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Group A
Theme of paper: Advances in Biomedical/instrumentation
Topic of paper: Braingate
Registration id : 324
Name : Ms.Snehal S. Mahajan
Contact no : 9595138231
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CONTENTS
• Abstract
•
Introduction
Brain Computer Interface
What Is Braingate?
• Main principle
• How Braingate works?
• The Braingate chip
• Advantages
• Disadvantages
• Future Expansion
• Conclusion
• References
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ABSRACT
Braingate was 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. 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. 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 activity is
translated into electrically charged
signals and is then sent and decoded
using a program, thus moving the arm.
According to the Cyberkinetics'
website, two patients have been
implanted with the Braingate system.
INTRODUCTION
The Braingate technology is the
application of brain computer
interface technology. The brain-
computer interface is the origin for
Braingate technology. Before goinginto the details of Braingate system,
let us first see brain computer
interface technology in brief:
BRAIN COMPUTER
INTERFACE:
BCI uses brain activity to command,
control, actuate and communicate with
the world directly through brain
integration with peripheral devices and
systems. A brain –computer interface
(BCI), some times called a direct neural
interface and is a direct communication
pathway between a human or animal
brain (and brain cell culture) and an
external device.
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In one way BCIs,, computer 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
organile life form rather than the mind.
computer means any processing or
computational devices, from simple
circuits to silicon chips.
WHAT IS BRAINGATE?
Braingate converts brain activity in
to 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 that brain
activity data to a near by computer.
The brain is “hardwired” with
connections, which are made by billions
of neurons that make electricity when
ever they are simulated. The electrical
patterns are called brain waves. Neurons
act like the wires and gates in a
computer.
Brain controls motor function.
Motor neurons carry a signal 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.
A technique called
neurofeedback uses connecting sensors
on the scalp to translate brain waves in
to information a person can learn from.
This enables the person learning the
gradual adaptation of motor commands
which takes place after the execution of
one or more movements.The sensors register different
frequencies of the signals produced in
the brain.These changes in the brain
wave patterns indicate whether someone
is concentrating or suppressing his
impulses, or whether he is relaxed or
tense.
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Fig(a):The overall Braingate
system
MAIN PRINCIPLE
The system has a small chip that
will be implanted in the human brain.
This chip can analyse brain signals. The
main principle behind this system is that
with intact brain function, brain signals
are functioning normal and can be
generated even though they are not sent
to the arms and legs.
This means that these signals can be
‘read’ through this chip and translated
into functions that a computer can
understand. For example a cursor
movement. Using this system a person
can move a cursor on a computer screen
by his thoughts, the same way
somebody uses a mouse.
Fig(b):patient implanted with
Braingate chip
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HOW BRAINGATE WORKS?
Main principle behind this interface
is the bioelectrical activity of nerves and
muscles. It is now well established that
the human body, which is composed of
living tissues, can be considered as a
power station generating multiple
electrical signals with two internal
sources, namely muscles and nerves.
We know that brain is the most
important part of human body. It
controls all the emotions and functions
of the human body. The brain is
composed of billions of neurons. These
neurons work together in complex logic
and produce thought and signals that
control our bodies. When the neuron
fires, or activates, there is a voltage
change across the cell, (~100mv) which
can be read through a variety of devices.
When we want to make a voluntary
action, the command generates from the
frontal lobe.
Muscles in the body’s limbs containembedded 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. The electrodes do the same
work as muscle spindles do. Even if
paralysis or disease damages the part of
the brain that process movement, the
brain still makes neural signals. They
are just not being sent to the arms,
hands and legs. These small signals are,
however, measurable. A neuron
depolarizes to generate an impulse; this
action causes small changes in the
electric field around the neuron. These
changes are measured as 0 (no impulse)
or 1 (impulse generated) by the
electrodes. These Signals are generated
on the surface of the brain. These
electric signals are different in
magnitude and frequency. Bymonitoring and analyzing these signals
we can understand the working of brain.
Now the question arises how the signal
analysis is done to implement the exact
task set by the thoughts? This is done by
classifiers. We know that the brainwave
consists of different frequency contents.
These frequency contents are grouped
into different groups. Each group
corresponds to different medical tasks.
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The classifiers are used to classify these
groups to perform corresponding mental
tasks.
BRAINGATE CHIP
The four-millimeter square chip is
placed on the surface of the motor
cortex area of the brain which detect
neural electrical activity. The sensor is
then connected to a computer via a
small wire attached to a pedestal
mounted on the skull. The brainwaves
are recorded with electrodes, which are
placed on the scalp. Electrodes are
small plates, which conduct electricity.
They provide the electrical contact
between the skin and the brainwave
recording apparatus by transforming the
ionic current on the skin to the electrical
current in the wires. To improve the
stability of the signal, the outer layer of
the skin called stratum corneum should
be at least partly removed under the
electrode. Electrolyte gel is applied
between the electrode and the skin inorder to provide good electrical contact.
Currently the chip uses 100 hair-thin
electrodes that sense the
electromagnetic signature of neurons
firing in specific areas of the brain. For
example, the area that controls arm
movement. The activity is translated
into electrically charged signals and is
then sent and decoded using a program,
which can move either a robotic arm or
a computer cursor. According to the
Cyberkinetics’ website, two patients
have been implanted with the Brain
Gate system. The chip is shown in the
fig(c).
There are a few major problems that
must be addressed when developing
neural implants. These must be made
out of biocompatible material or
insulated with biocompatible material
that the body won’t reject and isolate.One option among the biocompatible
materials is Teflon coating that protects
the implant from the body.
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Fig(c):The Brain chip
Fig (d):Basic elements of the
chip
For working the Braingate chip
requires some basic elements.
Neurochips use amplifiers to boost low-
voltage biological signals, analog-to-
digital converters (ADCs) to digitize
these signals, microcomputers to
process the signals, onboard memory to
store the signals, digital-to-analog
converters (DACs) to stimulate nerves,
and software to control the overall
experiment.
Figure (d) shows a brain chip’s
basic elements. The key requirements
are that the brain chip be small and
lightweight enough to fit inside or onto
the animal, have adequate signal fidelity
for interacting with the mill volt-levelsignals characteristic of nerve tissue,
and have sufficient processing power to
perform experiments of real scientific
value.
ADVANTAGES
The Braingate 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
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hands of a person. The Brain
Gate System may offer
substantial improvement over
existing technologies.
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 United States.
It provides better and
independent living to those who
have lost control of their limbs
or other bodily functions.
Braingate system enables the
patient to 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.
Fig:patient availing
braingate system
DISADVANTAGE
Connecting to the nervous
system could lead to permanent
brain damage, resulting in the
loss of feelings or movement, or
continual pain.
Virus attacks may occur to brain
causing ill effects.
The U.S. Food and Drug
Administration (FDA) has not
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approved the Brain Gate Non
Interface System for general use.
This investigate can only be
used in pre-marketing clinical
trials approved by the FDA.
Although many are able to
control the computer with these
systems, such techniques remain
dependent on the muscular
functions and require extensive
training.
FUTURE EXPANSION
Cyber kinetics is developing product
for robotic control, such as a thought-
controlled wheel chair.
In the future, the Brain Gate System
could be used by those individuals who
are in severe condition. Next generation
products may be able to provide an
individual with the control of the device
that allows breathing, bladder and
bowel movements.Also this technology
will become wireless in near future.
CONCLUSION
If we consider a paralysed person as
‘not normal’, the Braingate system can
make this paralysed person normal
again. So from that perspective
Braingate is necessary. It is like the
Braingate can’t work without a human
brain and the human brain (from
someone who is paralysed) can’t
function without the Braingate system.
The goal of this development would be
able to allow these individuals to one
day use their own arms and hands
movement. These developments are
currently at the research stage and are
not available with the existing Brain
Gate System. BCI’s will have the ability
to give people back their vision and
hearing. They will also change the way
a person looks at the world. Someday
these devices might be more common
than keyboards. To put in a nutshell,
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this technology really means “putting
thoughts into action”.
REFERENCES
http:/www.cyberkineticsinc.com
http:/www.fda.gov/cdrh/devadvi
ce/ide/index.shtml
http:/www.usatoday.com/news/h
ealth/2004-10-10-braingate-
cover_x.htm
http:/www.cnn.com/2004/TECH
/10/20/explorers.braingate/
http://www.brown.edu/Administ
ration/News_Bureau/2004-
05/04-035.html
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