BRAIN GATE SYSTEM

Brain gate system

BRAIN GATE SYSTEM

ABSTRACT:

The mind-to-movement system that

allows a quadriplegic man to control a

computer using only his thoughts is a

scientific milestone. It was reached, in

large part, through the brain gate

system. This system has become a boon

to the paralyzed. The Brain Gate

System is based on Cyber kinetics

platform technology to sense, transmit,

analyze and apply the language of

neurons. The principle of operation

behind the Brain Gate 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 Brain

Gate pathway to control a computer

with thought, just as individuals who

have the ability to move their hands

use a mouse.

The 'Brain Gate' contains tiny spikes

that will extend down about one

millimetre into the brain after being

implanted beneath the skull,

monitoring the activity from a small

group of neurons. It will now be

possible for a patient with spinal cord

injury to produce brain signals that

relay the intention of moving the

paralyzed limbs, as signals to an

implanted sensor, which is then output

as electronic impulses. These impulses

enable the user to operate mechanical

devices with the help of a computer

cursor. Matthew Nagle, a 25-year-old

Massachusetts man with a severe

spinal cord injury, has been paralyzed

from the neck down since 2001.After

taking part in a clinical trial of this

system, he has opened e-mail, switched

TV channels, turned on lights. He even

moved a robotic hand from his

wheelchair. This marks the first time

that neural movement signals have

been recorded and decoded in a

human with spinal cord injury. The

system is also the first to allow a

human to control his surrounding

environment using his mind.

Dept. of ECE, svpcet, puttur.

Brain gate system

INTRODUCTION:

Brain Gate: Turning Thoughts into

Action.

The concept of using thought to move

a robotic device, a wheelchair, a

prosthetic, or a computer was once

strictly the stuff of science fiction, but

no longer. Brain Gate collects and

analyzes the brainwaves of individuals

with pronounced physical disabilities,

turning thoughts into actions. The

potential to better communicate,

interact, and improve people’s way of

life is about to explode.

BRAIN-COMPUTER

INTERFACE (or) DIRED

NEURAL 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 and

an external device.

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.

Following years of animal

expermentation, early working

implants in humans now exist,

designed to restore damaged hearing,

sight and movement.

 BCI:

Direct communication pathway

between a brain or brain cell culture

and a device (computer)

One way BCIs:

Information passes from brain to

computer or computer to brain

Two way BCIs:

Information is exchanged between

brain and computer

Invasive BCI:

The chip is implanted directly into

the grey matter of the brain.

Produces the highest quality signals

but are prone to scar tissue build up.

Scar tissue causes the signal to become

weaker and even lost as the body reacts

to a foreign object.

HOW DOES THE BRAIN

CONTROL MOTOR

FUNCTION?The brain is "hardwired" with

connections, which are made by

billions of neurons that make

electricity whenever they are

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Brain gate system

stimulated. The electrical patterns are

called brain waves. Neurons act like

the wires and gates in a computer,

gathering and transmitting

electrochemical signals over distances

as far as several feet. The brain

encodes information not by relying on

single neurons, but by spreading it

across large populations of neurons,

and by rapidly adapting to new

circumstances.

Motor neurons carry signals from the

central nervous system to the muscles,

skin and glands of the body, while

sensory neurons carry signals from

those outer parts of the body to the

central nervous system. Receptors

sense things like chemicals, light, and

sound and encode this information into

electrochemical signals transmitted by

the sensory neurons. And interneurons

tie everything together by connecting

the various neurons within the brain

and spinal cord. The part of the brain

that controls motor skills is located at

the ear of the frontal lobe.

COMMUNICATION WITH

THE BODY: Muscles in the body's limbs contain

embedded sensors called muscle

spindles that measure the length and

speed of the muscles as they stretch

and contract as you move. Other

sensors in the skin respond to

stretching and pressure. Even if

paralysis or disease damages the part

of the brain that processes movement,

the brain still makes neural signals.

They're just not being sent to the arms,

hands and legs.

A technique called neurofeedback

uses connecting sensors on the

scalp to translate brain waves into

information a person can learn

from. The sensors register different

frequencies of the signals produced

in the brain. These changes in brain

wave patterns indicate whether

someone is concentrating or

suppressing his impulses, or

whether he is relaxed or tense.

NEUROPROSTHETIC

DEVICE:

A neuroprosthetic device known as

Brain gate converts brain activity into

computer commands. A sensor is

implanted on the brain, and electrodes

are hooked up to wires that travel to a

pedestal on the scalp. From there, a

fiber optic cable carries the brain

activity data to a nearby computer.

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Brain gate system

PRINCIPLE:"The principle of operation of the

Brain Gate Neural Interface System is

that with intact brain function, neural

signals are generated even though they

are not sent to the arms, hands and

legs. These signals are interpreted by

the System and a cursor is shown to

the user on a computer screen that

provides an alternate "Brain Gate

pathway". The user can use that cursor

to control the computer, just as a

mouse is used."

Brain Gate is a brain implant system

developed by the bio-tech company

Cyber kinetics 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 patient and

converts the intention of the user into

computer commands.

The Brain Gate System consists of a

4x4 millimeter sensor, about the size of

a baby aspirin, with 100 tiny

electrodes, each thinner than a human

hair. The sensor is implanted on the

surface of the area of the brain

responsible for voluntary movement,

the motor cortex. The electrodes

penetrate about 1 mm into the surface

of the brain where they pick up

electrical signals -- known as neural

spiking, the language of the brain --

from nearby neurons and transmit them

through thin gold wires to a titanium

pedestal that protrudes about an inch

above the patient's scalp. An external

cable connects the pedestal to

computers, signal processors and

monitors.

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Brain gate system

Converting digitized intentions into

meaningful action, however, is not

simple. Active neurons fire between 20

and 200 times a second and they work

in teams.

NUERO CHIP:

Currently the chip uses 100 hair-thin

electrodes that 'hear' 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 Cyber kinetics'

website, three patients have been

implanted with the Brain Gate system.

The company has confirmed that one

patient (Matt Nagle) has a spinal cord

injury, whilst another has advanced

ALS.

In addition to real-time analysis of

neuron patterns to relay movement, the

Brain gate array is also capable of

recording electrical data for later

analysis. A potential use of this feature

would be for a neurologist to study

seizure patterns in a patient with

epilepsy.

Brain gate is currently recruiting

patients with a range of neuromuscular

and neurodegenerative conditions for

pilot clinical trials in the United States.

WORKING:

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Brain gate system

Operation of the BCI system is not

simply listening the EEG of user in a

way that let’s tap this EEG in and

listen what happens. The user usually

generates some sort of mental activity

pattern that is later detected and

classified.

CLINICAL TRIALS:Partnering with leading rehabilitation

centers in Boston, Chicago and

providence.

Cyber kinetics is currently recruiting

patients to enroll in a pilot clinical trial

of the neural interface system.

The brain gate system is designed to

provide a means for people with severe

most impairment a new method  to

communicate with a computer directly

with their investigational device, the

brain gate system is only offered

through the clinical commercially

available.

The disclaimers in clinical trials are the

U.S food and drug administration

(FDA) has not approved the brain gate

non interface system for general use

The brain gate system is an

investigational device in the United

States, and is uni status. 

RESEARCH PRODUCT:

In the 13 July 2006 issue of Nature, the

researchers presented the first

published results from the initial

participants in a clinical trial of the

Brain Gate Neural Interface

System,”neuromotor prosthesis"

developed by Cyber kinetics

Neurotechnology Systems, Inc., of Fox

borough, Mass.

Cyber kinetics neurotechnology

systems provides turn-key solutions for

neuroscience researchers invested in

recording neural signals from

populations of neurons over a long

period of time. Their solutions include

Multi electrode array, the cerebus 128

channel data acquisition system, and a

surgical training program.

A team of neuroscientists had

implanted a chip in to the brain of a

quadriplegic man, allowing him to

control a computer has been able to

check email and play computer games

simply using thoughts. He can also

turn lights on and off and control a

television, all while talking and

moving his head.

The chip called Brain gate, is being

developed by Massachusetts-based

neurotechnology company cyber

kinetics. 

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Brain gate system

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 Cyber kinetics, 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. 

Cyber kinetics 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 an institutions

such as Brown University, the

Massachusetts Institute of Technology

University, and the University of Utah.

BRAINGATE INTERFACE: December 7, 2004 an implantable,

brain-computer interface the size of an

aspirin has been clinically tested on

humans by American company Cyber

kinetics. The 'Brain Gate' device can

provide paralyzed or motor-impaired

patients a mode of communication

through the translation of thought into

direct computer control. The

technology driving this breakthrough

in the Brain-Machine-Interface field

has a myriad of potential applications.

Including the development of human

augmentation for military and

commercial purposes.

Researchers at the University of

Pittsburgh have already demonstrated

that a monkey can feed itself with a

robotic arm simply by using signals

from its brain, an advance that could

enhance prosthetics for people,

especially those with spinal cord

injuries. Now, using the Brain Gate

system in the current human trials, a 25

year old quadriplegic has successfully

been able to switch on lights, adjust the

volume on a TV. Change channels and

read e-mail using only his brain.

Crucially, the patient was able to do

these tasks while carrying on a

conversation and moving his head at

the same time

HOW DIFFICULT IS THIS

SURGERY?The surgeon makes a craniotomy that's

the diameter of a 50-cent piece. The

sensor, which is the size of a baby

aspirin with 100 tiny hair-like

appendages, is implanted in the region

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Brain gate system

that issues commands to the arms. The

software tells the surgeon exactly

where to go and the whole surgical

procedure takes about two and a half

hours. Afterward only a penny-sized

connector to the computer can be seen

from the outside.

HOW DOES THE SYSTEM

WORK?

The patient directs his thoughts to

move the cursor on his computer

screen. The sensor in his brain picks up

those hard-to-detect electrical signals

and sends them through three

computers that process them into

signals just like those from a computer

mouse. These processors, which

currently sit on a cart and are not

mobile, will eventually become

wireless and small enough to fit inside

the body.

So when he's connected, the patient

can just "think" the cursor from place

to place on-screen like the rest of us

use a mouse. What else can he do?

He can also connect to other devices

through the computer, such as a TV

set, the control that opens and closes

the curtains, a powered wheelchair or

even a mechanical hand. Eventually

we could hook this up to the person's

actual hand.

PREPROCESSING:

The raw EEG signal requires some

preprocessing before the feature

extraction. This preprocessing includes

removing unnecessary frequency

bands, averaging the current brain

activity level, transforming the

measured scalp potentials to cortex

potentials and denoising. Frequency

bands of the EEG:

Band

Frequency [Hz]

Amplitude [V]

Location

Alpha (α)

8-12 10 -150

Occipital/Parietal regions

µ-rhythm

9-11 varies Precentral/Post central regions

Beta (β)

14 -30 25 typically frontal regions

Th 4-7 varies varies

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Brain gate system

eta (θ) Delta (δ)

<3 varies varies

DETECTION:The detection of the input from the

user and them translating it into an

action could be considered as key part

of any BCI system. This detection

means to try to find out these mental

tasks from the EEG signal. It can be

done in time-domain, e.g. by

comparing amplitudes of the EEG and

in frequency-domain. This involves

usually digital signal processing for

sampling and band pass filtering the

signal, then calculating these time -or

frequency domain features and then

classifying them. These classification

algorithms include simple comparison

of amplitudes linear and non-linear

equations and artificial neural

networks. By constant feedback from

user to the system and vice versa, both

partners gradually learn more from

each other and improve the overall

performance.

CONTROL: The final part consists of applying the

will of the user to the used application.

The user chooses an action by

controlling his brain activity, which is

then detected and classified to

corresponding action. Feedback is

provided to user by audio-visual means

e.g. when typing with virtual keyboard,

letter appears to the message box etc.

TRAINING: The training is the part where the user

adapts to the BCI system. This training

begins with very simple exercises

where the user is familiarized with

mental activity which is used to relay

the information to the computer.

Motivation, frustration, fatigue, etc.

apply also here and their effect should

be taken into consideration when

planning the training procedures

BIO FEEDBACK: The definition of the biofeedback is

biological information which is

returned to the source that created it, so

that source can understand it and have

control over it. This biofeedback in

BCI systems is usually provided by

visually, e.g. the user sees cursor

moving up or down or letter being

selected from the alphabet.

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Brain gate system

A BOON TO THE

PARALYZED -BRAIN GATE

NEURAL INTERFACE

SYSTEM:

The first patient, Matthew Nagle, a 25-

year-old Massachusetts man with a

severe spinal cord injury, has been

paralyzed from the neck down since

2001. Nagle is unable to move his

arms and legs after he was stabbed in

the neck. During 57 sessions, at New

England Sinai Hospital and

Rehabilitation Center, Nagle learned to

open simulated e-mail, draw circular

shapes using a paint program on the

computer and play a simple

videogame, "neural Pong," using only

his thoughts. He could change the

channel and adjust the volume on a

television, even while conversing. He

was ultimately able to open and close

the fingers of a prosthetic hand and use

a robotic limb to grasp and move

objects. Despite a decline in neural

signals after few months, Nagle

remained an active participant in the

trial and continued to aid the clinical

team in producing valuable feedback

concerning the Brain Gate` technology.

NAGLE’S STATEMENT:“I can't put it into words. It's just—I

use my brain. I just thought it. I said,

"Cursor go up to the top right." And it

did, and now I can control it all over

the screen. It will give me a sense of

independence.”

Dept. of ECE, svpcet, puttur.

Brain gate system

The second patient, a 55-year-old man

with a similar injury, had the sensor

implanted by surgeons at the

University of Chicago in April 2005

and was followed by researchers from

the Rehabilitation Institute of Chicago

and Cyber kinetics. Although his

device initially had electrical problems,

these were repaired and he was able to

learn to control the cursor from months

even through 10 of the trial, until a

technical issue caused signal loss at

most electrodes.

PATIENT GAINING

ACCURACY: Cyber kinetics technicians work with

the former football player three times a

week, trying to fine-tune the system so

he can do more tasks. He can move a

cursor around a screen. If he leaves

the cursor on a spot and dwells on it,

that works like a mouse click.

Once he can control a computer, the

possibilities get interesting. A

computer could drive a motorized

wheelchair, allowing him to go where

he thinks about going. It could control

his environment - lights, heat, locking

or unlocking doors. And he could tap

out e-mails, albeit slowly.

In the next two years, Cyber

kinetics hopes to refine the chip

to develop a wireless version

No need for a plug

Safer

Less visible.

OTHER APPLICATIONS:Experiments were performed on dogs

that were raised confined in cages.

When released, the dogs were excited,

constantly ran around, and required

several attempts to learn to avoid pain.

When pain such as a pinch or contact

with a burning match was encountered,

the animals could not take action to

avoid the stimulus immediately. This

finding seemed to demonstrate that

pain is understood and avoided only by

experience- aversion to it is not inbuilt

or automatic, and the organism has no

way to know what will cause repeated

pain without a repeated experience.

Afferent pain-receptive nerves, those

that bring signals to the brain,

comprise at least two kinds of fibers - a

fast, relatively thick, myelinated "A8"

fiber that carries messages quickly

with intense pain, and a small,

unmyelinated, slow "C" fiber that

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Brain gate system

carries the longer-term throbbing and

chronic pain. Large-diameter Afi fibers

are nonnociceptive and inhibit the

effects of firing by A8 and C fibers.

The central nervous system has centers

at which pain stimuli can be regulated.

Some areas in the dorsal horn of the

spinal cord that are involved in

receiving pain stimuli from A8 and C

fibers, called laminae, also receive

input from Ap fibers. In other parts of

the laminae, pain fibers also inhibit the

effects of nonnociceptive fibers,

'opening the gate'.

BCI IN RATS AND

MONKEYS:

Rats implanted with BCIs in Theodore

Berger's experiments. Several

laboratories have managed to record

signals from monkey and rat cerebral

cortexes in order to operate BCIs to

carry out movement. Monkeys have

navigated computer cursors on screen

and commanded robotic arms to

perform simple tasks simply by

thinking about the task and without

any motor output. Other research on

cats has decoded visual signals.

Garrett Stanley's recordings of cat

vision using a BCI implanted in the

lateral geniculate nucleus (top row:

original image; bottom row: recording)

In 1999, researchers led by Garrett

Stanley at Harvard University decoded

neuronal firings to reproduce images

seen by cats. The team used an array of

electrodes embedded in the thalamus

(which integrates all of the brain’s

sensory input) of sharp-eyed cats.

Researchers targeted 177 brain cells in

the thalamus lateral geniculate nucleus

area, which decodes signals from the

retina. The cats were shown eight short

movies, and their neuron firings were

recorded. Using mathematical filters,

the researchers decoded the signals to

generate movies of what the cats saw

and were able to reconstruct

recognizable scenes and moving

objects.

Dept. of ECE, svpcet, puttur.

Brain gate system

In the 1980s, Apostolos Georgopoulos

at Johns Hopkins University found a

mathematical relationship between the

(based on a cosine function). He also

found that dispersed groups of neurons

in different areas of the brain

collectively controlled motor

commands but was only able to record

the firings of neurons in one area at a

time because of technical limitations

imposed by his equipment.

There has been rapid development in

BCIs since the mid-1990s. Several

groups have been able to capture

complex brain motor centre signals

using recordings from neural

ensembles (groups of neurons) and use

these to control external devices,

including research groups led by

Richard Andersen, John Donoghue,

Phillip Kennedy, Miguel Nicolelis, and

Andrew Schwartz.

Fig: Diagram of the BCI developed

by Miguel Nicolelis and colleagues

for use on Rhesus monkeysNicolelis' group conducted their initial primate experiments using owl monkeys. By 2000, they had gained experience in implanting owl monkeys with electrode arrays in multiple < brain areas and built a BCI that reproduced monkey movements while the monkey operated a joystick or reached for food.Later experiments led by Miguel Nicolelis on rhesus monkeys succeeded in closing the loop.Later experiments by Nicolelis using

rhesus monkeys, succeeded in closing

the feedback loop and reproduced

monkey reaching and grasping

movements in a robot arm. With their

deeply cleft and furrowed brains,

rhesus monkeys are considered to be

better models for human

neurophysiology than owl monkeys.

The monkeys were trained to reach and

grasp objects on a computer screen by

manipulating a joystick while

corresponding movements by a robot

arm were hidden. The monkeys were

later shown the robot directly and

learned to control it by viewing its

movements. The BCI used velocity

predictions to control reaching

movements and simultaneously

predicted hand gripping force.

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Brain gate system

Other labs that develop BCIs and

algorithms that decode neuron signals

include John Donoghue from Brown

University, Andrew Schwartz from the

University of Pittsburgh and Richard

Andersen from Caltech. These

researchers were able to produce

working BCIs even though they

recorded signals from far fewer

neurons than Nicolelis (15–30 neurons

versus 50–200 neurons).

Donoghue's group reported training

rhesus monkeys to use a BCI to track

visual targets on a computer screen

with or without assistance of a joystick

(closed-loop BCI). Schwartz's group

created a BCI for three-dimensional

tracking in virtual reality and also

reproduced BCI control in a robotic

arm.

ADVANTAGES: 

The brain crate system is based on

cyber kinetics platform technology to

sense, transmit analyze and apply the

language of neurons.

The Brain Gate Neural Interface

System is being designed to one day

allow the interface with a computer

and / or even faster than, what is

possible with the hands of a person.

The Brain Gate System may offer

substantial improvement over existing

technologies.

Currently available assistive device has

significant limitations for both the pers

and caregiver. For example, even

simple switches must be adjusted

frequent that can be time consuming.

In addition, these devices are often

obtrusive and user from being able to

simultaneously use the device and at

the same time contact or carry on

conversations with others.

Potential advantages of the Brain Gate

System over other muscle driven or

brain computer interface approaches

include : its potential to interface with

a compute weeks or months of

training; its potential to be used in an

interactive environment user’s ability

to operate the device is not affected by

their speech, eye movement noise; and

the ability to provide significantly

more usefulness and utility than other

approaches by connecting directly to

the part of the brain that controls hand 

gestures. 

DISADVANTAGES:

The U.S. Food and Drug

Administration (FDA) have not

approved the Brain Gate Non Interface

System for general use. 

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Brain gate system

The Brain Gate System is an

investigational device in the United

States, and is status (Investigational

Device Exemption). In the United

States, this investigate can only be

used in pre-marketing clinical trials

approved by the FDA. 

FUTURE SCOPE: Brain Gate, a tiny sensor array

implanted in the brain, has allowed a

quadriplegic man to check e-mail and

play computer games - even

manipulate the controls on a television.

It is the most sophisticated implant of

its kind.

In the future, the Brain Gate

System could be used by those

individuals whose injuries are less

severe. Next generation products may

be able to provide an individual with

the ability to control devices that allow

breathing, bladder and bowel

movements Once he can control a

computer, the possibilities get

interesting. A computer could drive a

motorized wheelchair, allowing him to

go where he thinks about going. It

could control his environment - lights,

heat, locking or unlocking doors. And

he could tap out e-mails, albeit slowly.

CONCLUSION:

The idea of moving robots or

prosthetic devices not by manual

control, but by mere “thinking” (i.e.,

the brain activity of human subjects)

has been a fascinated approach.

Medical cures are unavailable for

many forms of neural and muscular

paralysis. The enormity of the deficits

caused by paralysis is a strong

motivation to pursue BMI solutions.

So this idea helps many patients to

control the prosthetic devices of their

own by simply thinking about the task.

This technology is

well supported by the latest fields of

Biomedical Instrumentation,

Microelectronics; signal processing,

Artificial Neural Networks and

Robotics which has overwhelming

developments. Hope these systems will

be effectively implemented for many

biomedical applications.

REFERENCES:http://www.seminartopics.net/

http://www.google.com/

http://www.wikipedia.com/

Dept. of ECE, svpcet, puttur.

Brain gate system

Dept. of ECE, svpcet, puttur.