Rewiring The BrainThe Group 4- Team 1

How the Brain Works

The Human Nervous SystemOrgan system composed of specialized cells

o Neurons- transmit signals through body to control actions and reactions

Central Nervous System

• Comprised of brain, spinal cord & retina (eyes)o Integrates information received through the five senses

o Coordinates activity in response to stimulation

Peripheral Nervous System

• Consists of sensory neurons, groupings of neurons (ganglia tissue) & nerveso Primary duty is to link the central nervous system to the body limbs and organs

*The Central Nervous System, specifically the brain, will be the focus of this study*

Retina

Brain/ Upper Spinal Cord

Lower Spinal Cord

Mapping the Human Brain• The brain can be broken into four interconnected structures

o Cerebrum: identifies with higher brain function (thought/ action) Frontal Lobe: controls reasoning, speech & emotions

Parietal Lobe: responsible for movement/ orientation & processing of stimulation

Occipital Lobe: controls visual perception

Temporal Lobe: processes memory and auditory stimulation

o Cerebellum: two hemispheres that regulate coordination, posture & balance o Brain Stem: largely responsible for innate/ subconscious bodily functions

Midbrain: controls eye and body movement & hearing

Pons: responsible for sensory analysis and motor function

Medulla: maintains vital life functions (breathing, heartbeat etc.)

Mapping the Human Braino The Limbic System: controls memory, behaviour, emotion & olfactory senses

Thalamus: regulates consciousness (sleep/ alertness)

Hypothalamus: links the endocrine system to the brain through the pituitary gland

• Ex. In reaction to stimuli, the release of chemicals from the endocrine system

induces an “emotional” reaction

Amygdala: processes and compartmentalizes emotional reactions

• Memorizes specific chemical (emotional) reactions to certain outside stimuli

Hippocampus: stores long term memory and controls spatial coordination

Rational Thought

Subconscious Thought

Coordination

Emotions

Transmitting Messages • The brain= intricate communications system

o Consists of billions of neurons and neural tissue (ganglia)

• Every action/ reaction, sensation, memory & emotion is invoked through a system of

electrical signals sent through the body

o Sent across Neurons Electrically stimulated (non- duplicating) somatic cells that process and

transmit info via electrical/ chemical signals

Transmitting Messages • Neurons can be categorized into specialized roles

o Sensory neurons respond to stimuli affecting our sensory organs

o Motor neurons receive signals from the brain & spinal cord, thereby causing

muscle contractions and affecting glands (endocrine system)

o Interneurons connect neurons within the same region of the brain/ spinal cord

Transmitting Messages Anatomy of a Neuron

• Soma: central part of the neuron (contains the nucleus)

o Where most protein synthesis occurs

• Dendrite: cellular branches/ extensions to the neuron that facilitate information input

• Axon: fine, cable- like projection that carries nerve signals to & from the soma

o Axon is relatively long compared to soma (tens of thousands of times longer)

o Often has several branches which enable communication with numerous target cells

• Axon Terminal: contain synapses (structures wherein neurotransmitter chemicals are

release) that communicate with adjacent neurons

Neural Communication1) Dendrite receives input from outside stimulation.

2) Neuron reads this information and sends an electrical impulse through the neuron.

3) Electrical signal travels down the axon until it branches toward next target neuron.

4) Electrical signal travels down axon terminal where it approaches a synapse; there, neurotransmitter chemicals (each specified to invoke a certain response from neurons) carry the signal across the synaptic cleft (area between two neurons’ synapses) to an adjacent neuron. Once a neurotransmitter’s function is fulfilled, it is sent back to the neuron via transporters, shutting off the signal between the neurons.

The Damaged Brain

Damaging the Brain- Drugs• Drugs are essentially unfamiliar chemicals introduced to the body

o These chemicals (when taken in excessive amounts) interfere with the process of neural

information transfer

• Drugs (ie. Heroine) fool the chemical receptors found on the synapses, lock onto them and

activate the neurons

o Cause neurons to send abnormal messages to through brain

Results in disorientation and altered perception (“high” feeling)

• Other drugs (ie. Cocaine) cause neurons to release excessive levels of the naturally

produced neurotransmitters

o Inhibits the recycling of these brain chemicals- ultimately destroys these communication

channels

Brain Function MRI Brain Function MRI

Decreased Function

Damaging the Brain- Injury• There exist three main processes that cause injury to the brain

o Bruising/ Bleeding: When soft brain tissue collides against the cranium, it “squishes”

Blood vessels that had once provided oxygen and nutrients for the brain are

damaged and pool blood into areas surrounding the brain

Causes pressure against neurons= neural death

o Tearing: Sudden jolt can either tear glial cells from cranium or tear the established

connections between neurons

Faulty connection prevents the transference of electrical signals

• In extreme circumstances, movement, memory and speech are restricted

Damaging the Brain- Injuryo Swelling:

When injured, location of injury often characterized by bruising and swelling

This phenomena is a result of body recognizing injury and attempting to heal it

Similarly with the brain:

• The body recognizes an injury in the cranial area and sends agents to the

specified area

• This causes swelling- putting pressure on the brain, ultimately killing/

damaging neurons

Bruised/ Bleeding Brain

Tearing

Vessels torn from inside of cranium, damaging the blood vessels and the surrounding neurons alike.

Swelling

Dangerous swelling to the brain; pressure is put on the brain tissue.

Damaging the Brain- Stroke• Strokes are one of the leading cause of neural debilitation in the United States

o Strokes are results of clogged arteries or a coagulated clump of blood travelling through

the arteries, preventing blood from arriving to areas of the body

If such clump of blood inhibits the flow of blood to the brain (thereby, inhibiting

oxygen) the neurons do not receive the required nutrients and oxygen

Depending on the period of time this deprivation is in effect, neurons can either die

or suffer extreme damage

This results (depending on area of damage)in the temporary or permanent

paralysis of certain limbs/ a speech impediment

Result of a Damaged Brain• Damage to the brain, although not uncommon, can be very debilitating

o The damaging or death of large areas of neurons can result in the following:

Memory Loss: certain connections of neurons store specific memories; if these

connections are destroyed, the memory is as well

Speech Impediment: either as a result of memory loss or inability for neurons to

transmit the will to speak to the vocal chords

Coma: Injury to the thalamus

Inability to Coordinate Movement: Interrupted neural network cannot transmit the

act of movement

• It is said that adult neurons cannot divide, although not strictly true (as interneurons can

divide as the adult brain develops), once a neuron is damaged or dead, it is irreplaceable, thus

the debility it brings is thought to be permanent

Nature Rewiring the Brain

Indication of Rewiring• Neuroscience is a fairly new field of study as only recently have scientists been able to take

proper imaging of the brain and explored its continual development

o Until recently it was assumed that once a specific area of the brain was damaged, it was

irredeemable

o This view has been tested on several occasion due to the rehabilitation of those who

were thought to have permanently damaged their brain

Natural Rewiring• Discovery by researchers as the Brain & Mind Institute of the EPFLo Brain naturally rewires itself after an experience

• Research indicates that the process of creation, testing & configuration of brain

circuits occurs over span of a few hours- brain evolves exponentially over course of

a day

• Scientists know the strength of neural connections shape memory & that youth

allows for greater brain plasticity (the ability to form neural connections)

o New study indicates that these connections switch rapidly

o Adaptive natural rewiring= continuous changing and strengthening of neural

circuitry

Natural Rewiring • Study included observation of neuron clusters of neonatal rats

o Instead of observing preferential growth patters, study concluded that neurons

have no particular such affinity Neurons perpetually ready to configure new circuits

o Over the course of several hours, neural connections formed/ reformed several

times

• This continual rewiring of the micro circuitry of the brain is likened to Darwinian

evolution

o New experiences trigger connections- only the fittest survive

• Implies that the natural plasticity can be used to artificially rewire the brain

Mouse Brain Naturally Rewires• Research group led by Professor Junichi Nabekura of the National Institute

for Physiological Sciences o Observed that mouse brain rewires its neural circuits to recuperate

from damaged neural function after stroke

• Researchers induced cerebral store to right side of mouse brain

o Investigated the rearrangement of neural circuitry using two-photon laser

microscopy in vivo (fluorescence imaging technique that allows imaging

of living tissue at depth

Inducing stroke to the right side (observer’s left side) of a mouse’s brain.

• Once stroke had been induced, researchers monitored neural activity

o In the two weeks after the stroke, the left side of the mouse brain began to actively

rearrange its neural circuitryo By the fourth week, the left side of the brain started to receive sensory information from

the left leg

Usually this information is delivered to the right side of the brain

• Scientists monitored the above rearrangement by stimulating the left and right limbs of the

mouse and tracking the electrical signals sent to the brain- this data was then compared to

normal mouse data (control group)

• This data reveals that the small mammals’ (and perhaps human) bodies are able to

naturally invoke the recuperation process of rewiring the brain

Mouse Brain Naturally Rewires

Rewiring the Brain

Behavioural Rewiring• Scientists from Carnegie Mellon University have uncovered evidence of behavioural

rewiring of the braino Found that intensive instruction to improve reading skills in young children causes brain

to physically rewire itself

New white matter is created- improves communication within the brain

• Brain imaging of children between ages of 8-10 showed that quality of white matter (brain

tissue that carries signals between areas of grey matter where information is processed)

improved significantly after children received 100 hours of remedial training

• Discovering the possibility of rewiring the brain's white matter has important implications

o Aids in the treatment of reading disabilities and other developmental disorders, i.e.

autism

Artificial Electrical Impulses• Scientists at the Case Western Reserve University have developed method to transmit

electrical impulses to muscles that are no longer connected to neurotransmitters

o Coined FES: Functional Electrical Stimulation Taking the body’s pre-existing electrical signals to control muscles that have been cut

off from the neurotransmitters and the nervous system

• Implants a sensor that reads electrical signals into one of the muscles that is in functioning order

o Signals are transmitted through thin implants to the muscle that can’t move

This muscle can then be used my moving the muscle with the implant

• However, implanting too many sensors is not practical

o Can begin to affect the fully functioning muscles’ mobility

Microchip Technology• Researchers in the Midwest (Case Western Reserve University & Kansas University

Medical Center) are electronically rewiring the braino Developing micro electric circuitry to guide the growth of axons in a damaged

brain

o Goal is to rewire the brain to bypass region injured from trauma

Will connect uninjured neurons to other areas of the brain & restore normal

behaviour/ movement

Microchip Technology• Researchers believe that repeated communications between distant neurons via

simulated electrical impulses in the weeks after an injury may spark long- reaching axons

to form & connect

o Found that the month following an injury, brain is most susceptible to redeveloping

Fibres naturally connect different parts of the brain, performing extensive

rewiring so as to recuperate

• This is the window of opportunity for scientists to develop their

treatment

Microchip Technology• Scientists have built a multichannel micro electronic device to facilitate this rewiring

o A brain- machine- brain interface composed of a microchip & a circuit board Microchip amplifies signals called neural action potentials, produced by one

part of the brain, and uses an algorithm to separate this from ambient noise

Once this brain spike is isolated, the microchip sends a current pulse to

stimulate neurons in the other area of the brain

This allows the artificial connection of the two parts of the brain

• This experiment is still in its early stages- current testing is done on rats, and will

graduate to non- human primates

Global Impact

Social Impact• Behavioural Rewiring:

o Developmental Disability Rehabilitation

Currently implemented as a treatment method for children with learning disabilities

Enables them to be integrated into society and mentally mature with their cohorts

• Microchip Technology:

o Can Revolutionize Teaching Methods

Instead of memorizing information, students can use electrical impulses to store

specific data and information

o Potential Rehabilitation for Stroke & Brain Trauma Patients

Enables the restoration of normal behaviour and movement of patients

Ethical Impact• Behavioural Rewiring:

o The fairness and mental stresses of implementing strenuous treatment on youth

and children

• Microchip Technology:

o Memory/ knowledge is recalled through repeated connection of neurons- can

artificially connect these neurons

Can implant a specific belief or thought in a mind if the carefully control of

these microchips are not monitored

How can we be certain that the development of our personality and character

is all our own?

Economic Impact• Studies in both the natural and artificial rewiring of the brain are fairly new

o Still in elementary and experimental stages

Large values of grant and research money are required for the continuation

and better understanding of this branch of neuroscience

Money could either come from universities, private donors, or the

Government

• Becomes an ethical issue if the Government or a private corporation

become proprietor of microchip technology- what will they do with it?

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