primer on the brain revised

A Primer on the Brainand its Functions

Dr. Stan KutcherKatie Radchuck

Jillian SohSun Life Financial Chair in Adolescent Mental Health

Dalhousie UniversityIWK Health Centre

The Human Brain: A Brief Tour

The brain is a remarkable organ,

controlling everything from heart rate to

digestion to sexual functioning, and

everything in-between! It produces our y g p

thoughts and speech, and allows us to

create works of art – complex activitiescreate works of art complex activities

which help define our humanity.


The human brain weighs approximately 1100-1200 grams, or around 2.5 pounds.

Your body and organs are made upYour body and organs are made up of cells, and the brain is no different. Neurons are a type of nerve cell which form networks in yourNeurons are a type of nerve cell which form networks in your brain to relay information. Glial cells tend to provide support to the brain (nourishment mechanical support immune response etc )brain (nourishment, mechanical support, immune response, etc.).

DID YOU KNOW?The brain contains an estimated 100 BILLION nerveThe brain contains an estimated 100 BILLION nerve

cells, more cells than there are stars in the Milky Way galaxy. That’s not all, glial cells are thought to outnumbergalaxy. That s not all, glial cells are thought to outnumber the nerve cells by as many as 10 to 50 times!

Source: Encyclopedia Britannica. Astronomy. 2000


Neurons are cells specialized to send and receive information. Generally, a neuron is made up of three basic parts:

Dendrites: consisting of many branches this isDendrites: consisting of many branches, this is the area where the cell receives information

Soma (Cell Body): contains the cell nucleusSoma (Cell Body): contains the cell nucleus, which acts like a blueprint for the production of proteins and other materials that keeps the cell p prunning smoothly

Axon: carries information received by the ydendrites, sometimes over long distances, to other cells. The axon is sometimes covered in myelin sheaths, another type of cell that speeds up the signal.

What’s This “Information” Anyway?

In the same way humans use sounds to talk to one another and share information, neurons use both electricity and chemicals to talk to each other. These chemical messengers are called neurotransmitters.

J st a fe e amples of ne rotransmittersJust a few examples of neurotransmitters:

(Glutamate) (Dopamine)(Serotonin)

(Acetylcholine)

(Serotonin)

(Epinephrine/Adrenaline)

Photo credit (CC 2.0): Anselm Hook

( cety c o e) Adrenaline)


These neurotransmitters play a major role in the brain and heavily influence consciousness, emotions, and behavior. In a y , ,group of people, if someone is whispering their ideas may not be heard. In the same way, too little of a neurotransmitter may causeheard. In the same way, too little of a neurotransmitter may cause communication failures between brain areas, affecting how we think, feel, and act.think, feel, and act.



You can see then, how important communication is in the brain. If it is disrupted, either through chemical imbalances or problems with the neurons themselves, this may contribute to brain dysfunction and mental illness.



Two basic layers of the brain can beTwo basic layers of the brain can be seen with the naked eye. There is the outer layer known as grey matter asouter layer, known as grey matter, as well as the inner layer, known as white mattermatter.

The gray matter is made up of densely packed neuronal bodies, whose long axons make up the white matter. Remember how axonswhose long axons make up the white matter. Remember how axons are sometimes covered in myelin sheaths? This myelin is quite fatty, giving the tissue a white-ish color.y, g g

Grey matter, containing the cell Grey matter, containing the cell bodies is where all the thinkingbodies is where all the thinkingbodies, is where all the thinking bodies, is where all the thinking

happens. This is your brain’s happens. This is your brain’s processing centreprocessing centre. .

White matter, containing those White matter, containing those long axons, are like a long axons, are like a super super highwayhighway. They transport . They transport information to different parts information to different parts of your brainof your brainof your brain.of your brain.

Photo credit (CC 2.0): facemepls, MSVG

The Central and Peripheral Nervous System

The brain along with your spinalThe brain, along with your spinal cord, makes up your body’s Central Nervous System (CNS). From the spinal cord extend nerve cells that receive sensory information (such

th h d h t f thas the roughness and heat of the beach) and transmit that to the brain. These outside nerves make up theThese outside nerves make up the Peripheral Nervous System (PNS). It’s a two-way street, The brain can also send signals through the spinal cord and PNS to control the

t f li b d t kmovement of your limbs and trunk.

The CNS and PNS

It takes around11.5 milliseconds to transmit a signal from the tip of your toe to your brain. This may seem pretty fast but in some cases – like when accidentally putting your hand on a hot stovetop – this delay is too long and would cause your hand to burn. Instead of sending a signal all the way to the brain and waiting for a return signal to move your hand away, a network of cells withinthe spinal cord receive the sensory information, then pass it on to motor neurons which are cells that control your musclesmotor neurons, which are cells that control your muscles. Bypassing the brain like this is called a reflex. Your muscle will contract causing you to pull away from the hot stovetop – it is onlycontract causing you to pull away from the hot stovetop – it is only after a short delay that your brain catches up and realizes your hand hurts!a d u ts

Photo credit (CC 2.0): Ndecam

The CNS and PNS

Speaking of signal transmission speeds, some nerve fibers transmit signals faster than others. Usually it depends on whether they are myelinated or not (remember that myelin speeds up transmission!).

Think about when you stub your toe. You definitely feel it right away since the touch signals reach your brain almostright away since the touch signals reach your brain almostinstantaneously. However it’ll take a few seconds before the pain signal will reach your brain, and when it does –pain signal will reach your brain, and when it does

YEOWCH!Photo credit (CC 2.0): Ndecam

So now we know what the brain is d f W k th t diff tmade of. We know that different

parts of the brain communicateith th iwith one another using

neurotransmitters, and this i ti t dcommunication can extend

down the spinal cord to the rest of your body.

But what does the brain actually DOand HOW does it do it?and HOW does it do it?

Photo credit (CC 2.0): perpetualplum

There are 6 functions of the Brain There are 6 functions of the Brain

2 E ti & F li

1. Thinking & Cognition

2. Emotion & Feeling

3. Signaling (being responsive and3. Signaling (being responsive and reacting to the environment)

4 Perception & Sensing4. Perception & Sensing

5. Physical Functions

6. Behavior

Thinking & CognitionThinking and Cognition includes all of our internal

mental processes and functions

Communicating Processing

Higher Cognitive FunctionsCommunicating

Arithmetic

Processing

Reading

Insight

Pl i

Focusing

Att diPlanning

Judgement

Attending

Memory

Comprehension Contemplation

Thinking & CognitionFACT SHEETFACT SHEET

Location: Frontal Lobes

Overview

Neural Pathways: 2-way connection between

Your frontal lobes are responsible cortical and limbic areas

Main Neurotransmitters:

Your frontal lobes are responsible for the majority of your conscious thought This area works closely with Dopamine, serotonin, and

adrenaline

thought. This area works closely with the limbic system, a section deep within the brain responsible for moodwithin the brain responsible for mood, emotion, and storage of memories.

Thinking & CognitionThe Limbic System

The limbic system includes severalThe limbic system includes several brain structures: the amygdala, hippocampus anterior thalamichippocampus, anterior thalamic nuclei, and limbic cortex.

The hippocampus, responsible mainly for the storage of long termmainly for the storage of long-term memory, is one of the first places affected by Alzheimer’s Diseaseaffected by Alzheimer s Disease.

Thinking & CognitionAttention

Your frontal lobes also include anYour frontal lobes also include an area called the prefrontal cortex, which controls many of your cognitivewhich controls many of your cognitive abilities, such as attention.

However, this area of the brain changes drastically during adolescence and is one of the last brain areas to matureadolescence, and is one of the last brain areas to mature completely!

Thinking & Cognition

Is your attention drifting right now? Don’t worry! Scientists

Attention

Is your attention drifting right now? Don t worry! Scientists have measured attention in adolescents, and have discovered that performance increases with age.p g

So that means…Yes, attentional

capacity might improve as you and your brain matures!

Anderson et al (2001)Anderson et al. (2001)

Thinking & CognitionPhineas Gage

We know that some parts of pthe brain are specialized for certain tasks. An injury to specific, limited parts of the brain can help scientists know for sure what that part of the brain is responsible for. Take for example the case of poor Phineas Gage.

Photo credit: From the collection of Jack and Beverly Wilgus.


In 1848, Phineas was a young man working on clearing out some rock for the construction of aon clearing out some rock for the construction of a railroad. An explosive was set off accidentally, thrusting a large iron rod under Phineas’ left cheek bone and outa large iron rod under Phineas’ left cheek bone and out the top of his head. The force of the explosion was so severe that the rod completely left Phineas to land 90 feet away, taking with it most of the left frontal lobe.

Photo credit (CC 2.0): Kevin Dooley


His recovery was long and at some points bleak but he eventually regained his memory andbleak, but he eventually regained his memory and physical strength. He suffered no motor or speech impairments however a startling change had occurredimpairments, however a startling change had occurred with his personality and behavior.



He became rash, where before he was mellowwhere before he was mellow. He used to be a good worker, but now his colleagues couldbut now his colleagues could not handle his temper. He had trouble forming and executing plans, didn’t think before he acted, and often made choices against his best interests.


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Although the front left portion

Phineas Gage

of his brain was destroyed, Phineas was still able to function well. He could walk and talk, since the brain areas responsible for that wasn’t affected.

However, the frontal lobes are responsible for judgment,l i d d fi iplanning, and defining your

personality. All of these changed after his brain injurychanged after his brain injury.

Photo credit: From the collection of Jack and Beverly Wilgus.


Your brain also has specific

Speech and Comprehension

pareas dedicated to speech and language comprehension.Broca’s AreaMainly responsible for language production. People who have damage to this area are still able to understand language, and know

h t th t t th j t ’t ‘ t it t’what they want to say, they just can’t ‘get it out’.Wernicke’s Area

M i l ibl f l h i P l hMainly responsible for language comprehension. People who have damage to this area can still produce speech but it tends to have no meaning This is known as ‘word salad’:have no meaning. This is known as word salad :

Example: “Colorless green ideas sleep furiously.”

Emotion is the ability to experience feelings and to express those

feelings to others.

Happy Sad Anxious ppy Excited Calm Peaceful

Depressed Guilty Ashamed

Worried Fearful Nervous

Content Serene Joyful

Angry Irritated Annoyed

Panicky Inferior Inadequate

Pleased Carefree

Resentful Frustrated

Lonely Discouraged

We can also call our emotions and We can also call our emotions and feelings “MOODS”

Emotion & FeelingsFACT SHEETFACT SHEET

Location: Prefrontal

Overview

cortex, amygdala

Main Neurotransmitters: Regulating your emotions is yet

another complex thing your brain has Serotonin and dopamineto do. Your prefrontal cortex

produces cognitive emotions (“thinking with you head”) while the amygdala produces instinctive

ti (“thi ki ith h t”)emotions (“thinking with your heart”).

Serotonin and dopamine and two i t t t ittvery important neurotransmitters

needed to regulate your emotional statestate.

Emotion & FeelingsNeural Correlates

Different parts of your brain are active depending on what type of emotion you are feeling.

For example, the top brain scan shows which areas of our brain are active when we feel sadness. The bottom brain scan shows which areas of our brain are active when we feel h ihappiness.

The brain really does create all of tiour emotions.

Emotions & Feelings

Since the brain produces much of

Serotonin and Mood

pwhat we feel, when something goes

ith th b iwrong with the brain our emotions can get messed up. Clinical depression is characterized by a persistentcharacterized by a persistent, intense negative mood, which affects a person’s normal lifenormal life.

Photo credit (CC 2.0): Alejandro Cordon

Emotions & Feelings

Research has found that Serotonin and Mood

serotonin is important for communication between thecommunication between the prefrontal cortex and amygdala areas of the brain Remember howthe brain. Remember how those two areas are important for regulating emotions?emotions?


Emotions & Feelings

S l ith j d i d ’t

Serotonin and Mood

Some people with major depression don’t have a good connection between the prefrontal cortex and amygdala. By increasing the amount of serotonin in the brain with drugs, this connection can bethis connection can be strengthened and help people regain a better moodregain a better mood.


Signaling is the brain’s way of responding to a perceived threat, danger, or stress

from the environment.

Photo credit (CC 2.0): GE Healthcare

SignalingFACT SHEETFACT SHEET

Location: Cortex, Your brain is constantly alert taking

Overview

thalamus, amygdala, hippocampus

Your brain is constantly alert, taking note of your surroundings. When it perceives a danger such as an

Main Neurotransmitters: Adrenalin, serotonin

perceives a danger, such as an oncoming car, the brain begins a physiologic cascade with the help of p y g pneurotransmitters like adrenalin and serotonin. Your heart rate and alertness go up, more blood is pumped to your muscles, and your senses become sharper. Your brain then makes a decision whether to runfrom the danger, or stay and fight it.

SignalingFight or FlightFight or Flight

SSensory Perception

(Ears, eyes, smell, t t t h)

InternalSignals+

taste, touch)

When faced with DANGER, your 5 senses perceive it and sends a signal to the BRAIN

Your brain initiates a Physiologic

Cascade

Heart Rate Alertness

Tension

Alertness Perception Now you are ready to

FIGHT or FLEE for your safety and protection

Photo credit (CC 2.0): Mangpages, Phillipe Put

safety and protection

SignalingAnxietyAnxiety

SSensory Perception

(Ears, eyes, smell, t t t h)

InternalSignals+

taste, touch)

Anxiety happens when the brain believes there is danger, but there isn’t any

Your brain initiates a Physiologic This

Cascade

Heart Rate Alertness

produces feelings of ANXIETY

Tension

Alertness Perception

ANXIETY

Photo credit (CC 2.0): Mangpages, flequi

Signaling

Normal anxiety happens to all of us.

Anxiety

Normal anxiety happens to all of us.

A situation t i it

Which causes f li fcan trigger it:

First date

feelings of anxiety:

Preparing for an exam

Performing at a concert

Apprehension

Nervousness

Giving a speech

Moving from home

Tension

Edginess

Climbing a tall ladder

Etc.

Nausea

Sweating

Trembling

SignalingAnxiety

Normal anxiety:

I t i t hi h th t it ill ft hilIs transient, which means that it will go away after a while

Does not significantly interfere with a person’s well-being

Does not prevent a person from achieving their goals

Signaling

Some people suffer from pathologic anxiety.

Anxiety

Some people suffer from pathologic anxiety.

A situation, or nothingt i it

Which causes i t i tcan trigger it:

First date

intense anxiety:

Feels like a heart attack

Preparing for an exam

Performing at a concert

Feels like you’re dying

Feels like you’re going h i

Giving a speech

Moving from home

crazy or having a nervous breakdown

Climbing a tall ladder

NOTHING!

This happens when there is a dysfunction in the i li h isignaling mechanisms.

SignalingAnxiety

Pathological anxiety:

I i t t i t t d f l t lIs persistent, meaning symptoms stay around for a lot longer than they should

Is excessive, intense, and inappropriate to the situation –feeling like you are having a heart attack before giving a speech is not how the brain should react

Leads to impairment in a person’s everyday life where theyLeads to impairment in a person s everyday life, where they may avoid people and act withdrawn in an attempt to avoid trigger situationsgg

Perception is the way your five senses work with your five senses work with your brain to take in your surroundingssurroundings.

Photo credit (CC 2.0): Mohamed Malik

Perception & SensingOverview

We have five senses that work together to give awareness ofWe have five senses that work together to give awareness of our environment:

See Hear Smell Taste Touch

Perception & SensingVision

For us to see, light must enter into ourFor us to see, light must enter into our pupils and hit the retina lining the back of the eye.y

Cones are cells in the retina that give us our color vision while rods are cellsus our color vision, while rods are cells that give us black and white (night) visionvision.

The optic nerve carries the signal through the lateral geniculate nucleus to the back of the brain, the primary i l tvisual cortex.

Perception & SensingVision

The primary visual cortex transmits theThe primary visual cortex transmits the signal to two different areas of the brain:

Temporal lobesTemporal lobesResponsible for object recognition, “what” the object iswhat the object is

Conscious processing

Parietal LobesResponsible for object location, “where” the object is

Unconscious processing of the relationship between the object and your body

Perception & SensingVision: BlindsightVision: Blindsight

People who sustain damage to h i l l b d ltheir temporal lobes may develop a condition known as blindsight.

Since the temporal lobes are responsible for the consciousprocessing of vision they would not be able to ‘see’ normallyprocessing of vision, they would not be able to see normally, and would be considered legally blind. However, their unconscious spatial processing has not been damaged sounconscious, spatial processing has not been damaged, so even though they may not be able to identify objects in a room they can walk around tables and chairs without bumping intothey can walk around tables and chairs without bumping into them. They can follow objects with their fingers and may even be able to catch a ball thrown at them

Photo credit (CC 2.0): Jim Simonson

able to catch a ball thrown at them.

Perception & SensingHearing

Many tiny hairs in your innerMany tiny hairs in your inner ear vibrate to sounds in the environment Those vibrationsenvironment. Those vibrations are felt by cells in the ear and the signal is transferred along the g gbrain to eventually reach the primary auditory cortex.

DID YOU KNOW?As people age their ability to hear very low and highAs people age, their ability to hear very low and high

frequency noises diminishes. An anti-loitering alarm was developed that plays a high-pitched, annoying noise thatdeveloped that plays a high pitched, annoying noise that only teenagers can hear. Talk about discrimination!

Perception & SensingSmell

Smell exists as tinySmell exists as tiny molecular odorants that travel up your nose to be detectedup your nose to be detected by cells in the olfactory epithelium. This signal travels p gthrough the olfactory nerve to your brain, where the signal is processed by the olfactory cortex. Some of the signal makes it to the limbic system, where long-term, emotional memories are stored. This is why smells can sometimes help you remember strong memories, maybe of your home or childhood!

Photo credit (CC 2.0): DrJimiGlide

Perception & SensingTaste

Taste buds which cover the surfaceTaste buds which cover the surface of the tongue allows us to distinguish different flavors in our food There aredifferent flavors in our food. There are five basic tastes:

SSweetSourSaltyBitterUmami (savoury)

Photo credit (CC 2.0): Zoe Shuttleworth

Perception & SensingTaste

Information from the taste buds travel up cranial nerves to reachInformation from the taste buds travel up cranial nerves to reach the brain stem, where the signal is passed onwards to the primary gustatory cortexgustatory cortex.

DID YOU KNOW?Not everyone perceives food the same way! SomeNot everyone perceives food the same way! Some

people have a lot more taste buds than average, and are known as ‘super tasters’ Your genes determineare known as super tasters . Your genes determine whether you are a ‘super taster’, ‘taster’, or even a ‘non-taster’. Super tasters tend to be very sensitive tonon taster . Super tasters tend to be very sensitive to different foods, especially bitter things like broccoli and coffee, and may be picky eaters.

Tepper et al. 2009; Photo credit: Zoe Shuttleworth

, y p y

Perception & SensingTouch

Your body is full of touchYour body is full of touch receptor cells near the surface of the skin When activated theythe skin. When activated, they send a signal up to your brain to let it know. Some areas of your ybody have many more touch receptors than others, and thus have a larger representation in the brain, in a place called the somatosensory cortex.

Photo credit (CC 3.0): btarski

Perception & SensingTouch

A homunculus is a representation of what a human would look like if made in the same proportions as the brain area assigned to it. The hands and facial

i ll th li dareas, especially the lips and tongue, are highly sensitive!

Dr. Penfield, the famous Canadian neuroscientist (yes, the ‘burnt toast’ guy!) came up with the homunculus by mapping limb locations to different

f th b iareas of the brain.

Signaling is the brain’s way of responding to a perceived threat, danger, or stress

from the environment.

Your brain takes Your brain takes care of many

different physical different physical functions, such as

digestion, breathing, digestion, breathing, controlling your

muscles, etc.Photo credit (CC 2.0): GE Healthcare

muscles, etc.

Physical FunctionsVoluntary Movement

In the same way thatIn the same way that different brain regions are assigned forare assigned for sensing different areas of your body, different y y,brain regions control different areas of your body. Places where fine motor control isneeded, such as your hands and mouth (for producing speech and eating), take up a larger area in the brain! This place is called the

t tmotor cortex.

Physical FunctionsVoluntary Movement

Your prefrontal cortex – which if youYour prefrontal cortex – which if you remember is where all your thinking happens – sends a signal to the motorhappens sends a signal to the motor cortex area assigned to a body part. This signal travels down the spinal g pcord to alpha motor neurons, which tell muscles to contract. This whole process allows us to produce thought-directed, voluntary movements.

This entire complex arrangement is known as the somatic nervous systemnervous system.

Physical FunctionsInvoluntary Movement

What about involuntary movement?What about involuntary movement? Stuff you can’t control consciously? Your heart needs to keep beatingYour heart needs to keep beating and your stomach needs to keep churning for you to stay alive. If you g y y yhad to consciously think about every breath you took you probably would be too distracted to think about much else. This is where the autonomic(from ‘automatic’) nervous systemcomes in.

Photo credit (CC 2.0): David DeHetre

Physical FunctionsInvoluntary Movement

Your autonomic system is basically inYour autonomic system is basically in charge of all your internal organs, and controls what they do unconsciouslycontrols what they do unconsciously (although some things, like your breathing, can be taken over by the conscious mind). y )It is divided into two parts: the Sympathetic Nervous System, and the Parasympathetic Nervous System.

Physical FunctionsInvoluntary MovementInvoluntary Movement

Sympathetic Nervous SystemR b h i li d i t k ?Remember how signaling and anxiety works?

Your sympathetic nervous system controls that ‘fight or flight’ mechanism (makes the heart pumpfight or flight mechanism (makes the heart pumpfaster, inhibits digestion, raises blood pressure, etc ) It also maintains equilibrium or homeostasisetc.). It also maintains equilibrium, or homeostasis.Stuff like making sure your body temperature is just right, and balancing youris just right, and balancing your blood sugar levels.

Photo credit (CC 2.0): Mark Robinson

Physical FunctionsInvoluntary MovementInvoluntary Movement

Parasympathetic Nervous SystemWhil th th tiWhile the sympathetic nervous

system is most active when you’re stressed the parasympatheticstressed, the parasympathetic nervous system works when you are resting so it’s known as the ‘restresting, so it s known as the rest and digest’ system. Think of it working in the opposite direction,working in the opposite direction, instead of speeding up your heart rate it slows it down. It lowers your yblood pressure. Since, at rest, your body can expend energy to relax and eat, much more saliva is produced.

Behavior is simply the way we act, usually in response to our environment. It includes

feverything from running to joking, f di t

Photo credit (CC 2.0): Jamie Davis

from reading to working.

BehaviorOverview

Teens don’t ‘get’ their parents. What’s with all the rules and

t i ti ? A d t d ’t lik threstrictions? And parents don’t like the things teens do – they always seem to be experimenting and takingbe experimenting and taking unnecessary risks.

This seeming rift between teens and adults has a lot to do with behavior, and behavior has a lot to do with the brain.

Photo credit (CC 2.0): Ollie Crafoord

Behavior One example of a behavioral difference is motivation. Motivation is your drive to do

Motivationy

stuff – like studying hard to do well on a test, or finishing a marathon, or beating one more

level of a video game.

Photo credit (CC 2.0): shirokazin

BehaviorMotivation

Motivation is influenced heavily by the reward pathway in the brain. A

d d ’t h t breward doesn’t have to be something physical, it can be getting a good mark or a positive feelinga good mark or a positive feeling. Drug addiction causes your brain to constantly seek out that positiveconstantly seek out that positive ‘feeling’, and your brain becomes dependant on it as a reward. Thedependant on it as a reward. The danger comes when that feeling can only be achieved by drugs!y y g

Photo credit (CC 2.0): Ollie Crafoord

BehaviorMotivation

In teens, the reward pathway of the brain is stronger than in adults. Also, th iti t f th b i th tthe cognitive parts of the brain that think about things logically and weighs the pros and cons are not asthe pros and cons are not as developed in teens. This means teens may be motivated to try riskiermay be motivated to try riskier behaviors and be more impulsive than adults would be, and are more proneadults would be, and are more prone to push beyond their limits and boundaries without weighing g gconsequences (Smith et al., 2011).

Behavior This isn’t always a bad thing. Si th b i t i thiMotivation Since the brain matures in this way,

young people can be extremely i t b t th thi thpassionate about the things they

care about, they work hard to achieve things that are important to

them. They open their eyes to the world and have new experiences,

and become better people for it.

It’s all about the choices you makemake.

Photo credit (CC 2.0): James Tosh

So now we know the six basic functions of the brain, but how does such a complex organ develop?

NewScientist (2009)NewScientist (2009) suggests that there are 5 different ‘ages’ of the brain:different ages of the brain:

1. Gestation

2. Childhood

3. Adolescence

4. Adulthood

5 Old A5. Old AgePhoto credit (CC 2.0): Neil Conway

GestationOverview

Gestation is the stage of developmentGestation is the stage of development where you are still in your mom’s womb. It is this time where your brain undergoesIt is this time where your brain undergoesinitial development, and your cells differentiate to create your first neurons y(this process is called neurogenesis).

Neurogenesis is a hot topic right nowNeurogenesis is a hot topic right now, because while people are really good at making new neurons when they are fetuses it gets much harder when they are adults If we learnthey are fetuses, it gets much harder when they are adults. If we learn how to create new neurons where we want them, we may be able to help people with brain diseases and spinal cord injurieshelp people with brain diseases and spinal cord injuries.

ChildhoodOverview

Childhood is the stage where ourChildhood is the stage where ourbrains probably undergo the biggestchanges It is this time where wechanges. It is this time where welearn language, how to store memories, and how to think.,

Timeline:6 years:

2-3 months:cortex develops

18 months:develop a sense of self

apply logic and trust, understands personal thought process

6-12 months: 3-4 years:frontal lobe develops

ysense that other people

have minds too

AdolescenceOverview

Adolescence is the teenageAdolescence is the teenage years. It is around this time that your brain areas start to fully mature andbrain areas start to fully mature and develop. Your sensory and motor areas are the first to mature, which is why teens can be ‘sensation , yseekers’. Your prefrontal cortex matures last, which helps in decision making, emotional control, and temper.

Most teens pass through these years without severe or prolonged difficulties but 15% of teens will experience significant mental healthdifficulties, but 15% of teens will experience significant mental health problems during their adolescent years.

AdolescenceOverview

Adolescence is the time whereyour brain gets rid of neural

th th t it d ’t dpathways that it doesn’t need.When you’re young, you havea high volume of gray matter ina high volume of gray matter inyour brain. During adolescence,this gray matter is pruned awaythis gray matter is pruned away.This is thought to make the brain more efficient. What gets removed depends a lot on usage. It’s really ‘use it or lose it!’ It is important todepends a lot on usage. It s really use it or lose it! It is important to keep your brain active and healthy during these years.

AdulthoodOverview

You’ve finally made it to your adultYou ve finally made it to your adultyears! People’s brains peak aroundthe age of 22 This is when they canthe age of 22. This is when they canprocess things the fastest and learnnew things easier. When you hit 27g yyears, your brain will progressivelystart to decline. However, adults are excellent at crystallized intelligence, or wisdom, which is the ability to use and apply everything you’ve learned up till now.

You can keep your brain sharp and slow down that decline by being mentally and physically activementally and physically active.

Old AgeOverview

In your golden years, you brain is in themost danger of deteriorating. Death of brain

ll i th hi l d tcells in the hippocampus area can lead tomemory loss. Again, by keeping fit andeating healthy you can stimulate braineating healthy, you can stimulate braincell growth and slow this decline.

The elderly are more prone to diseases such as Alzheimer’s – plaques and tangles are seen in the brain wrapped around cells responsible for memory and retrieval. Parkinson’s is another disease which mainly affects the elderly, and i d b th d th f ll ibl f tis caused by the death of cells responsible for movement.

Old AgeOverview

The chance of experiencing a stroke also increases hen o ’re older A stroke occ rs hen the bloodOverview when you’re older. A stroke occurs when the blood

supply to the brain has been disturbed. A portion of your brain may lose its functioning (causing paralysisyour brain may lose its functioning (causing paralysis on one side of the body, loss of speech, etc.).

Neuroplasticity is the brain’s ability to rearrangeNeuroplasticity is the brain s ability to rearrange neural pathways and repair itself. It used to be thought that this could only occur in very young people, but y y y g p p ,recent research has shown that neuroplasticity can still occur in older adults, even in the elderly. There’s a lot of science being done now to see if we can enhance neuroplasticity to help treat stroke patients and speed up their recoveryup their recovery.

Photo credit (CC 2.0): TheArches

Think upon this…

W ’ ithe Brain

We’re usingthe Brain

to studyto studythe Brainthe Brain

And there’s still a lot to learn! WhatAnd there s still a lot to learn! What you’ve read here is just the tip of our current knowledge, and our current knowledge is just the tip of what is goingknowledge is just the tip of what is going on in that spongy mass of tissue. As science advances, the brain will come to b tt d t d it lf S k l i !

Photo credit (CC 2.0): dierk schaefer

better understand itself. So keep learning!

Sun Life Financial ChairIn Adolescent Mental HealthIn Adolescent Mental Health

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ReferencesDaftarya, S.S., Pankseppb, J., Dongb, Y., and Saal, D.B. 2009. Stress-induced, glucocorticoid-dependent strengthening of glutamatergic synaptic transmission in g p g g g g y pmidbrain dopamine neurons. Neuroscience Letters 452, 3: 273-276.

Lenroot, R.K., Giedd, J.N. 2006. Brain development in children and adolescents: Insights from anatomical magnetic resonance imaging. Neuroscience and g g g gBiobehavioral Reviews. 30: 718-729.

Sowell, E.R., Thompson, P.M., Holmes, C.J., Jernigan, T.L., Toga, A.W. 1999. In vivo evidence for post-adolescent brain maturation in frontal and striatal regions. Natureevidence for post adolescent brain maturation in frontal and striatal regions. Nature Neuroscience. 2: 859-861.

Sowell, E.R., Thompson, P.M., Toga, A.W. 2001. Mapping continued brain growth and gray matter density reduction in dorsal frontal cortex: Inverse relationships duringand gray matter density reduction in dorsal frontal cortex: Inverse relationships during postadolescent brain maturation. The Journal of Neuroscience. 21: 8819-8829.

Grant, J.E., Correia, S., Brennan-Krohn, T., Malloy, P.F., Laidlaw, D.H., Schulz, S.C. 2007 Frontal White Matter Integrity in Borderline Personality Disorder With Self-2007. Frontal White Matter Integrity in Borderline Personality Disorder With Self-Injurious Behavior. Journal of Neuropsychiatry Clinical Neuroscience 19:383-390.

ReferencesChambers, R.A., Taylor, J.R., Potenza, M.N. 2003. Developmental Neurocircuitry of Motivation in Adolescence: A Critical Period of Addiction Vulnerability. American Journal of Psychiatry 160:1041-1052Journal of Psychiatry 160:1041 1052.

Firedel et al, 17 December 2008 / Accepted: 30 March 2009. Springer-Verlag 2009

S CThe auditory cortex Andrew J. King and Jan W.H. Schnupp Current Biology Vol 17 No 7.2007The five ages of the brain: 05 April 2009 by Graham Lawton, Caroline Williams, Helen Phillips, Anna Gosline, Helen Thomson, . NewScientist Magazine issue 2702

Romer, D. 2010. Adolescent risk taking, impulsitivity, and brain development: implications for prevention. Developmental Psychobiology 52:263-276.

Smith, A. B., Halari, R., Giampetro, V., Brammer, M., Rubia, K. 2011. Developmental effects of reward on sustained attention networks. NeuroImage 56: 1693-1704.

Tepper, B. J., Williams, T. Z. A., Burgess, J. R., Antalis, C. J., Mattes, R. D. 2009.Tepper, B. J., Williams, T. Z. A., Burgess, J. R., Antalis, C. J., Mattes, R. D. 2009. Genetic variation in bitter taste and plasma markers of anti-oxidant status in college women. International Journal of Food Sciences and Nutrition 60:35-45.

Overgaard M 2011 Visual experience and blindsight: a methodological review ExpOvergaard, M. 2011. Visual experience and blindsight: a methodological review. Exp Brain Res 209: 473-479.

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