BRAIN GATETECHNOLOGY

SEMINAR BY:NAMRATA KOLEY(C.S.E. III YEAR)OM DAYAL GROUP OF INSTITUTION,ULUBERRIAWEST BENGAL

INTRODUCTIONWhat is Brain Gate Technology?• Brain gate is a neuroprosthetic device that

converts brain activity into computer commands.

• This system is designed to help those who have lost control of their limbs, or other bodily functions, such as patients with amyotropic lateral sclerosis  (ALS) or  spinal cord injury.

DEVELOPMENT

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 .

In July 2009, a second clinical trial (dubbed "BrainGate2") was initiated by researchers at Massachusetts General Hospital, Brown University, and the Providence VA.

Nicholas HatsopoulosJeff StibelJudy Hackett

UNDERLYING PRINCIPLE

The brain is hardwired with connections, which are made by billions of neurons that make electricital signals whenever they are stimulated.

”The principle of operation of the BrainGate 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”.

WORKING 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 preprocessor ,then digitizer and then to a nearby computer.

WORKING ALGORITHM

NEUROCHIP

The chip uses 100 hair-thin electrodes that 'hear' neurons firing in specific areas of the brain It is made of silicon that is doped in such a way that it contains EOSFETs (that can sense the electrical activity of the neurons. It also contains capacitors for the electrical stimulation of the neurons. It is embeddedd in primary motor cortex region .

INVASIVE Invasive BCIs are implanted directly into the grey matter of the brain during neurosurgery . Invasive BCI provides the highest quality of signals among BCIs but are prone to scar –tissue build- ups.

PARTIALLY INVASIVE

Partially invasive BCI devices are implanted inside the skull but rest outside the brain rather than within the grey matter. They produce better resolution signals than non-invasive BCIs where the bone tissue of the cranium deflects and deforms signals and have a lower risk of forming scar-tissue Eg:::::ELECTROCORTICOGRAPH (ECoG)

NON -INVASIVE

No break in the skin is made .Activities are carried out on the scalp.Eg :Electroencephalography(EEG) Magnetoencephalography(EEG)

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 Frequecny [Hz] Amplitude Location

Alpha (_) 8-12 10 -150 Occipital/Parietal regions

µ-rhythm 9-11 varies Precentral/Postcentral regions

Beta (_) 14 -30 25 typically Frontal regions

Theta (_) 4-7 varies varies

Delta (_) <3 varies varies

DETECTION

• The 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 isprovided to user by audio-visual means

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.Users learn over a series of 40-min sessions to control the cursor. They participate in 2–3 sessions per week for about six months.

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.

COMPONENTS

NEUROCHIP

CONNECTOR(PEDESTAL)

PREPROCESSING SECTIONCOMPUTEREXERNAL DEVICES

Software behind Brain Gate…

The computers translate brain activity and create the communication output using custom decoding software.System uses translation algoithm in which a linear equation translates mu-rhythm orbeta-rhythm into cursor movement of10 times/s,adaptive algorithms and pattern-matching techniques to facilitate communication. The algorithms are written in C, JAVA and MATLAB

DENOISING AMPLIFIER

averaging the current brain activity level

Measure scalp potentials to cortex potentials

removing unnecessary frequency bands

the user controls vertical cursor movement bycontrolling the amplitude of a 12-Hz mu rhythm focused over leftsensorimotor cortex.

CURSOR In our brain–computer interface (BCI) people motor disabilities learn to control mu- and/or beta-rhythm amplitudes to move a cursor in one or two dimensions to choices on acomputer screen

With this control, users can move the cursor to answer spoken yes/no questions with accuracies >95%

DO YOU WANT TO MOVE YOUR HAND RIGHT?

• YES NO

Brain Gate Research in animals:

At first, rats were implanted with BCI .

Signals recorded from the cerebral cortex of rat to operate BCI to carry out the movement.

Researchers at the University of Pittsburgh had demonstarted on a monkey that can feed itself with a robotic arm simply by using signals from its brain. Using only its mind the monkey was able to control a cursor on a computer monitor via Brain Gate.

APPLICATIONS:

In Foxborough, a 25-year-old quadriplegic sits in a wheelchair with wires coming out of a bottle-cap-size connector stuck in his skull. The wires run from 100 tiny sensors implanted in his brain and out to a computer. Using just his thoughts, he was playing the computer game Pong.

CONCLUSION

According to the Cyberkinetics' website, two patients have been implanted with the Brain Gate system.

Using the system, called Brain Gate, the patient can read e-mail, play video games, turn lights on or off and change channels or adjust the volume of a television set.

In early test sessions, the patient was able to control the TV and carry on a conversation and move his head at the same time.

The results are spectacular and almost unbelievable.

Brain Gate can help paralyzed people move by controlling their own electric wheelchairs, communicate by using e-mail and Internet-based phone systems, and be independent by controlling items such as televisions and thermostats.

Finally BRAIN GATE has proved to be a boon for paralyzed patient .

Brain gate is a powerful gift Because it can bring the

Gift of hope THANK YOU