1. Neuroprosthetics
Kaushik Padmanabhan, Sandeep Balaji Krishnamoorthy
Department of Electronics and Communication Engineering
Velammal Engineering College, TN, India
Abstract - Neuroprosthetics involves the concept of usage of Brain signals, which are acquired from neurons, for
numerous purposes. It involves the usage of nanotechnology (i.e.) NANO MULTIELECTRODE ARRAYS for receiving
and transfering the brain signals. The use of nano MEAs in place of ordinary MEAs increase the electrode conduction
and also reduces the miscontact between the brain signals. It involves both invivo and invitro methods. It will be a greater
advantage for the paralytic patients to resume their movement soon when an amplified brain signal is given to the
paralysed organ. This concept is very much useful in the drug research by understanding the behaviour and emotions of
the animals after a new drug has been introduced to it. By this method the oral skill of a person can also be increased to a
part.
Keywords - Nano MEA, Neurons, Prosthetics, Paralytics.
INTRODUCTION
Neuroprosthetics is a discipline related to concerned
with developing neural prostheses, artificial implantable
devices to replace or improve the function of an
impaired nervous system. Neuroprosthetics are the set
of physical devices that interact with the brain or other
neural tissue to augment, restore, or otherwise impact
function. Neuroprosthetics are electrical stimulation
technologies that replace or assist damaged or
malfunctioning neuromuscular organ system and
attempt to restore normal body processes, create or
improve function, and/or reduce pain. These systems are
either implanted or worn externally on the body. Such
assistive devices range from intramuscular stimulation
systems designed to limit limb atrophy in paralysis,
implanted bladder voiding systems and more complex
implanted neuromuscular control.
The process of transitioning this technology into a
clinically useful device will require two parallel paths of
research. In the first path, experimental paradigms
involving microelectrode array recordings in behaving
signal processing techniques for studying the unknown
aspects of neural coding and functional
neurophysiology. These signal processing techniques
will then be implemented in portable, low-power,
wireless hardware. The second path, high-density array
ECG recordings in humans, provides a less invasive
technique for neural interfaces however it still remains
unknown how to extract BMI control signatures that are
sufficiently spatially and temporally resolved.
Neuroprosthetics is an area of intense scientific and
clinical interest and rapid progress. The word prosthesis
is derived m the Greek word for addition.
1. Bypassing the body, and letting the mind
interface directly with VR, for the ultimate
immersive experience – the virtual body becomes as
the normal functioning body
2. Augmented body parts will be able to be fitted
to the body, and controlled by the brain as if you were
born with them – after a little training, without
conscious thought.
HISTORY
The first cochlear implant dates back to 1957. Other
landmarks include the first motor prosthesis for foot
drop in hemiplegic in 1961, the first auditory brain stem
implant in 1977 and a peripheral nerve bridge implanted
into spinal cord of adult rat in 1981.
Paraplegics were helped in standing with a lumbar
anterior root implant (1988) and in walking with

2. functional electrical simulation (FES). Regarding the
development of electrodes implanted in the brain, an
early difficulty was reliably locating the electrodes,
originally done by inserting the electrodes with needles
and breaking off the needles at the desired depth. Recent
systems utilize more advanced probes, such as those
used in deep brain stimulation to alle iate the s
pto s of Parkisso s disease. Over the
past four decades, research in neuroprosthetic has
generated a handful of clinical successes and has gained
lasting acceptance in the scientific community
noteworthy advances have been made.
BMI is currently growing with exponential speed, with
real successes in linking human brains to computers,
and the control of virtual, and physical prosethic limb
via pure thought control . Neuroprosthetics , brain
emulation and mind uploading are together perhaps the
most extreme end of the trend towards virtual reality.
All three are BMI, or Brain-Machine-Interface . BMI is
an old field, stretching back over six decades, concerned
with direct-connecting the human brain to machines, in
order to improve the function of both. A BMI uses a
computer to implement brain models that translate
signals from individual neurons into artificial limb
commands. Discovery of the knowledge needed to
uncover the unknown aspects of systems-based neural
encoding and decoding for complex tasks needs highly
demanding computational modeling. The architecture
consists of multiple forward-inverse pairs of dynamic
models for movement planning and control. The
movement commands are the combined outputs of
selected pairs of models on the basis of real-time
feedback signals The research aims to (1) identify the
types, numbers and combinations of models for
complex movement control and (2) deploy the cyber
infrastructures for both BMI implementation and
research. It uses closed loop experiments where a
computer processes brain signals from rats to control
robotic movements
TODAY’S NEED OF NEUROPROSTHETICS
Whether caused by disease, an accident, or a
necessary surgery, damage to major nerves extends
beyond the cellular level. Without speech,
completely immobile individuals can be cut off from
friends and family. Loss of limb function to paralysis
may trans-late into a loss of independence and good
health. And the deaf or blind may be severed from
their work in addition to the sights and sounds of
everyday life.
Scientists are hotly pursuing a means to repair
nerves, in particular by using stem cells to replace or
support function of injured neurons. However, this
field is in its early stages, and learning how to
manipulate therapeutic cells will likely take several
years.
Neural prostheses can be engineered to take on the
role of impaired neural cells, relaying electrical
signals between parts of the body or between the
body and a specialized machine. Such devices have
already enabled the immobile to operate computers
by thought alone, the partially paralyzed to walk and
groom themselves, the deaf to hear, and the blind to
see. Toda s prostheses de o strate ar i g degrees of
success and, even at
their best, cannot match the performance of natural
tissues. Certainly, we are far from the times of Luke
Skywalker, when replacement robotic parts can be
installed upon the night of an injury. Nevertheless,
application of this technology has realized initial steps
toward this dream and offered new hope to many
patients.
MEA TECHNOLOGY
We use Multielectrode arrays from multi channel array
on which neurons are cultured for weeks or months at a
time. These consist of 60 electrodes made of indium-tin
oxide (ITO) or silicon nitride on a glass substrate.
Because the multielectrode arrays are transparent, we
can observe neuronal morphology, using an inverted
microscope, through the bottom of the culture dish. The
dish is connected to amplifiers and a computer that
allows continuous stimulation of and recording from
neurons lying on or near electrodes.
PROPOSED IMPROVISATION BY NANO-
TECHNOLOGY
The MEAs can be improved with the help of
nanotechnology(i.e.) use of nano materials of many
suitable elements like carbon ,gold etc, for reducing the
electrode impedance and increase the conduction of
brain signals. The major advantage in using the nano-
materials is that it will sharply make contact with the
required neuron thereby avoiding the miscontact with
the other neurons. By this any side effects occurred due
to the miscontact can be reduced. The nano MEAs are
fabricated through the Top-Bottom approach of the
carbon material. These fabrication could be
sophisticated and special care should be taken , while
manufacturing it. The carbon nanosensors are connected
to the MEAs, and should be carefully fitted over the
nerve. These sensors detect the brain impulse on the
nerve and , the sensed data is sent to the other circuit

3. consisting of an amplifier, a modulator along with the
radio frequency generator and mixer circuits , connected
to form the transmitter circuit. The receiving part of the
circuitry is placed over the receiving mixer circuit,
demodulator , multiplexer circuit to the hybrid
computer, which reads the whole information from the
nerve. The radio frequency could be used, in case of the
wireless transmissions. An external EEG/EMG/ENG
can be attached and monitored, depending upon the
application.
TYPES
Microelectrode arrays can be divided up into
subcategories based on their potential use: in vitro
and in vivo arrays.
In vitro arrays
The standard type of in vitro MEA comes in a pattern
of 8 x 8 or 6 x 10 electrodes. Electrodes are typically
composed of titanium and have diameters in
microns. These arra s
are normally used for single-cell cultures or acute
brain slices.
In another special design, 60 electrodes are split i to
arra s separated μ .
Electrodes within a group are separated by 30 u ith
dia eters of μ . Arra s su h as
this are used to examine local responses of neurons
while also studying functional connectivity of
organotypic slices.
Spatial resolution is one of the key advantages of MEAs
and allows signals sent over a long distance to be taken
with higher precision when a high-density MEA is used.
These arrays usually have a square grid pattern of 256
electrodes that cover an area of 2.8 by 2.8 mm.
An advancement can be shown to the invitro arrays by
means of employing the principles of
a o te h olog . The urre t apparatus ould
be fabricated at nano-scale, by either top-bottom
approach or bottom-top approach. The fabricated nano
MEAs can be made more flexible than the present
MEAs, being at nanoscale it has more tensile strength.
Being bio-degradable, the nano MEAs can be operated
more efficiently than the silicon chip and also would
show longer lifespan. The three major categories of
implantable MEAs are microwire, silicon- based, and
flexible microelectrode arrays. Microwire MEAs are
largely made of stainless steel or tungsten and they can
be used to estimate the position of individual recorded
neurons by triangulation.
In vivo arrays
Schematic of the "Utah" in vivo electrode array.
Silicon-based microelectrode arrays include two
specific models: the Michigan and Utah arrays.
Michigan arrays allow a higher density of sensors for
implantation as well as a higher spatial resolution than
microwire MEAs. They also allow signals to be
obtained along the length of the shank, rather than just
at the ends of the shanks. In contrast to Michigan arrays,
Utah arrays are 3-D, consisting of 100 conductive
silicon needles. However, in a Utah array signals are
only received from the tips of each electrode, which
limits the amount of information that can be obtained at
one time. Furthermore, Utah arrays are manufactured
with set dimensions and parameters while the Michigan
array allows for more design freedom. Flexible arrays,
made withbenzocyclobutene, provide an advantage over
rigid microelectrode arrays because they provide a
closer mechanical at h, as the You g s modulus of sili o
is much larger than that of brain tissue, contributing to
shear-induced inflammation. The nano fibres can be
replaced in the process, for better functioning as well as
better accuracy over the affected neuron. The
nanotechnology can be employed to the advancement of
the invivo array by combining both the advantageous
properties of the Michigan array and Utah array. The
nano MEAs can be so designed from the nano carbon,
resembling the characteristics of both the arrays. The
array can be made 3-D( like Utah array) with numerous
conductive fibre to the nerves. It could also be made to
receive the signals from the whole shank (like Michigan
array).
APPLICATION
ACTIVATE THE PARALYSISED ORGANS
Paralytic problems occur mainly due to the malfunction
of the nervous system (i.e.) problem in the conduction
in the brain signal.It is one of the major human disorder.
This can be eradicated by neuroprosthetics. Here we use

4. MEAs to treat this problem, it can be done by invivo and
invitro methods.
In invivo method, we can implant the nano MEAs near
the spinal cord so that the neurons will be in contact with
the nano electrodes. Other part of the electrode is
connected to the paralyzed organ. This electrode
receives the nerve impulse and transfer it to the
paralyzed organ (i.e.) it triggers an action potential if it
is a neuron or a twitch if it is a muscle cell. This nerve
impulse will excite the cells in the paralyzed part of the
body. Hence the normal operation of the organ retrieves
to a part. For example if the right part of the body
becomes paralyzed due to the malfunctioning of the left
brain, the nano electrodes are connected to the neurons
coming from the right brain so that it receives the
impulse and sends it to the paralyzed organ by
connecting it to the right side. In invitro method the
electrodes are connected outside the body and we can
also analyze the brain waves of that person by
connecting it to the hybrid computer. The process
involves the usage of nano sensors to the neural tissue;
it is used for detecting the correct neural network
through appropriate guiding pulses from the computer.
The impulses from the other normal part are sent to the
paralyzed part through the nano cables. The impulse to
the paralyzed part is observed and recorded and then, it
is passed through the amplifier and is sent to the
paralyzed part and thereby , the nerve cells get excited
and normal functioning is retrieved. The analog
computer will regulate the periodic pulse to the neural
network. By using the electromyogram (EMG), the
impulse to the paralyzed part can be checked and can be
useful to evaluate the brain impulse, by amplifying it for
proper retrieval of the paralyzed part.
DETECTING WORDS AND IMPROVISING THE
ORAL SKILL
We can detect articulated words from signals re ei
ed ele trodes o the rai s surfa e.
This might one day enable patients with locked-in
syndrome to communicate with their surroundings.
Here we can use grids of microelectrodes or nano
electrodes placed on the cortical surface over
speech centres during craniotomy in a patient with
severe epileptic seizures. The microelectrodes
consisted of 16 non penetrating micro wires at
millimetre intervals in a 4×4 grid pattern. We can
record local field potentials from the surface of face
otor orte a d Wer i ke s area. The a o
electrodes are carefully, made to contact with the
hypoglossal nerve, near the medulla oblongata. The
invitro circuitry is set up over the neck. This circuitry
consists of an amplifier, modulator, oscillator and the
radio frequency generator is used for modulating the
brain signals. The electric impulse from the
hypoglossal nerve is detected through the nano-
sensor, is sent to the transmitter circuit through the
MEA. The modulated signal is transmitted to the
receiver circuit( consisting of RF amplifiers, mixers,
filter circuits) processes the brain waves by the help
of the electroencephalogram (EEG) and thus the
impulses is useful in revealing the words to be
pronounced, before it is orally revealed. Another
study of the experiment can be set up for these
patients, suffering from the locked-in syndrome, by
setting up an independent circuit to the larynx and to
the hypoglossal nerve in the medulla oblongata.
Also, these MEAs are made in contact with the
relevant extrinsic tongue muscles (genioglossus
muscle, hyoglossus muscle, styloglossus muscles),
that are originating from the hypoglossal nerves. An
invivo circuit can be set up to the neck. These invivo
circuit could comprise of an amplifier and a
modulator to transmit the brain waves to the receiver
circuit embedded to the hybrid computer, through the
nano cables. By applying regular pulses to the
MEAs, the larynx muscles can be activated and the
functionality of the tongue muscles can be
improvised. This could result in better pronunciation
of words as well as an improvement in the
communication skills of the patient. Thus, along with
BRAIN
NANO
MEA
AMPLIFIER
NANO-
TRANSMITTER
CIRCUIT
NANO-
RECEIVER
CIRCUIT
HYBRID
COMPUTER
PARALYZED
ORGAN

5. clinical medication, it would be beneficial in treating
the locked-in syndrome.
STUDYING THE PSYCHOLOGY OF THE
ANIMALS
Different animals show different behaviors at different
circumstances. Hence it is difficult to judge its
psychological behavior. The character can be analyzed
through the embedment of the nano MEAs along with
the nano sensor, to the brain stem and the cerebellum.
The twelve pairs of the direct brain nerves (cranial
nerves) are made in contact to the nano MEAs as well
as with the nano sensor; selective nerves are made
contact from the spinal cord. The sensor detect the
impulse from the nerves, while the MEAs will transfer
the impulse to the transmitter ( consisting of the
modulator circuits with a radio frequency generator,
amplifiers as well as an nano antenna/ nano carbon
cables). The receiving part employs the use of
amplifiers, multiplexer circuit to the hybrid computer,
which is used to record the received brain signals and
analyze them. The mode of transmission could be either
wired or wireless, depending upon the circumstance and
current behavior of the animal. Any behavior of the
animal can be analyzed and also could be experimented
on various circumstances (i.e.) anger, sorrow, happiness
etc. Such observations will be useful in case of research
of a drug or sample over the animals. The sudden
fluctuations in the impulses are recorded and can be
used to analyze the cause for these change in behavior
of the animal. These circuitry would be more beneficial
for further research on the drug. The entire electronic
setup can be made either invivo or invitro to the animal.
CONCLUSION
The nanotechnology which is getting advanced in this
world can be implemented for bringing a good change
in the Neuroprosthetics world. But Neuroprosthetics
research will not be easily or quickly overcome, but
existing technology offers solutions sufficient for
meaningful clinical applications. Physical therapy in not
the only venue for electrical simulation and
Neuroprostheses. Neuroprostheses industry may prove
instrumental in uniting venture capilists with
researchers, and in helping both groups to identify
further broadly applicable trends in Neurotechnology.
All current Neuroprosthetics devices rely on the
electrode-nerve interface as the sole means including
neural response, and thus restored function.
REFERENCE
-http://www.medgadget.com/2010/09/detectin
g_words_from_brain_signals.html
-www.biomedikal.in/neuroprosthetics
-http://www3.imperial.ac.uk/bioinspiredtechno
logy/research/neural
- http://jn.physiology.org/content/102/3/152
-http://www.doctorhugo.org/brainwaves/brain
waves.html
-http://jonlieffmd.com/blog/neuronal-connecti ons-and-
the-mind-the-connectome
BRAIN
NANO
MEA AMPLIFIER
NANO
TRANSMITTER
NANO
RECEIVER
HYBRID
COMPUTER
EEG/EMG