biopsychology

Question 1

what are the two main divisions of the human nervous system

Answer 1

-central nervous system
-peripheral nervous system

Question 2

what is the CNS

Answer 2

-consists of the human brain and spinal cord
-is the origin of all complex commands and decisions

Question 3

what are the two subdivisions of the CNS

Answer 3

-brain
-spinal cord

Question 4

what is the PNS

Answer 4

-regulates body functions whilst at rest
-“rest and digest” or “feed and breed”
-this is your normal state

Question 5

what are the two divisions of the PNS

Answer 5

-autonomic nervous system (ANS)
-somatic nervous system (SNS)

Question 6

what is the SNS

Answer 6

-controls the body’s responses to perceived threats
-“fight or flight”
-this responds to times of stress

Question 7

what is the ANS

Answer 7

controls bodily functions e.g. breathing,heart rate,sexual arousal,stress

Question 8

what is a gland

Answer 8

-an organ in the body that synthesises substances such as hormones

Question 9

what are hormones

Answer 9

-biological substances that circulate in the blood but only affects target organs
-produced in large quantities but disappear quickly

Question 10

Describe the fight or flight response

Answer 10

1) Sensory organs detect a stressor.
2) Message is sent to the hypothalamus.
3) Sympathetic nervous system and endocrine system are activated by the hypothalamus.
4) Adrenal gland releases adrenaline as a result.
5) Fight/flight now ready (causing various behavioural responses e.g. increased breathing and heart rate, slowed digestion, pupil dilation etc

Question 11

What happens if the stressor continues vs when the stressor subsides?

Answer 11

-If the stressor continues, the pituitary gland releases cortisol which aids our metabolism, but too much over a long period of time can weaken our immune system, which is why people get sick when they are stressed.
-If the stressor subsides, the parasympathetic nervous system kicks in and returns everything to the resting state

Question 12

what does the endocrine system do

Answer 12

-instructs glands to release hormones into the bloodstream
-these hormones are then carried to specific organs in the body via bloodstream

Question 13

name the glands within the endocrine system

Answer 13

-pituitary gland
-thyroid gland
-adrenal gland
-ovaries and testes

Question 14

pituitary gland

Answer 14

This is the ‘master gland’ and is located in the brain. It controls the release of the hormones from all of the other endocrine glands in the body.

Question 15

thyroid gland

Answer 15

Produces the hormone thyroxine which increases heart rate. It also increases metabolic rate which affects growth

Question 16

Adrenal Gland

Answer 16

Produces adrenaline in the adrenal medulla.
It triggers increased heart rate and contracting blood vessels, which creates physiological arousal for the fight or flight response.

Question 17

Ovaries and testes

Answer 17

-These are the female and male gland respectively.
-Ovaries secrete oestrogen
-Testes secrete testosterone
-Both used for reproduction

Question 18

what is a neuron

Answer 18

nerve cells that process and transmit messages through electrical and chemical signals

Question 19

The function of a neuron

Answer 19

there are 100 billion neurons in the human nervous system, 80% of which are located in the brain. By transmitting signals electrically and chemically,these neurons provide the nervous system with its primary means of communication.

Question 20

describe sensory neurons

Answer 20

-carry messages from PNS to CNS
-have long dendrites and short axons

Question 21

describe relay neurons

Answer 21

-connect the sensory neurons to motor or other relay neurons
-have short dendrites and short axons

Question 22

describe motor neurons

Answer 22

• connect the CNS to effectors such as muscles and glands
  -have short dendrites and long axons

Question 23

Describe the general structure of a neuron.

Answer 23

-cell body contains the nucleus, which contains all the genetic information of the cell.
-Branch-like structures called dendrites protrude from the cell body and carry nerve impulses from the adjacent neurons towards the cell body.
-Axons carry info away from the cell body and down the length of the neuron.
-Axons are covered in fatty layers of myelin sheath which protect the axons and speed up transmission.
-Between segments of myelin sheath are gaps called nodes of Ranvier; the transmission is forced to “jump” these gaps which speeds up the transmission of the impulse.
-At the end of each axon is an axon terminal button which communicates with the next neuron via synaptic transmission

Question 24

Describe electrical transmission.

Answer 24

-at a resting state, the inside of a neuron is negatively charged in comparison to the outside.
-When a neuron is activated by a stimulus, the inside becomes positively charged for a split second, causing an action potential to occur.
-This causes an electrical impulse to travel down the axon and towards the end of the neuron, i.e. the axon terminal button.

Question 25

Chemical transmission

Answer 25

-Neurons communicate with each other within groups known as neural networks. (Separated by a tiny gap known as a synapse)
-The synapse is between the terminal button one of neuron and the dendrite of another.
-Signals within neurons are transmitted electrically (action potential), however signals between neurons are transmitted chemically in the synapse.

Question 26

synapse transmission

Answer 26

-The axon carries the vesicle containing the neurotransmitter to the presynaptic nerve terminal.
- vesicle releases the neurotransmitter at the presynaptic neurons’ membrane into the synapse.
-The neurotransmitters diffuse across the synapse and binds to the receptor site on the post synaptic neurons membrane.
-If the signal from the neurotransmitter is excitatory an electrical signal is generated (action potential) and passes along the neuron
-if its inhibitory no action potential is generated.
-Direction of travel of the chemical message can only be one way because of the structures in the pre and post synaptic membranes.

Question 27

Neurotransmitters

Answer 27

Each has its own specific molecular structure that fits into a post synaptic receptor site (like a lock and key). They all have their own specific functions.

Question 28

what is meant by Excitation

Answer 28

a neurotransmitter (e.g. adrenaline) increases the positive charge of the postsynaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse.

Question 29

what is meant by Inhibition

Answer 29

a neurotransmitter (e.g. serotonin) increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the neuron will fire and pass on the electrical impulse.

Question 30

what is meant by summation

Answer 30

-Whether a neuron fires or not is down to the overall net effect on the post synaptic neuron.
-Many neurotransmitters are being released at once into the synapse, some excitatory and some inhibitory.
- Its the overall charge on the post synaptic membrane that ‘decides’ if an action potential or not will be created.

Question 31

Explain why neurons can only transmit information in one direction at a synapse.

Answer 31

-the synaptic vesicles containing the neurotransmitter are only present on / released from the presynaptic membrane
- the receptors for the neurotransmitters are only present on the postsynaptic membrane
- it is the binding of the neurotransmitter to the receptor which enables the signal / information to be passed / transmitted on (to the next neuron)
-diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the presynaptic to the postsynaptic membrane.

Question 32

what is localisation of function

Answer 32

The theory that different areas of the brain are responsible for specific behaviours, processes or activities.

Question 33

What are the hemispheres of the brain

Answer 33

-the brain is divided into 2 hemispheres
-activity on the right side of the body is controlled by the left side of the brain and vice versa

Question 34

cerebral cortex

Answer 34

-the outer layer of both hemispheres
-responsible for higher level processing
-human cortex’s are more developed than other animals
-it’s grey due to the location of cell bodies

Question 35

Frontal lobe-motor area

Answer 35

Voluntary movement in opposite side of the body (damage to this area of the brain may result in a loss of control over fine movements

Question 36

Parietal lobe- somatosensory lobe

Answer 36

-where sensory information from the skin is represented
-the amount of somatosensory area devoted to a particular body part denotes its sensitivity

Question 37

Occipital lobe- visual area

Answer 37

Each eye sends info from the right visual field to the left visual cortex and vice versa
(damage in a visual cortex can produce blindness in the opposite visual field)

Question 38

Temporal lobe-auditory area

Answer 38

Analyses speech
(damage may produce hearing loss or the ability to comprehend languages)

Question 39

What hemisphere is language restricted to

Answer 39

left

Question 40

Broca’s area

Answer 40

-identified a small region in the left frontal lobe responsible for speech production
-Damage to the area causes Broca’s aphasia
-Slow speech, laborious and lacking in fluency

Question 41

Wernicke’s area

Answer 41

-Identified a region in the left temporal lobe responsible for language comprehension
-Damage to this area causes Wernicke’s aphasia
-Producing nonsense words as part of their speech

Question 42

The case of Phineas gage

Answer 42

-preparing to blast a section of rock when he dropped his tampering iron which caused the explosive to ignite
-This caused a metre length pole through Gages pre frontal cortex which exited his skull from the top of his head taking a portion of his brain out
-He survived the damage to his brain, the only mark being on his personality
- Went from calm and reserved to quick tempered

Question 43

evaluation 1- evidence from neurosurgery ( localisation of function in the brain)

Answer 43

-strength
-damage to areas of the brain has been linked to mental disorders.
-targeting specific areas of the brain which may be involved.
-e.g. cingulotomy involves isolating a region called the cingulate gyrus which has been implicated in OCD.
-Dougherty reported on 44 people with OCD who had undergone a cingulotomy.
-At post-surgical follow-up after 32 weeks, about 30% had met the criteria for successful response to the surgery
-The success of these procedures suggests that behaviours associated with serious mental disorders may be localised.

Question 44

evaluation 2- evidence from brain scans ( localisation of function in the brain)

Answer 44

-strength
-brain scans support the idea that many everyday brain functions are localised.
-Petersen used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.
-also Buckner and Petersen revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
-These studies confirm localised areas for everyday behaviours.
-Therefore research provided evidence that many brain functions are localised.

Question 45

evaluation 3- counterpoint of evidence from brain scans (localisation of function in the brain)

Answer 45

-Lashley removed areas of the cortex (between 10% and 50%) in rats that were learning the route through a maze.
-No area was proven to be more important than any other area in terms of the rats’ ability to learn the route.
-The process of learning seemed to require every part of the cortex rather than being confined to a particular area.
-This suggests that higher cognitive processes, such as learning, are not localised but distributed in a more holistic way in the brain.

Question 46

evaluation 4- language localisation questioned( localisation of function in the brain)

Answer 46

-limitation
-language may not be localised just to Broca’s and Wernicke’s areas.
-Dick and Tremblay found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas.
-It seems that language function is distributed far more holistically in the brain than was first thought.
-So-called language streams have been identified across the cortex, including brain regions in the right hemisphere, as well as subcortical regions such as the thalamus.
-This suggests that language may be organised more holistically in the brain, which contradicts localisation theory.

Question 47

what is lateralisation

Answer 47

The idea that the two hemispheres of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere

Question 48

How is language both localised and lateralised

Answer 48

-only in the left hemisphere
-Broca’s area/Wernicke’s area
-however the right hemisphere can produce rudimentary words and contribute to emotional context
-LH - analyser
-RH- synthesiser

Question 49

Contralateral wiring

Answer 49

The brain in some cases is cross wired. In the motor area the right hemisphere controls movement on the left side of the body and vice versa

Question 50

How does contralateral wiring work in vision

Answer 50

-its both contralateral and ipsilateral
-each eye receives information from the left visual field and right
-the left visual field is connected to the right hemisphere and vice versa (aids depth perception)

Question 51

evaluation 1- lateralisation in the connected brain ( hemispheric lateralisation)

Answer 51

-strength
-research showing that even in connected brains the two hemispheres process information differently.
-Fink et al used PET scans to identify which brain areas were active during a visual processing task.
-When participants with connected brains were asked to attend to global elements of an image, regions of the RH were much more active.
-When required to focus in on the finer detail, the specific areas of the LH tended to dominate.
-This suggests that hemispheric lateralisation is a feature of the connected brain as well as the split-brain.

Question 52

evaluation 2- one brain ( hemispheric lateralisation)

Answer 52

-limitation
- idea that the LH as analyser and RH as synthesiser may be wrong.
-Nielsen et al analysed brain scans from over 1000 people aged 7 to 29 years and did find that people used certain hemispheres for certain tasks (evidence for lateralisation).
-But there was no evidence of a dominant side, i.e. not artist’s brain or mathematician’s brain.
-This suggests that the notion of right- or left-brained people is wrong.

Question 53

Split-brain research

Answer 53

-A series of studies that began in the 1960s involving people with epilepsy who had experienced a surgical separation of the hemispheres of their brain to reduce the severity of their epilepsy.
-This enabled researchers to test lateral functions of the brain in isolation

Question 54

Split brain operation

Answer 54

-severing the connections between the RH and the LH (corpus callosum)
-During an epileptic seizure excessive electrical activity travels from one hemisphere to the other

Question 55

Sperry’s procedure ( split brain research)

Answer 55

-Eleven people who had a split-brain operation were studied
-an image could be projected to a participant’s RVF (processed by the LH) and the same, or different, image could be projected to the LVF (processed by the RH).
-In the ‘normal’ brain, the corpus callosum would immediately share the info between both hemispheres giving a complete picture of the visual world.
-However, presenting the image to one hemisphere of a split-brain participant meant that the information cannot be conveyed from that hemisphere to the other.

Question 56

Sperry’s Findings ( split brain research )

Answer 56

-When a pic of an object was shown to a participant’s RVF (linked to LH), the participant could describe what was seen.
-But they could not do this if the object was shown to the LVF (RH) - they said there was ‘nothing there’. This is because, in the connected brain, messages from the RH are relayed to the language centres in the LH.
-Although participants could not give verbal labels , they could select a matching object out of sight using their left hand (linked to RH). The left hand was also able to select an object that was most closely associated with an object presented to the LVF
-If a pinup pic was shown to the LVF there was an emotional reaction (e.g. a giggle) but the participants usually reported seeing nothing or just a flash of light.

Question 57

Sperry’s conclusion ( split brain research)

Answer 57

These observations show how certain functions are lateralised in the brain and support the view that the LH is verbal and the RH is ‘silent’ but emotional.

Question 58

evaluation 1- research support (split brain research)

Answer 58

-strength
-support from more recent split-brain research.
-Gazzaniga showed that split-brain participants actually perform better than connected controls on certain tasks.
-e.g. they were faster at identifying the odd one out in an array of similar objects than normal controls.
-In the normal brain, the LHs better cognitive strategies are ‘watered down’ by the inferior RH
-This supports Sperry’s earlier findings that the left brain’ and right brain’ are distinct.

Question 59

evaluation 2- generalisations issues ( split brain research)

Answer 59

-limitation
-causal relationships are hard to establish.
-issue is that none of the participants in the control group had epilepsy.
-This is a major confounding variable.
-Any differences that were observed between the two groups may be the result of the epilepsy rather than the split brain.
-This means that some of the unique features of the split-brain participants’ cognitive abilities might have been due to their epilepsy

Question 60

what is plasticity

Answer 60

the tendency for the brain to change and adapt as a result of experience and learning

Question 61

what is synaptic pruning

Answer 61

As we age rarely used connections are deleted and frequently used ones are strengthened

Question 62

What did Gopnik suggest about brain plasticity

Answer 62

there is a rapid growth in the number of synaptic connections in infancy which peaks at approx’ 15,000 at age 2-3 which is twice as many as in the adult brain

Question 63

Research into brain plasticity

Answer 63

-Maguire et al. (2000) studied the brains of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group.
-This part of the brain is associated with the development of spatial and navigational skills in humans and other animals.
-London cabbies must take a complex test called The Knowledge, which assesses their recall of the city streets and possible routes.
-Maguire et al. found that this learning experience alters the structure of the taxi drivers’ brains. They also found that the longer the taxi drivers had been in the job, the more pronounced was the structural difference.

Question 64

evaluation 1- negative plasticity (plasticity)

Answer 64

-limitation
-it may have negative behavioural consequences.
-brain’s adaptation to prolonged drug use leads to poorer cognitive functioning in later life and increased risk of dementia (Medina et al. 2007).
-60-80% of amputees have been known to develop phantom limb syndrome - the continued experience of sensations in the missing limb as if it were still there.
-These sensations are usually unpleasant, painful and are thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss
-This suggests that the brain’s ability to adapt to damage is not always beneficial.

Question 65

evaluation 2- age and plasticity (plasticity)

Answer 65

-strength
-it may be a life-long ability.
-In general plasticity reduces with age.
-However, Bezzola demonstrated how 40 hours of golf training produced changes in the neural representations of movement in participants aged 40-60.
-Using fMRI, the researchers observed reduced motor cortex activity in the golfers compared to a control group, suggesting more efficient neural representations after training.
-This shows that neural plasticity can continue throughout the lifespan.

Question 66

what is Functional recovery

Answer 66

A form of plasticity. Following damage through trauma, the brain’s ability to redistribute or transfer functions usually performed by a damaged area(s) to other, undamaged area(s).

Question 67

Critical period for adults for brain plasticity

Answer 67

-once believed that when an adults brain was developed, plasticity would not be possible as it had gone past the critical period of development
-However more recent research suggests that any time in life existing neural connections can change or new neural connections can be formed as a result of learning

Question 68

What is functional plasticity an example of

Answer 68

neural plasticity

Question 69

spontaneous vs slow recovery

Answer 69

-redistribution can quickly occur after trauma (spontaneous recovery) but then slow down after several weeks/months
-People may need rehabilitation therapy to further their recovery

Question 70

What happens in the brain during recovery

Answer 70

-the brain rewires and reorganises itself by making new synaptic connections
-neural pathways that would not normally be used to carry out certain functions are activated (unmasked) to allow functions to carry on in the same way as before

Question 71

What are structural changes that occur in the brain during recovery

Answer 71

-axonal sprouting
-denervation super sensitivity
-recruitment of homologous areas

Question 72

Axonal sprouting

Answer 72

The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

Question 73

Denervation super sensitivity

Answer 73

This occurs when axons that do similar jobs become aroused to a higher level to compromise for the ones that are lost

Question 74

Recruitment of homologous areas on the opposite side of the brain

Answer 74

Specific tasks can still be performed.

Question 75

evaluation 1- real world application ( functional recovery)

Answer 75

• strength
  -has real-world application.
• has contributed to the field of neurorehabilitation.
• understanding that axonal growth is possible encourages new therapies to be tried.
  -e.g. constraint-induced movement therapy is used with stroke patients whereby they repeatedly practise using the affected part of their body
  -This shows that research into functional recovery is useful as it helps medical professionals know when interventions need to be made.

Question 76

evaluation 2- cognitive reserve ( functional recovery)

Answer 76

• limitation
• level of education may influence recovery rates.
• Schneider revealed that the more time people with a brain injury had spent in education the greater their chances of a disability-free recovery (DFR).
  -40% of those who achieved DFR had more than 16 years’ education compared to about 10% of those who had less than 12 years’ education.
  -This would imply that people with brain damage who have insufficient DFR are less likely to achieve a full recovery.

Question 77

Functional magnetic resonance imaging

Answer 77

-works by detecting the changes in both blood oxygenation and flow that occur as a result of neural activity in specific parts of the brain.
-When a brain area is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to the active area.
-fMRI produces three-dimensional images (activation maps) showing which parts of the brain are involved in a particular mental process

Question 78

Strengths of Functional magnetic resonance imaging

Answer 78

-Doesn’t not rely on the use of radiation.
-If administered correctly it is virtually risk-free, non-invasive and straightforward to use.
- produces images that have very high spatial resolution, depicting detail by the millimetre, and providing a clear picture of how brain activity is localised.
- This means that fMRI can safely provide a clear picture of brain activity.

Question 79

Limitations of Functional magnetic resonance imaging

Answer 79

-expensive compared to other neuroimaging techniques.
-It has poor temporal resolution because there is around a 5-second time-lag behind the image on screen and the initial firing of neuronal activity.
-This means fMRI may not truly represent moment-to-moment brain activity.

Question 80

Electroencephalogram (EEG)

Answer 80

-measures electrical activity within the brain via electrodes that are fixed to an individual’s scalp using a skull cap.
-The scan recording represents the brainwave patterns that are generated from the action of thousands of neurons, providing an overall account of brain activity.
-EEG is often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities such as epilepsy, tumours or some sleep disorders.

Question 81

Strengths of Electroencephalogram (EEG)

Answer 81

-has been useful in studying the stages of sleep and in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can easily be detected on screen.
-high temporal resolution.
-Today’s EEG technology can accurately detect brain activity at a resolution of a single millisecond
.-This shows the real-world usefulness of the technique.

Question 82

Limitations of Electroencephalogram (EEG)

Answer 82

-generalised nature of the information received (that of many thousands of neurons).
- The EEG signal is also not useful for pinpointing the exact source of neural activity
- it does not allow researchers to distinguish between activities originating in different but adjacent locations.

Question 83

Event-related potentials

Answer 83

-overly general measure of brain activity.
- within EEG data are contained all the neural responses associated with specific sensory, cognitive and motor events that may be of interest to cognitive neuroscientists.
-researchers have developed a way of teasing out and isolating these responses.
-Using a statistical averaging technique, all extraneous brain activity is filtered out leaving only those responses that relate to the presentation of a specific stimulus or performance of a specific task.
-What remains are event-related potentials (ERPs) - types of brainwave that are triggered by particular events.
-Research has revealed many different forms of ERP and how, for example, these are linked to cognitive processes such as attention and perception

Question 84

Strengths of Event-related potentials

Answer 84

• they have excellent temporal resolution, especially when compared to neuroimaging techniques such as fMRI.
  -This means that ERPs are frequently used to measure cognitive functions and deficits such as the allocation of attentional resources and the maintenance of working memory.

Question 85

Limitations of Event-related potentials

Answer 85

• lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings.
• in order to establish pure data in ERP studies, background ‘noise’ and extraneous material must be completely eliminated. This is a problem because it may not always be easy to achieve

Question 86

Post mortem examinations

Answer 86

• technique involving the analysis of a person’s brain following their death.
• individuals whose brains are subject to a post-mortem examination are likely to be those who have a rare disorder and have experienced unusual deficits in cognitive processes or behaviour during their lifetime. -Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person experienced.
  -This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.

Question 87

strengths of Post mortem examinations

Answer 87

-Post-mortem evidence was vital in providing a foundation for early understanding of key processes in the brain. Broca and Wernicke both relied on post-mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became a possibility.
-Post-mortem studies were also used to study HM’s brain to identify the areas of damage, which could then be associated with his memory deficits.
-This means post-mortems continue to provide useful information.

Question 88

limitations of Post mortem examinations

Answer 88

-Causation is an issue within these studies. Observed damage to the brain may not be linked to the deficits under review but to some other unrelated trauma or decay.
-raise ethical issues of consent from the individual before death. Participants may not be able to provide informed consent, for example in the case of HM, was not able to provide such consent - nevertheless post-mortem research has been conducted on his brain.
-This challenges the usefulness of post-mortem studies in psychological research.

Question 89

Biological rhythms

Answer 89

Distinct patterns of changes in body activity that conform to cyclical time periods. Biological rhythms are influenced by internal body clocks (endogenous pacemakers) as well as external changes to the environment (exogenous zeitgebers).

Question 90

Circadian rhythms

Answer 90

Biological rhythms, subject to a 24-hour cycle, which regulate a number of body processes such as the sleep/wake cycle and changes in core body temperature.

Question 91

What is the sleep/wake cycle governed by

Answer 91

-daylight- exogenous zeitgeber
-suprachiasmatic nucleus- endogenous pacemaker

Question 92

Siffre’s cave study ( circadian rhythms)

Answer 92

-spent several extended periods underground to study the effects on his own biological rhythms.
-Deprived of exposure to natural light and sound, but with access to adequate food and drink,
-resurfaced in mid September after two months in the caves of the Southern Alps believing it to be mid-August!
-A decade later he performed a similar feat but this time for six months in a Texan cave.
-In each case, his ‘free-running’ biological rhythm settled down to one that was just beyond the usual 24 hours (around 25 hours) though he did continue to fall asleep and wake up on a regular schedule.

Question 93

Aschoff’s and Wever’s research on sleep/wake cycle

Answer 93

-convinced a group of participants to spend four weeks in a World War 2 bunker deprived of natural light
-All but one of the participants (whose sleep/wake cycle extended to 29 hours) displayed a circadian rhythm between 24 and 25 hours.
-Both Siffre’s experience and the bunker study suggest that the ‘natural’ sleep/wake cycle may be slightly longer than 24 hours but that it is entrained by exogenous zeitgebers associated with our 24-hour day (such as the number of daylight hours, typical mealtimes, etc.).

Question 94

evaluation 1- shift work (circadian rhythms)

Answer 94

-strength
- provides an understanding of desynchronisation
-e.g. Boivin->night workers engaged in shift work experience a period of reduced concentration around 6 in the morning (a circadian trough) meaning mistakes and accidents are more likely
-Knutsson also pointed to a relationship between shift work and poor health - shift workers are three times more likely to develop heart disease than people who work more typical work patterns
-This shows that research into the sleep/wake cycle may have real-world economic implications in terms of how best to manage worker productivity.

Question 95

evaluation 2- counterpoint of shift work (circadian rhythms)

Answer 95

-studies investigating the effects of shift work tend to use correlational methods.
-This means it is difficult to establish whether desynchronisation of the sleep/wake cycle is actually a cause of negative effects.
-There may be other factors e.g. Solomon concluded that high divorce rates in shift workers might be due to the strain of deprived sleep and other influences such as missing out on important family events.
-This suggests that it may not be biological factors that create the adverse consequences associated with shift work.

Question 96

evaluation 3- medical treatment (circadian rhythms)

Answer 96

-strength
-research has been used to improve medical treatments.
-Circadian rhythms co-ordinate heart rate, digestion and hormone levels.
-These rise and fall during the course of a day which has led to the field of chronotherapeutic - how medical treatment can be administered in a way that corresponds to a person’s biological rhythms.
-e.g.aspirin as a treatment for heart attacks is most effective if taken last thing at night.
-Heart attacks are most likely to occur early in the morning, so the timing of taking aspirin matters.
-This shows that circadian rhythm research can help increase the effectiveness of drug treatments.

Question 97

evaluation 4- individual differences (circadian rhythms)

Answer 97

-limitation
-generalisations are difficult to make.
-The studies are based on very small samples of participants
- It seems that Sleep/wake cycles may vary widely from person to person.
-Czeisler found individual differences in sleep/wake cycles varying from 13 to 65 hours. I
-Duffy revealed that some people have a natural preference for going to bed early and rising early (known as ‘larks’) Whereas others prefer the opposite (owls)
-This means that it is difficult to use the research data to discuss anything more than averages, which may be meaningless.

Question 98

Infradian rhythms

Answer 98

A type of biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation and seasonal affective disorder.

Question 99

Menstrual cycle

Answer 99

-governed by monthly hormone levels which regulate ovulation
-typically takes 28 days
-rising levels of oestrogen cause the ovary to develop an egg and release it
-progesterone makes the womb lining grow thicker ready for an egg

Question 100

Stem and Mclintock (menstrual cycle)

Answer 100

-studied 29 women with a history of irregular periods.
-Samples of pheromones were gathered from 9 of the women at different stages of their menstrual cycles, via a cotton pad placed in their armpit.
-The pads were worn for at least 8 hours and were treated with alcohol and frozen, to be rubbed on the upper lip of the other participants.
-On day one, pads from the start of the menstrual cycle were applied to all 20 women
- on day two they were all given a pad from the second day of the cycle, and so on.
- found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor

Question 101

seasonal affective disorder

Answer 101

-depressive disorder which has a seasonal pattern of onset
-diagnosed as a mental disorder in DSM-5.
-the main symptoms : low mood, general lack of activity and interest in life.
- triggered during the winter months when the number of daylight hours becomes shorter.
-Psychologists suggested that the hormone melatonin is implicated in the cause of SAD :During the night, the pineal gland secretes melatonin until dawn when there is an increase in light. During winter, the lack of light in the morning means this secretion process continues for longer.
-This is thought to have a knock-on effect on the production of serotonin in the brain - a chemical that has been linked to the onset of depressive symptoms

Question 102

evaluation 1- evolutionary basis (infradian rhythms)

Answer 102

-strength
-menstrual synchrony research may be explained by natural selection.
-Synchronisation of the menstrual cycle, of the kind observed in the Stern and McClintock study is thought by some to have evolutionary value.
-For our distant ancestors it may have been advantageous for women to menstruate together and become pregnant at the same time.
-In a social group, this would allow babies who had lost their mothers during or after childbirth to have access to breast milk, thereby improving their chances of survival.
-This suggests that synchronisation is an adaptive strategy

Question 103

evaluation 2- methodological limitations (infradian rhythms)

Answer 103

-limitation
-synchronisation studies have methodological shortcomings.
-There are many factors that may effect change to the menstrual cycle, including stress, changes in diet, exercise, etc.
-These may act as confounding variables
-This may explain why other studies (e.g. Trevathan ) have failed to replicate the findings.
-this suggests that menstrual synchrony studies are flawed

Question 104

Ultradian rhythms

Answer 104

A type of biological rhythm with a frequency of more than one cycle in 24 hours, such as the stages of sleep (the sleep cycle).

Question 105

What are the 5 stages of sleep

Answer 105

-Stages 1 and 2- This is light sleep a person may be easily woken.
-In stage 1, brain waves are high frequency and have a short amplitude. These are alpha waves.
-In stage 2, the alpha waves continue but there are occasional random changes in pattern called sleep spindles.
-Stages 3 and 4- This is known as deep sleep or slow wave sleep. The brain waves are delta waves with lower frequency and higher amplitude. It is difficult to wake someone at this point.
-Stage 5 (REM sleep)- The body is paralysed yet brain activity closely resembles that of the awake brain. During this time, the brain produces theta waves and the eyes occasionally move around, thus rapid eye movement. Dreams are most often experienced during REM sleep, but may also occur in deep sleep

Question 106

evaluation 1- improved understanding ( ultradian rhythms)

Answer 106

-strength
-it has improved understanding of age-related changes in sleep.
-Sleep scientists have observed that SWS reduces with age.
-Growth hormone is mostly produced during SWS therefore this is reduced in older people.
-According to Cauter , the resulting sleep deficit may explain various issues in old age, such as reduced alertness.
-In order to increase SWS, relaxation and medication may be used.
-This suggests that knowledge of ultradian rhythms has practical value.

Question 107

evaluation 2- individual differences ( ultradian rhythms)

Answer 107

-limitation
-there is significant variation between people.
-Tucker found large differences between participants in terms of the duration of each sleep stage, particularly stages 3 and 4.
-Tucker suggests that these differences are likely to be biologically determined.
-This makes it difficult to describe ‘normal sleep’ in any meaningful way.

Question 108

Endogenous pacemakers

Answer 108

Internal body clocks that regulate many of our biological rhythms, such as the influence of the suprachiasmatic nucleus (SCN) on the sleep/wake cycle.

Question 109

suprachiasmatic nucleus

Answer 109

lies above the optic chiasm so provides information from the eye about light.
Sends messages to the pineal gland about light levels
-If light levels are low the pineal gland releases melatonin and we feel sleepy

Question 110

where is the suprachiasmatic nucleus found

Answer 110

Hypothalamus in both hemispheres

Question 111

animal studies and the SCN- DeCoursey (Endogenous pacemakers and the sleep/wake cycle)

Answer 111

-DeCoursey et al destroyed the SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days.
-The sleep/wake cycle of the chipmunks disappeared and by the end of the study a significant proportion of them had been killed by predators
-(presumably because they were awake, active and vulnerable to attack when they should have been asleep).

Question 112

animal studies and SCN- Ralph (Endogenous pacemakers and the sleep/wake cycle)

Answer 112

-Ralph et al bred ‘mutant’ hamsters with a 20-hour sleep/wake cycle.
-When SCN cells from the foetal tissue of mutant hamsters were transplanted into the brains of normal hamsters, the cycles of the second group defaulted to 20 hours.

Question 113

evaluation 1- beyond the master clock (Endogenous pacemakers and the sleep/wake cycle)

Answer 113

• limitation
  -SCN research may obscure other body clocks.
  -Research has revealed that there are numerous circadian rhythms in many organs and cells in the body.
  -These peripheral oscillators are found in the organs including the lungs, pancreas and skin.
  -They are influenced by the actions of the SCN, but also act independently.
• Damiola demonstrated how changing feeding patterns in mice could alter the circadian rhythms of cells in the liver by up to 12 hours, whilst leaving the rhythm of the SCN unaffected.
  -This suggests other complex influences on the sleep/wake cycle.

Question 114

Evaluation 2- interactionist system (Endogenous pacemakers and the sleep/wake cycle)

Answer 114

• limitation
  -endogenous pacemakers cannot be studied in isolation.
  -Total isolation studies, such as Siffre’s cave study are extremely rare.
• Siffre also made use of artificial light which could have reset his biological clock every time he turned his lamp on.
• In everyday life, pacemakers and zeitgebers interact, and it may make little sense to separate the two for the purpose of research.
  -This suggests the more researchers attempt to isolate the influence of internal pacemakers, the lower the validity of the research.

Question 115

Exogenous zeitgebers

Answer 115

External factors that affect or entrain our biological rhythms, such as the influence of light on the sleep/wake cycle.

Question 116

Light as an exogenous zeitgeber

Answer 116

-It can reset the body’s main endogenous pacemaker, the SCN, and thus plays a role in the maintenance of the sleep/wake cycle.
-Light also has an indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation.

Question 117

social cues as an exogenous zeitgeber

Answer 117

-new born babies’ initial sleep/wake cycle is pretty much random. At about 6 weeks of age, the circadian rhythms begin and, by about 16 weeks, babies’ rhythms have been entrained by the schedules imposed by parents, including adult-determined mealtimes and bedtimes.
-Research on jet lag suggests that adapting to local times for eating and sleeping (rather than responding to one’s own feelings of hunger and fatigue) is an effective way of entraining circadian rhythms and beating jet lag when travelling long distances.

Question 118

evaluation 1- environmental observations ( exogenous zeitgebers and the sleep/wake cycle)

Answer 118

• limitation
  -exogenous zeitgebers do not have the same effect in all environments.
  -The experience of people who live in places where there is very little darkness in summer and very little light in winter tell a different story from the usual narrative.
• people who live within the Arctic Circle have similar sleep patterns all-year round, despite spending around six months in almost total darkness.
  -This suggests the sleep/wake cycle is primarily controlled by endogenous pacemakers that can override environmental changes in light:

Question 119

evaluation 2- case study evidence ( exogenous zeitgebers and the sleep/wake cycle)

Answer 119

-limitation
-evidence challenges the role of exogenous zeitgebers.
- Miles et al. recount the study of a young man, blind from birth, who had an abnormal circadian rhythm of 24.9 hours.
-Despite exposure to social cues, such as regular mealtimes, his sleep/wake cycle could not be adjusted.
-This suggests that social cues alone are not effective in resetting the biological rhythm.