Brain Basics S

8/11/2019 Brain Basics S

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Brain Basics

Facts and Misconceptions

Perception and RealityThings Are Not Always

As They Seem...


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Brain Basics

Overview

Brain Facts Discussion and Questions

General Facts

Parts of the BrainFunctions

Brain Misconceptions Discussion

Properties of Neurons Discussion


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Brain Facts

The adult human brain is about 4 to 5 pounds. A babysbrain weighs about 1.5 pounds.

However, a babys body weighs about 15-30 timessmaller than an adults body. So a babys brain is 6

times bigger compared to its body weight!!!(that is why babies have huge heads compared to their

bodies)

Human brain has over 100 billion! neurons(a type ofbrain cell); thats about 20 times the total number ofpeople in the world.

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


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Brain Lobes

The Cerebral Cortex(wrinkledoutside part of the brain) isarbitrarily divided into 4lobesbased upon the things

that scientists think they doThe occipital lobeprocesses

the visual information fromyour eyes

The frontal lobemakes high-

level decisions, plansmovements, coordinatesspeech, and has a large rolein determining personalityand morality (Phineas Gage)


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Brain Lobes

Theparietal lobeprocessesyou sense of touch,

processes your conceptof spatial relationships

(where things are)

The temporal lobehelpsidentify things (what

things are), helps youremember things, andprocesses sounds(hearing)


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Other Brain Parts

The Cerebellumhas asmany neurons as theentire cerebral cortex!

Its main role it to

coordinate movementsor brain activities (makesure their timing isright)

The Brainstemcontrolsthe body processes thatyou dont have to thinkabout (like your heart

beat)


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Brain Misconceptions

10%

Do people only use 10% of their brain?

No.

Different parts of your brain do differentthings. So not all of your brain needs to bedoing something all of the time. However,using modern technology we have shown

almost every area of the brain active duringsome task.

For many hard tasks, a large percentage ofyour brain may be active at one time.


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Wrinkles

Why are there wrinkles in the brain? Do more wrinkles

appear when you learn something new?

No.

Your cerebral cortex is essentially a flat sheet (like alarge sheet of paper) that it has to fit in your skull

(which is like a cup) A crumpled up sheet of paper

fits in a cup easier than an unfolded one.

Most scientists think that new learning is changed

connections between neurons (brain cells; similar to

different wiring in a computer).


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Gender and Brain Size

Do boys have bigger brains and are they smarter thangirls or the opposite?

(1) Men on average actually do have larger brainsthan women (just like they have bigger bodies on

average). But, elephants have much bigger brainsthan humans (4 times as heavy) and cats are about 45times smaller.

(2) A bigger brain does not mean you are smarter.

Men and women have the same intelligence level onaverage (although there is some evidence that eachmay be slightly better at specific tasks). Two peoplewith the biggest and one of the smallest brains everfound both belong to professional writers!


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Computers (1)

Is the brain like the CPU of a computer?

Not really.

Computers are made of metal and use electricity to

process information. Brains are made of organic cellsand use a mix of electrical signals and chemicals to

process information.

If one part of a computer breaks it can do almostnothing. If one part of your brain gets damaged only

certain things are hard to do and it can sometimes

gradually repair itself.


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Computers (2)

Are humans smarter than computers or computerssmarter than people?

Neither, they work in different ways.

Computers are currently allprogrammed to do aspecific task by peoplewho give them specificinstructions about how to do it. Computers are muchfaster at doing many of these things.

Currently, computers are not able to do things they

are not specifically told how to do. This is changingas people figure out ways to make computers learn todo new tasks on their own.

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


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Drug Addiction (1)

If you are careful you wont get addicted to drugs, right?

Examples of addictive Drugsall types of Cocaine (crack);Heroin; Opium; Ecstasy;

Mostly affect the parts of your brain that process reward

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

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

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


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Drug Addiction (2)Do drugs really hurt you long-term?

Yes.Long-term overuse of the systems of reward through drugs:

Strong addiction to the drugs.

Leads to less sense of reward for other activities that are

actually good for you so you stop doing them.As cells die from overuse (or become habituated), you needmore and more drugs to get the same high.

Then when you are not doing drugs you feel worse than youdid before you started.

In other words:Drugs damage your brain more the longer andmore you do them (much of which will never recover).

They trick your brain into thinking life is great when youare on them and much worse when you are not (evencompared to before you started) so they are harder to stop.


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Neuron s

These brain cells share most of the properties ofcells in every living organism.

They have a nucleus; and a membranethroughwhich they exchange things with the blood.

They require nutrients and energy(from theblood).

They must get rid of waste and heat(to the

blood).

They require timeto perform any of theirfunctions and also time to reset, so they can

perform the function again.


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Dendrites, Cell Body, Axon

A neuron is made up of 3 parts (diagram in next slide):The dendrites(sometimes called a dendritic tree) get

the chemical inputs from other neurons

The axonis the output mechanism that sends messages

to other neurons

The cell bodydoes all of the processing of the

information received from the dendrite and

determines what message should be sent out throughthe axon

The connection between one cell (from an axon) and

another (usually to a dendrite) is called a synapse


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Neuron Diagram

Cell Body

Axon

Synapse

Dendrites


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Similarities with Other Cells

These brain cells share most of the properties ofthe cells in every living organism.

They have a nucleus; and a membranethroughwhich they exchange things with the blood.

They require nutrients and energy(from theblood).

They must get rid of waste and heat(to the

blood).They require timeto perform any of theirfunctions and also time to reset, so they can

perform the function again.


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Differences

There are some differences however:

Neurons are extremely energy expensive cells;

over a third (and sometimes more than a half)of all our energy goes to our brains.

Because of this, neurons create a lot of heat.

Neurons require special chemical nutrients

(most cells just need glucose, water,).Neurons communicate with other cells (mostcells do not).

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