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BRAIN COMPUTER
INTERFACE
Presented by:
Shri Charan K.M.
Roll no. 1DB06CS051.Department of Computer Science Engg.
DonBosco Institute of Technology.
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OVERVIEW
Definition
General Principle
Background
Components
Simplified Model of BCI
Current Brain ComputerInterface (BCI) Approaches
Invasive Approach
Semi-Invasive Approach
Non-Invasive Approach
BCI Applications
BCI Drawbacks
ConclusionReferences
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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..
MOVIE FICTION: THE MATRIX
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DEFINITION
A brain-computerinterface,
sometimes called adirect neural
interface or a brainmachine interface, is
a direct
communicationpathway between a
human or animalbrain (and brain cell
culture) and an
external device.
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BrainBrain NeuronsNeurons BrainBrain isis filledfilled withwith
NeuronsNeurons..
SignalsSignals areare inin formform ofof smallsmall
NerveNerve cellscells areare connectedconnected
byby DendritesDendrites && AxonsAxons..
Electronic,Electronic, asas fastfast asas 250250mphmph..
SignalsSignals areare generatedgenerated byby
differencedifference inin ElectricElectric potentialpotential
carriedcarried byby IonsIons onon thethe
MembraneMembrane ofof eacheach NeuronNeuron..
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GENERAL PRINCIPLE
(a) (b) (c)
(a) In healthy subjects, primary motor area sends movementcommands 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 ofneurons read.
Cerebral electric activity
recorded.Signals are amplified.
Transmitted to computer
Transformed to device
control commands.Using computer chips andprograms.
Signals translated into action.
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CURRENT BCI APPROACHES
BCI
APPROACHES
INVASIVESEMI
INVASIVE
NONINVASIVE
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INVASIVE BCIOne of the first scientists to comeup with a working brain interface torestore sight as private researcher,William Dobelle IN 1978.
Are directly implanted into the greymatter of the brain duringneurosurgery.
Targeted in repairing damagedsight and providing newfunctionality to paralyzed people.
But these BCIs are prone tobuilding up of scar-tissue whichcauses the signal to becomeweaker and even lost as bodyreacts to a foreign object in the
brain.
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SEMI-INVASIVE BCI
Partially invasive BCI devices are implantedinside the skull but rest outside the brainrather than amidst the grey matter.
Electrocardiography (ECoG), electrodesare embedded in a thin plastic pad that isplaced above the cortex, beneath the Duramater.
Light Reactive Imaging BCI,The laserwould be trained on a single neuron and the
neurons reflectance measured by a separatesensor. When neuron fires, the laser lightpattern and wavelengths it reflects wouldchange slightly.
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M1 Handarea RoI
Scalp EEG
Virtual electrode
NON-INVASIVE BCI
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One of the biggest challenges BCI
facing is the Basic Mechanism of the
Interface itself
The Easiest & least invasive method is
a set of electrodes & the device whichis attached to the scalp is known as
ELECTROENCEPHALOGRAPH(EEG)ELECTROENCEPHALOGRAPH(EEG)..
The Electrodes can read the Brain
signals.
BCI EEG
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EEG COMPONENTS
Signal acquisition
Preprocessing
Feature extraction
Classification
Application Interface
Feedback
Brain signal
Control signal
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Electrode Placement
Standard 10-20 System
Spaced apart 10-20%
Letter for region
F - Frontal Lobe
T - Temporal Lobe
C - Center
O - Occipital Lobe
Number for exact position Odd numbers - left
Even numbers - right
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Electrode Placement
A more detailed view:
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J.R. Wolpaw et al. 2002
SIMPLIFIED MODEL OF THE BCI SYSTEM
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BCI Applications1.Development of devices that can be
controlled by thoughts.
2.If you think, a remote control is convenient,
imagine changing channels with your mind.
3.A more difficult task is interpreting the
brain signals for movement in someone who
can't physically move their own arm.
4.Once the basic mechanism of convertingthoughts to computerized or robotic action is
perfected, the potential uses for the technology
are almost limitless.
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BCI Applications
Medical applications:
Possibly only communication
channel for people sufferingfrom e.g. paraplegia,amyotrophia
Neuroprosthetics: Surgically implanted devices
used as replacement fordamaged neurons
Currently available: cochlear
implant (bionic ear)
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BCI Applications
Human enhancement
BCI that translates brainsignals into computer control
signals Exocortex (intelligence
booster)
Human manipulation Mind-Control
Neurohacking: unwantedreading of information from
the brain
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EEG
University college, London & TU Graz
VR application, controlling a wheelchair
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BCI Drawbacks There are about 100billionThere are about 100billion
neurons in a human brain.neurons in a human brain.Each neuron is constantlyEach neuron is constantlysending & receivingsending & receivingsignals through a WEB ofsignals through a WEB ofconnectionsconnections..
EEG measure tiny voltageEEG measure tiny voltagepotentials, sometimes apotentials, sometimes asimple as the blinkingsimple as the blinkingeyelids of the subject caneyelids of the subject cangenerate much Strongergenerate much Stronger
Signals.Signals. Some BCIs still require aSome BCIs still require a
wired connection to thewired connection to theequipment, & those thatequipment, & those thatare wireless require theare wireless require thesubject to carry asubject to carry a
computer that can weighcomputer that can weigharound 10pounds.around 10pounds.
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CONCLUSION
Brain-Computer Interface (BCI) is a
method of communication based on
voluntary neural activity generated by thebrain and independent of its normal output
pathways of peripheral nerves and
muscles.
The neural activity used in BCI can berecorded using invasive or noninvasive
techniques.
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REFERENCES
BCI-info.org
Brain- computer interface, www.wikipedia.org
http://en.wikipedia.org/wiki/ Brain- computer-interface#Invasive-BCIs
www.bci2000.org
Berlin Brain-Computer Interface
http://ida.first.fraunhofer.de/projects/bci/bbci-official/index-en.html
Lebedev MA, Nicoleis MA(2006), Brain-machine
interfaces: past, present and future.
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THANK YOU
FOR YOUR
ATTENTION