Biopsychology Flashcards
(120 cards)
1
Q
Areas of the brain
A
Motor cortex/frontal lobe Auditory cortex/ temporal lobe Brain stem Somatosensory cortex/ parietal lobe Visual cortex/ occipital lobe Cerebellum
2
Q
Motor cortex / frontal lobe
A
Involved in higher thought processing like abstract reasoning and memory
Also involved in voluntary motor processing / body movement
3
Q
Auditory cortex / temporal lobe
A
Involved in auditory processes
Dysfunction can result in hallucinations
Helps us understand language and speech
(LANGUAGE IS A LEFT HEMISPHERE ACTIVITY)
4
Q
Somatosensory cortex / parietal lobe
A
Processes sensations from the skin
Known as sensory processor
5
Q
Visual cortex / occipital lobe
A
Processes visual information
6
Q
Cerebellum
A
The little brain
Important for motor control
7
Q
Localisation
A
The theory that different areas of the brain are responsible for different behaviours, processes or activities
If an area of the brain gets damaged the function associated with that area will also be damaged
8
Q
Localisation V holistic theory
A
During 19th century Broca and Wernicke discovered localisation
Before this and before Phineas Gage scientists supported the holistic theory that all parts of the brain were involved in the processing of thought and action
9
Q
Phineas Gage
A
In 1848 25 year old Gage’s injury whilst working resulted in a metre length pole going through his left cheek, passing behind his left eye and coming out of the skull from the top of his head.
This took most of his frontal lobe away
He survived but turned from someone who was calm to quick tempered and rude
So the change in his temper following the accident suggests the frontal lobe may be responsible for regulating mood
10
Q
General rule on the hemispheres:
A
The activity on the left side of the body is controlled by right hemisphere
And activity on right side is caused by left hemisphere
The outer layers of both hemispheres is the grey cerebral cortex.
The cortex of both hemispheres is divided into 4 lobes
11
Q
The back of the frontal lobe
A
Contains motor area
Controls voluntary movement on opposite sides of the body
If it was damaged it would affect control of fine movements (also involved in reasoning and abstract thinking)
12
Q
Front of the parietal lobe
A
Contains somatosensory area
Processes sensory information like touch pain and temperature
13
Q
Back of the brain
A
Contains occipital lobe/ visual cortex
Interprets visual info
14
Q
Temporal lobe / auditory area
A
Helps us understand language and speech
15
Q
Broca and localisation
A
His theory was that part of the frontal lobe (lower part) was responsible for speech production. Damage to this area results in speech lacking fluency
Damage to Broca’s area causes Brocas asphasia = speech that is slow and lacking fluency
His case study = patient tan who was paralysed on right side and could only say one syllable
When Broca did an autopsy after his deaths he found a lesion on the left frontal lobe which was the cause behind his speech problems
when that area got damaged he lost that function for speech
16
Q
Wernicke’s area
A
Wernicke’s aphasia = the left frontal lobe being responsible for speech comprehension
So they had fluent speech but was meaningless
17
Q
Wernicke’s case study
A
His patient had a stroke
He could produce words fluently but they didn’t make sense like gibberish
He found that the patient had a lesion in the parietal, temporal and occipital lobes
18
Q
Strength of localisation
A
There’s evidence for it from brain scans
Petersen et al used brain scans to demonstrate how Broca’s area was active during a reading task
And how wernickes area was active during a listening task
19
Q
Strength of localisation pt 2
A
There’s neurosurgical evidence
Success of procedures in extreme cases like OCD suggests symptoms and behaviours associated with serious mental disorders are localised
20
Q
Strength of localisation pt 3
A
There’s case study evidence
Phineas gage, broca and wernicke
But evidence from brain damaged patients might be unreliable as they’re unique people that have had traumatising experiences
21
Q
Limitation of localisation
A
Lashleys research
Believes functions are holistic
Removed areas (10-50%) in rats and they had to navigate through a maze
After the removal their ability didn’t change
This suggests learning is complex and instead of localisation requires the whole brain
22
Q
Limitation of localisation pt 2
A
Plasticity
The brain adapts and changes in structures because of learning new experiences
The brain compensated for the loss of functions
Lashley said this is the law of equipotentiality where the surviving brain circuits chip in so the same neurological action can happen.
This doesn’t happen every time but we see this with stroke victims
23
Q
4 methods of studying the brain
A
FMRI (functional magnetic resonance imaging)
EEG (Electroence phalogram)
ERP (event related potential)
Post-mortem examination
24
Q
FMRI
A
Detects changes in blood flow and oxygenation that’s caused by activity in specific parts of the brain
The more active it is the more oxygen it consumes
25
Strengths of FMRI
It doesn’t rely on use of radiation
If done properly it’s risk free, non invasive and straightforward to use
It’s imaged have high spatial resolution which provides a clear picture on how brain activity is localised
26
Weaknesses of FMRI
Expensive
Can only get a clear image if the person stays completely still
Poor temporal resolution as there’s a 5 second time lag between firing of neuronal activity and image on screen
Can only measure blood flow on brain not activity of individual neuron
27
EEG (Electroencephalogram)
A skull cap is put on the person. It measures electrical activity in the brain through electrodes.
The scan recording shows brainwave patterns
It measures whole brain activity
Used for unusual patterns of activity like epilepsy
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Strengths of EEG
Detects random outbursts of activity in the brain, so helps diagnose epilepsy
Helps us understand the stages of sleep
Has extremely high temporal resolution. Can detect brain activity at a single millisecond
29
Weaknesses of EEG
Generalised info.
Poor spatial resolution.
The signal doesn’t pinpoint exactly where neural activity is from
30
ERP (Event related potentials)
General measure of brain activity
A skull cap is used and presented with a stimulus
Finds a statistical average
31
Strengths of ERP
Specific when measuring neural processes than EEG
Good temporal resolution so used to measure cognitive functions E.g the P300 is involved in allocation of attention resources and maintaining working memory
32
Weaknesses of ERP
Lack of standardised method between different research methods so hard to confirm findings
To get pure data can’t have background noise and extraneous material which is hard to do
33
Post mortem examination
Analysing the brain after their death E.g Phineas Gage
* don’t mention this when talking about scanning techniques because you can’t scan an inactive brain
34
Strengths of post mortem
Helped early understanding of certain processes in the brain
Broca + Wernicke used this before neuroimaging was possible
Help improve medical knowledge and generate more hypothesis to study further
35
Weaknesses of post mortem
Hard to know causation
Damage to brain could be because of trauma or decay or even during the process
Ethical issues
Might not be able to provide consent before death E.g HM couldn’t form memories but post mortem was conducted on him
36
Difference between spacial and temporal
Spacial shows which areas are active and where
Temporal is a time lag
37
Plasticity
The brains ability to adapt and change its structures because of learning new things and experiences
38
Functional recovery
Some abilities can be moved or redistributed rather than getting lost after trauma or damage to the brain
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Brain plasticity
The brain is ‘plastic’ changes throughout life
Infancy is when brain forms the most neural connections because infants are constantly experiencing new things
The amount of synaptic connections peaks at 15,000 age 2-3
That’s twice as much there is in the adult brain
40
Synaptic pruning
The frequently used connections get stronger
The connections rarely used are deleted
41
Research (Maguire’s black cabs)
In her study of London taxi drivers where they have to do a complex test assessing their knowledge of the city’s routes
She found they had more grey matter in their posterior hippocampus than those in the matched control group
The longer they had been in the job the more pronounced the structural difference was
So brain can form new connections at any point in life when needed
As the increased grey matter in the brain is due to the job
42
More studies:
Draganski
Mechelli
Draganski looked at medical students 3 months before and after final exams
They found changes due to learning in the posterior hippocampus and parietal cortex due to the exam
Mechelli found those who were bilingual had a bigger parietal cortex compared to matched monolingual control group
Supports localisation because specific areas grew
Also doesn’t support because if brain can create more connections, other areas can pick up functions too
43
Functional recover pt 2
Neuroscientists say function recovery can occur quickly after trauma but slow down after a few weeks/months
Then they might need rehabilitative therapy to help recovery
44
What happens in the brain whilst recovering?
Rewires itself by forming new synaptic connections near damaged area (like avoiding roadworks and finding a new route)
45
Unmasking
Activation of secondary neural pathways to carry out new functions
Help functioning to continue
46
Structural changes in the brain
Axonal sprouting = growth of new nerve endings that connect with undamaged nerve cells to form new neuronal pathways
Reformation of blood vessels
Recruitment of homologous (similar areas) on opposite side of brain to do specific tasks
E.g if Broca’s area was damaged on left side the right side equivalent would carry out the functions. After a bit of time functionality may shift back to left side
47
Study showing the recruitment of homologous areas work
Danellie (2013)
At 2 and a half years old had left hemisphere removed because of tumour
Lost linguistic ability as it’s in left hemisphere
Had intensive rehab, improved age 5
By 8 had no language issues
He got tested at 17 found right hemisphere compensated for loss but showed grammatical issues and slower at naming objects in pics
48
Sarah Scott (stroke victim)
Had stroke at 18 lost multiple functions like talking
After treatment she slowly got some functions back
Some functional therapy involves motor therapy and electrical stimulation of brain to help improve cognitive functions of those suffering from injuries
Plasticity led to these developments and helped support people with treatments
49
Strength of plasticity
Has practical applications, helped neuro rehabilitation
If we didn’t understand plasticity we wouldn’t be able to support people with treatment
Also brain can fix itself to a point we need further intervention for it to be successful
50
Limitation of plasticity
It can be maladaptive, not adjustive to environment
Prolonged drugs use can result in poorer cognitive functioning and an increase chance of dementia later
60-80% of amputees have known to have phantom limb syndrome
Can feel sensations that their limb is there, is painful a
51
Limitation of plasticity
| Bezzola
It reduced with age
it’s easier in childhood as they’re already adapting to new experiences
Bezzola showed how 40 hours of golf training changes neural movements in people aged 40-60
Fmri showed that they had reduced motor cornered activity compared to control group
Shows neural plasticity continues through lifespan
52
Limitation of plasticity
| Hubel + Wiesel
Early support for neuroplasticity and functional recovery came from unethical animal studies
Hubel + Wiesal sewed a kittens eye closed to analyse brains cortical responses
They found that it continues to process info from the open eye
and the area of the visual cortex associated with shit eye wasn’t as idle as they though
53
Limitation of plasticity
Concept of cognitive reserve
Suggests person educational attainment might influence how well the brain adapts after injury
Schneider found the more time brain injury patients had spent in education the better their chance was of disability free recovery
2/5 of patients studied that became disability free had 16+ years of education
Compared to 10% of patients who has less than 12 years of education
54
Lateralisation (split brain)
Two halves of the brain have different functions
| Certain behaviours/processes are controlled by one hemisphere
55
What does contralateral mean?
hemispheres control opposite sides of body
The right side processes info from left side of body E.g visual info from left eye
The left side of the body produces info from right half of body
56
What functions are lateralised to the left hemisphere?
Language
| More analytical
57
Which functions are lateralised to the right hemisphere?
Face recognition
Drawing ability
Spatial tasks
It’s more creative
58
Split brain study (Sperry)
Included patients that did an operation called corpus colostomy (tissues that connect both hemispheres were cut down)
To prevent seizures
Allowed sperry to see if hemispheres had specialised functions and performed tasks independently
59
Procedure of Sperry’s study
```
Quasi experiment (naturally occurring difference)
IG
IV = split brain patient or not
DV = performance on task
```
Small sample control group didn’t have epilepsy
60
Procedure of Sperry’s study pt 2
Image or word was shown to patients right eye and the same/different image was shown to the left eye
In the normal brain the corpus collosum would share info between hemispheres and give a complete picture of the work E.g key and ring
But with split brain patients they couldn’t share info between hemispheres
He studies 11 split brain patients and had a control group
61
Findings (Sperry’s study)
| Task: describing what they see
When a pic was shown to right eye the patient could describe it (language processes by left hemisphere)
But if shown to left eye they couldn’t describe what was seen or said there was nothing there
In the normal brain messages from right hemisphere would be sent to language centre in left hemisphere
62
Findings (Sperry)
| Task: recognition by touch
Shown object to one eye then had to pick object from behind a screen with the same side (shown to left eye pick with left hand)
Shown object to one eye and select it with other hand (shown to left eye pick with right hand)
Left hand can select it because it’s all done by right hemisphere
Right hand can’t select it as split brain can’t transfer info
63
Findings (Sperry)
| Task: drawing ability
Left hand can draw because it’s controlled by right side
64
Findings (Sperry)
| Task: composite words
E. key + ring
Can’t say key it’s on left side but could pick it up
Can say ring because right eye saw it
65
Findings (Sperry)
| Task: face recognition
Shown image (half woman half man) and have to say what they’ve seen
Shown image and have to select male or female
Face processing is on right hemisphere
Language is on left
If seen through left eye they can recognise face but can’t say
The right eye can’t process face so don’t see it
Would see the man through right eye so can say man because language is on left hemisphere
Would be able to select woman because if they see through left eye can pick with left hand
66
Strength of split brain research
Demonstrated lateralised brain functions
Sperry + Gazzaniga’s research helps us understand brain processes because we see left is more analytical and verbal tasks but right is more spatial tasks and music
67
Split brain research Strength
Used specialised and standardised procedures
He ensured only one hemisphere was receiving the info at a time. One eye had to fixate on the point and other eye was blindfolded
68
Limitation of split brain research
Theoretical basis about the communication between both hemispheres in everyday functioning
Pucetti suggested as the hemispheres are so different we have two minds so this situation is only more emphasised rather than creates in split brain patients
Other argue both hemispheres have an integrated system and both involved in everyday tasks
69
Limitation of split brain research
Issues with generalisation
Only 11 took part in all variations all who has history of epileptic seizures. This could cause unique change in the brain and influenced findings
Also some PP experiences more disconnection of both hemispheres as part of their surgical procedure than others
Sperry’s control group had 11 people that had no history of epilepsy
70
Limitation of split brain research
Differences in functions might be overstated and oversimplified
Modern neuroscientists say verbal and non verbal labels are more messier and less clear cut
In normal brain both hemispheres are in constant communication and when needed the other can perform the function. (Plasticity
71
Split brain GRAVE evaluation
Generalisable = no only 11 people
Replicable = yes he used a standardised procedure
Application =
Validity = yes his work is a solid body of scientific evidence
Ecological validity = no they use 2 eyes in real life. Task is artificial
72
Biological rhythms
Periodic activity governed by
Internal biological clocks (endogenous pacemakers)
External changes in the environment (exogenous zeitgebers)
Ultradian rhythms = occur many times during the day
Infradian Rhythms = take longer than a day to finish
Circannual rhythms = take much longer
73
How long do circadian rhythms last for?
24 hours
74
Examples of circadian rhythms
Sleep/wake cycle
| Core body temperature
75
Sleep/wake cycle (exogenous zeitgebers)
we feel drowsy at night time and alert during the day
| Shows effect of daylight on the cycle
76
Sleep/wake cycle ( endogenous pacemakers)
Free running = A biological clock without influence of external stimuli like light
The rhythm is governed by the suprachiasmaric nucleus (SCN)
It lies above the optic chiasm and receives info about light from this structure
The light (exogenous zietgeber) can reset the SCN
77
Siffre’s cave study
| Attempt to find out what happens to the free running SCN when not reset by exogenous zeitgebers
1962 = wasn’t exposed to natural light and sound in cave but had food and drink.
He resurfaced in mid September after two months. He thought it was mid August
1970s = similar but for 6 months
In each study his free running rhythm was just above 24 hours (around 25)
But he slept and woke up on regular schedule
78
Aschoff and Wever (1976)
Group of PP spent 4 weeks in a war bunker without natural light
Most had a circadian rhythm of 24-25 hours
One had sleep/wake cycle of 29 hours
79
Both studies show sleep/wake cycle is just longer than 24 hours
This is because our 24 day had exogenous zeitgebers like
Meal times
Daylight hours
80
Shouldn’t overestimate influence of environmental cues on internal biological clock
( Folkard)
Study had 12 people
Lived in dark cave for 3 weeks
Looked at clock and
Slept at 11:45pm, woke at 7:45am
The PP didn’t know researchers slowly sped up clock so 24 hour day only lasted 22
Only 1 PP comfortable adjusted to this
So if you have a strong free running circadian rhythm can’t easily be overridden by external environment
81
Core body temperature
Varies around 2•C during the day
Lowest at 4am 36•C
Peaks at 6pm 38•C
Body temperature might have an effect on our mental abilities
If we’re warmer, our cognitive performance is better
82
Core body temperature studies
Folkard = children who had stories read to them at 3pm had better recall and comprehension after 1 week compared to children who heard the story at 9am
Gupta = found better performance on IQ test when PP assessed at 7pm compared to 2pm / 9am
83
Teenage circadian rhythm
Their circadian rhythm starts 2 hours after adults
As school starts early they can’t focus properly because they still need sleep
And at bed time aren’t as tired
84
Teenage circadian rhythm
| pilot study
2010 high school in North Tyneside
Headteacher Dr Paul Kelley changed start of school day to 10am for 2 years
Had positive academic and health outcomes
Results went up
Less illness
Atmosphere changed and students were nicer
85
Strength of circadian rhythms
Practical application to night shift work
Boivin found shift workers have less concentration around 6am so likely to make mistakes and have accidents
Link between night shift and poor health
3 times more likely to develop heart disease
Sleep/wake cycle has economic implications when managing worker productivity
86
Strength of circadian rhythms pt 2
Practical application to drug treatments
Circadian rhythms coordinate processes like digestion and hormone levels
This has implications of how well drugs are absorbed/ distributed in the body
There are certain times during the day/night where drugs are more effective
Has real life medical benefits
87
Limitation of circadian rhythms
Use of case studies and small sample in research
```
Studies into sleep/wake cycle use small groups of PP (Aschoff + Wever) or
single individuals (Siffre)
```
Isn’t representative of wider population can’t make generalisations
Siffre found that his internal clock ticked more slowly at 60 compared to when he was younger
So even when same person is involved there are factors stopping general conclusions being made
88
Limitation of circadian rhythms pt 2
Poor control in research studies
PP that didn’t get natural light still had artificial light
(Siffre had a lamp on) but it’s assumed that artificial light doesn’t have an effect on free running rhythms
Czeisler adjusted PP circadian rhythms from 22-28 hours using dim lighting
Artificial light could be like taking a drug that resets PP biological clock
Researchers have ignored an important confounding variable
89
Limitation of circadian rhythms pt 3
Individual differences may have influenced results
Individual cycles can vary from 13/65 hours (Czeisler)
Duffy found some people have a natural preference for sleeping and waking up early (larks)
Some prefer opposite (owls)
Also age difference
Findings might not fully represent individual differences within population
90
Endogenous pacemakers + sleep/wake cycle
Suprachiasmatic nucleus SCN
Animal studies and SCN
Pineal gland and melatonin
91
Suprachiasmatic nucleus (SCN)
Tiny bundle of nerve cells in hypothalamus
Helps maintain circadian rhythms
Nerve fibres from the eye cross at the optic chiasm on the way to the visual cortex
SCN lies just above optic chiasm and gets info about light directly from the structure
Happens even when our eyes are closed so the biological clock can adjust to changing patterns of daylight when we’re asleep
92
Animal studies + SCN
| DeCoursey
Decoursey = destroyed SCN connections in 30 chipmunks
Then returned to their natural habitat for 80 days
Their sleep/wake cycle was gone and were killed by predators. As they were awake and vulnerable to attack when they should’ve been asleep
93
Animal studies + SCN
| Ralph et al
Bred mutant hamsters with 20 hour sleep/wake cycle
SCN cells were transplanted from foetal tissue of these hamsters Anna into brain of normal hamsters
Both studies emphasise role of SCN in having the sleep/wake cycle
94
Pineal gland + melatonin
SCN passes info to pineal gland this increases production of melatonin during night
The hormone Melatonin induced sleep. Suggested that it’s a factor in seasonal affective disorder
95
Limitation of endogenous pacemakers
The research into SCN May obscure other body clocks
Body clocks found in many organs and cells like liver and skin.
Highly influenced by SCN but can act independently
Damiola found changing mice’s feeding patterns could change their circadian rhythms of cells in the liver by 12 hours leaving SCN rhythm unaffected
Apart from master clock (SCN) their could be other complex influences on sleep/wake cycle
96
Limitation of endogenous pacemakers pt 2
Use of animals
Can’t generalise findings from animals because cognitive factors might be seen more in humans
Unethical as animals were exposed to harm when back in their natural habitat
97
Exogenous zeitgebers and the sleep/wake cycle
External factors in the environment
Entrainment = factors that reset our biological clocks
Without external cues the free running biological clock ticks in a cyclical pattern (Siffre cave study)
E.g light and social cues
98
Exogenous zeitgebers and light
Light can reset the body’s SCN
| Has an indirect influence on processes in the body like blood circulation
99
Light study Cambell + Murphy
15 PP
Woke them up at various times and shone a light on the back of their knees
Produced a deviation in the cycle of up to 3 hours
Light is a powerful external factor detected by skin receptor sites
Doesn’t rely on eyes to influence SCN
100
Exogenous zeitgebers + social cues
Most newborns have a random cycle but trained by 6 weeks
Because of schedules determined by adults like meal and bed times
Research shows adapting to local times for eating and sleeping trains the circadian rhythm and avoids jet lag
101
Limitation of exogenous zeitgebers
Their influence might be overstated
Miles argues that a man blind from birth had a circadian rhythm of 24.9 hours. He had to take sedatives at night and stimulants in morning to stay in line with 24 hour world
Studies of those that live in the artic (sun doesn’t set in summer months) shows that they have normal sleep patterns even though they’re exposed to light for a long time
102
Limitation of exogenous zeitgebers pt 2
Methodical issues in the research
Cambell + Murphys study hasn’t been replicated and criticised of a confounding variable that there could’ve been some light exposure to PP eyes
Isolating light doesn’t give us insight into other zeitgebers that influence the cycle
Some studies have ignored or underplayed the way different zeitgebers interact
103
Limitation of exogenous zeitgebers pt 3
It’s an interactionist system
Only in rare circumstances are endogenous pacemakers free run unaffected by exogenous zeitgebers
Total isolation periods (Siffres study) are rare and unrealistic on how the system works
Endogenous pacemakers and exogenous zeitgebers work together in real life so why separate them for research purposes
104
Infradian rhythms
Menstrual cycle
| Seasonal affective disorder
105
Menstrual cycle
28 days
For the ovary to develop and release an egg (ovulation) have rising levels of oestrogen
Progesterone helps womb lining thicken ready for pregnancy
If pregnancy doesn’t happen the egg is absorbed into the body and womb lining sheds
106
Exogenous zeitgebers can synchronise menstrual cycles
Stern + McClintock
Studies 29 women with irregular periods
Pheromones were taken at different stages of their cycles
By a cotton pad worn under their arms for 8 hours to make sure pheromones were picked up
The pads were cleaned with alcohol and rubbed on upper lips of other PP
68% women had changes to their cycle and brought them closer to the cycle of the odour donor
Shows how female pheromones influence synchronisation of menstrual cycles
107
Seasonal affective disorder (SAD)
It’s a depressive disorder with a seasonal pattern
Low mood, lack of activity
Can be called winter blues because symptoms triggered during winter months
It’s an Infradian rhythm called a circannual yearly cycle
Could be caused by melatonin
During night the pineal gland secretes melatonin until dawn when light increases
During winter lack of light means secretion is longer
Knock on effect of production of serotonin in brain
Low serotonin is linked to depressive symptoms
108
Strength of Infradian rhythms
Research on menstrual cycle shows evolutionary value
It would be better for female ancestors to menstruate together, get pregnant so offspring could be collectively raised. Increased chance of survival
BUT
Schank questioned validity of this too many females cycling together produced competition for highest quality male
So the avoidance of synchrony is the most adaptive strategy that’s now naturally selected
109
Limitation of Infradian rhythms
Methodology used in synchronisation studies
There’s many factors that change a woman’s cycle which is a confounding variable (stress, exercise)
Pattern of synchronisation could happen by chance
Also has small sample and relies on self reporting
So study lacks validity
110
Limitation of Infradian rhythms pt 2
Use of animals in research
Our knowledge comes from role of pheromones in animal sexual behaviours E.g sea urchins release pheromones into surrounding water. Other urchins in the colony eject their sex cells too
But evidence for effects of pheromones on human behaviour isn’t clear
111
Strength of Infradian rhythms pt 2
Research into SAD has practical applications like treatments 
One treatment is phototherapy which resets melatonin levels by a strong light in morning and evening
(Eastman) Relives symptoms by 60%
But the study did record a placebo effect of 30% using a sham negative ion generator
doubt about real value of phototherapy which might only be effective because of expectations
112
Ultradian rhythms
Stages of sleep
113
Stages of sleep
Sleep patterns are in 90 minute periods (more than one cycle in 24 hours)
Divided into 5 stages that have a different level of brainwave activity
Measured by EEG in sleep labs
114
Stage 1 and 2 of sleep
Light sleep
Easily woken up
Brainwaves get more slower and rhythmic
Alpha waves slow down as sleep gets deeper so theta waves
115
Stages 3 and 4 of sleep
Difficult to wake someone
Deep sleep or slow wave sleep
Delta waves which are slower and have more amplitude
116
Stage 5 of sleep
Rapid eye movement sleep (REM)
Fast jerky activity of eyes 
Body is paralysed but brain activity speeds up
Research suggests REM activity during sleep is correlated with dreaming
117
Dreams aren’t restricted to REM sleep
Hypnogogic sleep occurs during stages 1 and 2 after drifting off to sleep
We might experience being out of control or feel like we’re falling
We often wake up with a jolt (hypnic twitch) because we think we’re about to hit the ground
118
The basic rest-activity cycle (BRAC)
Evidence from EEG recordings show 90 minute cycle during sleep
Kleitman suggests the 90 minute rhythm carry’s on during waking hours
BRAC has a period of alertness followed by physiological fatigue
119
Evidence for basic rest activity cycle (BRAC)
The observation that students find it hard to concentrate for more than 90 minutes at a time
Just like most people need a coffee break to divide their working morning and afternoon
Ericsson found that with violinists that best performers practised for 3 sessions a day no longer than 90 minutes each
There was a break between each session to recharge
120
Strength of Ultradian rhythms
Evidence supports the idea of stages in sleep
A study by Dement + Kleitman monitored sleep patterns of 9 PP in sleep labs and found evidence for stages especially REM sleep
REM correlated with dreaming
Brain activity varied depending on how vivid the dream was
PP that woke up during dreaming could recall it
Suggests REM (dreaming) sleep is an important component of Ultradian sleep cycle
