Brain computer interface

BRAIN COMPUTER INTERFACE
PRESENTED BY :
SUMAN CHANDRA

Brain–computer interface (BCI) is also sometimes called a neural-
control interface (NCI), mind-machine interface (MMI), direct neural
interface (DNI), or brain–machine interface (BMI).
BCI is direct communication pathway between an enhanced or wired
brain and an external device.
One of the biggest challenges in developing BCI technology has been
the development of electrode devices and/or surgical methods that are
minimally invasive.
In the traditional BCI model, the brain accepts an implanted
mechanical device and controls the device as a natural part of its
representation of the body. Much current research is focused on the
potential on non-invasive BCI.

HISTORY:
Research on BCIs began in the 1970s at the University of California, Los
Angeles (UCLA) under a grant from the National Science Foundation,
followed by a contract from DARPA.
The papers published after this research also mark the first appearance of
the expression brain–computer interface in scientific literature.
The field of BCI research and development has since focused primarily on
neuroprosthetics applications that aim at restoring damaged hearing, sight
and movement.

Amyotrophic Lateral sclerosis –
Muscle weakness and atrophy throughout the body caused by the
degeneration of upper and lower motor neurons.
Individuals may ultimately lose ability to initiate and control all
voluntary movement
For the most part, cognitive function is preserved
Sensory nerves and the autonomic nervous system are generally
unaffected
THOSE WHO DEPENDS

BCI systems have the ability to allow a paralyzed, “locked-in” patient to
communicate words, letters and simple commands to a computer
interface that recognizes different outputs of EEG signals and translates
them through use of assigned algorithms into a specific function or
computing output that the user has the ability to control.
A complex mechanical BCI system would allow a user to control an
external system possibly an artificial limb by creating an output of
specific EEG frequency
THOSE WHO DEPENDS

NEURON
Neurons are the fundamental units of the brain and nervous system.
The cells responsible for receiving sensory input from the external world, for
sending motor commands to our muscles, and for transforming and relaying
the electrical signals at every step in between.
More than that, their interactions define who we are as people. Having said
that, our roughly 100 billion neurons do interact closely with other cell types,
broadly classified as glia (these may actually outnumber neurons, although it’s
not really known).
A neuron has three main parts: dendrites, an axon, and a cell body or soma ,
which can be represented as the branches, roots and trunk of a tree,
respectively.

AXON
The axon (tree roots) is the output structure of the neuron; when a neuron
wants to talk to another neuron, it sends an electrical message called
an action potential throughout the entire axon.
The soma (tree trunk) is where the nucleus lies, where the neuron’s DNA is
housed, and where potential are made to be transported throughout the
axon and dendrites.
An axon, or nerve fiber, is a long slender projection of a nerve cell, or
neuron, that conducts electrical impulses away from the neuron's cell body
or soma.
Axons are in effect the primary transmission lines of the nervous system,
and as bundles they help make up nerves.

DENDRIED
The receiving part of the neuron. Dendrites receive synaptic inputs from
axons, with the sum total of dendritic inputs determining whether the
neuron will fire an action potential.
Function of Dendrites. In order for neurons to become active, they must
receive action potentials or other stimuli. Dendrites are the structures on
the neuron that receive electrical messages. These messages come in two
basic forms: excitatory and inhibitory.
Neurons have specialized projections called dendrites and axons. Dendrites
bring information to the cell body and axons take information away from
the cell body. Information from one neuron flows to another neuron across
a synapse. The synapse contains a small gap separating neurons.

SPINE
The cell body, also called the soma, is the spherical part of the neuron that
contains the nucleus.
The cell body connects to the dendrites, which bring information to the
neuron, and the axon, which sends information to other neurons.
CELL BODY
The small protrusions found on dendrites that are, for many synapses, the
postsynaptic contact site.

ACTION POTENTIAL
Brief electrical event typically generated in the axon that signals the neuron
as 'active'. An action potential travels the length of the axon and causes
release of neurotransmitter into the synapse.
The action potential and consequent transmitter release allow the neuron to
communicate with other neurons.
An action potential occurs when a neuron sends information down an axon,
away from the cell body.
Neuroscientists use other words, such as a "spike" or an "impulse" for the
action potential. Action potentials are caused when different ions cross the
neuron membrane.
An Action potential is the neurons way of transporting electrical signals from
one cell to the next.

SYNAPSE
A junction between two nerve cells, consisting of a minute gap across which
impulses pass by diffusion of a neurotransmitter.
In the nervous system, a synapse is a structure that permits a neuron (or
nerve cell) to pass an electrical or chemical signal to another neuron.
The key to neural function is the synaptic signaling process, which is partly
electrical and partly chemical. Once the electrical signal reaches the synapse, a
special molecule called neurotransmitter is released by the neuron. This
neurotransmitter will then stimulate the second neuron, triggering a new wave
of electrical impulse

HUMAN BRAIN
When a child is born, what does the child know?
When the child grows, the step by step learning process begins. Every time
a child learns something, it is encoded into some portion of the brain.
Some information or instances are "hard-coded" within the brain. As a
result, we never forget certain things.
Whatever is incompletely learned will lose its strength and not be retained
in our brain.
So, if we do not practice what we learned, we start to forget. Consequently,
by practice or training, we can hard-code some selected things into our
brains.

Many neuroscientists believe that learning stimulates new dendrite
connections between neurons.
Greater usage of the brain through learning and stimulation creates
greater dendrite connectivity.
Thus, as we learn more and more, we become more intelligent. Wisdom is
not created through genetics. Wisdom and knowledge are based on how
we learn and how we practice what we learned.
HUMAN BRAIN

Brain-computer interface (BCI) is a collaboration between a brain and a
device that enables signals from the brain to direct some external activity,
such as control of a cursor or a prosthetic limb.
The interface enables a direct communications pathway between the brain
and the object to be controlled.
In the case of cursor control, for example, the signal is transmitted directly
from the brain to the mechanism directing the cursor, rather than taking the
normal route through the body's neuromuscular system from the brain to
the finger on a mouse.

By reading signals from an array of neurons and using computer chips
and programs to translate the signals into action.
BCI can enable a person suffering from paralysis to write a book or
control a motorized wheelchair or prosthetic limb through thought alone.
Current brain-interface devices require deliberate conscious thought;
some future applications, such as prosthetic control, are likely to work
effortlessly.
A BCI records and interprets or decodes brain signals. Brain cells
(neurons) communicate with each other by sending and receiving very
small electrical signals. ... Healthy people are able to move because the
brain sends signals via the central nervous system to the muscles of the
body.

HOW BCI WORK
Every time we think, move, feel or remember something, our neurons are at
work. That work is carried out by small electric signals that zip from neuron
to neuron as fast as 250 mph.
The signals are generated by differences in electric potential carried by ions
on the membrane of each neuron.
BCI work in EEG technology.EEG means Electroencephalography.
Our mind produce various waves , Scientists can detect those signals,
interpret what they mean ans use them to direct a device of some kind.
The recording of electrical activity along the scalp produced by the firing of
neurons within the brain.

SIGNAL ACQUISITION
A BCI system allows to record bio-signals.
Technologies based on the information extracted from these bio-signals are
able to act on the environment.
The brain activity can be used to control systems from the technical
surroundings.
Electroencephalogram (EEG) signals are the recorded potentials of
collective activity of synchronized cortical cell populations chained to an
external system.
Our basic tasks are to improve the signal-to-noise ratio and to solve spatial
and temporal actions of the measured signals on the external environment.
For these reasons we propose a completely new concept of active
electrodes, named Smart Active Electrodes (SAE).

FEATURE EXTRACTION
The purpose of a brain-computer interface (BCI) is to detect and quantify
characteristics of brain signals that indicate what the user wants the BCI to
do, to translate these measurements in real time into the desired device
commands, and to provide concurrent feedback to the user.
The brain signal characteristics used for this purpose are called signal
features, or simply features.
Feature extraction is the process of distinguishing the pertinent signal
characteristics from extraneous content and representing them in a compact
and/or meaningful form, amenable to interpretation by a human or
computer.

NEUROPROSTHETICS CONTROL
classification is the problem of identifying to which of a set of
categories (sub-populations) a new observation belongs, on the basis
of a training set of data containing observations (or instances) whose
category membership is known.
The brain is comprised of specialized cells called neurons. One of the
things that makes these cells unique is that they send information via
electrical signals, which travel quickly through large networks of
neurons to coordinate various brain functions.
CLASSIFICATION ALGORITHM

NEURAL SPELLING
This paradigm use visual stimulation enabling to write by spelling.
The method consists in displaying a 6x6 matrix composed by the figures
and letters. Lines and columns of the matrix are successively highlighted.
When the line or the column contain the chosen letter, a P300 ERP(Event
Related Potential) appears.
A classifier is then used to determine if this signal correspond to a positive
response or not.

SENSORY FEEDBACK
Sensory feedback is feedback provided within the sensory systems where
information from sensory receptors is returned along the afferent pathways
so the brain can monitor the consequence of actions.

NEURO SKY
Developers at NeuroSky created the Brainwave, a comprehensive non-invasive
BCI that connects the user to iOS and Android platforms, and transfers all
signal information through Bluetooth as opposed to radio.
The EEG outputs for this setup are controlled primarily by variations in brain-
state. In order to achieve a specific level of EEG the user may be prompted to
relax or improve focus, thus altering the specific output of brain energy and
ultimately changing the level of expressed EEG signals

Brain computer interface

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