[NORMAL] Brain Computer Interface ppt

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BRAIN COMPUTER

INTERFACE

Presented by:

V.Lakshana

Regd. No.: 0601106040

Information Technology

CET, Bhubaneswar

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Brain Computer Interface

from fiction

to reality ...

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In the futuristic vision of the Wachowski brothers’ movie

trilogy “The Matrix”, humans dive into a virtual world by

connecting their brains directly to a computer……..

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OVERVIEW

Definition General Principle Background Component

Simplified model of BCI Training of BCI system Current BCI approaches

EEG Based BCI EEG Based BCI BCI for Tetraplegics Brain controlled robots

Present Development and Future Applications

BCI for Healthy Users Advantages

Computational Challenges Future Expansion

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DEFINITION

A Brain Computer

Interface (BCI) is a

collaboration in which

a brain accepts and

controls a mechanical

device as a natural part

of its representation of

the body.

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GENERAL PRINCIPLE

(a) (b) (c)

(a) In healthy subjects, primary motor area sends movement

commands to muscles via spinal cord.

(b) In paralyzed people this pathway is interrupted.

(c) Computer based decoder translates this activity into

commands for muscle control.

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BACKGROUND

Signals from an array of

neurons read.

Cerebral electric activity

recorded.

Signals are amplified.

Transmitted to computer

Transformed to device

control commands.

Using computer chips and

programs.

Signals translated into

action.

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BASIC COMPONENTS

The implant device, or chronic multi-electrode array

The signal recording and processing

section

An external device An external device the subject uses to produce & control motion

A feedback section to the subject

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Implant Device

Conduct electricity

Biocompatible material(teflon)

Placed on the scalp

Chemically inert

Provide the electrical contact

between the skin and the EEG

recording apparatus

AN ARRAY OF MICROELECTRODES

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Signal Processing Section

Multichannel Acquisition Systems

Spike Detection

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SIMPLIFIED MODEL OF THE BCI SYSTEM

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TRAINING OF BCI SYSTEM

Two different approaches: Pattern Recognition Approach

Operant Conditioning Approach

BLOCK DIAGRAM FOR LEARNING MODE

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CURRENT BCI APPROACHES

BCI APPROACHES INVASIVE SEMI-INVASIVE NON-INVASIVE

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EEG Based BCI

Electroencephalography (EEG) is a method used in measuring the electrical activity of the brain.

The basic frequency of the

EEG range is classified

into five bands for

Band Frequency [Hz] Delta 0.5- 4 Theta 4- 8 Alpha 8- 13 Beta 13- 22 Gamma 22-30

into five bands for

purposes of EEG analysis called brain rhythms .

The alpha rhythm is one of the principal components of the EEG and is an

indicator of the state of alertness of the brain.

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Development of BCI

Early work

Algorithms to reconstruct movements from motor cortex neurons, which control movement were developed in 1970s. The first Intra-Cortical Brain-Computer Interface was built by implanting neurotrophiccone electrodes into monkeys.

After conducting initial studies in rats during the 1990s, researchers developed Brain Computer Interfaces that decoded brain activity in monkeys and used the devices to reproduce monkey movements in monkeys and used the devices to reproduce monkey movements in robotic arms.

Present Developments

BCI for Tereaplegics Brain controlled Robot ‘BRAINGATE’ BCI

ATR and HONDA’s new BCI BCI2000

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BCI for Tetraplegics

6- channel EEG BCI used. Sensory & motor cortices activated during attempts. Control scheme sends movement intention to movement intention to Prosthetic Controller. Prosthetic returns force sensory information to Controller.

Feedback processed and grip is adjusted.

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BRAIN CONTROLLED ROBOTS

Robot hand mimics subject’s

finger movements.

Signals extracted and

decoded by computer

program.

Transferred to hand shaped

robot.

To simulate original

movement performed.

Robot executes commands

using onboard sensor

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‘BRAINGATE’ BCI

The ‘Braingate’ device can provide motor-impaired patients a mode of communication through the translation of thought into direct computer control.

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FEATURES OF BRAINGATE BCI

Neural Interface Device.

Consists of signal sensor and

external processors.

Converts neural signals to output

signals.

Sensor consists of tiny chip with

electrode sensors.

Chip implanted on brain surface.

Cable connects sensor to external

signal processor.

Create communication o/p using

decoding software.

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ATR & HONDA DEVELOP NEW BCI

BCI for manipulating

robots using brain signals.

Enables decoding natural

brain activity.

MRI based neural decoding.

No invasive incision of

head and Brain.

By tracking haemodynamic

responses in brain.

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BCI2000

BCI2000 is an open-source,

general-purpose system for BCI research.

It can also be used for data acquisition,

stimulus presentation, and brain

monitoring applications.

During operation, BCI2000 stores data

in a common format (BCI2000 native or

GDF).

BCI2000 also includes several tools for

data import or conversion and export

facilities into ASCII.

BCI2000 also facilitates interactions

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BCI APPLICATIONS

Medical applications(restoration of a

communication channel for patients with

locked-in syndrome and the control of neuroprostheses

in patients affected by spinal cord injuries )

Military applications

Counter terrorism(10 times faster image search)

multimedia and virtual reality applications

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BCI FOR HEALTHY USERS

Induced disability.

Ease of use in hardware.

Ease of use in software.

Otherwise unavailable

information.

Improved training or

performance.

Confidentiality.

Speed.

Novelty.

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DRAWBACKS

EEGs measure tiny voltage potentials. The

signal is weak and prone to interference.

Each neuron is constantly sending and

receiving signals through a complex web

of connections. There are chemical

processes involved as well, which EEGs

can't pick up on.

The equipment heavy(~10 lbs.) & hence

not portable.

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COMPUTATIONAL CHALLENGES

AND

FUTURE IMPLEMENTATIONS

Minimally invasive surgical methods.

Next generation Neuroprosthesis.

Vision prosthesis.

BCI for totally paralyzed.

Minimal number of calibration trials.

Development of telemetry chip to collect

data without external cables.

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CONCLUSION

A potential therapeutic tool.

BCI System is nominated for the

European ICT Grand Prize.

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REFERENCES

www.howstuffworks.com

www.techalone.com

www.brainlab.org

Brain- computer –interface # Invasive-BCIs.

Berlin Brain- Computer Interface

Brain Computer Interface, www.wikipedia.org

http://en.wikipedia.org/wiki/

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Thank you

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