Biology/Psychology 2606

Dr. David Brodbeck

History and Origins of the Study of Brain and Behaviour

o The course is about the relationship between brain and behaviour

o This is a question that has involved many people, philosophers, physicians, psychologists and neuroscientists

o Once we define a couple of terms (notably ‘brain’ and ‘behaviour’) we can look at how these different groups of people have looked at the relationship

What is brain?

• Well you can kick it• Tissue• Organ• Is it just that wrinkly

thing in your head?– Technically yes

• However, you cannot do certain behaviours without say a spinal cord

Brain brain brain

• So, while the definition of brain really means just the thing in the head, we will have to concentrate not only on the brain itself but on the cerebellum, spinal column and indeed other parts of the nervous system if we want to relate the brain to behaviour.

• The ‘Mind-body’ problem

The Nervous system

• Central Nervous system (CNS)– Brain, spinal column, cerebellum– Communication is neural

• Peripheral Nervous system (PNS)– Nerves that make you move basically– Communication is neural

How does it work?

• Bicep curl for example• Muscle needs an agonist and an antagonist• Motor neuron sends message to bicep to curl

up• Sensory neuron tells you when to stop• Simple behaviour LOTS of neurons

In a Moth’s Ear….

• Moth Ear basically has two neurons A1 and A2

• They are not frequency sensitive, but do not respond to low frequencies

Those would be some tiny Q tips…..

Do Moths Have Ear Wax?

• A1 is responsive to intensity

• More firing with closer bat

• A2 only fires with very loud sounds

• A2 fires, bat must be very close

Moths and Bats, Charts and Graphs

• A1 on the left fires, that wing beats faster

• Moth’s course corrects to 180 degrees from bat

• So very and totally cool• A2, go crazy• 2 neuron ear can encode

where a predator in in 3 dimensional space!!!

Autonomic Nervous System• Different communication than in the CNS and PNS• Not neural, more chemical• Hormones secreted into bloodstream by ‘ductless

glands’• Pituitary gland is the master gland• Example, pituitary controls release of pitocin and

oxytocin which start labour• Another example, effects of testosterone on spatial

ability• psychoneuroendocrinology

Behaviour• And you thought our brain definition was

amorphous…• What is behaviour?• 1 : the manner of conducting oneself• 2 a : anything that an organism does involving action

and response to stimulation b : the response of an individual, group, or species to its environment —be·hav·ior·al or chiefly British be·hav·iour·al /-vy&-r&l/ adjective —be·hav·ior·al·ly or chiefly British be·hav·iour·al·ly /-r&-lE/ adverb

Hmmmmmmmmmm

• Action and response to stimuli eh– Stimuli, well, we tend to think of those as being

external things– But we can oh imagine pizza, and then have a

reaction….• An organism, so a plant can behave?• As a rule, dictionary definitions suck. • Behaviour is some observable reaction that

has no obvious substance

OK Mr. smart guy what does behaviour mean?

• That’s Dr. Smart Guy to you….• Action of an organism having cause and

function• So, in the moth example, the cause is the

sound, the function is evasion• This will include both learned behaviour and

inherited stuff• Not all behaviour has an obvious function

Some history

• First the earth cooled, then the dinosaurs ruled the world, then they died cuz of some big meteor, then the people showed up…

• Even early humans probably wondered about why we do what we do

• Then we started hanging around in towns

Aristotle

• Believed that the heart was the seat of behaviour

• He noted the importance of the brain (but it was for cooling blood he figured)

British Empiricists

• Thomas Hobbes (1588-1679)

• Contents of mind rest on experience

• John Locke (1632-1704)• ‘white paper’ or tabula

rasa

Rene Descartes

• Descartes said that we were machines with a soul

• The notion was that the mind and the body were separate

• Animals have no soul

And yadda yadda yadda….

• By the 19th century people were talking about psychology

• Still the philosophers held sway• Last half of the 19th century changed this• The zeitgeist of the time changed

What the hell does zeitgeist mean?

• I don’t speak freaky deaky Dutch Mr. Goldmember

• The spirit of history• The enlightenment of the 18th century was

affecting the common person• Science and technology could explain

everything

Gesundheit

• Even the origins of humanity could be explained without appealing to religion!

• Charles Darwin and the Origin of Species

• So like you could figure out anything with science!!

Natural Selection

• The Theory of Natural Selection is so simple that anyone can misunderstand it…. (Anonymous)

• Charles Darwin (1809-1882) saw three problems in need of a solution. – Darwin was not the only one to see these

problems BTW– Other ‘Naturalists’ were struggling with the same

issues

Problem the First

• There is change over time in the flora and fauna of the Earth– What we would commonly call ‘evolution’ today– The fossil record showed this to be pretty clear,

even to people in the mid 1800s– This was not controversial in Darwin’s time, and is

not now.

The Second Problem

• There is a taxonomic relationship among living things– People were big into classifying stuff– It was pretty obvious that there was a relationship

between different species• Different birds, different grasses, different cats etc

The Third Problem

• Adaptation– Different kinds of teeth for different animals, say

carnivore ripping teeth and herbivore grinding teeth

– Different tissues within species• Heart vs. eye etc.

The Solution!

• Natural Selection provides a mechanistic account of how these things occurred and shows how they are intimately related.

• It is one of those ‘oh man is that ever easy, why didn’t I think of that?’ type things.

How’s it work?

• There is competition among living things– More are born or hatched or whatever, than

survive and reproduce

• Reproduction occurs with variation– This variation is heritable– Remember, there was NO genetics back then,

Chuck knew, he just knew….– Realized that is wasn’t ‘blending’

How’s it Work?

• Selection Determines which individuals enter the adult breeding population– This selection is done by the environment– Those which are best suited reproduce– They pass these well suited characteristics on to

their young

How’s it Work?

• REPRODUCTION is the key, not merely survival

• If you survive to be 128 but have no kids, you are not doing as well as I am

• I have reproduced…• Assuming the traits that

made me successful will help them then I amore fit NOW than the 128 year old guy

This lecture keeps evolving…..

• Survival of the Fittest (which Chucky D NEVER said) means those who have the most offspring that reproduce

• So, the answer to the trilogy of problems is:• ‘Descent with modification from a common

ancestor, NOT random modification, but, modification shaped by natural selection’

So cause and function

• The causal part of the behaviour definition refers to the immediate cause, stimuli, that sort of thing

• Function is over evolutionary time usually• What does the behaviour accomplish• How does it increase fitness

Human evolution

• We split from the chimps about 5 million years ago

• For a long time we were basically not so hairy short apes

• What happened?• Diet change, maybe• Standing up was key• You have to pump blood up

Our Brains make us us

• If you get a heart so powerful that it can pump blood up, well you have lots of extra Oxygen and sugar you can use

• So get a bigger brain!• See we don’t have big teeth• We can’t run that fast (without steroids…)• But, we can outsmart our prey

Ok so….

• So you are saying that big brain means big smarts right?

• Sorta, encephalization quotient idea– Food storing vs non storing birds and Hp volume

• Within species?– Harder to tell