Brain BasicsBrain Basics

Facts and MisconceptionsFacts and Misconceptions

Perception and RealityPerception and RealityThings Are Not Always Things Are Not Always

As They Seem...As They Seem...

Brain BasicsBrain BasicsOverviewOverview

Brain Facts Discussion and QuestionsBrain Facts Discussion and Questions

General FactsGeneral Facts

Parts of the BrainParts of the Brain

FunctionsFunctions

Brain Misconceptions DiscussionBrain Misconceptions Discussion

Properties of Neurons DiscussionProperties of Neurons Discussion

Brain FactsBrain FactsThe adult human brain is about 4 to 5 pounds. A baby’s The adult human brain is about 4 to 5 pounds. A baby’s

brain weighs about 1.5 pounds. brain weighs about 1.5 pounds. However, a baby’s body weighs about 15-30 times However, a baby’s body weighs about 15-30 times

smaller than an adult’s body. So a baby’s brain is 6 smaller than an adult’s body. So a baby’s brain is 6 times bigger times bigger compared to its body weight!!!compared to its body weight!!!(that is why babies have (that is why babies have huge headshuge heads compared to compared to their bodies)their bodies)

Human brain has over 100 billion! Human brain has over 100 billion! neuronsneurons (a type of (a type of brain cell); that’s about 20 times the total number of brain cell); that’s about 20 times the total number of people in the world.people in the world.

Neurons require a lot of energy: Your brain uses over Neurons require a lot of energy: Your brain uses over half of all the energy in your body.half of all the energy in your body.

Brain LobesBrain Lobes

The The Cerebral CortexCerebral Cortex (wrinkled (wrinkled outside part of the brain) is outside part of the brain) is arbitrarily divided into 4 arbitrarily divided into 4 lobeslobes based upon the things based upon the things that scientists think they dothat scientists think they do

The The occipital lobeoccipital lobe processes processes the visual information from the visual information from your eyesyour eyes

The The frontal lobefrontal lobe makes high- makes high-level decisions, plans level decisions, plans movements, coordinates movements, coordinates speech, and has a large role speech, and has a large role in determining personality in determining personality and morality (Phineas Gage)and morality (Phineas Gage)

Brain LobesBrain Lobes

The The parietal lobeparietal lobe processes processes you sense of touch, you sense of touch, processes your concept processes your concept of spatial relationships of spatial relationships (where things are)(where things are)

The The temporal lobetemporal lobe helps helps identify things (what identify things (what things are), helps you things are), helps you remember things, and remember things, and processes sounds processes sounds (hearing)(hearing)

Other Brain PartsOther Brain PartsThe The CerebellumCerebellum has as has as

many neurons as the many neurons as the entire cerebral cortex!entire cerebral cortex!Its main role it to Its main role it to coordinate movements coordinate movements or brain activities (make or brain activities (make sure their timing is sure their timing is right)right)

The The BrainstemBrainstem controls controls the body processes that the body processes that you don’t have to think you don’t have to think about (like your heart about (like your heart beat) beat)

Brain MisconceptionsBrain Misconceptions10%10%

Do people only use 10% of their brain?Do people only use 10% of their brain?No. No. Different parts of your brain do different Different parts of your brain do different things. So not all of your brain needs to be things. So not all of your brain needs to be doing something all of the time. However, doing something all of the time. However, using modern technology we have shown using modern technology we have shown almost every area of the brain active during almost every area of the brain active during some task. some task. For many hard tasks, a large percentage of For many hard tasks, a large percentage of your brain may be active at one time.your brain may be active at one time.

Brain MisconceptionsBrain MisconceptionsWrinklesWrinkles

Why are there wrinkles in the brain? Do more wrinkles Why are there wrinkles in the brain? Do more wrinkles appear when you learn something new?appear when you learn something new?

No.No.

Your cerebral cortex is essentially a flat sheet (like a Your cerebral cortex is essentially a flat sheet (like a large sheet of paper) that it has to fit in your skull large sheet of paper) that it has to fit in your skull (which is like a cup)… A crumpled up sheet of paper (which is like a cup)… A crumpled up sheet of paper fits in a cup easier than an unfolded one. fits in a cup easier than an unfolded one.

Most scientists think that new learning is changed Most scientists think that new learning is changed connections between neurons (brain cells; similar to connections between neurons (brain cells; similar to different wiring in a computer). different wiring in a computer).

Brain MisconceptionsBrain MisconceptionsGender and Brain SizeGender and Brain Size

Do boys have bigger brains and are they smarter than Do boys have bigger brains and are they smarter than girls or the opposite?girls or the opposite?(1) Men on average actually do have larger brains (1) Men on average actually do have larger brains than women (just like they have bigger bodies on than women (just like they have bigger bodies on average). But, elephants have much bigger brains average). But, elephants have much bigger brains than humans (4 times as heavy) and cats are about 45 than humans (4 times as heavy) and cats are about 45 times smaller.times smaller.(2) (2) A bigger brain does not mean you are smarter.A bigger brain does not mean you are smarter. Men and women have the same intelligence level on Men and women have the same intelligence level on average (although there is some evidence that each average (although there is some evidence that each may be slightly better at specific tasks). Two people may be slightly better at specific tasks). Two people with the biggest and one of the smallest brains ever with the biggest and one of the smallest brains ever found both belong to professional writers!found both belong to professional writers!

Brain MisconceptionsBrain MisconceptionsComputers (1)Computers (1)

Is the brain like the CPU of a computer?Is the brain like the CPU of a computer?

Not really.Not really.

Computers are made of metal and use electricity to Computers are made of metal and use electricity to process information. Brains are made of organic cells process information. Brains are made of organic cells and use a mix of electrical signals and chemicals to and use a mix of electrical signals and chemicals to process information.process information.

If one part of a computer breaks it can do almost If one part of a computer breaks it can do almost nothing. If one part of your brain gets damaged only nothing. If one part of your brain gets damaged only certain things are hard to do and it can sometimes certain things are hard to do and it can sometimes gradually repair itself.gradually repair itself.

Brain MisconceptionsBrain MisconceptionsComputers (2)Computers (2)

Are humans smarter than computers or computers Are humans smarter than computers or computers smarter than people?smarter than people?Neither, they work in different ways.Neither, they work in different ways.

Computers are currently all Computers are currently all programmed to do a programmed to do a specific task by peoplespecific task by people who give them specific who give them specific instructions about how to do it. Computers are much instructions about how to do it. Computers are much faster at doing many of these things.faster at doing many of these things.Currently, computers are not able to do things they Currently, computers are not able to do things they are not specifically told how to do. This is changing are not specifically told how to do. This is changing as people figure out ways to make computers learn to as people figure out ways to make computers learn to do new tasks on their own. do new tasks on their own.

Humans, however, are Humans, however, are very good at figuring out very good at figuring out creative ways to do things on their own.creative ways to do things on their own.

Brain MisconceptionsBrain MisconceptionsDrug Addiction (1)Drug Addiction (1)

If you are careful you won’t get addicted to drugs, right?If you are careful you won’t get addicted to drugs, right?Examples of addictive Drugs Examples of addictive Drugs – all types of C– all types of Cocaine (crack); ocaine (crack);

Heroin; Opium; Ecstasy; … Heroin; Opium; Ecstasy; … Mostly affect the parts of your brain that process Mostly affect the parts of your brain that process reward reward

(pleasure) information or help you manage pain(pleasure) information or help you manage pain: when they : when they work normally, they help you in emergencies or to encourage work normally, they help you in emergencies or to encourage you to become addicted to good behavior (like eating you to become addicted to good behavior (like eating nutritious food) to make you want to do it again and again nutritious food) to make you want to do it again and again

The problem: these drugs either overuse or kill off cells in these The problem: these drugs either overuse or kill off cells in these systems so they work too strongly or eventually not enough… systems so they work too strongly or eventually not enough…

Some brain areas cause a little addiction even when working Some brain areas cause a little addiction even when working correctly; drugs cause these areas to work way too much…correctly; drugs cause these areas to work way too much…

Brain MisconceptionsBrain MisconceptionsDrug Addiction (2)Drug Addiction (2)

Do drugs really hurt you long-term? Do drugs really hurt you long-term? Yes.Yes. Long-term overuse of the systems of reward through drugs: Long-term overuse of the systems of reward through drugs:

Strong addiction to the drugs.Strong addiction to the drugs.Leads to less sense of reward for other activities that are Leads to less sense of reward for other activities that are actually good for you so you stop doing them.actually good for you so you stop doing them.As cells die from overuse (or become As cells die from overuse (or become habituatedhabituated), you need ), you need more and more drugs to get the same high.more and more drugs to get the same high.Then when you are not doing drugs you feel worse than you Then when you are not doing drugs you feel worse than you did before you started.did before you started.

In other words:In other words: Drugs damage your brain more the longer and Drugs damage your brain more the longer and more you do them more you do them (much of which will never recover).(much of which will never recover).They They trick your brain into thinking life is great when you trick your brain into thinking life is great when you are on them and much worse when you are not (even are on them and much worse when you are not (even compared to before you started) compared to before you started) so they are harder to stop.so they are harder to stop.

NeuronNeuronssThese brain cells share most of the properties of These brain cells share most of the properties of

cells in every living organism.cells in every living organism.They have a They have a nucleusnucleus; and a ; and a membranemembrane through through which they exchange things with the blood.which they exchange things with the blood.They require They require nutrients and energynutrients and energy (from the (from the blood).blood).They must get rid of They must get rid of waste and heatwaste and heat (to the (to the blood).blood).They require They require timetime to perform any of their to perform any of their functions and also time to reset, so they can functions and also time to reset, so they can perform the function again.perform the function again.

Dendrites, Cell Body, AxonDendrites, Cell Body, AxonA neuron is made up of 3 parts (diagram in next slide): A neuron is made up of 3 parts (diagram in next slide):

The The dendritesdendrites (sometimes called a dendritic tree) get (sometimes called a dendritic tree) get the chemical inputs from other neuronsthe chemical inputs from other neurons

The The axonaxon is the output mechanism that sends messages is the output mechanism that sends messages to other neuronsto other neurons

The The cell bodycell body does all of the processing of the does all of the processing of the information received from the dendrite and information received from the dendrite and determines what message should be sent out through determines what message should be sent out through the axonthe axon

The connection between one cell (from an axon) and The connection between one cell (from an axon) and another (usually to a dendrite) is called a another (usually to a dendrite) is called a synapsesynapse

Neuron DiagramNeuron Diagram

Cell Body

Axon

Synapse

Dendrites

Similarities with Other CellsSimilarities with Other CellsThese brain cells share most of the properties of These brain cells share most of the properties of

the cells in every living organism.the cells in every living organism.They have a They have a nucleusnucleus; and a ; and a membranemembrane through through which they exchange things with the blood.which they exchange things with the blood.They require They require nutrients and energynutrients and energy (from the (from the blood).blood).They must get rid of They must get rid of waste and heatwaste and heat (to the (to the blood).blood).They require They require timetime to perform any of their to perform any of their functions and also time to reset, so they can functions and also time to reset, so they can perform the function again.perform the function again.

DifferencesDifferences

There are some differences however:There are some differences however:Neurons are extremely Neurons are extremely energy expensive cellsenergy expensive cells;;over a third (and sometimes more than a half) over a third (and sometimes more than a half) of all our energy goes to our brains.of all our energy goes to our brains.Because of this, neurons Because of this, neurons create a lot of heatcreate a lot of heat. . Neurons require Neurons require special chemical nutrientsspecial chemical nutrients (most cells just need glucose, water,…).(most cells just need glucose, water,…).Neurons Neurons communicate communicate with other cells (most with other cells (most cells do not).cells do not).