4.2.2 - Biopsychology

Question 1

What are the 2 main functions of the nervous system?

Answer 1

1. to collect, process and respond to information in the environment
2. to co-ordinate the working of the different organs and cells in he body

Question 2

What does the nervous system split into?

Answer 2

• The central nervous system
• Peripheral nervous system

Question 3

What is involved in the central nervous system?

Answer 3

• brain and spinal cord
• the brain is used for functioning and planning
• the spinal cord transmits messages to and from the brain to the PNS
• involved in reflex action e.g. startled response

Question 4

What is involved in the peripheral nervous system?

Answer 4

• transmission of messages, via millions of neurons , to and from the CNS
• Has 2 parts :
• SNS = Somatic nervous system
• ANS - Automatic nervous system

Question 5

What does the somatic nervous system do?

Answer 5

Transmits information to and from senses to the CNS e.g. skeletal muscles and bones

Question 6

What does the Automatic nervous system do?

Answer 6

Transmits to and from internal organs to sustain life processes e.g. heartbeat and breathing

Question 7

What parts does the automatic nervous system split into?

Answer 7

• Parasympathetic branch (conserves. + stores resources)
• Sympathetic branch (activates arousal + energy)

These branches work antagonistically

Question 8

What is the endocrine system?

Answer 8

The endocrine system is made up of glands that make hormones.

• works alongside nervous system to control vital functions in the body
• acts slower than the nervous system but has very widespread powerful effects

Question 9

What is a gland?

Answer 9

An organ in the body that synthesises substances such as hormones

Question 10

What are hormones?

Answer 10

Chemical substances that circulate in the blood-stream and only affect target organs

Question 11

What is the master gland?

Answer 11

the Pituitary Gland

Question 12

How do glands and hormones work together?

Answer 12

Glands in the body secrete hormones into the bloodstream and affect any cell in the body that has a receptor specific to that hormone

Question 13

What does the Thyroid Gland secrete?

Answer 13

It secretes Thyroxine - increases heart rate and metabolic rate

Question 14

What does the Pituitary Gland do?

Answer 14

It controls the release of hormones from all other endocrine glands in the body

Question 15

Explain the fight or flight response

Answer 15

• A stressor is perceived and the Hypothalamus triggers activity in the automatic nervous system
• ANS changes from a parasympathetic (resting) state to a sympathetic (aroused) state
• Stress hormone Adrenaline released by Adrenal Medulla into bloodstream
• Adrenaline triggers physiological changes in the body necessary for the fight or flight response
• Once threat has passed, body returns to parasympathetic state

Question 16

What does the sympathetic state involve?

Answer 16

• increased HR
• increased breathing rate
• dilates pupils
• inhibits digestion
• inhibits saliva production

Question 17

What does the parasympathetic state involve?

Answer 17

• decreased HR
• decreases breathing
• constricts pupils
• stimulates digestion
• stimulates saliva production

Question 18

What are neurons?

Answer 18

Cells that conduct nerve impulses

Question 19

Features of a neuron?

Answer 19

• the cell body contains the nucleus from the cell body
• dendrites carry electrical impulses from other neurons towards the cell body
• axon carries the impulses away from the CB
• it is covered in a myelin sheath which increases the speed of the impulses
• breaks in the myelin sheath are called the nodes of Ranvier
• action potentials travelling down the axon ‘jump’ from node to node
• The terminal buttons at the end of the axon communicate with the next neuron in the chain

Question 20

What are the 3 types of neurons?

Answer 20

• sensory
• relay
• motor

Question 21

What do sensory neurons do?

Answer 21

carry signals from receptors to the spinal cord and brain

Question 22

What do relay neurons do?

Answer 22

carry messages from one part of the CNS to another

Question 23

What do motor neurons do?

Answer 23

carry signals from the CNS to effectors (muscles or glands)

Question 24

What is a synapse?

Answer 24

The gap between the end of one neuron and the dendrites of the next neuron

Question 25

Describe how a synaptic chemical transmission occurs

Answer 25

• an electrical impulse travels along the axon of the transmitting neuron
• this triggers nerve-ending of the pre synaptic neuron to release chemical messengers called neurotransmitters from vesicles
• these are chemicals which diffuse across the synapse and bind with receptor molecules on the membrane of the next neuron
• receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron - this stimulates the second neuron to transmit the electrical impulse
• reuptake - neurotransmitter reabsorbed in the vesicles of the pre-synaptic neuron after it has performed it’s function

Question 26

What is a exitatory synaptic connection?

Answer 26

Makes the neuron more positively charged - they make it more likely the next neuron will fire (such as adrenaline)

Question 27

What is an inhibitory synaptic connection?

Answer 27

Makes the neuron more negatively charged - less likely next neuron will fire (such as serotonin)

Question 28

Define localisation of function

Answer 28

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

Question 29

Who discovered that specific areas of the brain have different functions?

Answer 29

Paul Broca
Karl Wernicke

Question 30

What is the Hollistic theory of the brain?

Answer 30

All parts of the brain were involved in the processing of thoughts and actions.

Question 31

What is the cerebral cortex?

Answer 31

The outer layer of both hemispheres

Question 32

Define lateralisation

Answer 32

The dominance of one hemisphere of the brain for particular physical and psychological functions

Question 33

Typically, what hemisphere controls the right-hand side of the body?

Answer 33

The left hemisphere

Question 34

Typically, what hemisphere controls the left-hand side of the body?

Answer 34

The right hemisphere

Question 35

What is the largest and main part of the brain called?

Answer 35

The cerebrum

Question 36

What are ‘lobes’?

Answer 36

The centres the cortex of both hemispheres subdivide into

Question 37

What are the 4 lobes of the brain?

Answer 37

Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe

Question 38

Frontal lobe characteristics?

Answer 38

• contains motor area - this controls voluntary movement
• damage to this area of the brain may result in loss of control over fine movements

Question 39

Parietal lobe characteristics?

Answer 39

• contains somatosensory area - which stores sensory information from the skin
• the amount of somatosensory area devoted to a particular body part denotes it’s sensitivity
• recpetors for face and hands occupy overy half of the somatosensory area

Question 40

What separates the motor area and somatosensory area?

Answer 40

A valley called the central sulcus

Question 41

Occipital lobe characteristics?

Answer 41

• located at back of brain
• contains visual area (or visual cortex)
• each eye sends info from right visual field to left visual cortex and info from left visual field to right visual cortex

Question 42

Temporal lobe characteristics?

Answer 42

• houses the auditory area
• analyses speech-based info
• damage to this area may produce partial hearing loss
• damage to the Wernicke’s area of the temporal lobe may affect ability to comprehend language

Question 43

What are the language areas of the brain?

Answer 43

Broca’s area: responsible for speech production
- located in the left frontal lobe
- damage to this area causes Broca’s Aphasia - leads to speech that is slow, laborious and lacking in fluency

Wernicke’s Area: responsible for understanding language
- located in left temporal lobe
- damage to this area causes Wernicke’s Aphasia - leads to meaningless speech and nonsense words

Question 44

Localisation of function evaluation?

Answer 44

:) - Peterson et al. 1998 - Used brain scans to show how the Broca’s area was active during a reading task and how the Wernicke’s area was active during a listening task.

:) - Case of Phineas Gage - Metal pole embedded in skull destroying most of left frontal lobe, he had changed from calm and reserved to rude and quick tempered. Shows frontal lobe has role in regulating mood.

:( - Karl Lashley, 1950 - Removed areas of rats brains 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.

:( - Brain plasticity - Another part of the brain can take on the function of the damaged area of the brain.

Question 45

Define hemispheric lateralisation

Answer 45

The idea that the two halves (hemispheres) of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.

Question 46

Where is language lateralised?

Answer 46

In the left hemisphere.
The right hemisphere provides emotional context to what is being said.

This led to the suggestion that the LH is the analyser whilst the RH is the synthesiser.

Question 47

What is a split-brain operation?

Answer 47

Involves severing the connections between the RH and LH, mainly the corpus callosum.
This is a surgical procedure used to reduce epilepsy as the electrical storm cannot travel from one hemisphere to the other.

Question 48

Sperry’s split brain research procedure?

Answer 48

Rodger Sperry (1968)
Studied how the separate hemispheres deal with e.g. speech and vision.

𝐕𝐢𝐬𝐮𝐚𝐥 𝐭𝐚𝐬𝐤𝐬
→ 11 split-brain individuals were studied using a special set up in which an image or word could be projected to the ppts. right visual field and the same, or different image could be projected to the left visual field.
→ Wearing an eye patch and staring at the focal point were controls. These controls ensure that stimuli was presented only to the desired visual field.
→ All visual stimuli was presented for only 0.1 seconds. This was another control as it is too quick for eye movements to cause visual information to enter both visual fields.
→ In the ‘normal’ brain, the corpus callsum would immediately share the information between both hemispheres giving complete picture of the visual world.

𝐓𝐚𝐜𝐭𝐢𝐥𝐞 𝐭𝐚𝐬𝐤𝐬
→ The participants would put their hands under the tachistoscope such that they could reach the objects, but could not see them (control),
→ Participants were introduced to objects by an experimenter, who placed them in the participants’ hands.
→ Objects placed in the right hand of the participant are processed in the left hemisphere.
→ Objects placed in the left hand of the participant are processed in the right hemisphere.

Question 49

Sperry’s split-brain research findings?

Answer 49

𝐕𝐢𝐬𝐮𝐚𝐥 𝐭𝐚𝐬𝐤𝐬
→When a picture of an object was shown to a ppts. RVF, the participant could describe what was seen.
→However, they could not do this if the object was shown to the LVF (they said there was ‘nothing there’).
→This is because in the normal brain, messages from the right hemisphere are relayed to language centres in the left hemisphere, but this is not possible in split-brain.

𝐓𝐚𝐜𝐭𝐢𝐥𝐞 𝐭𝐚𝐬𝐤𝐬
→Objects placed in the right hand (left hemisphere) could be described in speech or writing (with the right hand). If the same objects were placed in the left hand (right hemisphere) participants could only make wild guesses and often seemed unaware they were holding anything.

Question 50

Sperry’s split-brain research conclusion?

Answer 50

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

Question 51

Evaluation of Sperry?

Answer 51

:) - Ethical as variables were not manipulated due to the study being quasi.
:) - Methodology - results were found from highly specialised and standardised procedures.
:( - Quasi experiments make cause and effect more difficult than other types of experiment.
:( - No control group, however, one was not needed in this study as the results of the tasks for people without split corpus callosums were already known.
:( - Lack of external validity.
:( - Issues with generalisation - Split-brain ppts. are an unusual sample of people, and some ppts. had experienced more disconnection of the 2 hemispheres than others.

Question 52

Hemispheric lateralisation evaluation?

Answer 52

:) - Support for lateralised brain functions - PET scans show when ‘normal’ ppts. attend to global elements of an image, the RH is more active ( suggests hemispherical lateralisation is a feature of both the normal and split-brain ).
:) - Support from more recent split-brain studies e.g. Luck et al (1989).
:( - Plasticity is more important in split-brain research as it deals with loss of lateralisation.

Question 53

Define plasticity.

Answer 53

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

Question 54

What is synaptic pruning?

Answer 54

As we age, rarely-used connections are deleted, and frequently used connections are strengthened. (enabled lifelong plasticity).

Question 55

Outline research into plasticity.

Answer 55

𝐄𝐥𝐞𝐚𝐧𝐨𝐫 𝐌𝐚𝐠𝐮𝐢𝐫𝐞 𝐞𝐭 𝐚𝐥. (𝟐𝟎𝟎𝟎)
→ Studied the brains of London taxi drivers and found significantly more grey volume of grey matter in the posterior hippocampus than in a matched control group.
→ As part of their taxi training, they must take a complex test called ‘The Knowledge’, which assesses their recall of the city streets and possible routes - this learning experience alters the structure of the taxi drivers’ brains.
𝐁𝐨𝐠𝐝𝐚𝐧 𝐃𝐫𝐚𝐠𝐚𝐧𝐬𝐤𝐢 𝐞𝐭 𝐚𝐥. (𝟐𝟎𝟎𝟔)
→ Imaged the brains of medical students 3 months before + after final exams.
→ Learning-induced changes occurred in the posterior hippocampus and the parietal cortex presumably as a result of learning.

Question 56

Define functional recovery.

Answer 56

A form of plasticity - Following damage through trauma, the brain’s ability to redistribute or transfer functions.

→Healthy brain areas may take over the functions of those areas that are damaged, destroyed, or even missing.
→Neuroscientists suggest this process can occur quickly after trauma and then slow down (spontaneous recovery).
→Individual may require rehabilitative therapy to recover further.

Question 57

What happens in the brain during recovery?

Answer 57

The brain is able to rewire and recognise itself by forming new synaptic connections close to the area of damage through:
𝐀𝐱𝐨𝐧𝐚𝐥 𝐬𝐩𝐫𝐨𝐮𝐭𝐢𝐧𝐠
The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
𝐃𝐞𝐧𝐞𝐫𝐯𝐚𝐭𝐢𝐨𝐧 𝐬𝐮𝐩𝐞𝐫𝐬𝐞𝐧𝐬𝐢𝐭𝐢𝐯𝐢𝐭𝐲
Occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost (More likely to fire). Can lead to effects such as pain.
𝐑𝐞𝐜𝐫𝐮𝐢𝐭𝐦𝐞𝐧𝐭 𝐨𝐟 𝐡𝐨𝐦𝐨𝐥𝐨𝐠𝐨𝐮𝐬 (𝐬𝐢𝐦𝐢𝐥𝐚𝐫) 𝐚𝐫𝐞𝐚𝐬 𝐨𝐧 𝐭𝐡𝐞 𝐨𝐩𝐩𝐨𝐬𝐢𝐭𝐞 𝐬𝐢𝐝𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐛𝐫𝐚𝐢𝐧
Means specific tasks can still be performed. (e.g. is Broca’s area is damaged, the right side equivalent would carry out its functions).

Question 58

Evaluation of plasticity?

Answer 58

:) - Age and plasticity - Does not always decline sharply with age meaning neural plasticity can continue throughout the lifespan.

:( - Negative plasticity - May have negative behavioural consequences
• Medina et al (2007) - The brain’s adaptation to prolonged drug use leads to poorer cognitive functioning later in life, as well as an increased risk of dementia.
• Ramachandran + Hirstein (1998) - 60-80% of amputees have phantom limb syndrome (continued experience of sensations in missing limb). These sensations can be unpleasant + painful.

The brain’s ability to adapt is not always beneficial.

Question 58

Evaluation of functional recovery?

Answer 58

:) - Real world application - Plasticity processes have contributed towards neurorehabilitation - simply understanding axonal growth is possible encourages new therapies e.g. constraint-induced movement therapy for stroke patients.
It helps medical professionals know when interventions need to be made.

:( - Cognitive reverse - Level of education may influence recovery rates.
Implies the more time brain injury patients are in education, the greater their chances of a disability free recovery, and those who were in education for less time, are less likely to achieve full recovery.

Question 59

What are the 4 ways of studying the brain?

Answer 59

fMRI
EEG
ERPs
Post-mortem examinations

Question 60

What is fMRI?

Answer 60

Functional Magnetic Resonance Imaging

A method used to measure brain activity while a person is performing a task.
Detects radio waves from changing magnetic fields which enables researchers to determine which regions of the brain are rich in oxygen and thus are active (localisation of function).

Question 61

What is the haemodynamic response?

Answer 61

When a brain area is more active it consumes more oxygen, and to meet this increased demand, blood flow is directed to the active area.

Question 62

What is EEG?

Answer 62

Electroencephalogram

A record of the tiny electrical impulses produced by the brain’s activity via electrodes that are fixed to an individual’s scalp using a skull cap.
Measures characteristics of wave patterns and can help diagnose certain conditions of the brain e.g. epilepsy tumours or disorders of sleep.

Question 63

What are ERPs?

Answer 63

Event-related potentials

Where the electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data.

All extraneous brain activity from the original EEG recording is filtered out leaving only those responses that relate to, for example, the presentation of a specific stimulus or performance of a specific task.

Question 64

What are Post-mortem examinations?

Answer 64

Where the brain is analysed after death to determine whether certain observed behaviours during the person’s lifetime can be linked to structural abnormalities in the brain.
Areas of damage are examined to find the likely cause of rare disorders in individuals.

Question 65

Evaluation of fMRI?

Answer 65

𝐒𝐭𝐫𝐞𝐧𝐠𝐭𝐡𝐬:
- does not rely on the use of radiation
- risk-free, non-invasive, and straightforward to use
- images have high spatial resolution

𝐋𝐢𝐦𝐢𝐭𝐚𝐭𝐢𝐨𝐧𝐬:
- expensive compared to other neuroimaging techniques
- poor temporal resolution (5-second time lag which doesn’t truly represent moment-to-moment brain activity)

Question 66

Evaluation of EEG?

Answer 66

𝐒𝐭𝐫𝐞𝐧𝐠𝐭𝐡𝐬:
- useful in studying sleep and diagnosing conditions e.g. epilepsy
- high temporal resolution (detects activity within a millisecond)

𝐋𝐢𝐦𝐢𝐭𝐚𝐭𝐢𝐨𝐧𝐬:
- generalised - not useful for pinpointing the exact source of neural activity

Question 67

Evaluation of ERPs?

Answer 67

𝐒𝐭𝐫𝐞𝐧𝐠𝐭𝐡𝐬:
- bring more specificity to the measurement of neural processes
- excellent temporal resolution
- can be used to measure cognitive functions and deficits e.g. maintenance of working memory

𝐋𝐢𝐦𝐢𝐭𝐚𝐭𝐢𝐨𝐧𝐬:
- lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings

Question 68

Evaluation of Post-mortem examinations?

Answer 68

𝐒𝐭𝐫𝐞𝐧𝐠𝐭𝐡𝐬:
- vital in providing a foundation for early understanding of key processes in the brain
- increased understanding means medication can be improved

𝐋𝐢𝐦𝐢𝐭𝐚𝐭𝐢𝐨𝐧𝐬:
- causation issue → observed damage may not be linked to the deficits under review but to some other unrelated trauma/decay
- ethical issues → issue of consent from the individual before death, as they may not have been able to provide informed consent

Question 69

What are biological rhythms?

Answer 69

Distinct patterns of changes in the body activity that conform to cyclical time periods.

• influenced by internal body clocks (endogenous pacemakers)
• influenced by environmental changes (exogenous zeitgebers)

Question 70

What are circadian rhythms?

Answer 70

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

Question 71

How does the sleep/wake cycle work? (circadian rhythm)

Answer 71

• We feel drowsy when it’s night time and alert during the day, showing the effect of daylight (exogenous zeitgeber)
• Is also governed by an internal (endogenous pacemaker) - a biological ‘ clock’ called the suprachiasmatic nucleus (SCN)
• Light can reset the SCN

Question 72

What are endogenous pacemakers?

Answer 72

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

Question 73

What are exogenous zeitgebers?

Answer 73

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

Question 74

Outline Siffre’s cave study. (circadian rhythms)

Answer 74

• Spent multiple extended periods underground to study the effects on his own biological rhythms.
• He was deprived exposure to natural light and sound.
• He resurfaced in mid-September 1962 after 2 months in the caves of the Southern Alps believing it to be mid-August.
• He repeated this for 6 months in a Texan cave.
• Here his biological rhythm settled down to one hour just beyond the usual 24 hours, though he did continue to fall asleep and wake up on a regular schedule

Question 75

Other circadian rhythm research?

Answer 75

𝐉𝐮𝐫𝐠𝐞𝐧 𝐀𝐬𝐜𝐡𝐨𝐟𝐟 + 𝐑𝐮𝐭𝐠𝐞𝐫 𝐖𝐞𝐯𝐞𝐫
Ppts spent 4 weeks in a WW2 setting deprived of natural light. All but 1 ppts displayed a circadian rhythm between 24 and 25 hours.

May suggest ‘natural’ sleep/wake cycle is slightly longer than 24 hours.

𝐒𝐢𝐦𝐨𝐧 𝐅𝐨𝐥𝐤𝐚𝐫𝐝
12 ppts in dark cave for 3 weeks. Went to sleep at 11:45 and got up at 7:45. Over the course of the study, the clocks were sped up by the researchers so the day only lasted 22 hours.
Not one ppt could comfortably adjust to the new cycle.

Suggests the existence of a strong circadian rhythm that cannot be easily overridden by environmental changes.

Question 76

Evaluation of research into circadian rhythms?

Answer 76

:) - Practical application to shift work - Research into sleep/wake cycle may have economic implications in terms of how to best manage worker productivity.

:) - Practical application to drug treatments - Circadian rhythms co-ordinate many bodily processes so research has impacted pharmacokinetics (impact of drugs on body and how well they are absorbed + distributed) as research has shown there are peak times during the day/night where drugs are likely to be most effective.

:( - Use of case studies and small samples - limits the extent to which meaningful generalisations cannot be made.

:( - Poor control in studies - Ppts deprived of natural light but had access to artificial light (possible confounding variable).

:( - Individual differences - Individuals circadian rhythms can vary and are also impacted by the age of the individual according to Wolfson et al. (1998).

Question 77

What are infradian rhythms?

Answer 77

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

Question 78

Outline menstruation as an infradian rhythm.

Answer 78

• Governed by monthly changes in hormone levels which regulate ovulation.
• Refers to the time between the first day of a woman’s period, when the womb is shed, to the day before her next period.
• Takes approx. 28 days.
• Endogenous system but there is evidence to support that it may be influenced by exogenous factors e.g. the cycles of other women (Kathleen + Martha McClintock 1998).

Question 79

Outline seasonal affective disorder as an infradian rhythm.

Answer 79

• It is a depressive disorder which has a pattern of onset, and is described and is diagnosed as a mental disorder in the DSM-5.
• Main symptoms: persistent low mood, lack of activity, lack of interest in life.
• Referred to as winter blues and occurs in a yearly circannual cycle.

Psychologists believe SAD cause be caused by the hormone melatonin. During the night, the pineal gland secretes melatonin until dawn where there is an increase in light. During winter, the lack of light in the morning means the secretion process continues for longer, thus impacting the production of serotonin in the brain.

Question 80

Evaluation of research into infradian rhythms?

Answer 80

:) - Evolutionary basis - Menstrual synchrony research may be explained by natural selection.
For distant ancestors it may have been advantageous for females to menstruate together and become pregnant at the same time, so babies who lost their others during childbirth still had access to breast milk, therefore improving their chances of survival.
Suggests that synchronisation is an adaptive strategy. BUT challenged by Schank 2004.

:) - Animal studies → knowledge of effects of pheromones comes from these studies
:) - Practical app → SAD - treatment using phototherapy that relieves 60% sufferers HOWEVER research casts doubt on its effectiveness

:( - Methodological limitation - Synchronisation studies have methodological shortcomings.
There could have been confounding variables such as stress, changes in diet, exercise etc which could have impacted menstruation.
This may explain why other studies (e.g.Trevathan et al) have failed to repeat the findings.
This suggests that menstrual synchrony studies are flawed.

Question 81

What are ultradian rhythms?

Answer 81

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

Question 82

Outline the sleep cycle as an ultradian rhythm.

Answer 82

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

Question 83

What occurs in stage 1 of the sleep cycle?

Answer 83

Brain waves are high frequency and have a short amplitude.
These are alpha waves.

Question 84

What occurs in stage 2 of the sleep cycle?

Answer 84

The alpha waves continue but there are occasional random changes in pattern called sleep spindles.

Question 85

What occurs in stage 3 and 4 of the sleep cycle?

Answer 85

This is known as deep sleep or slow wave sleep (SWS).
The brain waves are delta waves with lower frequency and higher amplitude.
It is difficult to wake someone up at this point.

Question 86

What occurs in stage 5 of the sleep cycle?

Answer 86

REM
The body is paralysed yet brain activity closely resembles that of an awake brain.
During this time, the brain produces theta waves and the eyes occasionally move around, thus rapid eye movement (REM).
When dreams are most often experienced, but also in deep sleep.

Question 87

Evaluation of research into ultradian rhythms?

Answer 87

:) - Improved understanding - Research has improved the understanding of age-related changes in sleep.
Sleep scientists have observed that SWS reduces with age, reducing alertness.
- Other research: (Dement and Kleitman) found that REM activity highly correlated with dreaming in 9 adults.
This suggests that knowledge into ultradian rhythms has practical value.

:( - Individual differences - There are significant variations between people.
Adrienne Tucker et al. → found large differences between ppts. in terms of the duration of each sleep stage, particularly in stages 3 and 4. They are likely to be biologically determined.
This makes it difficult to describe ‘normal sleep’ in any meaningful way.

Question 88

What is the suprachiasmatic nucleus and what does it do?

Answer 88

→ It is a tiny bundle of nerve cells located in the hypothalamus in each hemisphere of the brain.
→ One of primary endogenous pacemakers in mammal species and is influential in maintaining circadian rhythms such as the sleep/wake cycle.
→ The SCN lies just above the optic chiasm.
→ Receives information about light directly from this structure - this continues even when our eyes are closed, enabling the biological rhythm to adjust to changing patterns of daylight whilst we are asleep.

Question 89

What animal research has been carried out into the suprachiasmatic nucleus?

Answer 89

DeCoursey et al. (2000)
→ Destroyed the SCN connection in brains of 30 chipmunks who were then returned to natural habitat. Observed for 80 days.
→ Sleep/wake cycle disappeared and a significant proportion were killed by predators (awake and vulnerable when they should have been asleep)

Ralph et al. (1990)
→ Bred mutant hamsters with a 20 hour sleep/wake cycle.
→ SCN from foetal tissue of mutant hamsters transplanted into brains of normal hamsters.
→ Cycle of normal group defaulted to 20 hours.

Question 90

How does the SCN and melatonin work together?

Answer 90

→ The SCN passes the information on day length and light that it receives to the pineal gland.
→ This is another endogenous mechanism guiding sleep/wake cycle.
→ During the night, the pineal gland increases production of melatonin.
→ This is a chemical that induces sleep and is inhibited during periods of wakefulness.
→ Melatonin has been suggested as a causal factor in seasonal affective disorder.

Question 91

Examples of exogenous zeitgebers in the sleep/wake cycle?

Answer 91

Light
Social cues

Question 92

What is the process of external factors in the environment resetting our biological clocks?

Answer 92

Entrainment

Question 93

How does the exogenous zeitgeber of light work?

Answer 93

→ Light is a key zeitgeber in humans.
→ can reset body’s main endogenous pacemaker, the SCN.
→ Also plays role in the maintenance of the sleep/wake cycle.
→ Has indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation.

Question 94

What did Scott Campbell and Patricia Murphy (1998) find out about light?

Answer 94

→Demonstrated light may be detected by the skin receptor sites on the body even when the same information was detected by the eyes.
→ 15 ppts. woken at various times and a light shone on back of knees.
→ Produced deviation in the participants usual sleep/wake cycle of up to 3 hours.
→ Suggest light is a powerful exogenous zeitgeber and does not necessarily rely on the eyes.

Question 95

Evaluation of Campbell and Murphy?

Answer 95

:( small sample
:( confounding variables
:( light could still bounce off wall into eye

Question 96

How does the exogenous zeitgeber of social cues work?

Answer 96

• Infant’s sleep/wake cycle is pretty much random
• Approx. 6 weeks of age, circadian rhythms begin and by 16 weeks, most babies are entrained
• Schedules imposed by parents are likely to be a key influence (adult-determined meal times/bed times)
• Research suggests that adapting to local times for eating and sleeping is an effective way of entraining circadian rhythms.

Question 97

Endogenous pacemakers evaluation?

Answer 97

:( - SCN research may obscure other body clocks → research has revealed there are ‘peripheral oscillators’ which are found in the organs that also have circadian rhythms.

:( - Ethics in animal studies → animals exposed to harm and subsequent risk when returned to habitats BUT we did learn useful scientific information :)

:( - Interactionist system → endogenous pacemaker’s cannot be studied in isolation (total isolation studies e.g. Siffre’s cave study very rare). In everyday life, EG’s and EZ’s intact.

Question 98

Exogenous zeitgebers evaluation?

Answer 98

:( - Environmental observations → EZ’s do not have the same effects in all environments e.g. the people who live in places where there is little darkness in summer but still have similar sleep patterns. Suggests the sleep/wake cycle is primarily controlled by EP’s that override environmental changes in light.

:( - Social cues not effective → Laughton Miles et al. study of young man, blind from birth, who had abnormal circadian rhythm of 24.9hrs. Despite exposure to social cues, his sleep/wake cycle couldn’t adjust.
Shows social cues alone are not effective in resetting biological rhythm.

:( - Methodological issues → Findings from Campbell and Murphy skin receptor study yet to be replicated.

Question 99

4 reasons for plasticity?

Answer 99

• as a result of developmental changes
• learning of new skills
• response to direct trauma to area of brain
• response to indirect effects of damage such as brain swelling and bleeding (from stroke)