Biopsychology

Question 1

What is the nervous system?

Answer 1

The part of an animal’s brain body that coordinates its voluntary and involuntary actions and transmits signals between different parts of its body

Question 2

What does the nervous system divide into?

Answer 2

Two main sub-systems;
1)The central nervous system (CNS)
2)The peripheral nervous system (PNS)

Question 3

What is the CNS?

Answer 3

• The CNS is made up of the brain and the spinal cord.
• The brain is the centre of awareness. The outer layer is called the cerebral cortex, which is highly developed in humans allowing high levels of mental functioning.
• The spinal cord is an extension of the brain and is responsible for reflex actions.

Question 4

What is the PNS?

Answer 4

• The peripheral nervous system transmits messages around the body via millions of neurons, to and from the CNS.
• The PNS is further sub-divided into the autonomic nervous system and the somatic nervous system.

Question 5

What is the autonomic nervous system?

Answer 5

Deals with vital functions that happen automatically such as breathing, heart rate, digestion and stress responses.

Question 6

What does the autonomic nervous system divide into?

Answer 6

The autonomic nervous system has two parts;
1)The sympathetic nervous system
2)The parasympathetic nervous system

Question 7

Describe the sympathetic nervous system

Answer 7

• This is primarily involved with responses that help us deal with emergencies (fight or flight)
• Neurons from the SNS travel to virtually every organ and gland within the body, preparing for rapid action

Question 8

Describe the parasympathetic nervous system

Answer 8

• The PNS relaxes the body once an emergency has passed, slowing down the blood pressure etc.
• Digestion begins again, after having been inhibited when the SNS was aroused

Question 9

Outline the somatic nervous system

Answer 9

• The somatic nervous system deals with muscle movements and receives information from sensory receptors
• The nerves have both sensory neurons and motor neurons
• Sensory neurons relay messages to the CNS
• Motor neurons relay information from the CNS

Question 10

What is the endocrine system?

Answer 10

• The endocrine system works alongside the nervous system to control vital functions in the body. The endocrine system acts much more slowly than the nervous system but has very widespread and powerful effects
• Various glands in the body, such as the thyroid gland, produce hormones. Hormones are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone

Question 11

What are glands?

Answer 11

Organs in the body that synthesise biochemical substances such as hormones

Question 12

What are hormones?

Answer 12

Biochemical substances that circulate in the bloodstream and only affect target organs. They are produced in large quantities but disappear quickly. Their affects are very powerful.

Question 13

Where is testosterone produced?

Answer 13

Testes

Question 14

When do the endocrine system and autonomic nervous system work together?

Answer 14

During fight or flight

Question 15

What does the SAM pathway stand for?

Answer 15

Sympathomedullary pathway

Question 16

Describe the role of the sympathomedullarly pathway

Answer 16

The SAM system is the name of the pathway that leads to the adrenal medulla (part of the adrenal gland), and stands for the Sympathetic Adrenal Medullary system, or the SYMPATHOMEDULLARY PATHWAY.

Question 17

Describe what happens during fight or flight

Answer 17

When we are acutely stressed, the SAM is activated. This prepares the body for fight or flight.
A stressor is perceived by the peripheral nervous system. The hypothalamus immediately activates the Sympathetic Branch of the Autonomic Nervous System. The ANS changes from its normal resting state (the parasympathetic state) to the physiologically aroused sympathetic state.

This stimulates the Adrenal Medulla (central part of adrenal gland) which secretes adrenaline which prepares the body for fight or flight by triggering physiological changes in the body:
- Increases heart rate
- Increases respiration (breathing) in rate and depth
- Increases blood and oxygen supply to the muscles
- Increases muscle tone
- Suppresses digestion
- Dilates pupils

These create the physiological arousal necessary for fight or flight response.

Question 18

What happens once the threat has passed during fight or flight?

Answer 18

One the threat has passed; the parasympathetic nervous system returns the body to its resting state. The parasympathetic branch of the ANS works in opposition to the sympathetic nervous stem - its actions are antagonistic to the sympathetic system. The parasympathetic system acts as a ‘brake’ and reduces the activities of the body that were increased by the actions of the sympathetic branch. This is sometimes referred to as the rest and digest response.

Question 19

What are neurons?

Answer 19

• A neuron is a cell that is the basic building block of the nervous system
• Neurons are specialised to transmit information throughout the body
• These highly specialised cells are responsible for communicating information in both chemical and electrical forms

Question 20

Draw and label a neuron

Answer 20

• Nucleus
• Dendrites
• Cell body
• Axon
• Myelin
• Axon terminal

Question 21

Describe the role of sensory neurons

Answer 21

o A sensory neuron is a nervous system cell that is involved in the transportation of sensory information from sensory organs to the brain
o These neural impulses are sent to the brain and translated into an understandable form so that the organism can react to the stimuli
o Such understandable forms include sensations of pain, heat, texture and visual input
o The reception of such stimuli is crucial to the survival of most organisms, as it keeps them informed of the world around them and allows them to respond accordingly
o Sensory neurons have long dendrites and short axons

Question 22

How to know whether a neuron is a sensory neuron in a picture

Answer 22

It is attached to skin

Question 23

Describe the role of motor neurons

Answer 23

o A motor neuron is a type of cell in the nervous system that directly or indirectly controls the contraction or relaxation of muscles, which in most cases leads to movement
o Motor neurons have short dendrites and long axons

Question 24

How to know whether a neuron is a motor neuron in a picture

Answer 24

Attached to a muscle

Question 25

Describe the role of relay neurons

Answer 25

o Relay neurons are responsible for carrying information from one part of the CNS to the other. Relay neurons connect other neurons together (e.g. sensory to motor, or other relay neurons)
o Relay neurons have sort dendrites and short axons

Question 26

Outline the structure and process involved in synaptic transmission - 6 marks

Answer 26

Impulses travel electrically down the pre-synaptic cell in vesicles containing neurotransmitters. When the electrical impulse reaches the end of the neuron, the presynaptic terminal, it triggers the release of neurotransmitters from synaptic vesicles. The neurotransmitters then chemically diffuse across the synapse to the next neuron in the chain. Once a neurotransmitter crosses the gap, it is taken up by a postsynaptic receptor site on the dendrites of the next neuron. Here, the chemical message is converted back into an electrical impulse and the process of transmission begins again in this other neuron. Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neuron. Excitation increases the probability that neurotransmitters will be released by the neuron and inhibition decreases the probability that neurotransmitters will be released by the neuron.

Question 27

What is excitation?

Answer 27

When a neuron sends an electrical message; this increases the probability that neurotransmitters will be released by the neuron- e.g. adrenaline

Question 28

What is inhibition?

Answer 28

Inhibition is when a neuron fails to send an electrical message; this decreases the probability that neurotransmitters will be released by the neuron- e.g. serotonin

Question 29

What is localised function?

Answer 29

The idea that different parts of the brain perform different tasks and are involved with different parts of the body
Therefore, if a certain area of the brain is damaged through illness or injury, the function associated with that area will also be affected

Question 30

Hemispheric Lateralisation

Answer 30

• The brain is divided into two symmetrical halves called the left and right hemispheres.
• Some of our physical and psychological functions are controlled by a particular hemisphere- this is called lateralisation.
• Activity on the right-hand side of the body is controlled by the left-hand side of the brain and vice versa e.g. language is linked to the left hemisphere

Question 31

Cerebral Cortex

Answer 31

• The outer layer of both hemispheres is the cerebral cortex.
• This is like a tea cosy covering the inner parts of the brain.
• About 3mm thick, the cortex appears grey due to the appearance of cell bodies and dendrites; it is often referred to as ‘grey matter.
• The cortex is divided into four lobes: the frontal lobe, the parietal lobe, the occipital lobe and the temporal lobe

Question 32

The motor area

Answer 32

• At the back of the frontal lobe is the motor area
• Controls voluntary movement in the opposite side of the body
• Damage to this area of the brain may result in a loss of control over fine movements

Question 33

The somatosensory area

Answer 33

• At the front of both parietal lobes is the somatosensory area
• Sensory information from the skin e.g. touch, heat, pressure, is represented

Question 34

The visual area

Answer 34

• In the occipital lobe at the back of the brain is the visual area
• Responsible for sight
• Damage to the left hemisphere can produce blindness in part of the right visual field of both eyes

Question 35

The auditory area

Answer 35

• Located in the temporal lobes
• Analyses speech-based information
• Damage may produce partial hearing loss and damage to a specific area (Wernicke’s area) may affect the ability to comprehend language

Question 36

What is Broca’s area?

Answer 36

• An area of the frontal lobe of the brain in the left hemisphere responsible for speech production.
• Identified by Paul Broca- a surgeon- in the 1880s.
• Damage to Broca’s area causes Broca’s aphasia which is characterised by speech that is slow, laborious and lacking in fluency.
• Does not affect understanding
• Difficulty with prepositions and junctions

Question 37

What is Wernicke’s area?

Answer 37

• An area of the temporal lobe in the left hemisphere, responsible for language comprehension.
• Wernicke’s aphasia occurs due to damage to this area and results in fluent, but meaningless language - have no problem producing language, but understanding it
• People with Wernicke’s aphasia will often produce nonsense words (neologisms) as part of the content of their speech.

Question 38

Evaluation of localisation of function - Phineas Gage

Answer 38

P - One strength is that there is research to support that the brain has localised functions.
E - Phineas Gage was working on a railroad and accidentally ignited an explosive causing a metre-length pole to hurl through his left cheek, passing behind his left eye, exiting his skull from the top of his head, taking a portion of his brain with it (most of his left frontal lobe). He survived and the only thing that changed was his personality which became rude and quick-tempered.
E - Gage is seen as a landmark case in science as the change in his temperament following the accident suggested that the frontal love may be responsible for regulating mood.

Question 39

Evaluation of localisation of function - brain scans

Answer 39

Evidence from brain scans
P - Another strength is evidence from brain scans that supports the idea that many everyday brain functions are localised
E - For example, Petersen et al (1988) 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, a review of long-term memory studies by Buckner and Petersen (1996) revealed that semantic and episodic memories reside in different parts of the prefrontal cortex. These studies confirm localised areas for everyday behaviours.
E - Therefore objective methods for measuring brain activity have provided sound scientific evidence that many brain functions are localised.

Question 40

Evaluation of localisation of function - language localisation questioned

Answer 40

P - One limitation is that language may not be localised just to Broca’s and Wernicke’s areas
E - A recent review by Dick and Tremblay (2016) found that only 2% of modern researchers think that language in the brain is completely controlled by Broca’s and Wernicke’s areas. Advances in brain imaging techniques, such as fMRI, mean that neural processes in the brain can be studied with more clarity than ever before. 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.
E - This suggests that, rather than being confined to a couple of key areas, language may be organised more holistically in the brain, which contradicts localisation theory.

Question 41

What is hemispheric lateralisation?

Answer 41

• 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 rather than the other, as in the example of language (which is localised and lateralised)
• The two hemispheres are connected through nerve fibres called the corpus callosum which facilitate inter-hemispheric communication.

Question 42

What is a split brain operation?

Answer 42

• A ‘split-brain’ operation involved severing the connection between the right hemisphere and left hemisphere, mainly the corpus callosum
• This is a surgical procedure to reduce epilepsy

Question 43

Aim of Sperry’s research

Answer 43

Sperry (1968) devised a system to study how two separated hemispheres deal with, for example, speech and vision

Question 44

Procedure of Sperry’s research

Answer 44

11 people who had a split-brain operation were studied - an image could be projected to a participants right visual field (RVF) - processed by the left hemisphere (LH) - and the same or different image could be projected to the left visual field (LVF) - processed by the right hemisphere (RH). In the ‘normal’ brain, the corpus callosum would immediately share the information 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 45

Findings of Sperry’s research

Answer 45

When a picture 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, but this is not possible in the split brain. Although participants could not give verbal labels to objects projected to the LVF, they could select a matching object out of sight using their left hand (RH), as well as the left hand. If a pinup picture was shown to the LVF there was an emotional reaction (e.g. giggle) but the participants usually reported seeing nothing or just a flash of light.

Question 46

Conclusion of Sperry’s research

Answer 46

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

Question 47

Evaluation of hemispheric lateralisation - split brain research

Answer 47

P – one strength of split-brain research into hemispheric lateralisation is that there is a wealth of information and research findings.
E – for example findings that the left hemisphere is more analytical that the right hemisphere.
E – this is important because it has contributed to our understanding of processes in the brain.

Question 48

Evaluation of hemispheric lateralisation - generalisation

Answer 48

P – Even though there is a lot of evidence from research, this does not mean that it is generalisable beyond the research setting.
E – Split brain patients do not have typical brains, as they have undergone a certain amount of trauma through the process of severing the corpus collosum.
E – This is a problem because we cannot necessarily generalise the findings to people who have not experienced this operation. Additionally, the findings may only show what happens when the communication channel is no longer intact – it does not show that this is still the case if the corpus collosum is allowing communication between the hemispheres.

Question 49

Evaluation of hemispheric lateralisation - method

Answer 49

P – a major strength of split-brain research is that it uses highly standardised procedures.
E – for example, the image projected was flashed up for only one-tenth of a second meaning that the image could only be viewed by one hemisphere.
E – this means that the research can be viewed as scientific, which is internally valid as it has controlled extraneous variables.

Question 50

What is neural plasticity?

Answer 50

• Plasticity, also referred to as neuroplasticity or cortical remapping, describes the brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning.
• During infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 at age 2-3 years.
• As we age, rarely used connections are deleted and frequently used connections are strengthened- synaptic pruning.
• It was originally thought that plasticity occurred in infancy and childhood and the adult brain remains fixed and static.
• However, more recent research suggests that at any time in life, existing neural connections can change, or new neural connections can be formed, as a result of learning and experience.

Question 51

Maguire et al

Answer 51

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

Question 52

Draganski et al. (2006)

Answer 52

by Draganski et al. imaged the brains of medical students three months before and after their final exams. Learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of learning.

Question 53

Evaluation of neural Plasticity - negative plasticity

Answer 53

P - One limitation of plasticity is that it may have negative behavioural consequences
E - Evidence has shown that the brain’s adaptation to prolonged drug use leads to poorer cognitive functioning in later life, as well as an increased risk of dementia (Medina et al. 2007). Also, 60-80% of amputees have been known to develop phantom limb syndrome - the continues 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.
E - This suggests that the brain’s ability to adapt to damage is not always beneficial

Question 54

Evaluation of neural Plasticity - age and plasticity

Answer 54

P - One strength is that brain plasticity may be a life-long ability.
E - In general plasticity reduces with age. However, Bezzola et al. (2012) demonstrated how 40 hours of gold training produced changes in the neural representations of movement in participants aged 40-60. Using fMRI, the researchers observed increased motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training.
E - This shows that neural plasticity can continue throughout the lifespan.

Question 55

Functional recovery after trauma explained

Answer 55

• Following physical injury, or other forms of trauma, unaffected areas of the brain are often able to adapt and compensate for those areas that are damaged.
• The functional recovery that may occur in the brain after trauma is another example of neuroplasticity.
• Healthy areas may take over the functions of those areas that are damaged, destroyed or missing.
• This can happen very quickly!

Question 56

Functional recovery after trauma evaluation - real-world application

Answer 56

P - One strength of functional recovery research is its real-world application.
E - understanding the processes involved in plasticity has contributed to the field of neurorehabilitation. Simply understanding that axonal growth is possible encourages new therapies to be tried. For example constraint-induced movement therapy is used with stroke patients whereby they repeatedly practise using the affected part of their body (such as an arm) while the unaffected arm is restrained.
E - This shows that research into functional recovery is useful as it helps medical professionals know when interventions need to be made.

Question 57

Functional recovery after trauma evaluation - cognitive reserve

Answer 57

P - One limitation of functional recovery is that level of education may influence recovery rates.
E - Schneider et al. (2014) revealed that the more time people with a brain injury had spent in education - taken as an indication of their ‘cognitive reserve’ - 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.
E - This would imply that people with brain damage who have insufficient DFR are less likely to achieve a full recovery.

Question 58

Describe the function of an fMRI

Answer 58

o fMRIs work in the same way as standard MRIs but show activity as it occurs (functions).
o fMRIs measure the energy released by haemoglobin (the protein content of blood).
o When an area of the brain is active, it uses more oxygen, and haemoglobin reacts differently when it has oxygen.
o When the brain is scanned, it picks up this change.
o The fMRI produces a 3D moving image, which shows which parts of the brain are active during particular mental processes, which is important for our understanding of localisation of function.

Question 59

Strengths of fMRI

Answer 59

o One strength of fMRI is, unlike other scanning techniques, such as PET, it does not rely on the use of radiation.
o If administered correctly it is virtually risk-free, non-invasive and straightforward to use. It also produces images that have very high spatial resolution, depicting detail by the millimetre, and providing a clear picture of how brain activity is localised.
o fMRI provides a moving picture of brain activity, which means that patterns of activity can be compared rather than just the physiology of the brain. This means that fMRI can safely provide a clear picture of brain activity.

Question 60

Limitations of fMRI

Answer 60

o fMRI machines are expensive to buy and maintain and they require trained operators.
o fMRI can only capture a clear image if the person stays perfectly still i
o It has poor temporal resolution because there is around a 5-second time0lag behind the image on screen and the initial firing of neuronal activity, meaning fMRI may not truly represent moment-to-moment brain activity.
o fMRI measures the blood flow, not the activity of individual neurons, so it can be difficult to tell what kind of brain activity is being picked up.

Question 61

EEG function

Answer 61

o Electroencephalograms are records of the tiny electrical impulses produced by the brain’s activity.
o Electrodes are placed on the scalp using a skull cap.
o By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain such as epilepsy and tumours.

Question 62

EEG strengths

Answer 62

o EEG 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.
o Unlike fMRI, EEG technology has extremely high temporal resolution.
o EEG can accurately detect brain activity at a resolution of a single millisecond - showing real-world usefulness of the technique
o Cheaper than other techniques

Question 63

EEG limitations

Answer 63

o Expertise is required to interpret the output from EEGs.
o The information received from EEGs is generalised, so they are not useful in pinpointing the exact source of neural activity - therefore does not allow researchers to distinguish between activities originating in different but adjacent locations

Question 64

ERP function

Answer 64

o Event-related potentials use the same apparatus as EEGs, but record when there is activity in response to a stimulus.
o Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out, leaving only the response to the given stimulus.

Question 65

ERP strengths

Answer 65

o ERPs are cheaper than other scanning techniques.
o The limitations of EEGs are addressed through ERPs because they are much more specific.
o ERPs are used in the measurement of cognitive functions and deficits.
o ERPs have much more temporal resolution (time it happens) than neuroimaging techniques such as fMRI.

Question 66

ERP limitations

Answer 66

o Expertise is required to interpret the output from EEGs.
o It can be very difficult to eliminate all background noise and extraneous material, which is necessary for the collection of ERP data.

Question 67

Post-Mortem examination functions

Answer 67

o Port-mortem examinations involve the brain being analysed after death to determine whether certain observed behaviours during the patient’s lifetime can be linked to abnormalities in the brain.

Question 68

Post-Mortem examination strengths

Answer 68

o There is no discomfort for the individual (as they are dead).
o Post-mortems have been an vital part of our early understanding of the brain (before neuroimaging was a possibility).
o Post-mortems help generate hypotheses for further study.
o Broca and Wernicke both relied on post-mortem studies in establishing links between language, brain and behaviour decades before neuroimaging ever became a possibility
o 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 - showing post-mortems continue to provide useful information

Question 69

Post mortem examinations limitations

Answer 69

o It is not possible to do a comparison with a brain before death, and some brains may have been affected by the cause of death, being subject to trauma or decay
o There is no brain activity, so only the structure of the brain can be studied (no processes).
o There may be ethical issues regarding informed consent from the individual, for example in the case of HM who lost his ability to form memories and was not able to provide such consent - nevertheless post-mortem research has been conducted on his brain.

Question 70

What is a biological rhythm?

Answer 70

Distinct patterns of changes in body activity that conform to cyclical time periods. All biological rhythms are subject to the body’s internal biological ‘clocks’ and external changes in the environment

Question 71

Describe what is meant by an infradian ryhthm

Answer 71

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

Question 72

Describe what is meant by an ultradian rhythm

Answer 72

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

Question 73

Describe what is meant by a circadian rhythm

Answer 73

A type of biological rhythm, subject to a 24-hour cycle, which regulates a number of body processes such as the sleep/wake cycle and changes in core body temperature

Question 74

What are endogenous pacemakers?

Answer 74

Internal body clock that regulate many of our biological mechanisms

Question 75

What are exogenous zeitgebers?

Answer 75

External cues that may affect our biological rhythms

Question 76

Explain endogenous pacemakers and exogenous zeitgebers in relation to sleep

Answer 76

o Our fairly consistent sleep pattern suggests an internal or endogenous mechanism - the biological clock
o However, this can be overridden by psychological factors, such as anxiety or by exogenous zeitgebers

Question 77

Michael Siffre’s cave study

Answer 77

PROCEDURES
o Michael Siffre is a self-styled caveman who has spent several extended periods underground to study the effects of his own biological rhythms
o Deprived of exposure to natural light and sound, but with access to adequate food and drink - Siffre resurfaced in mid-September 1962 after two months in the caved of the Southern Alps believing it to be mid-August
o A decade later he performed a similar feat but this time for six months in a Texan cave

FINDINGS
o 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 78

Aschoff and Wever’s (1976) research

Answer 78

PROCEDURES
o Similar results were recorded by Aschoff and Wever (1976) who convinced a group of participants to spend four weeks in a World War 2 bunkers deprived of natural light

FINDINGS
o All but one of the participants (whose sleep/wake cycle extended to 29 hours) displayed a circadian rhythm between 24 and 25 hours

CONCLUSIONS
o 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 79

Folkard et al research

Answer 79

PROCEDURES
o Folkard et al studied a group of 12 people who agreed to live in a dark cave for three weeks, retiring to bed when the clock said 11:45pm and rising when it said 7:45am
o Over the course of the study, the researchers gradually sped up the clock (unbeknownst to the participants) so an apparent 24-hour day eventually only lasted 22 hours

FINDINGS
o It was revealed that only one of the participants was able to comfortably adjust to the new regime

CONCLUSIONS
o This would suggest the existence of a strong free-running circadian rhythm that cannot easily be overridden by exogenous zeitgebers

Question 80

Evaluation of circadian rhythms - shift work

Answer 80

P - One strength of research into circadian rhythms is that it provides an understanding of the adverse consequences that occur when they are disrupted.
E - For example, night workers engaged in shift work experience a period of reduced concertation around 6 in the morning (a circadian trough) meaning mistakes and accidents are more likely. Research has 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.
E - 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 81

Evaluation of circadian rhythms - shift work counterpoint

Answer 81

P - However, 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 as there may be other factors.
E - For example, 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.
E - This suggests that it may not be biological factors that create the adverse consequences associated with shift work.

Question 82

Evaluation of circadian rhythms - medical treatment

Answer 82

P - Another strength of research into circadian rhythms is that it has been used to improve medical treatments.
E - Circadian rhythms co-ordinate a number of the body’s basic processes such as heart rate, digestion and hormone levels. This rise and fall during the course of a day which has led to the field of chronotherapeutics - how medical treatment can be administered in a way that corresponds to a person’s biological rhythms. For example, aspirin as a treatment for heart attacks is most effective if taken last thing at night. Aspirin reduces blood platelet activity, and this can reduce the risk of heart attack. Heart attacks are most likely to occur early in the morning, so the timing of taking aspirin matters - research has supported this.
E - This shows that circadian rhythm research can help increase the effectiveness of drug treatments.

Question 83

Evaluation of circadian rhythms - individual differences

Answer 83

P - One limitation of research into circadian rhythms is that generalisations are difficult to make
E - The studies of Aschoff and Wever and Siffre are based on very small samples of participants - for example Siffre only used himself as a case study. Research has found individual differences in sleep/wake cycles can vary from 13 to 65 hours. In addition, Duffy et al found that some people naturally prefer to go to bed early and wake up early and vice versa. Even Siffre found in a later study that his sleep/wake cycle has slowed down since he was a young man.
E - This means that it is difficult to use the research data to discuss anything more than averages, which may be meaningless.

Question 84

Describe the menstrual cycle as an infradian rhythm

Answer 84

• The female menstrual cycle is an example of an infradian rhythm, governed by monthly changes in hormone levels which regulate ovulation.
• The cycle refers to the time between the first day of a woman’s period, to the day before her next period.
• The typical cycle takes 28 Days to complete (between 24 and 35 is considered normal).
• Rising levels of the hormone oestrogen cause the ovary to develop and release an egg (ovulation).
• After this, the hormone progesterone helps the womb lining to thicken making the body ready for pregnancy.
• If pregnancy does not occur, the egg is absorbed into the body, the womb lining comes away and leaves the body (menstrual flow).

Question 85

Describe SAD as an infradian rhythm

Answer 85

• Seasonal affective disorder (SAD) is a depressive disorder which has a seasonal pattern of onset, and is described and diagnosed as a mental disorder in DSM-5
• Symptoms - low mood, general lack of activity and interest in life
• Often referred to as the winter blues - symptoms usually triggered in winter months when the number of daylight hours becomes shorter
• It is a type of infradian rhythm known as a circannual rhythm as it is subject to a yearly cycle
• Also be classed as a circadian rhythm as the experience of SAD may be due to the disruption of the sleep/wake cycle and this can be attributed to prolonged periods of daily darkness during winter
• It is hypothesised that the cause of SAD lies in the production of melatonin, because the extra melatonin secreted in winter months (because of the shorter days and longer nights) has an effect on the production of serotonin. Serotonin production is linked to depression.

Question 86

Evaluation of infradian rhythms - Reinberg

Answer 86

P - There is research to suggest that the menstrual cycle is to some extent governed by exogenous zeitgebers
E - Reinberg (1967) examined a woman who spent three months in a cave with only a small lamp to provide light. Reinberg noted that her menstrual cycle shortened from the usual 28 days to 25.7 days.
E - This result suggests that the lack of light (an exogenous zeitgeber) in the cave affected her menstrual cycle, and therefore this demonstrates the effect of external factors on infradian rhythms

Question 87

Evaluation of infradian rhythms - Russell et al

Answer 87

P - There is further evidence to suggest that exogenous zeitgebers can affect infradian rhythms.
E - Russell et al. (1980) found that female menstrual cycles became synchronised with other females through odour exposure. In one study, sweat samples from one group of women were rubbed onto the upper lip of another group. Despite the fact that the two groups were separate, their menstrual cycles synchronised.
E - This suggests that the synchronisation of menstrual cycles can be affected by pheromones, which have an effect on people nearby rather than on the person producing them.

Question 88

Evaluation of infradian rhythms - methodological limitations

Answer 88

P - One limitation of synchronisation studies is their methodological shortcomings.
E - 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, which means that any supposed pattern of synchronisation is no more than would have been expected to occur by chance. This may explain why other studies have failed to replicate the findings.
E - This suggests that menstrual synchrony studies are flawed.

Question 89

Evaluation of infradian rhythms - real world application + counter

Answer 89

P - one of the most effective treatments for SAD is light therapy, a box which stimulates very strong light to reset the body’s internal clock.
E - studies shows this helps reduce the effects of SAD in about 80% of people. Light therapy is also preferred over antidepressants to treat SAD as it is regarded as safe.

COUNTER
That said, light therapy can produce headaches and eye strain. Perhaps more tellingly, Kelly Rohan et al. (2009) recorded a relapse rate of 46% over successive winters, compared to 27% in a comparison group receiving CBT.

Question 90

Why do we need sleep?

Answer 90

• Sleep is viewed as necessary for physiological recovery; to restore the body and brain after the day’s exertions.

Question 91

Horne theory of sleep

Answer 91

• Horne (1988) believes that sleep is mainly a function both by and for the brain, which is brain restoration. He terms stage 4 of SWS and REM sleep as core sleep. Core sleep is essential for normal brain functioning since this is when the brain recovers and restores itself. Other stages of sleep are viewed as more adaptable and not so essential (‘optional sleep’).

Question 92

Oswald’s theory of sleep

Answer 92

• Oswald’s (1980) restoration model proposes that the high level of brain activity during REM reflects recovery of the brain, while the increase in hormone activity during SWS reflects restoration and recovery in the body.

Question 93

What stages of sleep have psychologists identified?

Answer 93

Psychologists have identified 5 distinct stages of sleep that altogether span approximately 90 minutes - a cycle that occurs throughout the course of the night. Each of these stages is characterised by a different level of brainwave activity which can be monitored using an EEG

Question 94

Describe stages 1 and 2 of sleep

Answer 94

Light sleep, person can be easily woken. Brainwave patterns become slower and more rhythmic (alpha waves), and become even slower as sleep becomes deeper (theta waves).

Question 95

Describe stages 2 and 3 of sleep

Answer 95

Involves delta waves (which are even slower than theta), they have a greater amplitude than earlier wave patterns. This is known as ‘deep sleep’ or ‘slow wave sleep’ and it is hard to wake a person at this point.

Question 96

Describe stages 4 and 5 of sleep

Answer 96

At this point the body is paralysed and brain activity speeds up in a way that resembles the awake brain. REM occurs at this point. Research suggests that REM is associated with dreaming.

Question 97

Evaluation of ultradian rhythms - Randy Gardener

Answer 97

P - The case study indicates the flexibility of ultradian rhythms
E - Randy Gardener remained awake for 264 hours. While he experienced numerous problems such as blurred vision and disorganised speech, he coped rather well with the massive sleep loss. After this experience, Randy slept for just 15 hours and over several nights he recovered only 25% of his lost sleep. Interestingly, he recovered 70% of Stage 4 sleep, 50% of his REM sleep, and very little of the other stages.
E - These results highlight the large degree of flexibility in terms of the different stages within the sleep cycle and the variable nature of this ultradian rhythm.

Question 98

Evaluation of ultradian rhythms - individual differences

Answer 98

P - The problem with studying sleep cycles is the differences observed in people, which make investigating patterns difficult.
E - Tucker et al. (2007) found significant differences between participants in terms of the duration of each stage, particularly stages 3 and 4 (just before REM sleep).
E - This demonstrates that there may be innate individual differences in ultradian rhythms, which means that it is worth focusing on these differences during investigations into sleep cycles.

Question 99

Evaluation of ultradian rhythms - improved understanding

Answer 99

P - One strength of research into ultradian rhythms is that it has improved understanding of age-related changes in sleep.
E - 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 Van Cauter et al. (2000), 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.
E - This suggests that knowledge of ultradian rhythms has practical value

Question 100

What is the main endogenous pacemaker in mammals?

Answer 100

In mammals, the main endogenous pacemaker is a tiny cluster of nerve cells called the suprachiasmatic nucleus (SCN), which lies in the hypothalamus in each hemisphere of the brain.

Question 101

Where exactly is the SCN?

Answer 101

Nerve fibres connected to the eye cross in an area called the optic chiasm on their way to the visual area of the cerebral cortex. The SCN lies just above (supra) the optic chiasm.

Question 102

What is the SCNa role?

Answer 102

The SCN plays an important role in generating the body’s circadian rhythm. It acts as the ‘master clock’, with links to other brain regions that control sleep and arousal, and has control over other biological clocks throughout the body. Neurons within the SCN spontaneously synchronise with each other, so that their target neurons in sites elsewhere in the body receive correctly time-coordinated signals.

Question 103

When does the SCN need resetting?

Answer 103

The SCN needs resetting only when external light levels change. It receives information about light levels via the optic nerve. This even happens when our eyes are shut, because light penetrate the eyelids
e.g. if the sun rises earlier than on the previous day, the morning light automatically adjusts the clock.

Question 104

What is another role of the SCN?

Answer 104

The SCN also regulates the manufacture and secretion of melatonin in the pineal gland.

Question 105

Animal studies on the SCN - Ralph et al

Answer 105

• Bred a strain of hamsters so that they had abnormal circadian rhythms of 20 hours rather than 24 hours.
• SCN neurons from these abnormal hamsters were then transplanted into the brains of normal hamsters.
• These normal hamsters then displayed the same abnormal circadian rhythm of 20 hours, showing that the transplanted SCN had imposed its pattern onto the recipient’s brains.

Question 106

Animal studies on the SCN - DeCoursey et al

Answer 106

• 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 (they were awake and vulnerable when they should have been asleep).

Question 107

What is the Pineal Gland?

Answer 107

The pineal gland is a pea like structure just behind the hypothalamus.
The SCN sends signals to the pineal gland directing it to increase production and secretion of the hormone melatonin at night and to decrease it as light levels increase in the morning.
Melatonin induces sleep by inhibiting the brain mechanisms that promote wakefulness.

Question 108

Explain light as an exogenous zeitegeber

Answer 108

• Receptors in the SCN are sensitive to changes in light levels during the day and use this information to synchronise the activity of the body’s organs and glands.
• Light resets the internal biological clock each day, keeping it to a 24-hour cycle.
• Rods and cones in the retina of the eye select light to form visual images.
• A third type of light-detecting cell in the retina gauges overall brightness to set the internal biological clock.
• A protein called melanopsin is critical in this. A small number of retinal cells contain melanopsin and carry signals to the SCN to set the daily cycle.

Question 109

Research support for light - Campbell and Murphy

Answer 109

• Demonstrated that light may be detected by skin receptor sites on the body even when the same information is not received by the eyes.
• 15 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 case.
• This suggests that light is a powerful exogenous zeitgeber that need not necessarily rely on the eyes to exert its influence on the brain.

Question 110

Research support for light - Burgess et al

Answer 110

Found that exposure to bright light prior to an east-west flight decreased the time needed to readjust to local time on arrival.

Volunteers participated in one of three treatments
1) Continuous bright light
2) Intermittent bright light
3) Dim light

each of which shifted their sleep-wake cycle back by one hour a day over 3 days.

Participants exposed to continuous bright light shifted their circadian rhythm by 2.1 hours over the course of the study, compared with 1.5 hours for intermittent bright light and 0.6 hours for dim light.

As a result, participants in the first group felt sleepier 2 hours earlier in the evening and woke 2 hours earlier in the morning which was closer to the local time conditions after the east-west flight.

Question 111

Explain social cues as an exogenous zeitgeber

Answer 111

• Social stimuli such as mealtimes and social activities may also have a role as zeitgebers.
• Aschoff et al (1971) showed that individuals are able to compensate for the absence of zeitgebers such as natural light by responding to social zeitgebers instead

Question 112

Research to support social cues - Klein and Wegmann (1974)

Answer 112

Found that the circadian rhythms of air travellers adjusted more quickly if they went outside more at their destination. This was thought to be because they were exposed to the social cues of their new time zone, which acted as a zeitgeber.