BRAIN CHIP

INTRODUCTION

the evolution and development of mankind began thousands and thousands of years before. And today our intelligence, our brain is a resultant of this long developmental phase.

Technology also has been on the path of development since when man appeared. It is man that gave technology its present form. But today, technology is entering a phase where it will out wit man in intelligence as well as efficiency.

Man has now to find a way in which he can keep in pace with technology, and one of the recent developments in this regard, is the brain chip implants.

Brain chips are made with a view to enhance the memory of human beings, to help paralyzed patients, and are also intended to serve military purposes. It is likely that implantable computer chips acting as sensors, or actuators, may soon assist not only failing memory, but even bestow fluency in a new language, or enable "recognition" of previously unmet individuals. The progress already made in therapeutic devices, in prosthetics and in computer science indicates that it may well be feasible to develop direct interfaces between the brain and computers.

This technology is only under developmental phase, although many implants have already been made on the human brain for experimental purposes. Let’s take a look at this developing technology.

Evolution towards Implantable Brain Chips

Worldwide there are at least three million people living with artificial implants. In particular, research on the cochlear implant and retinal vision have furthered the development of interfaces between neural tissues and silicon substrate micro probes. There have been many researches in order to enable the technology of implanting chips in the brain to develop. Some of them are mentioned below.

· The Study of the Brain

The study of the human brain is, obviously, the most complicated area of research. When we enter a discussion on this topic, the works of JOSE DELGADO need to be mentioned. Much of the work taking place at the NIH, Stanford and elsewhere is built on research done in the 1950s, notably that of Yale physiologist Jose Delgado, who implanted electrodes in animal brains and attached them to a "stimoceiver" under the skull. This device transmitted radio signals through the electrodes in a technique called electronic stimulation of the brain, or ESB, and culminated in a now-legendary photograph, in the early 1960s, of Delgado controlling a live bull with an electronic monitor

According to Delgado, "One of the possibilities with brain transmitters is to influence people so that they conform to the political system. Autonomic and somatic functions, individual and social behavior, emotional and mental reactions may be invoked, maintained, modified, or inhibited, both in animals and in man, by stimulation of specific cerebral structures. Physical control of many brain functions is a demonstrated fact. It is even possible to follow intentions, the development of thought and visual experiences."

Delgado, in a series of experiments terrifying in their human potential, implanted electrodes in the skull of a bull. Waving a red cape, Delgado provoked the animal to charge. Then, with a signal emitted from a tiny hand-held radio transmitter, he made the beast turn aside in mid-lunge and trot docilely away. He has [also] been able to “play” monkeys and cats like “little electronic toys” that yawn, hide, fight, play, mate and go to sleep on command. The individual is defenseless against direct manipulation of the brain [Delgado, Physical Control].

Such experiments were done even on human beings. Studies in human subjects with implanted electrodes have demonstrated that electrical stimulation of the depth of the brain can induce pleasurable manifestations, as evidenced by the spontaneous verbal reports of patients, their facial expression and general behavior, and their desire to repeat the experience. With such experiments, he unfolded many of the mysteries of the BRAIN, which contributed to the developments in brain implant technology. For e.g.: he understood how the sensation of suffering pain could be reduced by stimulating the frontal lobes of the brain.

Delgado was born in Rondo, Spain, and interestingly enough he is not a medical doctor or even a vet, but merely a biologist with a

degree from Madrid University. He, however, became an expert in neurobehavioral research and by the time he had published this book (Physical Control of the Mind ) in 1969, he had more than 200 publishing credits to his name. His research was sponsored by Yale University, Foundations Fund for Research in Psychiatry, United States Public Health Service1, Office of Naval Research2, United States Air Force 657-1st Aero medical Research Laboratory3, NeuroResearch Foundation, and the Spanish Council for Scientific Education, among others.

· Neural Networks:

Neural networks are loosely modeled on the networks of neurons in biological systems. They can learn to perform complex tasks. They are especially effective at recognizing patterns, classifying data, and processing noisy signals. They possess a distributed associative memory which gives it the ability to learn and generalize, i.e., adapt with experience.

The study of artificial neural networks has also added to the data required to create brain chips. They crudely mimic the fundamental properties of the brain. Researchers are working in both the biological and engineering fields to further decipher the key mechanisms of how man learns and reacts to everyday experiences.

The physiological evidences from the brain are followed to create these networks. Then the model is analyzed and simulated and compared with that of the brain. If any discrepancy is spotted between the model and the brain, the initial hypothesis is changed and the model is modified. This procedure is repeated until the model behaves in the same way as the brain.

When eventually a network model which resembles the brain in every aspect is created, it will be a major breakthrough in the evolution towards implantable brain chips.

· Brain Cells and Silicon Chips Linked Electronically:

One of the toughest problems in neural prosthetics is how to connect chips and real neurons. Today, many researchers are working on tiny electrode arrays that link the two. However, once a device is implanted the body develops so-called glial cells, defenses that surround the foreign object and prevent neurons and electrodes from making contact.

In Munich, the Max Planck team is taking a revolutionary approach: interfacing the nerves and silicon directly. "I think we are the only group doing this," Fromherz said.

Fromherz is at work on a six-month project to grow three or four neurons on a 180 x 180-transistor array supplied by Infineon, after having successfully grown a single neuron on the device. In a past experiment, the researcher placed a brain slice from the hippocampus of a monkey on a specially coated CMOS device in a Plexiglas container with electrolyte at 37 degrees C. In a few days dead tissue fell away and live nerve endings made contact with the chip.]

Fig-2: The Max Planck Institute grew this 'snail' neuron atop an Infineon Technologies CMOS device that measures the neuron's electrical activity, linking chips and living cells.

Their plan is to build a system with 15,000 neuron-transistor sites--a first step toward an eventual computational model of brain activity.

ACHIEVEMENTS IN THE FIELD

The achievements in the field of implantable chips, bio-chips, so far are significant. Some of them are mentioned below:

· Brain “Pacemakers”:

Researchers at the crossroads of medicine and electronics are developing implantable silicon neurons that one day could carry out the functions of a part of the brain that has been damaged by stroke, epilepsy or Alzheimer's disease.

The U.S. Food and Drug Administration have approved implantable neurostimulators and drug pumps for the treatment of chronic pain, spasticity and diabetes, according to a spokesman for Medtronic Inc. (Minneapolis). A sponsor of the Capri conference, Medtronic says it is already delivering benefits in neural engineering through its Activa therapy, which uses an implantable neurostimulator, commonly called a brain pacemaker, to treat symptoms of Parkinson's disease.

Surgeons implant a thin, insulated, coiled wire with four electrodes at the tip, and then thread an extension of that wire under the skin from the head, down the neck and into the upper chest. That wire is connected to the neurostimulator, a small, sealed patient-controlled device that produces electrical pulses to stimulate the brain.

These implants have helped patients suffering from Parkinson’s disease to a large extent.

Fig-3: Computer chip model of neural function for implanted brain protheses

· Retinomorphic Chips:

The famed mathematician Alan Turing predicted in 1950 that computers would match wits with humans by the end of the century. In the following decades, researchers in the new field of artificial intelligence worked hard to fulfill his prophecy, mostly following a top-down strategy: If we can just write enough code, they reasoned, we can simulate all the functions of the brain. The results have been dismal. Rapid improvements in computer power have yielded nothing resembling a thinking machine that can write music or run a company, much less unlock the secrets of consciousness. Kwabena Boahen, a lead researcher at the University of Pennsylvania's Neuroengineering Research Laboratory, is trying a different solution. Rather than imposing pseudo-smart software on a conventional silicon chip, he is studying the way human neurons are interconnected. Then he hopes to build electronic systems that re-create the results. In short, he is attempting to reverse-engineer the brain from the bottom up.

Boahen and his fellow neuromorphic engineers are now discovering that the brain's underlying structure is much simpler than the behaviors, insights, and feelings it incites. That is because our brains, unlike desktop computers, constantly change their own connections to revamp the way they process information. "We now have microscopes that can see individual connections between neurons. They show that the brain can retract connections and make new ones in minutes. The brain deals with complexity by wiring itself up on the fly, based on the activity going on around it," Boahen says. That helps explain how three pounds of neurons, drawing hardly any more power than a night-light, can perform all the operations associated with human thought.

The first product from Boahen's lab is a retinomorphic chip, which he is now putting through a battery of simple vision tests. Containing nearly 6,000 photoreceptors and 4,000 synthetic nerve connections, the chip is about one-eighth the size of a human retina. Just as impressive, the chip consumes only 0.06 watt of power, making it roughly three times as efficient as the real thing. A general-purpose digital computer, in contrast, uses a million times more energy per computation as does the human brain. "Building neural prostheses requires us to match the efficiency, not just the performance, of the brain," says Boahen. A retinal chip could be mounted inside an eyeball in a year or two, he says, after engineers solve the remaining challenges of building an efficient human-chip interface and a compact power supply.

Fig-4: This artificial eye contains working electronic versions of the four types of ganglion cells in the retina. The cumbersome array of electronics and optics surrounds an artificial retina, which is just one-tenth of an inch wide.

Remarkable as an artificial retina might be, it is just a baby step toward the big objective—reverse-engineering the brain's entire ornate structure down to the last dendrite. A thorough simulation would require a minutely detailed neural blueprint of the brain, from brain stem to frontal lobes.

· At Emory University – The Mental Mouse:

Dr. Philip R. Kennedy, an [sic] clinical assistant professor of neurology at Emory University in Georgia, reported that a paralyzed man was able to control a cursor with a cone-shaped, glass implant. Each [neurotrophic electrode] consists of a hollow glass cone about the size of a ball-point pen tip. The implants…contain an electrode that picks up impulses from the nerve endings. Before they are implanted, the cones are coated with chemicals — taken from tissue inside the patients’ own knees — to encourage nerve growth. The implants are then placed in the brain’s motor cortex — which controls body movement — and over the course of the next few months the chemicals encourage nerve cells to grow and attach to the electrodes. A transmitter just

inside the skull picks up signals from the cones and translates these into cursor commands on the computer.