BRAIN COMPUTER INTERFACE A SEMINAR REPORT

[seminar class]

Submitted By:
Swati Wadhwa & Kriti Sachdeva

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INTRODUCTION
 Muscles of patients paralyzed due to various
 neurological diseases making them feel locked in.
 But the brain is unimpaired.
 Faulty control over muscles causes existing
 computer communication aids to fail.
 Alternative method of electrical brain activity
 measurement leads to BCI.
WHAT IS BCI?
 Called Brain-Computer Interface or Direct Neural Interface.
 Direct communication pathway between brain and external device.
 One-way BCIs
 Two-way BCIs
 Communication without involving brain’s normal pathways.
 Achieved by Electroencephalography.
ELECTROENCEPHALOGRAPHY
 Neuropsychological measurement of electrical activity
of brain from electrodes to it.
 Traces called Electroencephalogram or
brainwaves.
 Rather than currents, voltage differences between
different parts of brain are measured.
 Individually wired electrodes or imbedded caps used.
BCI vs NEUROPROSTHESIS
 Neuroprosthesis = Neural + Prosthesis
 Examples-
Cochlear implant-Implanted in approx.
1,00,000 people up to 2006.
Retinal implant
Robotic Arm
Controller has inbuilt functionality to grip objects intelligently.
Neuromuscular Pathway Neuroprosthetic Pathway
1) Brain sends movement Non-invasive control
intention command to hand scheme sends intention
via spinal cord movement. to prosthetic controller.
2) Hand moves and returns Prosthetic returns force
feedback. sensory information to
controller.
3) Brain subconsciously Controller processes
processes feedback and feedback and adjusts grip.
dynamically adjusts grip.
4) Loops continuously until Loops until BCI input to
movement intent change. controller changes.
ANIMAL BCI RESEARCH
 In 1999, researchers at Harvard University decoded neural firings to reproduce images seen by cats.
 Used array of electrodes in thalamus of sharp-eyed cats.
 Cats shown short movies.
 Monkey Mouse Experiment
 Monkeys trained to move cursor.
 Then BrainGate attached to monkey’s neurons & only thoughts drove cursor.
HUMAN BCI RESEARCH
1.) Invasive BCIs:- Devices implanted directly into the grey matter of the brain. Used for acquired blindness.
 Advantage:- High quality signals.
Disadvantage:- Prone to scar tissue build up & poor signal.

2.) Partially Invasive BCIs:- Implanted inside the skull but outside the grey matter.
Use ECoG where electrodes are embedded in thin plastic pad above the cortex.
 Advantages:-
o Better resolution signals than non-invasive BCIs.
o Lower risk of scar tissue.
Disadvantage:-
Lower reslution than invasive BCIs.
3.) Non-invasive BCIs:- Caps or nets are worn outside the skull. Most popular device is EEG.
 Advantage:- Easy to use, relatively cheap and portable.
Disadvantage:- Poor signals and difficult to determine waves creating area of brain.
TRAINING PROCESS
Neils Birbaumer, a neuropsychologist in Germany has implemented a BCI system called TTD.
After gaining accuracy in the game(Figure 1), patients are trained on a word processor software called Language Support System(LSP).
EQUIPMENT USED FOR BCI
BRAIN SIGNALS MEASUREMENT AND PROCESSING
Brain patterns form wave shapes that are commonly sinusoidal.
Their measurement consists of-
1. Electrodes
- Disposable (gel-less & pre-gelled type )
- Reusable ( Gold, silver, tin etc. )
- Headbands & electrode caps
2. Amplifiers and Filters
- Amplify physiological signals & reject noise
- Guarantee protection from voltage & current surges
3. A/D Converter
APPLICATIONS
Neuroprosthetics
Image Processing:- Brain can be converted into automatic
image-identifying machines.
Processing power of brain + Computer Vision = C3
Vision developed by researchers at Columbia Univ.
Simulated Reality:- Reality computer simulated to a
degree indistinguishable from the ‘True” reality.
Virtual Reality is easily distinguishable from true reality.
Participant may receive adjustment to temporarily forget
being in virtual world.
Military Use:-
 Machinery operation evaluation
 Fighter pilots
Gaming:-
 Brain Pong
 Car Race