Transcript The Biological Bases of Behaviour

The Biological
Bases of
Behaviour
How does our BRAIN work??
Brain facts
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 BBC
History of the Brain
 UCLA1
 UCLA 2
 UCLA 3
 UCLA 4
 UCLA 5
 Brain Surgery 8:00
 Brain surgery 2
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Ways of studying the
brain
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1. Studying patients with brain damage can
link loss of structure with loss of function.
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A. Phineas Gage was the level-headed, calm
foreman of a railroad crew (1848) until an
explosion hurled a spike through his head.
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After the injury destroyed major parts of his
prefrontal lobes, Gage became extremely
volatile and violent.
Studying people who suffered gunshot wounds,
tumors, strokes, Alzheimer’s disease and so on
has enabled further mapping of the brain.
Sarah Video
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 2.
Producing lesions (damaging the
structure through medical procedures) at
specific brain sites enabled systematic
study of loss of function.
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This is mostly done on animals although it
can also happen when doctors have to
remove brain tumours from humans.
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3. Microscopic Examination of neural tissue by
scientists led to the understanding of the neuron as
the basic unit of structure and function of the
nervous system.
4.Direct electrical stimulation of the brain provides
another way to test the functions of certain brain
areas.
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
Wilder Penfield (1952) used an electrode to
localize the origin of seizures in patients.
Stimulating different areas caused movement for
different body parts, enabling mapping of the
brain.
Wilder Penfield
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 5.
An EEG (electroencephalogram) maps
regions of the brain
 produced when electrodes positioned in
direct contact with the scalp transmit
signals about the brain’s electrical activity
(“brain waves”) to an
electroencephalograph machine.
 http://www.youtube.com/watch?v=8Q57
q_kQPQY
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 6.
Imaging techniques in widespread use
provide images of brain anatomy.
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A. CAT scan (also called CT)—
computerized axial tomography
B. MRI—magnetic resonance imaging, the
most accurate method of studying what is
happening in the brain when we think or
experience emotions .
Inside the teenage brain.
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Brain Trivia
 Number
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 http://www.nature.com/neurosci/index.ht
ml
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The Neuron—Unit of Structure
and Function of the Nervous
System
The neuron is the basic cell of the nervous system.
There are many types of neurons, each performing
different functions, but they are structured similarly.
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 The
neuron, or nerve cell, sends and
receives signals that affect many aspects
of behavior and motor control.
 Neurons are individual cells in the nervous
system that receive, integrate and
transmit information.
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 http://science.nbcnews.com/_news/2013
/02/28/17123686-two-rats-thousands-ofmiles-apart-cooperate-telepathically-viabrain-implant?lite=&ocid=ansmsnbc11
 http://www.nature.com/nature/journal/v4
79/n7372/pdf/nature10489.pdf
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 Three
major structures in the neuron
enable the cell to communicate with
other cells.
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Soma
Dendrites
Axons
 https://www.youtube.com/watch?v=FR4S
1BqdFG4
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1. The cell body (or soma) contains cytoplasm
and the nucleus, which includes the
chromosomes.
2. Extending outward from the soma are
dendrites (Greek=little trees), the
receiving/input branches of the neuron.
3. The axon emerges from the soma as a long
thin fiber that transmits signals away from the
soma to other neurons, muscles or glands.
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The axon ends in a cluster of terminal buttons
that secrete chemicals called neurotransmitters
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http://www.massinformation.org/wp-content/uploads/2010/10/Neuron
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Outside the neuron
 Glia
are cells found throughout the
nervous system that help the neurons.
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They supply nourishment,
remove waste products and
provide insulation around the axons
 Glial
cells may play an important role in
memory formation
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The Neural Impulse
 The
neurons use energy to send
information.
 When a neuron is stimulated, an electrical
signal or neural impulse, moves through
the neuron.
 The neuron at rest is like a tiny battery with
a negative charge of about -70 millivolts.
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 Anytime
a neuron’s charge changes an
action potential is created.
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The action potential is a very brief shift in a
neuron’s charge that travels along an axon.
 The
neural impulse is an all or nothing
proposition, like firing a gun.
 Neural impulses move up to 100m/second
or 300 km/hr.
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The Synapse
 Neurons
do not actually touch
 The neural message travel across these
gaps by the release of neurotransmitters.
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These are chemicals that transmit
information from one neuron to another.
 The
closest point between the neurons t is
called a synapse.
 https://www.youtube.com/watch?v=LT3V
KAr4roo&list=PL480008A7A1FAE820
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http://fromyourdoctor.com/ext/neural_synapse.gif
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Neural networks: Integrating
the signals
 One
neuron can get signals from 1000s of
other neurons and pass its own message
along to 1000s more.
 A neuron therefore has to do more than
just pass the messages along, it must
integrate the signals that arrive at its
synapses before it “decides” whether to
fire a neural impulse.
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 It
takes millions of neurons firing together
to even have your eyelid twitch when you
are asleep, let alone produce a thought.
 There are about 100 billion neurons in the
human brain.
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Neurotransmitters and
Behaviour
 Remember
the nervous system relies on
neurotransmitters to communicate
information between neurons.
 These play a key role in everything from
muscles movement to moods and mental
health.
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There are 9 well-established, classic
transmitters and about 40 other additional
bio-chemicals that can act part-time as
neurotransmitters.
The most important transmitters are
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Acetylcholine
Monoamines ( Dopamine. Norepinephrine
,serotonin)
GABA and Glutamates
Endorphins
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Has effects on
Monoamines Pleasure
emotions,
sleep, eating,
agression
Acetylcholine Attention,
arousal,
memory,
skeletal muscles
GABA and
Learning and
Glutamates
memory,
anxiety
Endorphins
Pain relief
(Runner’s High),
pleasure
Neurotransmitter
Is affected by
Cocaine,
amphetamines,
Prozac
Nicotine
Valium
Opiate drugs: Heroin,
Morphine, Oxycontin
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http://static.sfdict.com/img/neuron-180866-400-320.jpg
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The Nervous System
 This
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is divided into two parts:
The peripheral nervous system
The central nervous system
 https://www.youtube.com/watch?v=xRkP
Nwqm0mM&list=PL480008A7A1FAE820
 Crash course
 Make me Genius
 School House Rock
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http://www.exploringnature.org/graphics/anatomy/nervous_system_diagra
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The Peripheral Nervous System
 This
is made up of all of the nerves that lie
outside the brain and spinal cord.
 Nerves are bundles of axons that are
routed together in the peripheral nervous
system
 These together control a person’s
voluntary and involuntary muscle
movements.
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http://www.indiana.edu/~p1013447/dictionary/perinerv.htm
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The central nervous system
 This
is made up of the brain and spinal
cord.
 The spinal cord connects the brain to the
rest of the body through the peripheral
nervous system and is really an extension
of the brain.
 It runs from the base of the brain to just
below the waist.
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http://health.allrefer.com/pictures-images/central-nervous-system-
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The Brain
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“the brain is the part of the central nervous system
that fills the upper portion of the skull”
It weighs about 1.5 kg but contains billions of
interacting cells that
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integrate information from inside and outside the
body
co-ordinate the body’s actions
enable us to talk, think, remember, plan, create
and dream.
http://www.youtube.com/watch?v=9UukcdU258A
https://www.youtube.com/watch?v=LT3VKAr4roo
&list=PL480008A7A1FAE820
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http://www.brainhealthandpuzzles.com/images/labeled_di
agram_human_brain_sagittal.jpg
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The Brain and Behaviour
 The
brain can be divided into three major
regions:
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The hindbrain
The midbrain
The forebrain
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http://facultypages.morris.umn.edu/~ratliffj/images/brain_slides/slide_5.h
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The Hindbrain
 Includes
the cerebellum, the medulla and
the pons
 The medulla attaches to the spinal cord
and is in charge of unconscious but vital
functions such as
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Circulating blood
Breathing
Reflexes such as sneezing and coughing
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 The
pons or bridge connects the
brainstem to the cerebellum
 It is involved with sleep and arousal
 The cerebellum (Little brain) co-ordinates
movement and balance and fine motor
skills.
 It is one of the parts of the brain first
affected by alcohol.
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The Mid-brain
 This
section of the brain is concerned with
integrating sensory process such as vision
and hearing.
 It is also involved in the perception of
pain.
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http://facultypages.morris.umn.edu/~ratliffj/images/brain_slides/slide_6.
htm
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The Forebrain
 This
the largest and most complex region
of the brain.
 It includes:
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the thalamus
The hypothalmus
The limbic system
The cerebrum and cerebral cortex
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 The
thalamus is the structure in the
forebrain through which all sensory
information (except smell) must pass
through to get to the cerebral cortex.
 It helps to put together the information we
gather from our senses.
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The hypothalmus is involved in controlling
basic biological needs.
These include the “four Fs”
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Fighting
Fleeing
Feeding and…
Mating ;-)
When researchers damage the hypothalmus
in animals, they must be fed intravenously or
they will starve.
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 The
limbic system is involved in the
regulation of memory, emotion and
motivation.
 It appears to be linked to an optimistic
attitude towards life.
 It is one of the areas that is rich in
emotional pleasure centers and maybe
most affected by cocaine and
amphetamines.
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The cerebrum is the largest and most complex
part of the human brain.
It is involved in learning, remembering,
thinking and consciousness.
It is divided into two halves or hemispheres
that are connected by the corpus callosum
The cerebrum is in charge of taking in all of
the information from the rest of the nervous
system and making it make sense.
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Right Brain/Left Brain
 The
left hemisphere is the one that
processes language/ verbal information
more quickly
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This means that it tends to be better at
language, speech, reading and writing
 The
right hemisphere is faster on visual
spatial tasks
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It is better at musical, spatial and visual
recognition tasks and the perception of
other people’s emotions.
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http://www.wirandha.com/right-brain-left-brain-function-make-kids-smart.h
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The Plasticity of the Brain
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This term refers to the brain’s ability to change
structure and function over time.
Violinists’ brains enlarge in the area that control
the left hand since that is the one that fingers the
strings.
Blind people’s the visual processing areas begin to
help with verbal processing
Scientists have also recently discovered that even
the adult brain can create new neurons and
therefore change.
http://www.youtube.com/watch?v=2MKNsI5CWo
U
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The Endochrine System
 Another
way the brain communicates
with the rest of the body is by the
endochrine system/hormones.
 Hormones are like neurotransmitters: they
are stored in the body and are released
as chemical messengers in the
BLOODSTREAM
 VENN DIAGRAM
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http://uploa
d.wikimedia.
org/wikipedi
a/commons
/c/c6/Illu_en
docrine_syst
em.jpg
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Most of the endocrine system is controlled by
the hypothalmus and the pituitary gland.
The adrenal hormones control our behaviour
in times of stress, fear (fight or flight response)
Testosterone is connected to aggression,
dominance, sexual behaviour and spatial
abilities.
Hormones are also connected to sexual
development and identity.
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Heredity and Behaviour
 One
of the oldest and newest topics in
psychology is question of how much of a
person’s behaviour is controlled by
genetics.
 Nature vs Nurture
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 Every
human cell (except eggs and
sperm) contain 46 chromosomes
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These operate as 23 pairs in which one
chromosome came from the mother and
one from the father.
 Each
chromosome is made up of 1000s of
genes that contain our DNA.
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http://ghr.nlm.nih.gov/handbo
ok/illustrations/normalkaryotyp
e.jpg
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http://www.somethingofthatilk.
com/comics/177.jpg
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You are a combination of each of your
parent’s 23 chromosomes that can be
scrambled in over 8 million different ways.
When the sperm and egg unite the
chromosomes can combine in roughly 70
trillion possible combinations.
This does not included any mutations that
might occur as well.
This is why every human on earth (except
identical twins) is unique.
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http://delsold.nas.edu/plant_genome/im
ages/DNA.jpg
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 Your
genes control all of your natural
physical and many of your psychological
characteristics
 It appears that most of these are affected
by an extremely complex inheritance
from your parents .
 Hereditary influences in humans are
studied by three methods: family studies,
twin studies and adoption studies
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Family Studies
 This
is a method by which researchers
assess the influence of heredity by
examining blood relatives to see how
much they resemble one another on a
specific trait.
 If heredity affects the trait then
researchers should find that the more
closely people are related the more
similar the trait is.
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 Schizophenia
affects 1% of the population
in general but
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9% of the siblings of schizophrenia patients
show schizophrenic tendencies
4% of cousins, nieces or nephews
2% of second cousins
 Family
studies can indicate whether a trait
runs in families but does not prove that it
does.
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Twin studies
 Researchers
compare the resemblance
of identical and fraternal twins with
respect to a specific trait.
 Since identical twins are clones whereas
fraternal twins are just like any other
siblings genetically but share more
environmental conditions than convential
siblings in terms of home life, birth order,
school years etc.
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http://www.scienceaid.co.uk/p
sychology/approaches/images
/twins.png
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 Twin
studies show that identical twins tend
to be more like each other than fraternal
twins in intelligence and personality which
suggest these can have a strong
hereditary component.
 However the fact that their intelligence
and personality are not exactly the same
shows the influence of the environment.
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Adoption studies
 These
assess hereditary influence by
examining the resemblance between
adopted children and both their
biological and adoptive parents .
 These are usually only done with people
who were adopted as infants before they
could experience many environmental
conditions .
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 If
the children resemble their biological
parents more than their adoptive parents
more on a given trait, researchers can
assume that it has a strong hereditary
component.
 If the children resemble their adoptive
parents more than their biological parents
more on a given trait, researchers can
assume that it has a strong environmental
component.
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Heredity and Environemnt
“
We inherit dispositions not destinies”
(Rose and Dick. 2002)
 Many researchers believe that we inherit
the tendency or vulnerability towards a
certain trait, but the environment often
determines whether the trait actually gets
activated or appears
 ALCOHOLISM
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Evolution and Behaviour
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Just as certain physical traits gave organisms a
competitive edge in their evolution, evolutionary
psychologist believe that some of our behaviours
are also the result of natural selection.
Among many animals the female requires
elaborate mating rituals before she allows the
male to mate with her.
This means that the male with the most
“attractive” dance will get to mate with the
female and pass his genetic material on.
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This means that his “dancing behaviour” is more likely
to be passed on as well.
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 http://science.discovery.com/top-
ten/2009/mating-ritual/mating-ritual.html
 http://www.wired.com/wiredscience/200
9/02/animalcourting/
 http://www.youtube.com/watch?v=DfOA
wpbDOhY