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Psych 3010 Mind, Brain and Behaviour
...


In our own environment the difference between top and
bottom has been significant, you can’t mistake the
bottom of a tree for the top
...


While there is a large pressure in the environment to be
symmetrical,

the

human

species

is

atypically

asymmetrical in its behavior
...


Definitions
...


The brain
...


The 2 sides are virtually identical in structure
...


The 2 sides do not operate in isolation; it is rather a joint
effort between the 2 sides of the brain
...


The corpus colossum can be dissected into 3 sections the
Geno the trunk and the splenium
...
e
...


The trunk connects the parietal lobes and is responsible
for somata senses such as touch
...


The corpus colossum has an inhibiting and excitory
functionality but it mainly is used as an inhibitory
instrument
...

Marsupials, notably kangaroos do not have a corpus
colossum;

instead

they

have

an

enlarged

anterior

commissure and people who are a-colossal; those who
are born congenitally without a corpus colossum also
have an enlarged anterior commissure
...


or

behavior

that

they

lack

a

corpus

There is the massur intermediar which connects the left
and right thalamus; though some people lack this
connectivity
...


How The Senses Connect To The 2 Sides Of The
Brain
...


It is not as simple as closing one eye and then you have
only one side of the brain working with one eye
...


The Retina
...


The temporal hemi retina connects to the ipsilateral side
(The same side) of the brain
...


Whereas the nasal hemi retina cross over when they
meet at the optic chiasm they decussate; meaning they

cross over to the other side of the brain
...


The Auditory pathways
...
Most of the
sensory data flows to the contralateral side of the brain,
using the inferior colliculus
...


The Somata Senses (touch)
...

There is the spina-thalamic, which is often involved with
temperature and pain
...
When this hits the central nervous system,
it then ascends and crosses over to the other side; to the
contra lateral side
...


The dorsal commons or the lyniscal system is concerned
with fine touch and vibration and is used most of the
time for writing and fine movements
...


The Motor pathways
...
These are characterized by very
long axons coming from the brain and following right
down to connect to a particular muscle
...


There are two systems involved
...
So for
instance the right side of the brain controls the left hand
and left foot and vice versa
...
It is
bilaterally organized
...


Lecture 2
...

And the Evolution of Laterality and Language
...


Even more so, behavior is difficult to ascertain as
prehistoric hominids are no longer living
...


This can be done through analogy, looking at primitive
tribes that are in existence in modern day, such as
certain tribes in New Guinea who are stone-age in their
development
...


Another way would be to get someone to try and make
the tool that has been found and making inferences from
that
...


The consensus view is that 13 to 18 million years ago we
broke away from apes we have Australopithecus who is a
pre-hominid, then homo habilus, homo erectus and then
Homo sapiens
...

They existed between 2 and 4 million years ago
...
They were broken down into 2 subspecies
Australopithecus

Africanis

and

Australopithecus

robustus
...
Africanis also did not have the
skull crest that a chimpanzee and robustus had
...
This meant that Africanis was
chewing finer foods while Robustus was still chewing a
coarser diet, so more plant materials that required
extensive chewing
...
e
...
This is mainly concerned with pelvis development
which then enabled us to develop the use of our hands
more

and

the

development

of

our

brains
...


With Australopithecus Africanis the idiom is twisted and
flattened, forming what we consider today to be a
homosapien hip bone
...


The neck of the femur in Africanis had also become
longer, as it does with Homo sapiens today
...


Finally the foot in Africanis changed
...
This was all determined by footprints
discovered by Mary Leaky in Tanzania where footprints
left by Australopithecus were discovered 6 million years
ago
...
The patalia are particular
bones in the skull which stand out more than others and
look like petals of sorts
...


Holloway compared the patalia of Australopithecus,
Homo

erectus,

homosapien

and

chimpanzees
...


This

showed

that

Australopithecus

was

developing

brain

asymmetry

comparable to humans
...


There has been an article published in Nature in 2015
showing that Australopithecus actually did use tools
...


Australopithecus made a deliberate attempt to make a
more sophisticated tool by flaking off parts of a stone
...


Brain size is measured relative to body size, thus coming
up with an accurate measure
...


Homo Habilus
...
They developed around
2
...


Using Endocasts, Holloway has indicated that Broca’s
area or at least the area corresponding to Broca’s area in
Homo sapiens was enlarged in Homo Habilus
...


In homo habilus there is the first evidence of a dramatic
increase in relative brain size
...


There

is

even

been

suggested

evidence

of

right-

handedness when it comes to the tools discovered
...
The
cortex or the outer part of the chip is always on the right
hand side, indicating the stone being chipped was being
held with the left hand and the tool shaping stone was
being used by a right-handed hominid
...


Homo erectus
...
Again they are taller than homo habilus and
less robust than our ape predecessors
...
There is also evidence that Homo erectus was
living together in larger social groups and that the social
environment was more complex
...


This group hunting is important as the group hunting
also meant more meat in the diet more often, which then
gives sufficient calories for more brain development
...
As the brain of the hominid grew larger,
there was also a need for a female pelvis to enlarge to
allow passage for a child to be born
...
Compared to chimpanzees, a
human’s brain size is dramatically smaller at birth in
comparison
...
This then meant that specialization had to
occur as well as the grouping together socially in order to

provide a stable environment where the infants and
children were brought up in
...

Developed from 800 thousand years ago to present day
...
Once more they are taller than
their predecessors and they are less robust
...


The tools that Homo sapiens now produce are now
complex and are becoming more complex as time passes
...
There are also
now ritualized burial procedures taking place up to 60
thousand years ago
...
Using striations
on the teeth of Homo sapiens researchers are able to
draw conclusions that they were using their right hands
to cut the meat as they held it between their teeth
...


It is argued that homo habilus could not speak due to
the position of the larynx as it was too high; being as
high as modern-day gorillas and thus not able to have
the range of sounds that modern-day Homo sapiens can
produce
...


This also shows how ontogeny often mimics phylogeny
...
It also seems that a lot of times primate
speech is not under volitional control whereas it is in
Homo sapiens
...
The areas where the
production of language for sign-language and for verbally
speaking is quite similar and there is a large amount of
overlap
...
For example speech is attention
getting, you do not need eye contact for speech and it
also allows for more effective teaching
...

We have a type of neuron called mirror neurons in our
frontal lobes and in position f5 which is homologous as
Broca’s area in humans but in the right side of the brain
...


This is key to communication because a person needs to
be able to code someone else’s words in terms of words
that they themselves would produce
...


The theory is then that in homo habilus and Homo
erectus is that gesture and vocalization were combined
and then to make it more efficient both gesture with the
right hand and speech were combined on one side, that
being the left side as most people are right handed
...


Mike Nichols published an article in psychological
science looking to see whether there was lateralization or
asymmetry

in

the

way

the

mouth

was

used

to

communicate
...


Nichols was able to show that observing the right side of
the mouth was more important when observing the
McGurk illusion than the left, showing that handedness
even in the mouth is important
...


There is another theory posited by Crowe in Oxford
...


It is also Crowe’s belief that there is no precedent of left
hemisphere language dominance and dextrality; that it
just suddenly emerged at the late stage of Homo sapiens
development and that is what gave us dextrality and left
hemisphere language dominance
...


To prove his theory, Fulk points to studies done which
shows

that

some

primates

have

left

hemisphere

dominance for communication, primitive as it may be;

although the vocalizations that are used may or may not
point to language
...


Development within the Individual
...


The brains evolution is interesting to look at individually
or ontologically
...


Then as we develop further, the forebrain increases in
size dramatically relative to the other parts of the brain
...


The size of the brain not only increases in size in-utero
but also develops much more after birth; hence the
reason for birth before total maturity as the size of the
head would be much too large for an upright pelvis to be
able to allow passing
...


Males actually take slightly longer to grow than females
...

Certain parts of the brain myelinate first compared to
others
...
The higher
order areas; areas associated with association and areas
associated with the production of language as well as
personality, complex spatial functions as well as the
temporal lobes associated with memory
...


Another area that grows a lot with development is the
corpus colossum
...

The fact that the corpus colossum is a relatively later
developing organ, adds to the argument that laterality
develops with age as it is responsible for transferring
information between the two hemispheres of the brain
...
She suffered no illeffects to her language skills and has only minimal
problems in using her right-hand side
...


Elizabeth looked at children who suffered a unilateral
lesion as well as children who had no such damage and
compared them to adults with either a unilateral lesion
or were normal
...
It was found that the children
with lesions made slightly more errors compared to the
children

without

lesions;

however,

there

was

no

difference between children who had left-sided lesions or
children who had right-sided lesions
...
This
indicates that when it comes to adults, damage to the left

side of the brain will severely impact their language
capabilities
...
They
will, however throughout their lives show some deficits
...

One theory is that lateralisation does not occur at birth,
but is a process that occurs later in life; essentially a
child is a blank slate at birth and functionality and
lateralisation are laid down as the child matures
...
This also coincides with the period for
attainment of language; if you had not attained language
skills by this time period, it would be much more difficult
to attain them
...


Research looking into when laterality occurs
...


They are Anatomical asymmetry’s, thumb sucking, facial
expressions, EEG and di-cotic listening
...


Ryder conducted a study into anatomical asymmetries
...


Generally what is found is that the left side of the
temporal plenum is enlarged when compared to the right
temporal plenum
...
This is probably due to
Werneky’s area being housed in this area
...


In the 100 infants the temporal plenum on the left-hand
side was 67% larger than the right temporal plenum
...


With the adults studied, they showed almost exactly the
same pattern
...


This shows that one of the structures that are important
for lateralisation is evident in infant’s in-utero, giving
strength to Ryder’s theory
...


A study performed by Hepper looked at ultrasounds
taken

at

different

gestational

periods
...

Hepper observed 274 cases where he studied an infant
sucking their thumb
...


It also doesn’t matter how the infant was sitting in the
womb, but irrespective of which way they were sitting,
infants were predominantly sucking their right thumb
...


Hepper then asked does this affect subsequent hand
performance
...


He used the Edenborough handedness inventory
...
10 out of 16, 66% ended
up being left handed
...

Hepper then went on further to theorise that it was this
early motor development, sucking your thumb, that then
leads to which hand you prefer to use
...


A paper published by hallowaka and Pettito

What they did was to video tape infants between 5 and
12 months of age
...


They then had someone who was blind to the aims of the
experiment to code the children for larger mouth
opening, left or right or no asymmetry in mouth opening
...
The reason for this
prediction is that the left side of the brain which is
dominant for language controls the right side of the
mouth
...
This is
because the right side of the brain, which is responsible
most for emotion, controls the left side of the face
...
The prediction for babbling was also predicted
correctly as shown by the majority of the cases seen in
the images
...


EEG Scans
...


It has excellent temporal resolution, so as time passes it
is very accurate to the changes inside the brain
...


We can identify lobes of activity, but not exact spots
...
Finally, it is
completely safe to the infants who are being measured
...
This is where you present a stimulus to an
individual

one

hundred

times,

measure

the

wave

produced by the brain’s response to that stimulus and
you can then measure the average response
...


The wave then produced is very meaningful and very
predictable
...
They were 6 months of
age, 10 children who are 6 years old and 10 adults
...
So there are mechanical sounds like a clock

ticking or it could be white noise
...
There was also Speech sounds, such as Ba
and Da which would expected to be a left hemisphere
bias developed and finally, there were words, which
would be expected to be processed in the left hemisphere
...


For the words, the wave made in the left side of the brain
for infants, children and adults are larger than in the
right
...


So it appears that the left hemisphere is more specialised
for these speech syllables than the right
...


For the mechanical sounds, the larger wave is in the
right-side of the hemisphere, indicating specialisation for
these types of noises in the right hemisphere
...


Dichotic Listening
...
Participants are then asked to
say which sound they heard
...

This is therefore known as the direct access model
...
Consequently it
would then be easier to give the sound presented to the
right ear than the left
...


Enters then conducted an experiment with infants where
he reinforced behaviour by producing interesting noises
...
This is similar to a rat
pressing a bar for food or a pigeon pecking to receive
food, it is the food-getting instinct
...


With this experiment, each ear was at first producing a
word sound, and then it would change at different
intervals for each ear
...
When music was played the dishabituation occurred
far more quickly in the right ear, showing a clear
disassociation
...

A study by Amanda wood looking at FMRI scans
...


There is however, no linear pattern, showing a clear
progression from childhood to adulthood and the link to
laterality
...


There was a second study conducted by Holland in
2001
...
They found that the same basic
areas were activated irrespective of age
...


Conclusions
...
However there are problems

with testing different groups, particularly the young as
they often more than not get side-tracked and create
random data
...


Laterality and individual differences
...

Areas like naturopathy, people who target worried
parents who think their children are right-sided for
language, and even financial interests are getting into the
science

of

differences
...


A perfect example of this is that while these pseudoscience areas have their theories, they do not test these
theories in an effort to debunk them-Karl Popper came
up with this idea
...


There

are

positive

and

negative

individual differences in lateralisation
...


Claire Porrick and Stanley corrin first put forward there
being a difference in mortality rates
...


They simply plotted those who are right handed in a
percentage on a graph
...


However this hypothesis has issues
...


Ken Hugdale looked at the modification hypothesis as it
was known, He actually showed that as age increased
and the number of left handers decreased the number
who actually switched hands increased
...


There is some evidence for this as left handed people are
more likely to have accidents where limbs are broken and
also may have more fatal accidents as well
...


Dyslexia can be defined as a specific reading disability;
this being despite normal achievement levels in other
areas of academic endeavour
...
The first
was that they possessed a number of characteristics
...


He also claimed that dyslexics were able to mirror write
...


He

therefore

came

up

with

the

idea

of

strathosymbolia; meaning twisted symbols
...


He believed that sinistral had a developmental delay and
specifically

they

failed

to

have

a

left

hemisphere

dominance developed for language
...
This then would mean that
dyslexics would have problems with supressing the right
side and would explain most symptoms discussed
already
...
Both visual systems
process symbols upside down and mirror reversed
...


approximately one third of dyslexics are sinistral but the
other two thirds are dextral
...


However it is hard for individuals to tell the difference
between left and right, so it is not necessarily a problem
only with dyslexics
...
Using 2
groups consisting of 23 dyslexics and 23 controls with at
least 1 sinistral in each group
...

The functional was the discotic listening experiment and
structural is a MRI measuring the temporal plenum
...


However they did find that the dyslexics had a smaller
left temporal plenum, which is where Werneky’s area is
located
...
Once again,
there was no real difference between the dyslexics and
the control group
...


Whereas for the controls there does not appear to be a
relationship
...


There are Problems with this study though as the
dyslexics have smaller brains overall so the comparison
may not be valid
...


Stuttering is defined as speech that is not fluent, due
either to verbal or non-verbal repetitions of syllables
...


A study by jones used sodium barbital to essentially
anaesthetise part of the brain in order to identify which
part of the brain was their language centre
...


They also found that when one side of the brain was
anaesthetised that stuttering ceased
...
He also asked does
delayed auditory feedback actually improve stutterers
...


MRI scans were conducted in order to measure the left
and right temporal plenum
...


The people were separated into three different conditions;
either no feedback, non-delayed feedback or finally
delayed feedback
...


With the feedback conditions, the control group was low,
which was to be expected, however their stuttering does
increase with the no feedback and the delayed feedback
conditions
...


It was noticed that the people with the right plenum
asymmetry who stuttered, generally stuttered worse than
those with the normal asymmetry
...


The theory proposed has a 2 loop auditory output model
...


The outer loop is where a person listens to themselves
...


The other loop is an internal loops and this feeds through
internal pathways
...

These two systems are usually aligned with each other in
normal-speaking people
...


They propose that with the people with the right
temporal plenum asymmetry, something has happened
to make the two systems come out of alignment
...
It is suggested that

there is some kind of damage in the temporal cortex and
this then causes the slowing down in the outer loop of
feedback
...


Schizophrenia is defined as a mental disorder defined by
delusional thoughts, hallucinations and inappropriate
effects
...


It does have environmental triggers and some say it is a
sane response to an insane world
...


There is generally increased ventricular volume in
sufferers
...


There

is

also

decreased

cortical

thickness

in

schizophrenia sufferers, but it is targeting, specifically in
the temporal lobe and in the frontal lobe
...


The amygdala is also affected, which is also important for
emotional expression and finally the hippocampus which
is particularly important for memory
...


Dragovich and Hammond proposed to ask through a
meta-analysis of other studies, whether there was a
higher percentage of schizophrenics who are mixed
handed or is there a higher preference for sinistrality?

In the meta-analysis, it showed that there were more
sinistral in the schizophrenia group than the control
group
...


A study by Nichols looking at schizotypy

Schizotypy is where a person may attribute causal
factors and outside events as having a special meaning
and does this somehow relate to handedness?

Barnett and corbilis found that handedness in it did not
have a relationship
...


It was found that schizotypy was related to absolute
handed and eye preference
...


Positive outcomes of laterality
...


They found around 10% was sinistral in first year and
that number increased to 16 percent in the later years of
the class
...


They went onto do a further study and found that a
higher proportion of sinistral were likely to graduate
compared to dextral
...


A subsequent study by wood and angleton found that
roughly 10% were left handed which is the norm
...


Intellectual ability and handedness
...


Nichols found in general that sinistral have reduced
cognitive ability
...


Lecture 7
Circadian rhythms
...


Every measure that you can measure has a 24 hour
rhythm
...


This can help with the treatment of cancer as normal cell
division is at its fastest at night and slows down during
the first part of the day and during the day time
...


There is a period of time in mid-afternoon which there is
usually a dip it is known as the post lunch dip where
arousal levels drop, meaning a slower reaction time
...


However not all behaviour is at its maximum when core
body temperature is greatest
...


They are maximal at late at night
...
More births and deaths occur early in the morning
...


This was done by keeping an individual inside a
laboratory in a bed-rest condition with lights always on
...


The conclusion made from this is that most circadian
rhythms are indigenous, meaning they are internally
created and maintained?

Research by drew dawson
...
The impairment was so bad, particularly
in the early morning; it was the equivalent to being
drunk
...


He also measured the same people under certain levels of
blood alcohol in the middle of the day as a comparison
...


What drives these changes though? Are there physical
precursors we follow? Is it behavioural?

Or is it being driven by an indigenous clock?

It actually has been shown it is probably all 3
...
It is
located in the hypo thalamus in the brain
...
The SCN also takes
account of what is in the blood, so when we eat, what we
consume
...


An experiment with squirrel monkeys
...


There was a group whose SCN had been lesioned
...


Generally it was found the SCN was operating in an
experiment conducted in people
...


Melatonin is secreted by the pineal gland; it is not
secreted during the day but begins being secreted during
the evening and reaches maxima while we are asleep
...


This location is bracketed by a location in either side in
which it is extremely difficult to fall asleep
...


While there is usually a normal distribution of people
who fall asleep the outliers have been studied
...
Then there are
evening types who steadily rise throughout the day,
peaking a few hours before midnight and then only
starting getting tired just before they sleep
...
5 hours compared
to the morning types
...
Maximal sleepiness
for morning types tends to be middle of the night while
evening types is just before they wake up
...


The problem then for evening types is that their whole
circadian rhythm is delayed by 3 hours, delaying the
wakeful time by 3 hours, so they tend to be sleepy first
thing in the morning
...


This may be why the Monday blues occur
...
When they have to
then wake up early on a Monday morning this will then
wake them during the deep sleep phase of their circadian
rhythm causing the Monday blues
...


There are also extreme morning types who wake up quite
early and therefore have to then go to sleep much earlier
in the evening
...


Circadian Rhythm mistiming and treatments
...


Sleep onset insomnia may be due to this mistiming
...
5 hours to fall asleep
...


Delayed sleep wake phase disorder is a more severe type
of sleep onset insomnia
...


Jet lag can also have this sort of effect
...


Season Affective disorder
...


The best treatment for this type of disorder is morning
bright light
...
a
...


Delayed sleep/wake phase disorder is the most common
sleep phase disorder
...


This is particularly prevalent in adolescence and usually
shows up as the individual having problems getting to
school on time
...


The question is though why they are stuck being delayed
when most people can adjust to new times
...


The average person does have a slower SCN than 24
hours, usually by about ten minutes
...
5
hours
...

It showed in this experiment that most people do delay
...
4 hours, compared to the average which was 24
...


As this was only a pilot study, it does suggest that the
tale is quite different between the normal average sleeper
and those with DSPD
...

In this study they actually found they had 4 people who
are free running delays
...

They found that average sleepers have a delay of 24
...
23 hours
...
6 hours
...


There are ways to re-set the body clock though
...


Presentation of bright light before core body temperature
minimum has been found to delay the body clock
...

This effectively means that people with DSPD can be
treated with bright light therapy
...
This was then used to treat people and test whether
their body clock has changed through the application of
the light
...
For those with early
DSPD, they would need to be presented in the evening to
delay their sleep phase
...


However the treatment of melatonin is different you need
to administer the melatonin almost 12 hours before the
expected time to sleep
...


Lecture 9

After finding that the use of broad spectrum light was
effective, further research was conducted to see which
colours in particular were the most effective, as led lights
come in specific colours
...


This then led the development of the bright light retimers
...


There is not much evidence that it actually helps with
sleep, although it will make you drowsy if you take it
during the day
...

Melatonin has been shown for instance to help with
jetlag
...


Normal Sleep Patterns
...


This Study was stimulated by the discovery that there
were 2 major states of sleep
...


And 2 was non rapid eye movement sleep or non rem
sleep
...


Rem sleep is known as paradoxical sleep
...

There are different ways to physiologically measure the
stages of sleep
...


Brainwaves actually change during the night as you
enter into different stages of sleep
...
The measurements are taken from the side of the
eyes on the temples as there is a different charge on the
front compared to the back
...


The last measuring tool is the mg or the electromyogram
which measures movement in muscles
...


Awake
...
This means you are subjectively aware of it
and are able to respond to cues in the environment
...


During this time a person will naturally produce alpha
waves that are picked up by the EEG
...


This is an indication that the person is in stage 1 sleep,
light sleep
...

At this point memory consolidation stops
...


It actually does stop 1 to 2 minutes before stage 1 sleep
is achieved
...

Beta waves are a higher frequency about 20 hz
...


A

person

will

then

move

onto

stage

2

sleep
...

They are commonly 12 to 15 Hz
...

A person will then move into stage 3 then stage 4 sleep
and this is characterised by delta waves which are a very
slow frequency but high amplitude
...

When a person reaches 50% delta waves that is then
classified as stage 4
...

This is an indication that the brain is no longer
processing or doing any work
...


The EEG

activity is that of stage 1 sleep as if the person

was alert and awake
...


The EMG also shows a further drop off in activity
All of the major muscles are actively inhibited during rem
sleep
...

This is known as a dream
...


Lecture 10

Rem sleep and non rem sleep were discovered in the
1950’s
...
This
may be evolutionary and as a group people who have 90

minute cycles there would always be one person who is
aware so that the group as a whole was safe
...


Rem sleep uses the sympathetic nervous system while
non rem sleep uses the parasympathetic system
...

Sleep apnea is likely to occur at sleep onset
...

Sleep walking can usually take place during non rem
sleep as the muscles are not restricted then
...

Blood flow is actually higher in rem sleep than in quiet
wakefulness
...
However, if they are concentrating on
what they are going to do in the day, then the memory of
the dream may be swamped by what the person is paying
attention to
...

Sleep tends to get lighter with age and the number of
awakenings increase
...


There is no standardised definition for what a nap is in
the literature
...


A more up to date definition is a sleep that is less than
50% of a person’s normal nocturnal sleep
...

It begins in infancy and persists for most into adulthood
...

This was undergraduate psychology students
...

A worldwide survey by Dinges found that the country
with the least amount of napping is England and this is
the country furthest from the equator
...

They are referred to as siesta cultures
...


This is also coinciding with the post-lunch dip in the
circadian rhythm that is common in most people
...

Recuperative or recovery napping

There is prophylactic napping, taken in anticipation of
sleep deprivation
...


Sleepiness is measured using the Epworth sleepiness
scale
...


There is not only decreased alertness but also decreased
cognitive functioning
...


However napping has been shown to have a great effect
in reducing excessive day time sleepiness
...

Therefore naps need to be long enough to affect this
homeostatic process and reduce sleepiness
...

Sleep inertia or Process w; this is where we feel sleepy or
groggy just after waking from sleep
...


Therefore the sleep needs to be long enough to affect
process s but not long enough to have too much slow
wave sleep, affecting sleep inertia or process w
...

This is a process that affects our levels of alertness
throughout the day
...


There are four factors that if achieved make the nap the
most beneficial for an individual
...


Short term naps are best for tasks being performed
immediately after
...


The circadian placement of the nap is also important
...


However a nap taken during the lowest core body
temperature has the least recuperative ability
...


The further from our prior wake time, the less beneficial
the nap is likely to be and the longer the nap is required
to be in order to be beneficial
...

Whether an individual is familiar with taking naps or not
and whether these gains they more benefit
...

Napping has also been used as a treatment for some
sleep disorders
...


Lecture 12Adolescent sleep
Adolescence is seen as a time of change and a time of
firsts, so therefore it is a time with new experiences
...


Mary carscade did a sleep study in 1980 and linked pupil
changes to daytime sleepiness
...


There was a 40% decrease in slow wave deep sleep over
adolescence
...

The united states national sleep council recommended
between 8 and 10 hours sleep but also recognise that
there will be individual differences
...
In later years though
there is no plateau effect for process is showing that they
then have the ability to stay up a lot later
...


The problem with a lot of these results is the individuals
are screened so much that it may not generalise to the
outside world
...

Social networking and technology has different effects on
sleep and is highly dependent on the individual
...

However it is not so much the amount of sleep missed as
much as daytime sleepiness that causes this
...

The more sleep deprivation suicidal ideation can occur
...

DSPD d prevalence is around 7-16%

Lecture 13
...


Selective

breeding

is

where

humans

have

taken

advantage of a certain genetic phenotype, particularly in
agriculture and animal husbandry
...


Galton was the first person to use Darwinian principles
in psychology
...


The study e looked at success in men and decided that
success was heritable
...


Many people considered this genetic determinism and
credited Galton as the first eugenicist
...


Sparta was essentially a culture led by eugenics
...


Goddard was the first in the 1920’s to talk of eugenics
and genetic determinism
...


The rise of Nazi Germany and their use of eugenics to
create the holocaust DE popularised eugenics in Europe
...


This all relates back to the theory of a child being a
tabula rasa- a blank slate
...


This dominated psychology up until the late 1960’s
...


This then led to the David Rymer case where people
considered gender to be only environmental
...


Traditional genetic methods include studies such as twin
studies and adoption studies
...

Also looks at shared and unshared environment as
contributing factors for behaviour
...


It is hypothesised that there are 3 laws to behavioural
genetics:

All human traits are heritable
...


A substantial portion of this effect in complex behaviours
is not counted for by family or genetics, it is by the
unique environment
...


There are 20 pairs of autosomal chromosomes; meaning
non-sex related chromosomes
...


There are roughly 3 billion base pairs coding 20
thousand genes
...


Behaviour is somewhat more subjective as traits exist on
a continuum
...


Familiarity, traits that run through families; depression,
alcoholism as well as traits like personality
...


For example, the odds of someone getting a disorder or
disease because they have a 1st degree relative who has
the particular disorder compared to a person in a healthy
normal population
...


Relative risk is done using cohort studies, whereas odds
studies using people who have the disorder vs a control
group
...


Heritability

definition,

a

phenotype

being

entirely

explained by genetic variation
...


There is the general definition and the narrow definition
...


Heritability is population specific not individual specific
...


This is calculated through natural experiments such as
family studies with twins in natural parent’s homes
versus twins in adopted homes and twins vs non-twin
siblings
...


It is however taken for granted that the common
environment is identical for mono and di-zygotic twins,
which it is not as each twin experiences their reality
according to their own internal perceptions
...

Concordance rates are calculated by taking the difference
in rates between di-zygotic and mono-zygotic twins and
doubling it
...

Is pretty much the same as categorical?

The more genes that are involved in a certain effect the
smaller effect size there is
...
C
...


Little to no shared environment is seen in most traits
...


DNA comprises of 4 base sugar phosphate molecules
adenine, guanine, thiamine and cytosine
...

The DNA strand runs anti parallel, which forms the
double helix
...


A D
...
A strand is 5 microns in length but is super-coiled
...

Each chromosome has a centromere with a P arm which
is the shorter arm and a Q arm which is the longer arm
...


There are 2 laws that mendell proposed the law of
segregation and the law of independent assortment
...


of

The second law described how the 2 pairs are randomly
mixed with no particular bias
...

There are 20 thousand genes in the human chromosome
...

Genotype is the combination of alleles and the phenotype
is the expression of those alleles
...


A genetic mutation is a polymorphism or a variation
...


There are germ line mutations, which are mutations that
you inherit
...
These occur after fertilisation
...

Polymorphism has a more than 1%

frequency in the

population, while a variant has less than 1%

Denovo can be inherited while somatic cannot be
inherited
...
N
...
P
...


Silent types where there is no discernible change in the
phenotype
There is a miss-sense snip which does change amino
acids which can change expression
...


Repeats are where alleles repeat this can be twice or
more, depending on the number of alleles are repeated
and this differs from snips which is just 1 pair
...

Then there is a positional variant which is where a gene
sequence can be flipped or transplanted to another
segment of DNA
...

Snips are far more abundant than copy repeats
...

Ligase zips it back up
...

Transcription is done by using primers which then
attach onto the exposed DNA strand, building to form
amino acids and eventually proteins
...


The outcomes of this transcription are 3 different types
...

TRNA is essentially a transfer system and brings amino
acids to the MRNA
...
This is that
the thiamine becomes uracil
...


This is then sent to the rysomes where translation occurs
and proteins are then created through the production of
amino acids
...
There are 20
different amino acids and 64 combinations of the three
base codons, so multiple codons code for one amino acid
...


There are 2 parts to DNA, the exon and the intron
...


Splicing actually is the process which gets rid of the
intron part of DNA to form the mature MRNA
...


Epigenetics

is

the

study

in

the

change

of

gene

expression
...


Essentially it is changing how the DNA is expressed
through environment and other factors
...


They essentially bind to a complimentary section of
MRNA and ultimately cause gene silencing
...


Micro RNA fit into the complex disease model and
perhaps genetic pre disposition affects how microRNA
can bind to genes
...


It essentially switches a gene off
...


This means that a transcription segment cannot bind
and so the gene is essentially switched off
...


Hyper and hypo methylation has been associated with
multiple cancer and tumour cells
...


So essentially methylation can affect transcription to
RNA and microRNA can affect translation to proteins
...


Most psychiatric disorders are on a continuum and being
at either end can lead to risk of disease
...


the

This can also lead to understanding the mechanisms
behind the co-morbidity of physiological disorders and
psychiatric disorders
...


Genetic studies at the molecular level include linkage
studies of micro satellite markers; those repeating codes
within the genetic structure and look for co-segregation
within families and pedigrees
...


While not specific, it is powerful within the family design
...


Association studies are generally done with unrelated
people, although you are looking at specific markers in
specific loci within the genome and while resolution is
high, the coverage is generally very low
...


A common variant is essentially a variant that is common
in the population, above 5% and looking at the
commonality of these alleles in common diseases
...


If

a

particular

disease

is

common

among

family

members, then you are able to look at rarer variants, but
they have to have a large effect
...


are

two

With hypothesis driven studies we are generally talking
about candidate genes, so researchers already have an
idea of which gene it is they are looking for and its
prevalence
...


An example for a candidate study we have a candidate
gene we assume is being disrupted when a particular
disorder is prevalent
...


Another way is through linkage studies
...


This type of study successfully identified chromosome 19
through a linkage study as having a linkage peak when it
came to Alzheimer's disease, so this means that this area
was co-segregating with those suffering from Alzheimer's
disease
...


It was found that APO e4was a risk gene for Alzheimer's
...


It was found that apo e4 was far more common, within
14% of the population compared to apo e2

If you carry 1 apo e4 gene, then your risk was increased
4 fold, if you had both apo e4 genes then your risk is
increased 12 fold
...


So this is an example of a common variant affecting a
common disease
...


Studies for conditions outside of Alzheimer's disease
have been inconsistent, as areas located in linkage
studies have not always been the same although with
schizophrenia there were one or two regions that
persistently came to the fore
...


With linkage studies, it really depends on which family
you are looking at and with candidate studies there
wasn’t a large enough population to look at to identify
the genes
...


This looks at snips only and using an alga-rhythmic
program, imputes what should then be there normally
...


Another advantage is it has great coverage and those
which are not covered can be imputed
...


Currently schizophrenia has over 108loci of genes that
are affected which puts it up with other complex
physiological disorders
...


75% of the genes were actually protein coding genes and
many of the genes were candidates that had been looked
at individually before
...


However someone came up with a polygenic risk score
which looked at the genes that were at risk and then
looked at the predictive value of these genes in an
independent sample
...


There was a very high significance in a highly variable
gene called c4
...


It does this by depositing another protein called c3 into
the cell and the more active that c4 is, the more synapses
that are pruned
...


So the current hypothesis is that there is a runaway
synaptic pruning process occurring during adolescence
in schizophrenics
...


Bi polar disorder, which is somewhat related as it is also
a psychotic disorder that has not had as much funding
and research is still ongoing in sequencing and has not
had genomic wide sequencing and or international
cooperation between researchers
...
However this result has not yet been replica
table and may be due to an over estimation of
significance
...

There has been some success in linkage studies but this
is more likely due to reducing phenotypic heterogeneity
...


Missing heritability is essentially after all the genetic
testing that we are able to do we cannot count for the
amount of heritability that we see with psychiatric
illnesses with the genetic variance we have found thus
far
...


The first is the samples studied
...


Then there is phenotypic heterogeneity
...


So all of this reduces the power of the results
...

Perhaps as well it is the type of variant that is wrong,
perhaps it is not snips
...


It could also epistasis or a gene-gene reaction that could
be affecting things
...


And then there is epigenetics
...


The gap between twin heritability and molecular studies
is what is known as the missing heritability
...


This can be problematic as one group, the cinical
population, is categorical, whereas the population group
is a continuous variable
...


There is also whether the depression is comorbid, i
...

because of a medical condition such as fibro myalgia
...


A Chinese study on depression that sequences common
variations but kept to strict phenotyping of depression to
recurrent

depression,

and

specifically

melancholic

depression
...


This means you have to be careful with stratification of
people within your study
...


Within the Chinese study they found genome wide
significant hits for genes that affect the condition
...


However

these

particular

sequences

had

more

significance within the Chinese population compared to
the PGC population, it was something like 30% to 10%
...


This is now known as the fourth law of behavioural
genetics
...


Rare variance vs common variance
...


people

that

are

causing

these

common

This is now particularly being looked at in schizophrenia
...


This was however only looking at exonic sequences; there
may be more intragenic information which may have
causal properties
...


People also started looking at the copy number variables
to see whether these may contribute
...

This is also missing the microsatellites that exist within
the genome which could add to the amount of heritability
not seen in depression studies
...

Environment also has an effect on heritability above and
beyond what environment does to affect a disorder
...


An example of the repeater gene hypothesis is the
serotonin enzyme transporter gene
...


There has been recent meta-analysis showing that
childhood trauma and medical disorders both show
significance when it comes to the serotonin transporter
enzyme
...

With epigenetics, not only can your genetics affect your
epigenetics but the environment can also affect the
epigenetics, when then affects your genetic expression
...


Epigenetics, Psychology and the environment
...


Epigenetics is the altered expression of genetics without
altering the sequence
...


DNA methylation occurs when a methyl enzyme attaches
to an RNA strand
...


It is always the cg sites that are methylated, attaching to
cytosine
...


This is critical for self-differentiation and for embryonic
development
...

So epigenetic marks could become biomarkers and
targets for treatment in the future for psychological
disorders
...


40% of mental health disorders have an early childhood
stress component
...


The HPA axis is critical to your stress response system
...


Also neurotransmitters and CRHR receptors have been
looked at as a hypothesised pathway for depression
...


Meanie and weaver found that rats that had attentive
mothers

had

reduced

glucocorticoid

methylation,

promoting gene expression
...
This
actually followed the rats into adulthood as well
...

This then had the effect of decreasing the glucocorticoid
methylation and this then followed the pups into
adulthood
...

They found there methylation of the GC receptors in
suicide victims who had suffered child abuse was
increased

This was also found to be in children who had suffered
stressful environments as babies
...


The serotonin transporter gene has also been studied in
this regard and has a fairly or bust relationship with
methylation being associated with childhood stress
events
...


This is a protein which is very important in the hpa axis
...


Further this methylation has also been associated with
trauma associated changes in the brain
...


Genome wide studies have shown reduced methylation of
the r6 promotor and so expression of this gene
...


Epigenetic changes in DNA methylation associated
with schizophrenia
...


The GC receptor is a candidate once more that shows up
for schizophrenia

There are a lot of changes but how they change things
and how it all works is not yet clear
...


One has to have had a look at genetics, epigenetics and
the environment to have a really clear picture
...


MicroRNA changes
...


A limitation of studying microRNA is that the only
samples able to be worked on come from blood cells and
not brain cells
...


There is evidence that trauma and stress do affect
microRNA expression
...


MicroRNA has already been found to be significant in
schizophrenia
...


Mer1202 has been associated with reaction time to
antidepressants
...


There may also be microRNA based therapeutics that
may be developed in the future
...

It has been found in recent mouse studies that
researchers were able to wipe out a learned behaviour by
removing methylation of a particular part of the genes

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