BRAIN - MACHINE INTERFACE

TUHIN DAS

PRESENTED BY:-

What is Brain-Machine Interface?

It is a collaboration in which a brain accepts and controls a mechanical device as a natural part of its representation of the body

By reading signals from an array of neurons and using computer chips and programs to translate the signals into action, scientists hope it will be possible for a person suffering from paralysis to control a motorized wheelchair or a prosthetic limb by just thinking about it

Concept of brain gate

The BrainGate system is a neuromotor prosthetic device consisting of an array of one hundred silicon microelectrodes, each of which is 1mm long and thinner than a human hair. The electrodes are arranged less than half a millimetre apart on the array, which is attached to a 13cm-long cable ribbon cable connecting it to a computer

Biological inspiration

Dendrites

Soma (cell body)

Axon

Biological inspiration

synapses

axon dendrites

The information transmission happens at the synapses.

Artificial neurons

Neurons work by processing information. They receive and provide information in form of spikes.

The McCullogh-Pitts model

Inputs

Outputw2

w1

w3

wn

wn-1

. . .

x1

x2

x3

…

xn-1

xn

y)(;

1

zHyxwzn

iii

Artificial neurons

Nonlinear generalization of the McCullogh-Pitts neuron:

),( wxfy y is the neuron’s output, x is the vector of inputs, and w is the vector of synaptic weights.

Examples:sigmoidal neuron

Gaussian neuron2

2

2

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1

1

a

wx

axw

ey

ey T

Neural network mathematics

Neural network: input / output transformation

),( WxFyout

W is the matrix of all weight vectors.

Cortical neural signal extraction: non-invasive vs. invasive recording

EEG Rhythms β and μ, P300, Slow cortical

potential (SCP) Sampling rate 200-1000Hz, # of channels, from 1 or 2 to 128 or 256

Electrodes Bioactive, allowing growth of nerve, or bio-

inactive multiple mircowires or multichannel electrode arrays

Superficial motor areas or deep brain structures

Primary motor, parietal, premotor, frontoparietal, basal ganglia

HOMONCULUS: The little guy

(d) Imagery is associated with decrease in µ (8–12 Hz) and β (18–26 Hz) bands.

imagining saying the word ‘move’

resting

A brain–computer interface using electrocorticographic signals in humans*Leuthardt et al 2004 J. Neural Eng. 1 63-71 

Cortical neural signal extraction: ECoG

CONTROLLING OF MACHINE :- BY HUMAN BRAIN

Directional control

Neural Interface Neural SignalsSignal Processing

Algorithms/Command Extraction

Sensors

Control Command

Vehicle State Signal

Vehicle

Environmental Feedback

The Brain-Controlled Vehicle

Application It can help to restore any loss of

senses 1.sense of vision2.sense of hearing3.sense of movementcreation of human robotsCreation of detective rats

Biggest reward

On 7th november 2009 toyota launched it’s wheel chair that works on thought

It has a reaction time of 123 milliseconds

THANK YOU…..