reality in the following way. The nanobots will take up positions in close physical proximity to every interneuron connection coming from all of our senses (e.g., eyes, ears, skin). When we want to experience real reality , the nanobot s would just stay in position (in the capillaries) and do nothing. If we want to enter virtual reality , they would suppress all of the inputs coming from the real senses, and replace them with the signals that would be appropriate for the virtual environment. </li></ul><ul><li>Ultimately, we will merge our own biological intelligence with our own creations as a way of continuing the exponential expansion of human knowledge and creative potential. </li></ul>