Brain Computer Interface ppt

BRAIN COMPUTER INTERFACE

Presented by: V.Lakshana Regd. No.: 0601106040 Information Technology CET, Bhubaneswar

Brain Computer Interface from

fiction to

reality ...

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…….. MOVIE FICTION:THE MATRIX

OVERVIEW Definition General Principle Background Component Simplified model of BCI Training of BCI system Current BCI approaches EEG Based BCI BCI for Tetraplegics Brain controlled robots Present Development and Future Applications BCI for Healthy Users Advantages Computational Challenges Future Expansion Conclusion

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.

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.

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.

BASIC COMPONENTS The implant device, or chronic multielectrode array The signal recording and processing section An external device the subject uses to produce & control motion A feedback section to the subject

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

BLOCK DIAGRAM OF THE NEUROTROPHIC ELECTRODES FOR IMPLANTATION IN HUMAN PATIENTS

Signal Processing Section Multichannel Acquisition Systems Spike Detection

SIMPLIFIED MODEL OF THE BCI SYSTEM

BLOCK DIAGRAM FOR LEARNING MODE

TRAINING OF BCI SYSTEM Two different approaches: Pattern Recognition Approach Operant Conditioning Approach

BLOCK DIAGRAM FOR LEARNING MODE

CURRENT

BCI

APPROACHES

BCI APPROACHES

INVASIVE

SEMIINVASIVE

NONINVASIVE

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 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.

Band

Frequency [Hz]

Delta

0.5- 4

Theta

4- 8

Alpha

8- 13

Beta

13- 22

Gamma

22-30

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 robotic arms.

Present Developments BCI for Tereaplegics Brain controlled Robot ‘BRAINGATE’ BCI ATR and HONDA’s new BCI BCI2000

BCI for Tetraplegics 6- channel EEG BCI used. Sensory & motor cortices activated during attempts. Control scheme sends movement intention to Prosthetic Controller. Prosthetic returns force sensory information to Controller. Feedback processed and grip is adjusted.

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 readings.

‘BRAINGATE’

BCI

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

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.

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. Accuracy of 85%

BCI2000 BCI2000 is an open-source, generalpurpose 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 with other software.

BCI APPLICATIONS Medical applications(restoration of a communication channel for patients with lockedin 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

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.

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.

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.

CONCLUSION A potential therapeutic tool. BCI System is nominated for the European ICT Grand Prize. Potentially high impact technology.

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/ www.betterhumans.com

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