Biopsychology

Question 1

What is the central nervous system comprised of?

Answer 1

The brain and the spinal cord

Question 2

What is the peripheral nervous system comprised of?

Answer 2

Autonomic and somatic and then further into the parasympathetic and sympathetic

Question 2

What does the somatic nervous system do?

Answer 2

It controls voluntary muscle movement. The somatic nervous system is also involved in reflex actions, which allows the reflex to occur very quickly.

Question 2

What does the autonomic nervous system do?

Answer 2

The autonomic nervous system governs the internal organs and glands of vital functions of the body without our conscious awareness (e.g. breathing, heart rate, digestion, sexual arousal and stress responses). Involuntary actions such as these are regulated by the autonomic nervous system. This system is necessary because vital bodily functions such as heartbeat and digestion would not work so efficiently if you had to think about them. It is made up of motor neurons only.

Question 3

What does the sympathetic nervous system do?

Answer 3

The sympathetic nervous system is primarily involved in responses that help us to deal with emergencies. It responds to a perceived threat. Neurons from the SNS travel to virtually every organ and gland within the body to produce physiological changes that prepare the body for fight or flight. E.g. pupils dilate, causes the body to release stored energy, heart rate and breathing increase, non-vital functions are inhibited e.g. digestion and urination.

Question 4

What does the parasympathetic nervous system do?

Answer 4

The parasympathetic nervous system restores normal physiological functioning when the threat has passed. E.g. heart rate and breathing slow down, blood pressure is reduced, digestion begins. Because the PNS is involved with energy conservation and digestion, it is sometimes referred to as the body’s rest and digest system.

Question 5

Describe the a) structure and b) function of sensory neurons

Answer 5

A - They have long dendrites and short axons

B - They convert information from the sensory receptors into neural impulses. They carry messages from sensory receptors via the PNS to the CNS

Question 6

Describe the a) structure and b) function of motor neurons

Answer 6

A - They have short dendrites and long axons

B - They send messages via long axons from the brain to muscles or effector

Question 7

Describe the a) structure and b) function of relay (inter) neurons

Answer 7

A - They have short dendrites and short axons

B - They connect with other neurones e.g. They allow sensory and motor neurones to communicate with each other

Question 8

What is a neurotransmitter?

Answer 8

Chemical messenger

Question 9

What happens in synaptic transmission?

Answer 9

Neural impulse (electrical message) reaches the axon terminal of the pre-synaptic neuron
This triggers the synaptic vesicles to release the neurotransmitters into the synaptic gap
The neurotransmitters diffuse across the synaptic gap
They then bind to the post-synaptic receptor sites
This conveys the message to the post-synaptic neuron
The neurotransmitters then get reabsorbed back into the pre-synaptic neuron in a process called reuptake (or they get broken down by enzymes in the synaptic gap)

Question 10

What is the process of summation in synaptic transmission?

Answer 10

The process that determines whether or not an action potential will be triggered, based on the combined effects of the excitatory and inhibitory signals of the neurotransmitters

Question 11

What does the endocrine system regulate?

Answer 11

Physiological processes of the human body e.g. growth, metabolism or reproduction

Question 12

What is an endocrine gland?

Answer 12

A special group of cells which produce and secrete hormones that regulate the activity of cells or organs in the body (e.g. pituitary and adrenal)

Question 13

What is a hormone?

Answer 13

They are chemical messengers that travel through the bloodstream and are carried to target sites throughout the body

Question 13

Which glands are involved in the fight or flight response?

Answer 13

Adrenal maybe pituitary

Question 14

Which hormones are involved in the fight or flight response?

Answer 14

Adrenaline

Question 15

What does adrenaline do in the fight or flight response?

Answer 15

Heart rate, respiration and sweating increase, oxygen support to skeletal muscles and the brain increase, blood vessels are constricted, blood is diverted away from the skin, kidneys and digestive system and glucose and fats are released

Question 16

What happens when the parasympathetic system regains control?

Answer 16

The body returns to its resting state e.g. heart rate and blood pressure are reduced and digestions begins again (rest and digest)

Question 17

Why may the fight or flight response no longer be adaptive for stressors we face today?

Answer 17

The physiological responses associated with fight or flight may be adaptive for a stress response that requires energetic behaviour (e.g. fleeing a lion or moving out of the path of an oncoming car). However, the stressors of modern life rarely require such physical activity (e.g. worrying about exams).
The problem for modern humans is when the stress response is repeatedly activated. The increased blood pressure can lead to physical damage to the blood vessels and eventually to heart disease. This suggests that the response may no longer be adaptive for stressors we face today. However, it could be argued that it is still adaptive for some stressors or threats that we face today e.g. narrowly avoiding being hit by a car.

Question 18

What is the ‘freeze’ response?

Answer 18

It has been suggested that the first phase of a reaction to a threat is not fight or flight, but is instead to avoid confrontation. Gray (1988) suggests that before responding with attacking or running away, most animals (including humans) typically display a ‘freeze’ response. This is essentially a ‘stop, look and listen’ response, where the animal is hyper-vigilant (alert to the slightest sign of danger).

Question 19

How does the ‘freeze’ response criticise fight or flight theory and why might it be adaptive?

Answer 19

This would have been adaptive for humans as it focuses attention and makes them look for new information in order to make the best response for that particular threat. Consequently, fight or flight may not be a complete explanation of our response to stress.

Question 20

What is the tend and befriend response?

Answer 20

During our evolutionary past (the environment of evolutionary adaptiveness or EEA), men and women had different roles in society. Men would have been the hunters, so the fight or flight response would have been appropriate. Women would have been gatherers whose primary role was to protect themselves and their young. This means that women may have a completely different response system for coping with stress because of this. Fleeing too readily at any sign of danger would put their offspring at risk. It would have been more adaptive for women to have a ‘tend and befriend’ response, in which a threat is met with tending to their offspring and befriending other females to form protective alliances. Studies have shown that females release oxytocin when under stress, and that this suppresses the fight or flight response.

Question 21

How does the evidence for a ‘tend and befriend’ response criticise the fight or flight theory?

Answer 21

There is a male bias and the assumption that fight or flight is a valid explanation of the stress response in all humans is a reflection of the bias towards male psychology.

Question 22

How does Speisman et al’s study suggest that cognition is actually involved in the body’s stress response?

Answer 22

Speisman et al. (1964) asked students to watch a primitive and gruesome medical procedure (initiation rites involving genital mutilation) on film whilst their heart rates were monitored. Beforehand, some participants were told that the initiation rites were voluntary and joyful rite of passage (because it signalled the arrival into manhood); others were told that the experience was traumatic and painful. They found that the heart rates of those in the first group actually decreased, but the heart rates of those in the second group increased. This suggests that humans aren’t passive in the face of stressors or threats like the fight or flight response theory would assume. Cognitions (thinking whether the stressor is a threat or not) are also important and therefore the theory is a limited explanation of our response to stress.

Question 23

What is localisation of brain function?

Answer 23

This is the theory that different areas of the brain are responsible for different behaviours, cognitive processes or activities and are associated with different parts of the body. This is sometimes called cortical specialisation.

Based on this theory, it is thought that if a certain area of the brain is damaged through illness or injury, the function associated with that area will also be affected.

Question 24

How is localisation of function theory different from the holistic theory of brain function?

Answer 24

Holistic theory is where all parts of the brain are involved in the processing of thought and action whereas localisation of function is where only certain areas are involved

Question 25

What is hemispheric lateralisation?

Answer 25

This is the idea that the two halves (hemispheres) of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by (specialised to) one hemisphere rather than the other. i.e. they have functional specialisations.

Question 26

Where is the motor cortex in the brain?

Answer 26

Frontal lobe

Question 27

Which functions is the motor cortex responsible for?

Answer 27

The motor cortex is responsible for the generation of voluntary motor movements

Question 28

What happens if the motor cortex is damaged?

Answer 28

Damage to this area may result in a loss of control over fine motor movements.

Question 29

Where is the somatosensory cortex in the brain?

Answer 29

Parietal lobe

Question 30

Which functions is the somatosensory cortex responsible for?

Answer 30

The somatosensory cortex is the region of the brain that processes input from sensory receptors in the body that are sensitive to touch

Question 31

What happens if the somatosensory cortex is damaged?

Answer 31

Damage to the somatosensory cortex can lead to numbness or sometimes parathesia (tingling sensation in parts of the body).

Question 32

Where is the brain’s visual centre?

Answer 32

The primary visual centre in the brain is located in the visual cortex, in the occipital lobe of the brain. It is the part of the occipital lobe that receives and processes visual information.

Question 33

What happens if the brain’s visual centre is damaged?

Answer 33

Damage to this area can lead to vision and perception problems, mostly blindness and visual hallucinations (seeing things that are not really there).

Question 34

Where is the brain’s auditory centre?

Answer 34

Most of this area lies within the temporal lobes on both sides of the brain, where we find the auditory cortex.

Question 35

What happens if the brain’s auditory centre is damaged?

Answer 35

Damage may produce partial hearing loss; the more extensive the damage, the more extensive the loss.

Question 36

Where is Broca’s area?

Answer 36

Frontal lobe

Question 37

What is Broca’s area responsible for?

Answer 37

This area is believed to be critical for speech production.

Question 38

What happens if Broca’s area is damaged?

Answer 38

People with damage to Broca’s area (called Broca’s aphasia) are often only able to talk in short meaningful sentences which take great effort (they are slow and laborious). The speech lacks fluency as there is a difficulty with words that help sentences to function (e.g. ‘it’, ‘the’ etc.).

Question 39

Where is Wernicke’s area?

Answer 39

Temporal lobe

Question 40

What is Wernicke’s area responsible for?

Answer 40

Understanding language (i.e. the interpretation of speech).

Question 41

What happens if Wernicke’s area is damaged

Answer 41

Wernicke found that patients with a lesion in Wernicke’s area (Wernicke’s aphasia) could speak but were unable to understand language, such that the speech they produced was fluent but meaningless. They often produce nonsense words (called neologisms) as part of the content of their speech.

Question 42

How does the case study of Phineas Gage support localisation of function theory?

Answer 42

Phineas Gage survived a metre-length pole passing through his left cheek, left eye and exiting his skull. The damage to his frontal lobe left a mark on his personality – he turned from a calm reserved person to someone who was quick-tempered and rude.

This suggests that the frontal lobe may be responsible for regulating mood, supporting localisation theory. However, as this is a case study, it cannot provide particularly strong support for localisation theory as it lacks external validity in that Gage may be a unique case.

Question 43

How does Lashley’s rats maze learning study support a more holistic explanation of brain function

Answer 43

Lashley removed areas of the cortex (10-50%) in rats that were learning a maze. No area was proven to be more important than any other area in terms of the rats’ ability to learn the maze. The process of learning appeared to require every part of the cortex, rather than being confined to one particular area. This seems to suggest that learning is too complex to be localised, and requires the involvement of the whole of the brain. Therefore, processes involved in learning may be distributed in a more holistic way in the brain. However, we should be cautious in drawing conclusions related to human learning from this study as the participants were rats and therefore they may learn (and their brains may be localised) differently to humans.

Question 44

How do findings about brain plasticity (neural reorganisation and neural regeneration) support a more holistic explanation of brain function?

Answer 44

When the brain has become damaged (e.g. illness, accident), and a particular function has been compromised or lost, the rest of the brain appears able to reorganise itself in an attempt to recover the lost function (plasticity). Although this doesn’t happen every time, there are several documented cases of stroke victims being able to recover those abilities that were seemingly lost as a result of the illness. This suggests that functioning may be more holistic rather than localised as different areas of the brain are able to recover the lost function of one particular area.

Question 45

What is the corpus callosum?

Answer 45

The corpus callosum is a thick bundle of nerves which connects the two hemispheres of the brain.

Question 46

What does the corpus callosum do?

Answer 46

It allows the two sides of the brain to communicate with each other so that the whole brain can work as one complete organ i.e. information received by one hemisphere can be sent to the other hemisphere.
In this way, the two hemispheres retain their own roles whilst working together to control behaviour in the whole body.

Question 47

What happens when the corpus callosum is severed?

Answer 47

The hemispheres work separately because they can’t communicate

Question 48

Where does information that enters the left visual field go?

Answer 48

Right hemisphere

Question 49

Where does information that enters the right visual field go?

Answer 49

Left hemisphere

Question 50

What equipment is involved in the investigation of split-brain research?

Answer 50

Stimuli (words, pictures etc)
Tachistoscope

Question 51

From Sperry and Gazzaniga’s split-brain research, explain what happens in two of the following tasks: describing what you see and composite words

Answer 51

Describing what you see - A picture of an object was shown to either the left or right visual field and the participant was asked to name the object.

Composite words - Two words were presented simultaneously, one on either side of the visual field (e.g. ‘key’ on the left and ‘ring’ on the right). Participants were asked to say what they saw and draw it if they couldn’t say it.

Question 52

Why is the Sperry and Gazzaniga procedure praised for the ability to determine cause and effect and thus support the internal validity of the hemispheric lateralisation theory?

Answer 52

Split-brain research made use of highly specialised and standardised procedures. The method of presenting visual information to one hemispheric field at a time was ingenious. Typically, participants would be asked to stare at a given point (the fixation point), whilst one eye was blindfolded. The image projected would be flashed up for 1/10 of the a second, meaning the split-brain patient would not have time to move their eye across the image and so spread the information across both sides of the visual field and consequently both hemispheres of the brain. This allowed the researchers to vary aspects of the basic procedure and ensured that only one hemisphere was receiving information at a time.

Question 53

What are the problems with Sperry and Gazzaniga’s sample?

Answer 53

The main researchers of split-brain research have urged caution in their widespread acceptance as split-brain patients constitute such an unusual sample of people. The sample size was very small as there were only 11 who took part in all variations of the basic procedure, all of whom had a history of epileptic seizures. It has been argued that this may have caused unique changes in the brain that may have influenced the findings. It is also the case that some participants had experienced more disconnection of the two hemispheres as part of their surgical procedure than others, and some patients had experienced drug therapy for much longer than others. The control group may have been inappropriate because they were people who had no history of epileptic seizures. Finally, the data was artificially produced as in real life, a severed corpus callosum can be compensated for by the unrestricted use of two eyes. This suggests that the research cannot be considered to be completely valid either internally or externally, and so we cannot confidently support the theory of hemispheric lateralisation from the split-brain research.

Question 54

Why might hemispheric lateralisation be more complex than originally stated by research such as Sperry and Gazzaniga’s?

Answer 54

In the normal brain, the two hemispheres are in constant communication when performing everyday tasks, and many of the behaviours typically associated with one hemisphere can be effectively performed by the other when the situation requires it. Therefore, hemispheric lateralisation may be more complex than originally stated and the brain may work more holistically.

Question 55

What is brain plasticity?

Answer 55

This describes the brain’s tendency to change and adapt as a result of experience and new learning. This generally involves the growth of new connections

Question 56

What is functional recovery of the brain?

Answer 56

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 57

Specifically, what is neural reorganisation?

Answer 57

This occurs when axons that do a similar job becomes aroused to a higher level to compensate for the ones that are lost. However, it can have the negative consequence of oversensitivity to messages such as pain

Question 57

Specifically, what is synaptic pruning?

Answer 57

As we age, rarely-used connections are deleted and frequently-used connections are strengthen

Question 58

What was the procedure and results of the Maguire et al taxi study?

Answer 58

Macguire et al. (2000) studied the brains of London taxi drivers. As part of their training, they have to take a complex test called ‘the Knowledge’, which assesses their recall of the city streets and possible routes.

They found that there was significantly more volume of grey matter in the posterior hippocampus of the taxi drivers compared to match controls. This part of the brain is associated with the development of spatial and navigational skills in humans and other animals. The longer they had been in the job, the more pronounced the structural difference (a positive correlation).

Question 59

How do the Maguire et al taxi study findings support the theory that the brain is highly plastic?

Answer 59

These studies suggest that the brain changes and adapts functionally and structurally as a result of experience, supporting the theory of plasticity.

Question 60

How has understanding the processes involved in plasticity contributed to the field of neurorehabilitation?

Answer 60

Following illness or injury to the brain, spontaneous recovery tends to slow down after a number of weeks. Therefore, forms of physical therapy may be required to maintain improvements in functioning (e.g.movement therapy). This suggests that although the brain may have the capacity to ‘fix’ itself to a point as a result of plasticity, the processes requires further intervention if it is to be completely successful. However, this has led to the development of therapies and interventions to ensure that functional recovery is completely successful (e.g. stimulation of opposite hemisphere of the brain to promote neural reorganisation).

Question 61

What did Bezzola et al find out about golfers?

Answer 61

Bezzola et al. demonstrated how 40 hours of golf training produced changes in the neural representation of movement in participants aged 40-60. Using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training.

Question 62

Does neural plasticity continues throughout the lifespan.

How does this support theory that suggests the brain is highly plastic?

Answer 62

This suggests that neural plasticity continues throughout the lifespan.

Question 63

How has having a college education been found to affect functional brain recovery?

Answer 63

Schneider et al. (2014) found that patients with the equivalent of a college education are seven times more likely than those who didn’t finish high school to be disability-free one year after a moderate to severe brain injury. We would expect brain plasticity, based on original theorising, to occur at the same rate for everyone (so everyone with a brain injury should recover at the same rate, regardless of their educational level).

Question 64

Having a college education

How is this a moderating factor for drawing conclusions about brain plasticity?

Answer 64

This suggests that educational attainment may influence how well the brain functionally adapts after injury and therefore acts as a moderating factor, meaning that we cannot see simple cause and effect; we can’t explain why it is that people with a college education to recover more quickly than those who didn’t finish high school.

Question 65

What is the procedure of an fMRI scan?

Answer 65

They take a series of slices of 2D pictures of the brain that can be put together.

Question 66

What is fMRI particularly useful for investigating?

Answer 66

Neural activity by seeing how much blood flow the part of the brain gets

Question 67

What is the procedure of an EEG?

Answer 67

Electrodes are placed on the scalp using a skull cap and detect small electrical charges resulting from neuronal activity directly below where they are placed (i.e. they directly measure the activity of neurons). Differing numbers of electrode can be used depending on the focus of the research. The scan recording represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity. Therefore, it is a recording of general brain activity, usually linked to states such as sleep and arousal.

Question 68

What is EEG particularly useful for investigating?

Answer 68

EEG is often used by clinicians as a diagnostic tool, as unusual arrhythmic patterns of activity (i.e. no particular rhythm) may indicate neurological abnormalities such as epilepsy, tumours, Alzheimer’s disease or disorders of sleep.

Question 69

What is the procedure of an ERP?

Answer 69

Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out, leaving only those responses that relate to a specific stimulus that is presented to the participant (event-related potentials or ERPs). To filter out the extraneous brain activity, many presentations of the specific stimulus and then the responses are averaged together. Any extraneous neural activity won’t occur consistently, whereas activity linked to the stimulus will.

Question 70

What is ERP particularly useful for investigating?

Answer 70

Measuring what the brain is doing whilst performing cognitive tasks, such as allocating attentional resources (directing attention, essentially), or performing recall tasks that measure working memory.

Question 71

What is the procedure of a post-mortem?

Answer 71

Areas of damage within the brain are examined after death to try to correlate structural abnormalities/damage to behaviour. This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.

Question 72

What are post-mortems particularly useful for investigating?

Answer 72

They are useful for providing information about the progression of disease, and potential causes of death in the individual, due to microscopic resolution (spatial) of individual cells and fibres in the brain.

Question 73

Which ways of investigating the brain are better for spatial resolution?

Answer 73

fMRIs

Question 74

Why are these methods better than others for spatial resolution?

Answer 74

They are able to depict detail by the millimetre. Therefore, they provide a clear picture of how brain activity is localised. However, they are not specific enough to hone in on individual neurons.

Question 75

Which ways of investigating the brain are better for temporal resolution?

Answer 75

EEGs

Question 76

Why is having methods with high temporal resolution good?

Answer 76

They can accurately detect brain activity at a resolution of a single millisecond (and even less in some cases). This means that the researcher can accurately measure a particular task or activity with the brain activity associated with it.

Question 77

What are the practical issues with fMRI?

Answer 77

fMRIs are more expensive than EEGs.
This means that smaller sample sizes have to be used. This expense is compounded because if a patient moves at all, a clear image cannot be captured.
Therefore, the results are less likely to be externally valid and fMRIs may be used less widely in research.

fMRIs are only an indirect measure of neural activity.
fMRI only measures the changes in blood flow in the brain rather than neural activity directly. This means that it is not a truly quantitative measure of mental activity in brain areas.

fMRIs have poor temporal resolution. There is around a 5-second time-lag behind the image on screen and the initial firing of neuronal activity.
This means that it is more difficult for a researcher to accurately measure a particular task or activity with the brain activity associated with it in real time.

fMRIs only focus on localised activity in the brain.
Critics of fMRIs claim that it is the communication among the different regions that is most critical to mental function. fMRIs are unable to capture such communication and so may not be the most useful way of investigating the communication between areas of the brain.

Question 78

What are the practical issues with EEG?

Answer 78

The main drawback of EEGs is their poor spatial resolution. The EEG signal is not useful for pinpointing the exact source of neuronal activity because electrical activity can be picked up by several neighbouring electrodes. As a result, researchers are unable to distinguish between activities originating in different but adjacent locations of the brain.

EEGs can only detect the activity in superficial regions of the brain. For example, this means that it cannot reveal what is going on in the deeper regions of the brain such as the hypothalamus or hippocampus. Electrodes can be implanted in non-human animals to achieve this, but it is not ethically permissible to do this with humans as it would be too invasive.

Question 79

What are the practical issues with ERP?

Answer 79

Not standardised - difficult to draw comparisons between studies

All extraneous interference has to be eliminated but that is very difficult - so if it is not necessary it is not used much

Question 80

What are the practical issues with post-mortems?

Answer 80

It’s retrospective study – there’s no opportunity for follow-up

Lots of confounding variables e.g. Dying at various stages of disease, length of time between death and post-mortem, drug treatments given before death, age at death… this makes direct comparisons for cause and effect pretty tricky!

Lack external validity as they made up of an abnormal sample – particular brains from particular people because post-mortems are done for a reason. So difficult to generalise from a lack of available brains.

Question 81

What are the ethical issues with fMRI?

Answer 81

It is quite invasive

Question 82

What are the ethical issues with post-mortem?

Answer 82

Informed consent – some patients lose the ability to consent during their lifetime due to the issues that make them of interest, but even those that do not are problematic because consent is needed from relatives (and needed quickly

Question 83

What is a circadian rhythm?

Answer 83

Circadian rhythms are a type of biological rhythm in which a pattern of behaviour occurs or recurs approximately every 24 hours. It is set and reset by environmental light levels.

Question 84

What happens in the sleep-wake cycle?

Answer 84

In the morning, cells in the eye detect light and so messages are sent via the optic nerve to the SCN which sends messages to raise our body temperature and blood pressure, and delay the release of hormones like melatonin from the pineal gland. Therefore, in the morning, we have our sharpest rise in blood pressure, and there is a reduction in secretion of melatonin causing us to feel awake. Early in the day, we have our highest level of cortisol which makes us feel awake.

In the evening, as the sun disappears, the SCN picks up signals of changing light from our eyes, and so it sends messages to ensure that our body temperature cools, and sleep inducing hormones like melatonin are released. Therefore, in the evening, our body temperature begins to decrease and the secretion of melatonin increases, signalling that it is time to sleep.

Question 85

What do Siffre’s and/or Aschoff and Wever (1976) findings about the free-running sleep-wake cycle suggest about the importance of exogenous zeitgebers in regulating the sleep-wake cycle?

Answer 85

There is research which supports the existence of circadian rhythms. Michael Siffre spend two months in the caves of the southern Alps deprived of light and sound, determining that his circadian rhythm remained between 24-25 hours. This suggests that the body’s internal clock is set 24-25 hours in the absence of external cues, and is intolerant of any major alterations to sleep and wake cycles, through processes such as shift work and jet lag. This is a strength as it shows that the concept has research support, and therefore may be valid.

Aschoff and Wever (1976)
They convinced a group of participants to spend four weeks in a WWII bunker deprived of natural light. All but one of the participants (whose sleep-wake cycle extended to 29 hours) displayed a circadian rhythm between 24-25 hours.

Both of these studies 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 e.g. number of daylight hours, typical meal-times etc.

Question 86

What does Folkard et al’s study suggest about the resilience of the sleep-wake cycle as an endogenous pacemaker despite the presence of misleading exogenous zeitgebers?

Ignore

Answer 86

They studied a group of 12 people who agreed to live in a dark cave for 3 weeks, retiring to bed when the clock said 11.45pm and rising when it said 7.45am. Over the course of the study, the researchers gradually sped up the clock (without the participants’ knowledge) so an apparent 24-hour day eventually lasted only 22 hours. It was revealed that not one of the participants were able to comfortably adjust to the new regime. This would suggest the existence of a strong free running circadian rhythm that cannot easily be overridden by changes in the external environment.

Question 87

What useful practical applications does studying the circadian rhythm of the sleep-wake cycle have?

Ignore

Answer 87

Shift work has been found to lead to desynchronization of circadian rhythms and can lead to adverse cognitive and physiological effects. Research has shown that night shift workers suffer a concentration lapse at 6am, increasing the likelihood of accidents, and shift workers are also three times more likely to suffer from heart disease as a result from the stress of adjusting to sleep/wake cycles. This is a strength of the research on circadian rhythms as it has many practical and economic implications, in terms of maintaining worker productivity and preventing accidents in the workplace.

Question 88

What useful application to pharmacokinetics does circadian rhythm research have?

Answer 88

By understanding circadian rhythms and their impact on health, it can help determine the best time to administer drug treatments. For example, the risk of heart attack is greatest in early morning so drugs can be taken at night, but not released until when they will be most effective at dusk. This is a strength as it gives the research has useful practical applications, such as the timing of drug dosing of a whole range of medications including anti-cancer, cardiovascular and anti-epileptic drugs. This means that there are peak times for administration and dosage of a variety of drugs that increase their efficacy.

Question 89

What are some problems with circadian rhythm research, which mean that we cannot draw clear conclusions about the extent to which they are internally (endogenous) or externally (exogenous) governed?

Answer 89

The Siffre study was only on one individual, and the Folkard, Wever and Aschoff studies were conducted on only a handful of people. Consequently, it is impossible to generalise these results to whole populations of people, as there may be some individual differences in the research sample that makes these participants respond the changes the sleep/wake cycle in atypical ways. For example, Siffre noted that when he went into the cave at 60yr his body responded very differently, with his body clock following more of a 48hr cycle. And Czeisler has found evidence that cycles can vary by as much as 13-65 hours. This is a weakness as it suggests that results lack external validity, as factors such as age and gender may have significant impacts on our circadian rhythms. FI: Poor control in studies idea

Question 90

What is an ultradian rhythm?

Answer 90

A type of biological rhythm that lasts less than 24 hours (more than one cycle in 24 hours)

Question 91

What happens in the sleep cycle, and how is that an example of an ultradian rhythm?

Answer 91

One of the most extensively researched ultradian rhythms is the stages of sleep – the sleep cycle. Psychologists have identified five distinct stages of sleep (REM and four non-REM) that altogether span approximately 90-100 minutes. Each stage of sleep has a different duration. A complete cycle consists of a progression through the four stages of non-REM sleep (stages 1-4) before entering a final stage of REM sleep, then the whole cycle stars again. This is a cycle that repeats throughout the course of the night and therefore occurs more than once in every 24 hours.

Each of the stages of sleep is characterised by a different level of brainwave activity which can be monitored using an EEG. As the person enters deep sleep, their brainwaves slow and their breathing and heart rate decreases. During the fifth stage (REM sleep), the EEG pattern resembles that of an awake person and it is in this stage that most dreaming occurs.

Question 92

What is the basic rest-activity cycle, and how is that an example of an ultradian rhythm?

Answer 92

Kleitman (1969) suggested that a similar 90-minute rhythm cycle continues during waking hours. He called this the Basic rest-activity cycle (BRAC).

This is characterised by a period of alertness followed by a spell of physiological fatigue. This occurs across a 90-minute cycle which then recurs during the course of the day.

Research suggests that the human mind can focus for about 90 minutes, and towards the end of these 90 minutes, the body begins to run out of resources, resulting in a loss of concentration, fatigue and hunger

Question 93

What did Dement and Kleitman find out about dreaming and REM sleep?

Answer 93

Derment and Kleitman (1957) monitored the sleep patterns of nine adult participants in a sleep lab. Brainwave activity was recorded on an EEG and the researchers controlled for the effects of caffeine and alcohol. REM activity during sleep was highly correlated with the experience of dreaming, brain activity varied according to how vivid dreams were, and participants woken during dreaming reported very accurate recall of their dreams.

Question 94

How do the Dement and Kleitman findings support ultradian rhythms (specifically, the stages of sleep)?

Answer 94

This suggests that REM sleep is an important component of the ultradian sleep cycle and that there are distinct stages of sleep. Replications of this investigation have noted similar findings, although the size of the original sample has been criticised.

Question 95

What did Ericsson et al find out about elite violinists’ practise regime?

Answer 95

Ericsson et al. (2006) studied a group of elite violinists and found that, among this group, practice sessions were usually limited to a duration of no more than 90 minutes at a time, with practice systematically distributed during the day in these 90-minute segments. The analysis also indicated that the violinists frequently napped to recover from practice, with the very best violinists napping more than their teachers. They found the same pattern among other musicians, athletes, chess players and writers.

Question 96

How do the Ericsson et al findings support ultradian rhythms (specifically, the basic rest-activity cycle)?

Answer 96

This is consistent with the claim that fatigue is a characteristic of the end of the BRAC cycle which occurs in a roughly 90 minute cycle, and therefore supports the ultradian rhythm.

Question 97

What is an infradian rhythm?

Answer 97

A type of biological rhythm with a duration of over 24 hours.

Question 97

What happens in seasonal affective disorder, and how is that an example of an infradian rhythm?

Answer 97

SAD is a depressive disorder which has a seasonal pattern of onset and is described and diagnosed in the DSM-5. As with other forms of depression, the main symptoms of SAD are persistent low mood alongside a general lack of activity and interest in life. SAD is often referred to as the winter blues as the symptoms are triggered during the winter blues as the symptoms are triggered during the winter months when the number of daylight hours becomes shorter. SAD is an infradian rhythm because it occurs less frequently than every 24 hours.

Psychologists have hypothesised that the hormone melatonin is implicated in the causes 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 has been linked to the onset of depressive symptoms.

Question 98

Explain the processes involved in the menstrual cycle, and how that makes the menstrual cycle an example of an infradian rhythm

Answer 98

The human female menstrual cycle is an example of an infradian rhythm which is governed by monthly changes in hormone levels which regulate ovulation (‘mensis’ is Latin for month). The cycle refers to the time between the first day of a woman’s period, when the womb lining is shed, to the day before her next period. The typical cycle takes approximately 28 days to complete (though anywhere between 24 and 35 days is generally considered normal).

During each cycle, rising levels of the hormone oestrogen cause the ovary to develop an egg and release it (ovulation). Ovulation occurs roughly halfway through the menstrual cycle when oestrogen levels are highest, and usually lasts for 16-32 hours. After ovulation, the levels of the hormone progesterone increase which helps the womb lining to grow thicker, readying the body for pregnancy. If pregnancy does not occur, the egg is absorbed into the body and the womb lining comes away and leaves the body (the menstrual flow).

Question 99

How is Stern and McClintock’s pheromones study both evidence for the menstrual cycle being endogenous (internal), and having an exogenous (external) influence?

Answer 99

They studied 29 women with 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 (worn for at least 8 hours to ensure the pheromones were picked up). The pads were treated with alcohol anf frozen, to be rubbed onto the upper lip of the other 20 participants. On day one, pads from the start of the menstrual cycle were applied to all 20 women, on day two they were given a pad from the second day of the cycle etc. They found that 68% of women experienced changes to their menstrual cycle which brought them closer to the cycle of their ‘odour donor’.
This supports the endogenous infradian rhythm of the menstrual cycle. However, it also suggests that it may be influenced by exogenous factors, such as the cycles of other women.

Question 100

Why might it have been evolutionarily adaptive for females to be menstruating at the same time (showing this infradian rhythm may have evolved to have both endogenous and exogenous features in order to promote the species)?

Answer 100

Menstrual synchrony as found in Stern and McClintock’s study is thought to have an evolutionary value. For our ancestors, it may have been advantageous for females to menstruate together and therefore fall pregnant at around the same time. This would mean that new-borns could be cared for collectively within a social group increasing the chances of the offspring’s survival. This supports the importance of the endogenous infradian rhythm of the menstrual cycle.

However, the validity of this evolutionary perspective has been questioned. If there were too many females cycling together within a social group, this would produce competition for the highest quality males (and thereby lowering the fitness of any potential offspring).

Question 101

What is an endogenous pacemaker?

Answer 101

Internal body clocks that regulate many of our biological rhythms, such as the influence of the SCN and pineal gland on the sleep-wake cycle.

Question 102

What is an exogenous zeitgeber?

Answer 102

External cues that may affect (or entrain or regulate) our biological rhythms, such as the influence of light on the sleep-wake cycle.

Question 103

Give an example of an endogenous pacemaker

Answer 103

SCN

Question 104

Give an example of an exogenous zeitgeber

Answer 104

Light

Question 105

What does the De Coursey et al chipmunk study suggest about the strength of endogenous pacemakers in regulating body function and behaviour?

Answer 105

They 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 and vulnerable to attack when they should have been asleep) [i.e. Not hidden away sleeping like they should be]. The animal studies emphasise the role of the SCN in establishing and maintaining the circadian sleep-wake cycle (you need to explain how; the process from your AO1 notes). This is therefore supporting evidence for the importance of the role of endogenous pacemakers.

Question 106

What does the Campbell and Murphy (light > back of knee) study suggest about the strength of exogenous zeitgebers in regulating body function and behaviour?

Answer 106

They demonstrated that light may be detected by skin receptor sites on the body even when the same information is not received by the eyes. Fifteen participants were woken at various times and a light pad was shone on the back of their knees. The researchers managed to produce a deviation in the participants’ usual sleep-wake cycle of up to 3 hours in some cases.

The light studies support that light is a powerful exogenous zeitgeber that need not necessarily rely on the eyes to exert its influence on the brain.

Question 107

Most of the research on endogenous pacemakers and exogenous zeitgebers has involved attempting to isolate the influence of each. Why does doing this make little sense in real life?

Answer 107

In real-life, pacemakers and zeitgebers interact, and it may make little sense to separate the two for the purpose of research.