Biopsychology

Fight or flight

- Threat detected by sensors (eyes) and passed to pituitary gland

- P.G releases adrenocorticotropic hormone (ACTH)

- ACTH detected by cells in the adrenal glands

- Adrenaline causes:

1. Increased heart rate to pump blood to vital organs

2. Stomach diverts blood to muscles to increase strength

3. Pupils dilate for imporved vision

4. Lungs increase breathing rate for more oxygen

- Parasympathetic response: after a few minutes, the parasympathetic branch of ANS is activated and body returns to normal by establishing homeostasis. Heart rate and respiritory rates decrease, adrenaline secretion slows, feeling of butterflies subsides and sweating stops

Endocrine system

Hypothalamus - Connected to pituitary gland and it stimulates/controls release of hormones from PG

Pituitary gland - Oxytocin, thyroid stimulating hormone (TSH), (ACTH) - 'Master gland'. TSH signals action in thyroid, ACTH signals action in adrenal glands

Thyroid gland - Thyroxine - Regulation of metabolism

Parathyroid gland - Parathyroid hormone - Increases concentration of calcium in blood

Pancreas - Insulin - Promotes absorption of glucose from blood into fat, liver and skeletal muscle cells. Insulin lowers blood sugar levels.

Adrenal glands - Adrenaline and noradrenaline - Reacting to threat via fight or flight response.

Pineal gland - Melatonin - Regulates sleep wake cycle.

Endocrine system continued (gender specific)

Ovaries - oestrogen and progesterone - development and regulation of female reproductive system and secondary sex characteristics

Testes - testosterone - development of male reproductive system and promoting secondary sex characteristics

Sensory neurons

Located in PNS, respond to stimulation in sensory receptors, send signals to CNS about this sensory experience. Most have long dendrites and short axons. Carry signals away from organ to brain/spinal cord (AFFERENT)

Motor neurons

In PNS, send messages from brain/spinal cord to glands/muscles. Usually have long axons/short dendrites. Help to produce movement/response (EFFERENT)

Relay neurons

Form connections between other neurons. Send signals to other relay neurons or form links between sensory/motor neurons. All neurons in CNS are relay (over 100 bil.) (INTERNEURON)

Excitation and inhibition

- Serotonin causes inhibition in receiving neuron meaning it is more negatively charged and less likely to fire.

- Acetylcholine has excitatory effect on post synaptic neuron by making it more positively charged and more likely to fire.

- Charge results in net effect on post synaptic neuron called summation. Membrane has to reach over a certain voltage to fire.

Synaptic transmission

- Electrical impulses passed through axon of a neuron to the synaptic terminal, causing depolarisation of presynaptic neuron. It can't go through the synaptic cleft.

- It causes calcium channels to open and positively charged calcium rushes into cell. Triggers vesicles containing neurotransmitters to move to membrane at axon terminal and release into synapse. Then diffuses across synapse.

- They then bind to receptors on post-synaptic neuron (DON'T ENTER). Triggers a singal in post synaptic neuron.

- Triggers a signal. Neurotransmitters can have an excitatory effect on neuron oo inhibitory effect

Neurons

- Nerve cells. Approx. 10 bil in nervous system

- 3 types: sensory, motor and relay. Typically consist of cell body, dendrites and an axon but each is unique

- Electrochemical messages/nerve impulses arrive at neuron through dendrites. Axon carries signal away from cell body (some have myelin sheath). When impulse reaches end of axon it is passed onto another neuron/gland/organ via axon terminals.

- Neurotransmitters are chemicals that pass from one neuron to another to pass the signal being transmitted

Automatic nervous system

- Sympathetic nervous system: activated in situations requiring arousal/energy. Prepares body for 'fight or flight' response and body's resources for immediate action. Produces higher heart and respiratory rates, increased blood flow to muscles and pupil dilation

- Parasympathetic nervous system: activated soon after threat of danger has passed. Allows body to return to homeostasis. Vital to conserve energy

Peripheral nervous system

- PNS consists of nerves outside brain/spinal cord. Divided into SNS and ANS

- Somatic nervous system: responsible for voluntary movement of skeletal muscles. Consists of nerves that carry messages to the eyes, ears, skeletal muscles. Transmits info between CNS and the senses.

- Automatic nervous system: controls involuntary movement. Transmits info from CNS to interal organs and from non-skeletal muscles

- SNS functions include posture/movement; ANS functions include secretion and control of metabolism

- SNS - invertabrates - included excitatory neurotransmitters

- ANS - invertebrates has both excitatory and inhibitory neurotransmitters

Central nervous system (CNS)

- Brain: outer layer (cerebral cortex) involved in higher cognitive, emotional, sensory and motor functions; brain divided into 2 symmetrical hemispheres: left (language, rational, analytical thinking and logic) and right (musical and artistic abilities) - further divided into 4 lobes: frontal lobe, parietal lobe, occipital lobe and temporal lobe

- Spinal cord: bundle of nerves which runs along a canal in the backbone. Sends nerve signals from brain to body and body to brain. Involved in reflex actions. Brain connected to it via brain stem

The Nervous System

- Divided into CNS and PNS

- CNS divided into brain and spinal cord

- PNS divided into automatic and somatic

- Automatic divided into sympathetic and parasympathetic

Localisation of function theory

- Motor area: region in the frontal lobe involved in regulating movement

- Somatosensroy area: area of the parietal lobe that processes info

- Visual area: part of the occipital lobe that receives and processes visual info

- Auditory area: located in temporal love and concerned with analysis of speech

- Broca's area: area of frontal lobe in left hemisphere responsible for speech production

- Wernnicke's area: area of temporal lobe (encircling auditory cortex) in left hemisphere responsible for language comprehension

Localised areas: motor and somatosensory

Motor area: situated at back of frontal lobe in both hemispheres, controls voluntary movement in opposite side of body. Dmage may result in loss of control over fine movements. Humunculus man represents amount of fine movements in certain body parts

Somatosensory: situated at front of parietal lobe. Sensory info from skin presented. Amount of somatosensory area devoted to a body part denotes its sensitivity. Humunculus man shows receptors in face/hands occupy over half of the somatosensory area.

Localised areas: visual and auditory

Visual: in occipital love at back of brain. Eye sends info from right visual field to left visual cortex and from left visual field to right visual cortex. Damage to left hemisphere for ex. cna cause blindness in right eye

Auditory: temporal lobe houses auditory area which has speech based info. Damage may produce partial hearing loss. Damage to Wernicke's area may affect ability to comprehend language.

Language centres

Broca's area: Paul Broca identified area responsible for speech production. Damage can cause Broca's Asphasia - characterised by slow speech lacking fluency. Not all words affected equally ex. nouns and verbs seem relatively fine but conjunctions can't be spoken. Used post mortem of 'Tan' (only word he could say) - showed extensive damage to left frontal lobe

Wernicke's area: Carl Wernicke found patients who had damage in area close to auditory cortex in left temporal lobe had specific language impairments including inability to comprehend language and struggle to locate the word they needed.

Localisation evalution point 1

Brain scan evidence

- Peterson et al used brian scans to show Wernicke's area active during listening task and Broca's during reading task

- In listening task pts have to understand what's being said whereas in reading task they're required to produce the words

- Findings support theory of localisation as they show evidence for specific areas of the brain having specific and different functions

Localisation EP 2

Neurosurgical evidence

- Dougherty et al reported on 44 OCD patients who had undergone a cingulotomy, a procedure that cuts the cingulate gyrus

- Findings showed 1/3 of patients' symptoms improved and further 14% showed partial improvement

- Success of these procedures strongly supports the symptoms and behaviours of mental disorders being localised

Localisation EP 3

Case study

- Clive Wearing had brain damage due to viral infection and damage to semantic long term memory but little to procedural

- This suggests localisation because if the function was spread throughout the entire brain then we would expect to see more global effects on his memory however a case study only provides evience not proof.

Localisation EP 4

Challenging research

- Lashley taught rats to solve a maze. This utilizes their frontal cortex. He removed 10-50% of areas of the cortex and observed whether they could still solve it

- No particular area was shown to be more important - they could still solve it when they had the lesions

- Suggests process of learning (especially spatial navigation) requires every part of the cortex. Suggests learning is too complex to be localised.

- However be cautious drawing conclusions due to animal study

Lateralisation

- Brain divided into 2 hemispheres

- Left controls language and is more logical

- Right is more creative

Sperry's procedure

- Devised a 'T-scope' to test hemispheric lateralisation

- Pts asked to focus on 'fixation point' and then image/word projected for 1/10th of a second to 1 or both visual fields

- To test for non-verbal processing it enabled pts to be able to pick up/match objects that were out of their sight

- In a 'normal' brain, the corpus callosum would immediately share info between both hemishperes but presenting image to one hemisphere of a split-brain patient meant info couldn't be conveyed

Sperry's findings

1) When image/word projected to right visual field patient could easily describe what had been shown. When shown to left visual field patient could not describe what had been shown.

2) Although they couldn't describe what was shown to L.V.F they could use left hand to point to matching object. R.H processed info and controls left hand but couldn't verbalise image

3) If 2 images shown together patient would say they never saw the one on the left but when asked to draw with left hand would draw the one on the right (pts unaware of this) thus seperate hemispheres and right hemisphere is creative

4) Object placed in pts' right hand could be easily described but when in left hand pts could only make wild guesses. When object taken and placed in bag with others they could retrieve it with left hand. Left hemisphere dominant for speech and writing.

Split brian research EP 1

- Experimental and uses specialised equipment that can objectively measure lateralisation of function in each hemisphere

- Allows image/word to be projected very quickly

- Split brain pts wouldn't have time to move eyes across the image so visual info only processed by 1 field - increased internal validity

Split brain research EP 2

- Standard procedures mean research can be checked for reliability

- Same procedure used on other split brain patients and found consistent results

Split brain research EP 3

Control group had no epileptic seizure history

- Should have used control of epileptic people who hadn't undergone SB procedure

Split brain research EP 4

- Small sample sizes make it hard to generalise findings

- Commissurotomy is a rare procedure meaning limited number of pts available thus small sample is unavoidable

Split brain research EP 5

- Artifical conditions

- In reality a severed corpus callum can be compensated for by unrestricted use of 2 eyes thus findings can't be generalised to SB patients in real life

Split brain research: usefulness and theoretical value

- Useful for demonstrating lateralisation of function. Led to improvement in understanding of hemispheres

- Prompted theoretical/philosophical debate about degree of communication between hemispheres. Some argue they are highly integrated and some that they are so functionally different they represent a form of 'duality'

- Modern neuroscientists suggests difference in function may be overstated and actual distinction is less clear. In a normal brain they are in constant communication and many tasks performed by one can be done by the other when required.

Plasticity

- Ability of the brain to be flexible and adapt to new situations

- Challenges localisation - suggests if a certain area is damaged others can take over their function

- During infancy brain experiences rapid growth in synaptic growth peaking at 15,000 age 2-3 (2x amount in adult brain) - as we age connections we don't use are lost (synaptic pruning)

Plasticity - Maguire

- Maguire et al studied London taxi drivers' brains and found greater volume of grey matter in posterior hippocampus than control

- Hippocampus associated with spatial and navigational skills

- Driver's need to take the 'knowledge test' (ability to recall names and locations of streets) - results show training alters brain

- Positive correlation between volume of grey matter and time on the job

Additional Plasticity Studies

- Kuhn et al found increase in grey matter in regions of brian after pts played video games (super mario 64) over 2 months for 30 mins a day (comp. to control) - experience can alter structure

- Draganski et al imaged brains of medical students 3 months before and after final exams. Learning induced changes occurred before and after final exams seen in posterior hippocampus and parietal cortex

- Mechelli et al found larger parietal cortex in brains of bilingual people compared to non-bilingual people

Functional recovery

- Brain able to recover from trauma from injury/illness

Unaffected areas often able to adapt and compensate for damaged ones

- Neuroscientists suggest this can originally be quick then slows

- Axonal sprouting: growth of new nerved endings which connect with undamaged nerved cells to form new neural pathways

- Reformation of blood vessels where blood flow increases to affected area

- Recruitment of homologous areas on other side of brain to take over specific tasks

Functional recovery case study

- Laura Danelli et al investigated EB, 17 year old Italian boy who had left hemisphere removed at 2 years old due to non-cancerous tumour

- By 5 years his language fluency improved due to intensive rehab and by 17 his lang appeared normal

- Suggests lang abilities can still function after severe trauma

Plasticity and functional recovery EP 1

- Understanding had contributed to field of neurorehabilitation (treatment of brain trauma)

- We know recovery slows down after a few weeks so we may need to start physical therapy soon

- Electrical stimulation of certain parts post stroke

- Suggests brain has ability to fix itself but intervention needed for full recovery

Plasticity and functional recovery EP 2

- Brain's ability to rewire not always positive

- Prolonged drug use has resulted in poorer cognitive function as well as increased risk of dementia later in life

- 60-80% of amputees develop phantom limb syndrome - thought to arise from cortical reorganisation in somatosensory cortex

Plasticity and functional recovery EP 3

- Functional recovery reduces with age - affects recovery speed

- Marquee et al found after brain trauma patients over 40 regained less function from treatment than younger ones - also more likely to decline function for 5 years post treatment

- Bezzola et al found 40 hours of golf training produced changes in neural rep of movement in pts aged 40-60. Via fMRI they found motor cortex activity was lower for novice golfers compared to control - higher efficient neural plasticity post training

- Supports view plasticity continues through life

- Evidence suggests women recover better as their function is not as lateralised

Plasticity and functional recovery EP 4

- Level of education attainment affects recovery

- Scheider found more time patients spent in education (aka cognitive reserve) the greater their chances of disability-free recovery

- Suggests cognitive reserve affects recovery

Functional Magnetic Resonance Imaging (fMRI)

- Detects changes in blood oxygenation and flow that results from neural activity in specific areas of brain

- Oxygen carried to brain by haemoglobin in red blood cells

- When as area becomes more active it requires more oxygen thus more haemoglobin present (haemodynamic response)

- Produces 3D images (activation maps) - shows involvement in activity

-fMRI machine creates strong magnetic field around pts head

- Measures these changes in oxygen levels in the blood

- Takes pictures of brain and shows which parts use most oxygen, indicating activity and compared to a baseline

fMRI strengths

- Doesn't rely on radiation - if administered correctly it is virtually risk-free, non-invasive and straightforward to use. As it is non-invasive there is no risk of infection or complication

- Produces images with very high spatial resolution, shows detail by milimeter, thus providing clear picture of how activity is localised. Can show which specific area is active during a specific task.

fMRI weaknesses

- Expensive compared to other neuroimaging techniques and can only capture an image if the person stays completely still. Due to price (around £1,200) many researchers only use small sample, impacting validity and generalisability

- Poor temporal resolution. Often shows activity 4-5 seconds after it occurred - could be misinterpreted

- Can only measure blood flow in brain, not exact activity of individual neurons, so it can be difficult to tell what kind of activity is being represented

Electroencephalogram (EEG)

- Measure electrical activity within brain via electrodes that are fixed to the scalp with a skull cap

- Scan recording represents brainwave patterns that are generated from action of millions of neurons, providing overall account of brain activity

- 4 main types of EEG waves are alpha, beta, theta and delta

- Brain activity can be measured by amplitude and frequency

- Often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities ex. epilepsy, tumours, sleep disorders

EEG strengths

- Valuable in helping diagnose conditions ex. epilepsy/schizophrenia as difference in brain activity can be detected on screen

- Contributed to our understanding of sleep stages and sleep problems

- Cheap - researchers can have larger samples, increasing validity and generalisability

- Extremely high temporal resolution - records brain activity in real time - can monitor responses to tasks

EEG weaknesses

- Represents brainwave patterns so cannot detect activity in deeper brain regions. Thus if issues were in hippocampus, EEG might not detect it

- Not useful in pinpointing exact source of neural activity, thus ahrd to work out area of brain the waves originate from

Event-related potentials (ERPs)

- Similar equipment to EEG however stimulus is presented to pts ex. picture/sound and researcher looks for activity related to stimulus and investigate how EEG wave pattern changes in response to stimulus (change = ERP)

- Stimulus presented 100s of times and average response is graphed - statistical average technique and it reduced extraneous brain activity.

ERP strengths

- Much more specific to measurement of neural processes than EEGs

- Provide continuous measure of processing in response to stimulus - provides quantitative experimental data

- Can identify ERPs of mental health issues ex. phobias. Those with phobias have ERPs of greater amplitude in response to feared objects than non-phobic people

ERP weaknesses

- Lack of standardisation in ERP methodology - hard to confirm findings

- Not always possible to completely eliminate backgroun noise and extraneous material needed to establish pure data - affects validity

Post-mortem examinations

- Analysis of person's brain following death

- In psych research, individuals whose brains are subject to post mortem likely to have had a rare disorder and have experienced unusual deficits in mental processes

- Areas of damage within brain are examined after death to establish likely cause of the affliction - may involve comparision with typical brain

Post-mortem strengths

- Vital in providing foundation for early understanding of key processes in brain ex. Broca's and Wernicke's areas

- Help improve medical knowledge and help generate hypotheses for further study ex. Zhou analysed brains of female-male trans people and found area of the brain associated with gender to be larger - more like a male

Post-mortem weaknesses

- Causation - observed damage may not be linked to defecits under review but unrelated trauma decay ex. drugs/age

- Raise ethical issues of consent from patient before death - pts may have significant damage thus be too ill to consent. Special consent from BPS, hard to get so small samples so reduces validity

Circadian rythms

- 24 hour rhythmic cycle with differing levels of consciousness ex. sleep wake cycle

Engogenous pacemakers

- Internal body clock that sets many bodily rhythms including sleep

- Suprachiasmatic nucleus (SCN) is the internal body clock

- Main EP is the SCN. It is a bundle of nerves located in the hypothalamus of the brain. SCN located above optic area

- It can receive info about light directly. SCN passes it to pineal gland

- Based on this info, pineal gland releases melatonin

- At night, pineal gland increases melatonin and reduces it during day

- Even in absence of light SCN generate rhythm related ot its production of protein. When it reaches a certain lelve of protein it passes message to pineal gland and melatonin still released/inhibited

- Daylight influences SCN but not essential

Exogenous zeitgebers

- Most influential one is light and it resets out biological clocks (entrainment)

- Light enters eye through retina and this info passed to SCN

- Low levels of light into retine - via optic area to SCN - SCN sends signals to pineal gland - pineal gland releases melatonin - induces sleep

- High levels of light into retina - via optic area to SCN - SCN sends signals to pineal gland - pineal gland inhibits the release of melatonin - induces wakefulness

Siffre's case study

- 1962 Michael Siffre spent 2 months living in complete isolation in a cave to study effects on circadian rhythm

- Deprived of natural light, a clock, a calendar and sound but access to food and drink

- Slept and ate when his body 'told him to'

- He resurfaced mid-September believing it to be mid-August

- Circadian rhythm settled around 25 hours

Aschoff and Wever

- Pts spent 4 weeks in WW2 bunker - shielded from natural light, temp changes or other environmental cues

- Had access to artificial light and could turn it on/off

- Displayed circadian rhythm of 25 hours (one up to 29 hours)

Simon Folkard et al

- 12 pts who lived in dark cave for 3 weeks (no natural light)

- Researchers manipulated clock - pts retired when clock read 11:45pm and awoke at 7:45am

- During the study, researchers sped up a clock so pts thought it was a normal 24 hour day but it was 22 hours

- Only 1 pts adjusted comfortably to new regime

Circadian rhythm EP 1

- Small sample sizes (in Siffre's cave study)

- Limits generalisation

Circadian rhythm EP 2

- Confounding variables

- Pts in Aschoff and Siffre had access to artifical light

- Czeisler 1999 found artifical light can have an influence

- May affect validity

Circadian rhythm EP 3

- Individual differences

- Individual cycles can vary (some have natural preferences for sleeping/waking early and vice versa)

- Age differences in sleep/wake cycles

Circadian rhythm EP 4

- Practical applications to shift work

- Night workers can experience lower concentration around 6am - mistakes more likely

- Poor health linked to night shifts

- Economic implications

Ralph's hamster cycle

- Martin Ralph removed and transplanted the SCNs from hamsters

- Mutant hamsters bred with circadian rhythm of 20 hours

- SCN cells from abnormal hamsters transplanted to normal ones

- They adopted 20 hour cycle of donor

- Hamsters with nocturnal patterns (normal) had SCNs replaced from mutated hamsters (opposite) and followed donor's activity patterns

Campbell and Murphy

- Light may be detected by skin receptor sites even when same info not received by eyes

- If pts woken up at various times and light pad shone on the back of their knees

- Researchers found change in their cycle up to 3 hours

Ralph and Campbell and Murphy Evaluation

- Ethics in animal studies - hamsters were harmed

- Methodological issues in research - C and M findings yet to be replicated. Critics suggest light may have been exposed to light which would be a confounding variable

Infradian rhythms

- Cycles occur longer than 24 hours ex. menstrual cycle

- Cycle begins on 1st days of period and ends day before next

- 21-35 days (avg = 28 days)

Governed by hormones

- Oestrogen at peak during ovulation. Egg is released

- Progesterone increases to prepare for possible pregnancy

- If pregnancy doesn't occur, egg absorbed and womb lining sheds

- Governed by endogenous pacemakers but can be affected by exogenous zeitgebers

Infradian rhythms research: Reinberg

- 1 female pts spent 3 months in a cave with only light from a small lamp

- Menstrual cycle shortened from 28 days to 25.7 days

- Lack of light (exogenous zeitgeber) affected menstrual cycle

McClintock and Stern

- 29 female uni studetns, not taking birth control pills

- Longitudinal experiment with independent measures

- Pheromone samples gathered from 9 women at different stages of cycle via cotton pad under armpit (worn for at least 8 hours) then treated with alcohol and frozen (control group)

- 20 women rubbed pads on upper lip to inhale the odour

- On day 1 pads from day one of cycle applied and so on

- When experimental group inhaled secretions from women about to ovulate, cycles shortened. When just ovulated cycles lengthened. 68% the sweat donation affected their cycles

- Can explain why women in close proximity synchronise

Infradian rhythms EP 1

- Methodological limitations in synchronisation studies - individual differences

- Factors other than pheromones like stress, diet, exercise etc. may be counfounding variables

- Research involves small sample self-reporting onset of cycle

Infradian rhythms EP 2

- Replication

- Similar study failed to find evidence of synchronisation

- Low reliability

Infradian rhythms EP 3

- Animal studies/pheromones

- Affects validity and generalisability

Infradian rhythms EP 4

- Evolutionary approach

- Synchronising could provide evolutionary advantage - synchronised pregnancies means childcare can be shared among mothers due to lactating and release of oxytocin

Infradian rhythms EP 5

- Application - optimise exercise performance

- During 1st half of cycle higher oestrogen good for HIT - recovery quicker and motivation higher

- When strength training performed frequently in 1st halft the gains are 14-40% greater than when distributed evenly across cycle

- During 2nd half core temp rises so lower intensity aerobic exercise is better

- Higher progesterone can affect coordination but lower anxiety and promote good sleep

- Adapting training can benefit performance

Ultraidan rhythms

- Less than 24 hours ex. stages of sleep

- Stages 1 and 2 = 'light sleep' stages: brain patterns slow starting with alpha waves, progressing to theta waves

Stages 3 and 4 = deep sleep (mainly associated with delta waves)

- Stage 5 (REM sleep). Body 'paralysed' to prevent acting out our dreams. Eyes move side to side rapidly. brain activity like awake

- Stages 1-4 = NREM (non-REM)

- Avg, entire cycle repeates every 90 mins. May have 4-5 cycles a night

Sleep cycles

- As we fall asleep we enter stage 1 - high frequency and low amplitude

- Stage 4 characterised by delta waves and is deepest. Hard to wake from. Heart rate and blood pressure drop and muscles relax (abt 30 mins)

- After around an hour we reverse changes but go to REM not stage 1

- Each cycle around 90 mins and good night of sleep has 4-5 cycles with episodes of REM sleep

Sleep cycles: Dement and Kleitman

- Lab experiment to investigate relationship between eye movement and dreaming

- 9 pts (7 males, 2 women). Pts connected to EEG at night (no caffeine)

- REM is predominantly dreaming and NREM not

- REM periods at regular intervals (each pts had individual pattern). Mean period between each phases was 92 mins (ranger 70-104)

- Stages of sleep follow a pattern

- Dreams mostly occur in REM

- Pts went into REM every 90 mins or so

- Dement compared pts deprived of REM to control deprived of NREM and REM group more irritable, aggressive and worse concentration

- Boxbley found REM deprived pts made 31 attempts to re-enter REM on night 1. 51 on night 2 and 60 on 3.

Randy Gardner

- Awake for 264 hours (11 days)

- Blurred vision and disorganised speech

- After slept only 15 hours and over several nights recovered only 25% of lost sleep

- Recovered around 70% stage 4, 50% of REM and little of others

- Wide flexibility regarding different stages and variable nature of this ultradian rhythm

Ultradian rhythms EP 1

- Individual differences

- Tucker et al found duration of stages (esp 3 and 4) differed between pts

- May be innate individual differences in ultradian rhythms

Ultradian rhythms EP 2

- Lack of ecological validity

- Normally investigated with high control in sleep labs

- Pts wear caps with electrodes, asked to sleep and woken at several points

- Invasive and artificial - may not reflect normal sleep cycle

- Could lead to false conclusions

Ultradian rhythms EP 3

- Flexible

- Randy Gardner's case study

- Suggests cycles more flexible than believed

- As a case study however there are issues with generalisability