Biopsychology

Question 1

Describe the nervous system, main functions

Answer 1

• specialised network of cells in the human body and is our primary internal communication system
• based on electrical and chemical signals whereas the endocrine system is based on hormones
• main functions are to collect, process and respond to information in the environment and to coordinate the working of different organs and cells in the body

Question 2

Branches of the nervous system

Answer 2

Question 3

Describe the central nervous system (CNS)

Answer 3

• receives sensory input and produces motor responses via nerves
• CNS receives information from and sends information to the peripheral nervous system.
• Made up of the brain and spinal cord
• the brain is the centre of all conscious awareness. The brains alter layer, the cerebral cortex, is only found in mammals; involved in higher order thinking, such as problem solving. The brain is highly developed in humans and is what distinguishes our higher mental functions from those of other animals, divided into two hemispheres. Many different parts of the brain, some are more primative and concerned with vital functioning.
• Spinal cord- extension of the brain- passes messages to and from the brain and connects nerves too the peripheral nervous system. Also responsible for reflex actions.

Question 4

Describe the peripheral nervous system (PNS)

Answer 4

• relays nerve impulses via neurons from the CNS to the rest of the body and from the body back to the CNS
• divided into the stomatic nervous system and the autonomic nervous system
• stomatic nervous system- the nerves that we actively control. Receives information from sensory receptors and sends this information to the CNS. Controls muscle movement.
• the autonomic nervous system- works automatically, we do not have to think in order for the nerves to work. The brain does this for us come out for example telling our heart to beat or our digestive system to release certain enzymes. Divided into the sympathetic and parasympathetic nervous system.

Question 5

Differences between stomatic and autonomic nervous systems

Answer 5

• The SNS has sensory and motor pathways while the ANS is purely motor
• the ANS controls internal organs and glands of the body while the SNS controls skeletal muscle and movement
• ANS control centres are in the brain stem whilst SNS carries commands from the motor cortex

Question 6

Describe the parasympathetic compared to the sympathetic nervous system

Answer 6

• sympathetic nervous system Prepares your body for emergencies (e.g. fight or flight). It makes physiological changes (e.g. increasing BP and heartrate, dilating blood vessels in muscles) that help you to physically cope in a stressful situation.
• Parasympathetic nervous system Returns your body back to ‘normal’- relaxes someone once emergency has passed- restoring energy and maintaining blood pressure, heart rate and breathing rate at a low level.

Question 7

What are neurons, name 3 types

Answer 7

• the building blocks of the nervous system- nerve cells that process and transmits messages through electrical and chemical signals
• 80% of neurons are located in the brain
• 100 billion neurones i the human nervous system
• provides the nervous system with its primary means of communication
• sensory, relay, motor

Question 8

Describe the structure of neurons

Answer 8

• includes a cell body, dendrites and an Axon
• dendrites at one end of the neuron receives signals from other neurons or from sensory receptors
• dendrites connected to the cell body
• the cell body, or soma, includes a nucleus which contains the genetic material of the cell
• the impulse is carried from the cell body along the Axon. The Axon is covered in a fatty layer of myelin sheath, which protects the Axon and speeds up the electrical impulse.
• if the myelin sheath was continuous this would have the reverse effect and slow down the electrical impulses- thus, it is segmented by gaps called nodes of Ranvier- these speeds up the transmission of the impulse by forcing it to jump across the gaps along the Axon
• at the ends of the Axon are terminal buttons, these communicate with the next neuron in the chain across a gap known as the synapse

Question 9

Describe sensory neurons

Answer 9

• carry messages from sensory receptors to the central nervous system
• sensory receptors can be found in the eyes, ears, tongue and skin
• sensory neurons convert information from these sensory receptors into neural impulses that are passed on to the brain or spinal cord (for reflex actions)
• they have long dendrites and short axons
• located outside of the CNS combat in the PNS in clusters known as ganglia

Question 10

Describe relay [inter] neurons

Answer 10

• connect the sensory neurons to the motor or other relay neurons
• they allow sensory and motor neurons to communicate with each other and are found in the CNS
• they have short dendrites and short axons
• make up 97% of all neurons and most are found within the brain and the visual system

Question 11

Describe motor neurones

Answer 11

• Connect the CNS to muscles and glands
• located in the CNS and project their axons outside the CNS (to the PNS) and directly or indirectly control muscles
• when stimulates, the motor neuron releases neurotransmitters that bind to the receptors on the muscle and trigger a response that leads to muscle movement
• have short dendrites and long axons

Question 12

Types of neurones diagram (together)

Answer 12

Question 13

Describe electrical transmission- the firing of a neuron

Answer 13

• when a neuron is in a resting state the inside of the cell is negatively charged compared to the outside
• when a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur
• this creates an electrical impulse that travels down the Axon towards the end of the neuron

Question 14

Types of neuron diagram (comparison)

Answer 14

Question 15

What must happen once an action potential has reached the terminal buttons

Answer 15

• it needs to be passed on to the next neuron- must cross the synapse

Question 16

Describe what happens at a synapse

Answer 16

• when the action potential/ electrical impulse reaches the end of the neuron, the presynaptic neuron releases neurotransmitters from synaptic vesicles into the synaptic gap

Question 17

Describe neurotransmitters

Answer 17

• chemicals that’s diffuse across the synapse to the next neuron in the chain
• once the neurotransmitter crosses the gap, it is taken up by a post synaptic receptor site on the dendrites of the next neuron (axons take signals to synapse, dendrites take away)
• here, the chemical message is converted back into an electrical impulse and the process of transmission begins again in this other neuron
• re-uptake then occurs, where the neurotransmitter returns back to the presynaptic neuron, where it is sorted ready for later release. The quicker the neurotransmitter is taken back up, the shorter the effects of the neurotransmitter will last. Enzymes can also ‘turn off’ a neurotransmitter after they have stimulated a post synaptic neuron, which makes the neurotransmitter ineffective.
• several dozen types of neurotransmitter have been identified in the brain, as well as in the spinal cord and some glands- each neurotransmitter has its own specific molecular structure that fits perfectly into a post synaptic receptor site, similar to a lock and key.
• Neurotransmitters also have specialist functions, for example acetylcholine is found at each point where a motor neuron meets a muscle, and upon its release comments will cause the muscles to contract

Question 18

how many directions can information travel at a synapse, why

Answer 18

Only 1:
- the synaptic vesicles containing the neurotransmitter are only released from the presynaptic membrane, the receptors for the neurotransmitters are only present on the postsynaptic membrane.
- It is the binding of the neurotransmitter to the receptor which enables the signal/information to be passed/transmitted on (to the next neuron).
- Diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the presynaptic to the postsynaptic membrane.
- neurotransmitters are released from the presynaptic neuron terminal and received by the post synaptic neuron

Question 19

Name 2 types of neurotransmitter effects

Answer 19

• excitation
• inhibition
  excitatory or inhibitory effect

Question 20

Describe excitation, inhibition and summation

Answer 20

• excitation- leads to the postsynaptic neuron becoming positively charged and more likely to fire-e.g. adrenaline
• inhibition- leads to the post synaptic neuron becoming negatively charged and less likely to fire- e.g. GABA, serotonin
• summation- the exicatory and inhibitory influences are summed- if the net effect on the postsynaptic neuron is inhibitory, the new run will be less likely to fire and if the net is exicatory, then the neuron will be more likely to fire
• the inside of the postsynaptic neuron momentarily becomes positively charged- once the electrical impulse is created it travels down the neuron
• therefore the action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold

Question 21

Describe the endocrine system

Answer 21

• works alongside the nervous system to control vital functions in the body
• acts more slowly than the nervous system but has very widespread and powerful effects
• made up of a network of specialist glands- release chemical messengers called hormones
• hormones are secreted into the blood stream and affect any cell in the body that has a receptor for that particular hormone
• most hormones affect cells in more than one body organ, leading to diverse and powerful responses
• the endocrine system regulates cell and organ activity within the body and controls vital physiological processes
• key endocrine gland is the pituitary gland, located in the brain- controls the release of hormones from all of the other endocrine glands in the body
• main glands are hypothalamus, thyroid, parathyroid, adrenals, pancreas, ovaries and testes

Question 22

Name four endocrine glands, the main hormone released, and the effects of these

Answer 22

• thyroid- thyroxine- regulates the body’s metabolic rate and growth rate
• pineal - melatonin- regulation of arousal, biological rhythms and the sleep wake cycle
• adrenal medulla- adrenaline and non adrenaline- fight or flight response- increased heart rate and blood flow to the brain and muscles, release of stored glucose and fats for use in fight or flight responses
• adrenal cortex- glucocorticoids such as cortisone, cortisol and corticosterone- further release of stored glucose and fats for energy expenditure, suppression of the immune system and the inflammatory response

Question 23

Where is the fight or flight response generated from, outline what time of response it is, what happens after response has finished

Answer 23

• generated from the automatic nervous system- the sympathetic branch.
• acute response
• It is a reflex response that is designed to help an individual when under threat and is activated when stressed.
• Helps an individual to react quicker than normal and facilitates optimal functioning, so that they can fight the threat or run away from it
• the automatic nervous system changes from its normal resting state- parasympathetic- to the physiologically aroused sympathetic state
• once the threat has passed, the Parasympathetic nervous system returns the body to its resting state- works to reduce the changes in the body that occured due to the activation of the sympathetic branch- works in opposition to the sympathetic nervous system- actions are antagonistic- reduces the activities of the body that were increased by the actions of the sympathetic branch- sometimes referred to as the rest and digest response

Question 24

Outline the initiation of the fight or flight response

Answer 24

• hypothalamus activates sympathetic nervous system
• activates adrenal medulla- releases adrenaline into bloodstream
• hypothalamus also activates adrenal-cortical system by releasing CRF
• Pituitary gland secretes hormone ACTH (Adrenocorticotrophic hormone)
• Adrenal cortex secretes stress hormones (e.g. cortisol)

Question 25

fight or flight- physical changes caused via sympathetic branch, effect on body

Answer 25

• increased heart rates- to speed up blood flow to vital organs
• faster breathing rate- to increase oxygen intake
• pupil dilation- to improve vision
• produced functioning of the digestive and immune systems- to save energy for prioritised functions, such as running
• muscle tension- to improve reaction time and speed

Question 26

Fight or flight- sympthetic vs parasympathetic branch action

Answer 26

Sympathetic- parasympathetic:
- increased heart rate- decreases heart rate
- faster breathing rate- decreases breathing rate
- pupil dilation- constricts pupils
- reduced functioning of the digestive and immune systems- stimulates digestion
- muscle tension- relaxes muscles

Question 27

Weaknesses of the fight or fight explanation

Answer 27

Alternative option- freeze:
- when faced with a dangerous situation our reaction is not always limited to the fight or flight response- some psychologists suggest that humans engage in an initial freeze response
- Gray (1998)- suggests that the first response to danger is to avoid confrontation altogether, which is demonstrated by a freeze response- during the freeze response animals and humans are hypervigilant, while they appraise the situation to decide the best course of action for the particular threat

Gender differences:
- define or flight response is typically a male response to danger and a more recent research suggests that females adopt a ‘tend and befriend’ response in stressful or dangerous situations
- Taylor et al (2000)- women are more likely to protect their offspring- tend- and form alliances with other woman- befriends a- rather than fight and adversary or flee
- furthermore, the fight or flight response may be counter intuitive for women, as running (flight) might be seen as a sign of weakness and put their offspring at risk of danger

Question 28

Describe two different theories about brain function

Answer 28

• holistic function- all parts of the brain are involved in the processing of thoughts and action
• localization of function- at different parts of the brain perform different tasks and are involved in with different parts of the body- if a certain area becomes damaged through illness or injury, the function associated with that area will also be affected

Question 29

Define localization of function

Answer 29

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

Question 30

Describe the hemispheres of the brain

Answer 30

The cerebrum is divided into 2 symmetrical halves- left and right hemisphere- some of our physical and physiological functions are controlled or dominated by a particular hemisphere- lateralisation
In general, the activity on the left hand side of the body is controlled by the right hemisphere, and vice versa

Question 31

what is the name of the outer layer of both hemispheres?

Answer 31

the cerebral cortex

Question 32

what are brain lobes, name 4

Answer 32

• a separate part of an organ
• frontal, parietal, occipital, temporal

Question 33

Name 6 areas of localised function

Answer 33

motor cortex, somatosensory cortex, visual cortex, auditory cortex, Broca’s area, Wernicke’s area

Question 34

Motor cortex- description, location, hemisphere

Answer 34

• responsible for all voluntary muscle movement
• has different areas that control specific parts of the body
• located in the frontal love of the brain in the precentral gyrus
• both hemispheres of the brain have a motor cortex

Question 35

somatosensory cortex- description, location, hemisphere

Answer 35

• processes sensory input from the skin, muscles and joints related to touch
• using sensory information, produces sensations of touch pressure, pain and temperature
• then localises this to specific body regions
• located in the parietal lobe
• both hemispheres have a similar to sensory cortex, with the cortex on one side of the brain receiving sensory information from the opposite side of the body inbox

Question 36

Visual cortex- description, location, hemisphere

Answer 36

• associated with vision- contains several different areas, each processing different types of visual information such as colour, shape or movement
• information from the eyes and retina are transmitted to this area of the brain
• located in the occipital lobe
• there is a visual cortex in each hemisphere- each hemisphere receives input from the opposite side of the visual field

Question 37

Auditory cortex- description, location, hemisphere

Answer 37

• the area of the brain concerns with hearing- main function to process sounds along with volume and pitch and the location of the sound
• information from the inner ear travels via nerve impulses to the auditory cortex
• located in the temporal lobe
• there is an auditory cortex in each hemisphere

Question 38

Localisation of function diagram

Answer 38

Question 39

Wernicke’s area- description, location, hemisphere

Answer 39

• involved in understanding language
• located in the left temporal lobe
• left hemisphere

Question 40

Broca’s area- description, location, hemisphere

Answer 40

• involved in speech production
• located in the frontal lobe
• left hemisphere

Question 41

Describe Broca’s aphasia

Answer 41

• manifests itself as an inability to articulate speech fluently, so that language may consist of disjointed words
• speech is slow, laborious and lacking in fluency
• tend to have difficulty with prepositions on conjunctions such as a, the, and
• normally writing is also disrupted
• understanding of language can be near to normal

Question 42

Describe Wernicke’s aphasia

Answer 42

• manifests itself as a breakdown in the ability to understand speech and to formulate coherent, meaningful sentences
• patients are often able to utter words, the grammar can often be correct, but sentences are deficient in meaning- speech can be fluent but meaningless
• often neologisms (nonsense words) are produced as part of the content of their speech

Question 43

Describe how Broca’s area and Wernicke’s area interact to produce language

Answer 43

• sensory region of the brain picks up auditory and visual inputs
• information is transferred via the audio/ visual cortex to
• Wernicke’s area recognises the inputs as language an associate set with meaning
• Broca’s area identifies what speech needs to be produced
• information is transferred via the motor cortex to produce speech

Question 44

Strengths of localization of function in the brain

Answer 44

Evidence from neurosurgery:
- neurosurgery targets specific areas of the brain which may be involved
- cingulotomy involves isolating a region called the cingulate gyrus which has been implicated in OCD
- doughtery et al report it on 44 people with OCD who had undergone this procedure- at post surgical follow up after 32 weeks, about 30% had met the criteria for successful response to the surgery and 14% full partial response
- the success of these procedures suggests that behaviours associated with serious mental disorders may be localised

Evidence from neuroimaging:
- Petersen et al (1998) used brain scans to demonstrate wernicke’s area was active during a listening task and Broca’s area was active during a reading/reasoning task
- Buckner and Petersen revealed that semantic and episodic memories reside in different parts of the prefrontal cortex
- these studies confirm localised areas for everyday behaviour’s- therefore objective methods for measuring brain activity have been provided around scientific evidence that many brain functions are localised
- Emmory (2006) found stats in individuals who can express themselves using both spoken & language, fMRIs shades that regardless of which type of language they use Broca’s area is activated
- Hickok et al (2002) found that damage to Wernicke’s area disrupts the understanding of sign language as well as sounds
- supports localization of function as it suggests common features in the organisation of spoken and sign languages in similar areas
COUNTER:
- Lashley (1950)- removed areas of the cortex- between at 10% and 50%- in rats that were learning the route through a maze- it know every out was proven to be more important than any other area in terms of the ability to learn at the roots- at the process of learning seemed to require every part of the cortex rather than being confined to a particular area- suggests that higher cognitive processes, such as learning, are not localised but distributed anymore holistic way in the brain

Case study evidence:
- unique cases of neurological damage support the localization theory- such as the case of Phineas Gage
- 25 year old- was impaled by a pole working on a railroad in 1848- past behind left eye, exiting skull from the top of his head taking most of his left frontal lobe
- survived but damage to his brain caused change in his personality- calm and reserved to quick tempered, rude and no longer him- suggests frontal lobe may be responsible for regulating moods

Practical applications:
- can use to work with individuals who have suffered from a stroke- for example depending on what symptoms of a stroke victim has such a speech impairment and paralysis in the arm, it can suggest which brain region is likely to be affected
- furthermore, this research has also been useful in developing techniques for treating stroke symptoms- for example, in order for the brain to reorganise, gradual retraining is necessary- in the case of loss of speech, such free training would normally be specific to speech
- therefore localization of function is useful in that it can help stroke victims on their road to recovery

Question 45

Weaknesses of localisation of function

Answer 45

Counter research:
- Danelli et al (2013)- reported of a boy (EB) who had most of his left hemisphere removed due to a tumour when he was two
- at that time, all of his linguistic abilities disappeared too
- he underwent an intensive rehabilitation programme and his language ability started to improve
- at the age of 17, his language was comparible to normal controls- but not perfect
- was found his right hemisphere had compensated for the loss of his left hemisphere
- questions the concept of localization, as it shows that brain plasticity can occur and that language is not fully localised to just Broca’s and Wernicke’s area

Methodological problems:
- the evidence is largely based on case studies
- case studies are usually of individuals who have suffered wounds, tumours, or strokes
- thus, they are very specific and idiosyncratic- each brain damage/lesion will be specific to that individual
- therefore the exact parts of the brain that are damaged are unlikely to be exactly the same and therefore may not be generalizable to non damaged brains
- we cannot therefore conclude that localization of function is apparent in normally functioning brains and it may be that how the different brain areas communicate is more important than localization

Language localisation questioned:
- Dick and Tremblay (2016) found but only 2% of modern researchers think that language in the brain is completely controlled by broca’s and wernicke’s area
- advances in brain imaging techniques, such as fMRI mean that neural processes in the brain can be studied with more clarity than ever before- seems that language function is distributed far more holistically in the brain than was first thought
- so-called language streams have been identified across the cortex, including brain regions in the right hemisphere, as well as subcortical regions such as the thalamus
- this suggests that, rather than being confined to a couple of key areas, language may be organised more holistically in the brain, which contradicts the localisation theory

Question 46

Describe hemispheric lateralisation

Answer 46

• 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
• each hemisphere is have functional specialisms for example the left hemisphere is dominant for language, some functions have localised areas in both hemispheres such as the visual area being in the left and right occipital lobe
• the two hemispheres are connected- allows information received by one hemisphere to be sent to the other hemisphere through the corpus callosum- a bundle of 200 to 300 million fibres

Question 47

Describe hemispheric lateralisation in terms of movement

Answer 47

• motor areas appear in both hemispheres however the motor area of the brain is cross wired- contralateral wiring
• the right hemisphere controls movement on the left side of the body whilst the left hemisphere controls movement on the right

Question 48

Describe hemispheric lateralisation in terms of vision

Answer 48

• vision is both contralateral and ipsilateral
• each eye receives light from the left visual field and the right visual field
• the left visual field of both eyes is connected to the right hemisphere and the right visual field of both eyes is connected to the left hemisphere
• this enables the official areas to compare the slightly different perspective from each eye and aids step perception- similar arrangement for auditory input to the auditory area and the disparity from the two inputs helps us locate the source of sounds

Question 49

Strengths of hemispheric lateralisation

Answer 49

Research evidence:
- Fink et al (1996)- used pet scans to identify which brain areas were active during a visual processing task
- when participants with connected brains were asked to attend to the global elements of an image such as looking at a picture of a whole forest, regions of the right hemisphere were much more active
- when required to focus in on the finer details such as individual trees, the specific areas of the left hemisphere tended to dominate
- suggests that hemispheric lateralisation is a feature of the connected brain as well as the split brain

Question 50

Weaknesses of hemispheric lateralisation

Answer 50

No ‘right/left-brained people:
- the idea of the left hemisphere as an analyser and the right hemisphere as a synthesiser may be wrong
- that may be different functions in the right and left hemisphere, but research suggests people do not have a dominant side of their brain which creates a different personality
- Neilsen et al (2013)- analysed brain scans from over 1000 people aged 7 to 2019 years- found that people used certain hemispheres for certain tasks- evidence for lateralisation- but no evidence of a dominant side- not an artists or a mathematicians brain etc
- suggests the notion of right or left brained people is wrong

lateralisation versus plasticity:
- lateralisation is adaptive as it enables 2 tasks to be performed simultaneously with greater efficiency
- Rogers et al (2004)- shoot that lateralised chickens could find food while watching for predators but normal chickens couldn’t
- on the other hand, neural plasticity could also be seen as adaptive- following damage through illness or trauma, some functions can be taken over by non-specialised areas in the opposite hemisphere- for instance, language function can literally switch sides- Holland et al 1996

Question 51

Describe split-brain research

Answer 51

• Sperry (1968)
• involved a group of individuals who had all undergone the same surgical procedure
• this procedure involved cutting the corpus callosum down the middle in order to separate the two hemispheres- done to treat epilepsy as reduces fits due to less excessive electrical activity

Question 52

Explanation of split brain research

Answer 52

• Sperry took advantage of the fact that information from the left visual fields goes to the right hemisphere and vice versa
• because the corpus callosum is cut in split brain patients, the information presented to one hemisphere has no way of travelling to the other hemisphere and can be processed only in the hemisphere that received it

Question 53

Split brain research method

Answer 53

• 11 people
• image presented briefly (250 milliseconds) to a participant’s right visual field after focusing on dot in middle - processed by the left hemisphere
• same, or different, image could be projected into the left visual field- processed by the right hemisphere
• 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 the information cannot be conveyed between hemispheres
• would then be asked to make responses with their left hand- controlled by right hemisphere, right hand- controlled by left hemisphere, or verbally- controlled by left hemisphere
• a control group of normal people who had not had the surgical section of the corpus callosum were used for comparison

Question 54

Findings of split brain research- verbal description

Answer 54

• a word being presented to the right visual field was immediately reported
• however the patient seemed unaware when a word flashed up in their left visual field- as left hemisphere deals with language and right hemisphere has no language system
• worked the same with describing an image being presented
• if a picture was shown to the left visual field there was an emotional reaction such as a giggle but the participant usually reported seeing nothing or a flash of light
• can conclude that the left hemisphere is dominant in terms of language

Question 55

Split brain research findings- recognition by touch

Answer 55

When left hand is behind a screen amongst a number of objects and a word is flashed to the right hemisphere- at the left hand can correctly select the object from the selection- shows the right hemisphere can recognise some basic nouns
- when the patient asked why they were holding the object, they cannot explain- needed speech from the left hemisphere but did not know what the right hemisphere had seen
- can conclude that the right hemisphere has some basic language ability

Question 56

Split brain research findings- matching faces

Answer 56

• when asked to match the face from a series of other faces, the picture processed by the right hemisphere- left visual field- was consistently selected, was the picture presented to the left hemisphere was consistently ignored
• when a composite picture made-up of two different halves of a face was presented, one to each hemisphere, the left hemisphere dominated in terms of verbal description whereas the right dominated in terms of selecting a matching picture
• can conclude that the right hemisphere is dominant in terms of recognising faces

Question 57

Strengths of split braain research

Answer 57

Supporting research in normal patients:
- Rasmussen and Milner (1977)- I find that the left hemisphere was more concerned with language and the right hemisphere is more concerned with spatial and artistic functioning
- Ornstein (1986)- reinforced this by stating that the right side of the brain is the creative side, whereas the left side of the brain was more logical- supports Sperry’s split brain research as it shows that the human brain is lateralised with each hemisphere having different functions

More recent split brain research:
- Gazzaniga (Luck et al 1989) showed that split brain participants actually performed better than connect to controls on certain tasks- for example faster at identifying the odd one out in an array of simple objects- in the normal brain, the left hemisphere is better cognitive strategies are watered down by the inferior right hemisphere (Kingstone et al, 1995)
- supports Sperry’s earlier findings that the left brain and right brain are distinct

Methodology:
- high levels of control used in research- Sperry created a very carefully controlled procedure
- for example to stop the natural tendency for participants to move their eyes towards the stimulus, the stimulus was only presented for around 200 milliseconds- ensured only the visual field aiming to be tested actually saw the stimulus, meaning only one hemisphere was tested at a time
- strength as it allowed sperry to carry out a wide range of variations on the original procedure such as testing faces, words and touch- extended our understanding on lateralisation
HOWEVER:
- means problem is lack of ecological validity
- the tasks that the participants were given today were very controlled
- buy sperry ensuring that participants had one eye covered and did not have enough time to move their eyes on their visual field- doesn’t reflect how the participants would use their brains in everyday life- likely that they would use both eyes to try to compensate for the cut corpus callosum
- therefore difficult to make generalisations of lateralisation based on just the split research

Ethics:
- the split brain operation was not performed for the purpose of the research- participants not deliberately harmed, all procedures explains and full informed consent obtained
HOWEVER, the trauma of the operation might mean that the participants did not later fully understand the implications of what they had agreed to
- they were subject to repeated testing over a lengthy period- may have been stressful over time

Question 58

Weaknesses of split brain research

Answer 58

Population validity:
- the amount of patients who had undergone this procedure to the corpus callosum original studies was 11 males
- there were also differences in the operations carried out, in some patients the smaller pathways which were not part of the corpus callosum which connects the two hemispheres were cut as well- not the case for all
- therefore can’t develop a model of hemispheric lateralisation using only split brain research, due to issues with generalising from the samples used

Confounding variable/ generalisation:
- in sperry’s split brain research participants were compared to a neurotypical control group- confounding variable as none of these had epilepsy- any differences that were observed between the two groups may be the result of the epilepsy rather than the split brain

Counter Evidence:
- split brain research suggests the right side of the brain cannot handle language, however, case studies have demonstrated that this is not necessarily the case
- Turk et al (JW)- developed the ability to speak out of the right hemisphere- can now talk about information that is presented in either the left or the right hemisphere
- contradicts the suggestion that each side of the brain only has certain functions- shows that the brain can adapt and plasticity can occur where some parts of the brain takeover the role of damaged parts

Question 59

Define brain plasticity

Answer 59

The ability of the brain to change and adapt synapses, pathways and structures in light of various experiences

Question 60

Describe how brain plasticity occurs

Answer 60

• in Childhood- by the end of the first year of life, the brain has more neurons thought it will when it is fully mature- during infancy the brain experiences a rapid growth in the number of synaptic Connections at has- peaking at about 15,000 per neuron at two- three years of age (Gopnik et al, 1990)
• as we get older, the brain is sculptured by our environment and experience- that helps the brain to adapt to the environment the baby is developing within
• pathways and networks that are not used will die off- synaptic pruning
• any Connections that are frequently used or strengthened
• recent research has suggested that at anytime of life existing neural Connections can change or new neural Connections comfortable as a result of learning and experience

Question 61

Who researched brain plasticity, name the aim of the study

Answer 61

Maguire et al- 2000- aimed to investigate whether changes to the brain occurred in London taxi drivers

Question 62

Describe Maguires procedure- brain plasticity

Answer 62

• 16 male taxi drivers compared to 50 male non taxi drivers
• MRI scans were used to analyse the amount of great matter in the posterior hippocampus- contains the neural cell bodies- 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 which assesses the recall of the city streets and possible routes

Question 63

Describe Maguires findings- brain plasticity

Answer 63

• the posterior hippocampus of the taxidrivers was significantly larger in comparison to the control group
• the volume of the hippocampus positively correlated with time spent as a taxi driver
• conclude that the requirement to learn ‘the knowledge’ may have altered the structure of the taxi drivers brain

Question 64

Strengths of brain plasticity

Answer 64

May be life long ability:
- in general, plasticity reduces with age
- However- Bezzola et al (2012)- demonstrated how 40 hours of golf training produced changes in the neural representations of movement in participants aged 40-60
- using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared to a control group- suggesting more efficient neural representations after training
- shows the neural plasticity can continue throughout the life span

Research evidence:
- Draganski et al- imaged the brains of medical students three months before and after their final exams
- learning induced changes were seen to have occured in the posterior hippocampus and the parietal cortex presumably as a result of the exam
- Michelli et a (2004)- found a larger parietal cortex in the brains of people who are bilingual compared to matched monolingual controls
- supports that changes in the brain- plasticity- can occur due to learning and experience

Seasonal brain changes:
- research suggests that there is seasonal plasticity in the brain in response to changes in environment
- E.g. supercharismatic nucleus (SCN)- regulates sleep/wake cycle- evidence that it shrinks in animals during spring and expands through autumn (Tramontin and Brenowitz, 2000)
BUT, most research done on animals (mostly songbirds)- human behaviour may be controlled differently

Question 65

Weaknesses of brain plasticity

Answer 65

Negative plasticity:
- may have negative behavioural consequences
- evidence suggests that the brains adaption to prolonged drug use leads to poorer cognitive functioning later in life, as well as an increased risk of dementia (Medina et al, 2007)
- 60-80% of amputees develop phantom limb symptom- the continued experience of sensations in the missing limb- usually unpleasant/painful and are thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss (Ramachardran and Hirstein, 1998)
- suggests top brains ability to adapt to damage is not always beneficial

Question 66

Describe functional recovery

Answer 66

• a form of neural plasticity
• following damage through trauma (e.g. accidents, strokes, meningitis), the brains ability to redistribute or transfer functions usually performed by a damaged area to other, undamaged area(s)- done to compensate
• neuroscientists suggest that this process can occur quickly after trauma- spontaneous recovery- and then slow down after several weeks or months
• at this point the individual may require rehabilitative therapy to further their recovery

Question 67

Overview how functional recovery happens

Answer 67

• the brain is able to rewire and reorganise itself by forming new synaptic Connections close to the area of damage
• secondary neural pathways that would not typically be used to carry out certain functions are activated or unmasked to enable functioning continue, often in the same way as before- Doidge, 2007
• this process is supported by a number of structural changes in the brain

Question 68

Name the structural changes in the brain involved with functional recovery

Answer 68

• axon sprouting
• denervation sensitivity
• recruitment of homogenous areas on the opposite side of the brain

Question 69

Describe axon sprouting

Answer 69

• the growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
• the axons of surviving neurons grow new branches that make synapses in areas of the brain formerly supplied by the damaged neurons

Question 70

Describe denervation supersensitivity

Answer 70

• occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost
• however, it’s can have the negative consequences of oversensitivity to messages such as pain

Question 71

Describe recruitment of homologous areas

Answer 71

• areas on the opposite side of the brain
• means that specific tasks can still be performed
• an example would be if broca’s area was damaged on the left side of the brain, the right sided equivalent would carry out its functions
• after a period of time, functionality may then shift back to the left side

Question 72

Describe research support for functional recovery

Answer 72

• Danelli et al (2013)
• Case study of a boy (EB)- had most of his left hemisphere removed due to a brain tumour when he was 2
• at the time, all his linguistic abilities were lost
• underwent intensive rehabilitation programme and his language abilities started to improve
• at age of 17, EBs language was comparable to ‘normal’ controlled (but not perfect)
• found that the RH had compensated for the loss of the LH
• shows that brain plasticity can occur and the non-specialist hemisphere can take over functions of the other hemisphere

Question 73

Strengths of functional recovery

Answer 73

Practical applications:
- contributed to the field of neurorehabilitation
- simple understanding that axonal sprouting happens encourages new therapies to be tried
- brain injury therapy can be used to try and maintain and continue improvements from spontaneous recovering in functioning
- gradual retraining is thought to be needed for the brain to be able to reorganise
- techniques may include movement therapy and electrical stimulation of the brain
- constraint induced movement therapy 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
- strength because it shows that the brain can change via plasticity/FR after trauma
- useful as it helps medical professionals know when intervention is needed

Research evidence:
- Schneider et al (2014)
- found that patients with a college education are 7x more likely than those who did not finish high school to be disability free one year after a moderate to severe traumatic brain injury
- supports plasticity as it suggests that this greater educational attainment could act as a ‘cognitive reserve’ and a factor in neural adaption during recovery from traumatic brain injury
BUT-
- may be confounding variable- money means could afford college- more likely to be able to afford medical care/therapy
- ALSO suggests that FR is not equally accesibke by all with brain damage

Question 74

Weaknesses of functional recovery

Answer 74

Not straight forward:
- not always a smooth transition as research suggests
- one function is recovered in an individual it can require considerable effort and although the person can do a task, it often requires large amounts of effort
- this can leave the individual fatigued
- other factors such as stress and alcohol can also affect the ability to use a function that has been regained- Fleet and Heilman, 1986
- suggests that plasticity can be affected by other factors and even when the brain recovers, it may lead to other issues

Gender difference:
- hard to draw conclusions around plasticity and functional recovery after trauma as gender can also affect the extent to which plasticity occurs
- Ratcliffe et al (2007)- examined 325 patients with brain trauma who had received rehabilitation and completed a follow up a year later
- when assessed for cognitive skills, woman performed significantly better than men on tests of attention/working memory and language
- males outperformed females in visual analytical tasks
- women also had a better recovery than men
- questions the extent to which plasticity and recovery after brain trauma can occur and how it occurs and reinforces the need for any rehabilitation programmes to account for gender

Small samples:
- Studies such as Benjeree et al
- treated people who had a total anterior circulation stroke with stem cells- all participants recovered compared to the more typical level of just 4% of recovery
- however this study drew conclusions based on just five participants and no control group- fairly typical of research on functional recovery- may not be generalisable

Question 75

Name four ways of studying the brain

Answer 75

• fMRI
• EEG
• ERP
• Post mortem

Question 76

Describe fMRI scans

Answer 76

Functional Magnetic Resonance Imaging:
- works by recording energy released from haemoglobin (the protein component of blood)
- when it is oxygenated, it reacts differently to when it is deoxygenated
- detects changes in both blood oxygenation and flow that occur as a result of neural activity
- when a brain area is more active, it consumes more action to meet this increased demand- blood flow is directed to the active area- haemodynamic response
- so, when an area is active and therefore using more oxygen, the fMRI scanner detects the amount of energy released (and therefore oxygen levels) by the haemoglobin and the change measured
- produces 3D images (activation maps)- shows which parts of the brain are involved in a particular function- important in understanding localisation of function
- gives moving picture and shows activity around one second after it occurs

Question 77

Strengths of fMRI

Answer 77

Non Invasive:
- does not require anything to be inserted into the body
- doesn’t require any radiation exposure (as in PET scans)
- means that if administered correctly it is virtually risk free, non-invasive and straight-forward- ethical

High spatial resolution:
- depicts detail by the millimeter
- provides a clear picture of how brain activity is localised

Objective:
- Other measures e.g. verbal reports are more subjective by both PP and researcher
- fMRIs have benefit of not being affected by researcher bias and can be seen as a reliable measurement

Question 78

Weaknesses of fMRI

Answer 78

Impractical:
- expensive compared to other neuroimaging techniques
- only produces a clear image if the person stays completely still- uncomfortable and noisy in an fMRI machine- images may nit be useful if moves
- may result in reduced sample size

Poor temporal resolution:
- around a 5 second lag behind the image on screen and the initial firing of neuronal activity
- means fMRI may not truly represent moment-to-moment brain activity

Question 79

Describe EEGs

Answer 79

Electroencephalogram:
- measure electrical activity in the brain
- information in the rain is processed as electrical activity- action potentials or nerve impulses being transmitted along neurones
- electrodes are placed on the scalp using a skull cap
- these detect small electrical changes resulting from the activity of brain cells
- The electrical signals over a period of time are shown on a graph- scan recording represents the brainwave patterns that are generated from the action of thousands of neurones, providing an overall account of brain activity
- Can be used by clinicians as a diagnostic tool for unusual arrhythmic patterns of activity- may indicate neurological abnormalities such as epilepsy, tumours, or sleep disorders

Question 80

Strengths of EEGs

Answer 80

High temporal resolution:
- provides recording of the brain in real time, rather than a still image
- can accurately detect brain activity at the resolution of a millisecond or even less
- allows the researcher to accurately measure a particular task or activity in the brain- more accurate at detecting brain activity

Real world application:
- has been useful in studying the stages of sleep
- has also been helpful in the diagnosis of conditions such as epilepsy- a disorder characterised by random bursts of activity in the brain that can be easily detected on screen

Question 81

Weaknesses of EEGs

Answer 81

Low Specificity:
- only gives a general overview of electrical activity
- cannot pinpoint the exact source of some neural activity and doesn’t allow researchers to distinguish between activities originating in different but adjacent locations
- information received in generalised- that of many thousands of neurones- EEG signal not always useful for pinpointing the exact location of neural activity

Surface measurement:
- can only detect the activity in superficial regions of the brain
- means it can’t reveal what is going on in the deeper regions such as the hypothalamus or hippocampus
- means it is limited as to what it can actually study in relation to psychological processes

Question 82

Weaknesses of EEGs

Answer 82

Low Specificity:
- only gives a general overview of electrical activity
- cannot pinpoint the exact source of some neural activity and doesn’t allow researchers to distinguish between activities originating in different but adjacent locations
- information received in generalised- that of many thousands of neurones- EEG signal not always useful for pinpointing the exact location of neural activity

Surface measurement:
- can only detect the activity in superficial regions of the brain
- means it can’t reveal what is going on in the deeper regions such as the hypothalamus or hippocampus
- means it is limited as to what it can actually study in relation to psychological processes

Question 83

Describe ERPs

Answer 83

Event-related potentials:
- similar to EEG in that it measures electrical activity, but much more specific
- in an EEG you get a general measure of brain activity, containing a number of neural responses
- In an reserachers ERP use statistical averaging techniques to philtre out extraneous brain activity from the original EEG recording, leaving only those that relate to the task of interest
- a stimulus such as a sounds old picture is presented to the participant a number of times- roughly 150- and the psychologist looks for specific electrical responses to that stimulus by finding an average
- only event related potentials remain- types of brain wave that are triggered by particular events
- researchers have found many different forms of ERP and how, for example, these are linked to cognitive processes such as attention and perception
-

Question 84

Strengths of ERP

Answer 84

Accuracy:
- provides a continuous measurement of processing in response to a stimulus
- preferable to fMRI scans, which do not give this continuous measurement
- beneficial as it makes it possible to determine how processing is affected by specific experimental manipulation, for example during presentation of different visual stimuli
- the limitations of EEG are partly addressed also- bring much more specificity to the measurement of neural processes that could never be achieved using raw EEG data

Reduces demand characteristics:
- able to measure how stimuli are responded to without the individual having to actually give a response
- for example ERP can measure the processing of a word in the middle of a sentence at the time the word is presented, rather than waiting for a response at the end of the sentence
- can also reduce any social desirability bias as participants have no conscious control over their brain activity and cannot therefore censor their responses

Temporal resolution:
- as derived from EEG, have excellent temporal resolution- especially when compared to fMRI
- means they are frequently used to measure cognitive functions and deficits such as the allocation of attentional resources and the maintenance of working memory

Question 85

ERP weaknesses

Answer 85

Standardisation:
- critics have pointed to a lack of standardisation in ERP methodology between different research studies
- makes it difficult to confirm the findings

Impractical:
- in order to establish pure data in ERP studies, background ‘noise’ and extraneous material must be completely eliminated
- problem because it may not always be easy to achieve

Surface measurement:
- ERP only detect Nero activity of a certain strength that can be measured at the scalp
- this means that any electrical activity occurring deeper in the brain comments such as in the amygdala, are not recorded
- issue as it means that important information may be missed

Question 86

describe post mortem examination

Answer 86

• carried out on the brain of an individual after they have passed away
• the brain is examined and this can be used to see where damage has occurred
• likely to be carried out on people who have a rare disorder and have experienced unusual deficits in mental processes in their behaviour
• allow researchers to identify the likely cause of symptoms shown
• for example, a post-mortem was carried out on tan’s brain from broccas work
• post mortem studies have also been used to establish a link between psychiatric disorders, such as schizophrenia and depression, and underlying brain abnormalities
• may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference

Question 87

Strengths of post mortem

Answer 87

Full brain access:
- allows detailed analysis of the brain that would not be possible through other methods
- for example, non-invasive scanning techniques such as fMRI and EEG do not give full access to the entire brain
- strength as it allows researchers to examine deeper areas of the brain such as the hypothalamus and hippocampus

Applications:
- vital in providing foundation for early understanding into key brain processes
- Broca and Wernicke- used PM in establishing link between language, brain and behaviour before neuroimaging was possible
- PM also used to study HM’s brain to identify the areas of damage, which could then be associated with memory deficits
- shows PM’s can provide useful information

Question 88

Weaknesses of post mortem

Answer 88

Lack of control:
- number if confounding variables that can influence the results of a PM
- E.g. cause of death, length of time between death and PM, drug treatments, age at death
- problem as any comparison to controls may not be valid

Retrospective/causation:
- issues with establishing causation
- PM studies are retrospective and the person is dead- impossible to follow up anything that arises
- any observed damage may nit be a result of the suspected cause, but something else e.g. unrelated trauma or decay
- problem as it means it is difficult to draw any firm conclusions from the research

Ethics:
- issue of informed consent before death
- E.g. HM- not able to provide informed consent due to condition- but PM research done on brain
- challenges the usefulness of PM in psychological research

Question 89

Describe biological rhythms

Answer 89

• distinct patterns of change in body activity that conform to regular cycles
• important influence in way in which body systems function
• governed by body’s internal clocks (endogenous pacemakers), and external changes to the environment (exogenous zeitgebers)

Question 90

Describe the different types of biological rhythm

Answer 90

• ultradian- occur multiple times during the day
• infradian- take longer than a day to complete
• circadian- last for around 24 hours

Question 91

Name an example of a circadian rhythm

Answer 91

The Sleep/Wake cycle

Question 92

Describe the sleep/wake cycle

Answer 92

• the body clock is regulated by an internal system including factors such as the release of hormones, metabolic rate and body temperature
• endogenous pacemakers and exogenous zeitgebers affect it

Question 93

Name 3 examples of research into the sleep/wake cycle

Answer 93

• Siffre (1975)
• Aschoff and Wever (1962)
• Folkard et al (1985)

Question 94

Describe Siffre’s rsearch

Answer 94

• spent 6 months in a sub tropical cave in texas
• measured sleep/wake cycle without any clues as to the time of day
• deprived of any natural light and sound
• had adequate food/drink
• main finding was that daily rhythm lengthened to 25-30 hours/day
• meant that when left cave, it was day 179, but siffre had only experienced 151
• but, fell asleep/woke up on regular schedule

Question 95

Describe Aschoff and Wever’s study

Answer 95

• PPs spent 3 weeks in WWII bunker, deprived of natural light
• had access to electric lights that they could turn on/off as they wished
• found that for the majority of PPs their body clocks settled into a sleep wake cycle of 25-27 hours

Question 96

Conclusions of Sifres/Aschoff and Webers studies

Answer 96

• demonstrate existence of an endogenous pacemaker as PPs stuck to a study circadian rhythm without external cue
• shows exogenous zeitgeber of light is needed to keep our cycle to 24 hour ‘normal’ day- without external cues, sleep/wake cycle is longer than 24 hours

Question 97

Describe Folkard et al’s resrecah (sleep/wake cycke)

Answer 97

• 12 PPs in dark cave for 3 weeks
• went to bed when clock read 11:45 pm, woke when said 7:45 am
• gradually sped up clock without PPs knowing- so apparent 24 hoir day lasted only 22 hours
• only 1 PP was able to comfortably adjust into new regime
• suggests the existence of a string free running circadian rhythm that cannot be overridden by exogenous zeitgebers

Question 98

Strengths of circadian rhythms

Answer 98

Supporting reserach:
- Folkard’s rsearch (see previous card) supports the existence of an internal clocks and strong circadian rhythm

Shift work (practical applications):
- provides understanding of adverse consequences that occur when circadian rhythms are disrupted (resynchronization)
- shift workers are required to shift sleep/wake cycle on a regular basis
- research has found that shift work has had consequences on health e.g. 3x more likely to develop heart disease (Knutson, 2003)
- also experience a period of reduced concentration at around 6 in the morning which can cause accidents (Boivin et al, 1996)
- this may bedue to stress of adjusting to a different sleep/wake cycle and the lack of good quality sleep during the day
- strength as it can have benefits for the economy (in terms of how to best manage worker productivity) and means that employees can consider this impact on health, which could reduce the burden on the NHS
BUT studies investigating the effects of shidt work tend to use correlational methods- difficult to establish whether desynchronisation of the sleep/wake cycle is actually a cause of negative effects- may be other factors- e.g. Solomon (1933) concluded that divorce rate in shift workers ,ay be due to strain of deprived sleep and missing family events- suggests it may not be biological factors that create the adverse cibsequneces associated with shift work

Medical treatment (practical applications):
- research has been used to improve medial treatment
- circadian rhythms coordinate a large number of the body’s basic processes such as heart rate, digestion and hormone levels
- these rise and fall during the day which has led to the field of chronotherapeutics- how medical treatments can be administered in a way that corresponds to a persons biological rhythms
- e.g. aspirin as a treatment for heart attacks is most effective if taken last thing at night- reduces blood platelet activity and can reduce risk of a heart attack- heart attacks are most likely to occur in the morning, so timing of taking aspirin matters- Bonten et al (2015) supports this
- shows that circadian rhythm research can help increase the effectiveness of drug treatments

Question 99

Weaknesses of circadian rhythms

Answer 99

Individual differences:
- theer are individual diffrences in terms of circadian rhythms
- e.g. the cycle length can vary from 13 to 65 hours (Czeisler et al, 1999)
- onset of the cycle also differs between people- Duffy et al (2001)- found that morning people prefer to rise early and go to bed early (about 6am to 10pm), and evening people prefer to wake up and go ti bed later (10am to 1am)
- problem as it shows that despite internal body clocks (endogenous pacemakers) being innate, there is some variation in them

Methodology- poor controls:
- in most studies, PPs are isolated from variables that may affect their circadian rhythm such as clocks, radio and daylihts
- however, they were not isolated from artificial light as it was generally through that dim artificial light wouldn’t affect circadian rhythms
- Czeisler et al (1999) found that they could adjust PPs circadian rhythms from 22 to 28 hours using dim (artificial) lighting
- problem as this artificial light may have affected the circadian rhythm, acting as an exogenous zeitgeber- confounding variable

Methodology- samples:
- some of the research is carried ot on very small sample sizes (e.g. Siffre- 1, Folkard- 12)
- there are individual differences in circadian rhythms- e.g. when Siffre conducted the same study again at age of 60, found that his internal clock (endogenous pacemaker) was much slower than when he was younger
- therefore difficult to make any genralisations from the samples used about circadian rhythms as a whole and prevent general conclusions from being made

Question 100

Describe what controls biological rhythms

Answer 100

• endogenous pacemakers- internal biological clocks- affected by environment but can still function without external cues
• exogenous zeitgebers- external cues- reset our ‘clocks’ each day to maintain coordination with the external world

Question 101

Name the endogenous pacemakers involved with the sleep/wake cycle

Answer 101

• the suprachaismatic nucleus (SCN)
• The pinneal gland (and melatonin)

Question 102

Describe the suprachiasmatic nucleus (SCN)

Answer 102

• small bundle of nerve cells located in the hypothalamus in each hemisphere of the brain
• regulated by light in the environment
• received light even when eyes are closed- can adjust to changing patterns of daylight even when asleep- important as the SCN has a built in circadian rhythm which only needs changing when external light levels change
• nerve fibred connected to the eye cross in an area called the optic chaism on their way to left and right visual area of the cerbral cortex- SCN lies just above the optic chaism- receives info about light directly from this structure

Question 103

Name reserach into the suprachiasmatic nucleus

Answer 103

Animal research:
- Ralph et al (1990)- hamsters
- DeCoursey et al (2000)- chipmunks

Question 104

Describe Ralph et als reserach (SCN)

Answer 104

• removed the SCN from genetically abnormal hamsters that had a 20 hour circadian rhythm (rather than usual 24)
• transplanted the SCN from the immature mutant hamsters into adult hamsters with the normal 24 hour circadian rhythm (whose SCN had been removed)
• found that the adult hamsters cycle changed to 20 hours

Question 105

Describe DeCoursey et al’s reserach (SCN)

Answer 105

• destroyed the SCN connections in the brains f 30 chipmunks
• returned to natural habitat
• observed for 80 days
• their sleep/wake cycle disappeared and a significant proportion of them had been killed by predators (presumably because they were awake, active and vulnerable to predators when they should have been asleep)

Question 106

Descirbe the Pinneal glands role in the sleep/wake cycle

Answer 106

• the SCN sends a signal to the pinneal gland- structure in the brain just behind the hypothalamus
• directs it to increase production and secretion of the hormone melatonin at night and to decrease it as light levels increase in the morning
• melatonin inhibits the brain mechanisms that promote wakefulllness
• malatonin also suggested as a factor in seasonal affective disorder
• thus, the SCN and the pinneal fland work together as endogenous pacemakers

Question 107

Endogenous pacemakers- strengths

Answer 107

Research evidence:
- Siffre’s study
- supports EP’s as shows how we have internal clock that tries to maintain 24 hour rhythm
- BUT issues with study- small sample size, individual differences- hard to generalise as low population validity

Practical applications:
- relationship between EPs and exogenous zeitgebers can help to explain jet lag and the effects of shift work
- night shift work- linked to heart attacks (Knutsson, 2003) and higher risk of car accidents (Gold et al, 1992)
- can help to reduce some of these problems e/g/ by having longer periods on the same shift pattern allowing pacemakers and zeitgebers to resynchronise

Question 108

Endogenous pacemakers- weaknesses

Answer 108

Methodology/interactionist sytem:
- endogenous pacemakers can’t be studied in isolation
- E.g. Siffre- total isolation- used artificial light which may have reset body clock every time he turned lamp on
- in reality, pacemakers and zeitgebers interact- makes little sense to separate the 2 for the purpose of research
- suggests that attempts to isolate the influence of internal pacemakers loqwers the validity of research

Other complex influences on cycle:
- SCN research may obscure other body clocks
- research has revealed that there are many circadian rhythms in many organs and cells in the body
- these peripheral oscillators are found in organs including the lungs, pancreas, and skin- thy are influenced by the SCN, but also act independently
- Damiola et al (2000)- demonstrated how changing feeding patterns in mice could alter the circadian rhythm of cells in the liver for up to 12 hours, while leaving the rhythm of the SCN unaffected
- suggests other complex influences on the sleep/wake cycle

Ethics:
- Issues with animal research- Decorsey et al- animals exposed to risk when returned ti their natural habitat- most died as a result

Question 109

Describe exogenous zeitgebers as part of the sleep/wake cycle

Answer 109

• external factors in the environment that reset our biological clocks through entrainment
• free running internal cycles are brought into line by exogenous zeitgebers- so there is an interaction of internal an external factors
• examples that effect the sleep/wake cycle are light and social cues

Question 110

Describe light as an exogenous zeitgeber, name a research study involving this

Answer 110

• light can reset the bodies main endogenous pacemaker- the SCN- and plays a role in the maintenance of the sleep/wake cycle
• also has an indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation
• Campbell and Murphy (1998)

Question 111

Describe Campbell and Murphy’s reserach (exogenous zeitgebers)

Answer 111

• 15 PPs
• woken at various times, light pad shone on the back of their knees
• researchers managed to produce a deviation in the PPs normal sleep/wake cycle of up to 3 hours
• suggests slight may be detected by skin receptor sites even when same info not received by the eyes
• shows light is such an important exogenous zeitgeber that it doesn’t necessarily need to rely on the eyes to influence the brain

Question 112

Describe social cues as exogenous zeitgebers, name a research study involving this

Answer 112

• social cues such as mealtimes and social activities may also have roles as zeitgebers
• adapting to local times of eating and sleeping can be an effective way to change ones circadian rhythm when travelling
• at around 6 weeks of age, the circadian rhythms begin, and by about 16 weeks, babies rhythms have been entrained by the schedules imposed by parents- e.g. adult determined mealtimes and bedtimes
• Klein and Wegmann (1974)

Question 113

Describe Klein and Wegmann’s research (exogenous zeitgebers)

Answer 113

• investigated jet lag
• found that the circadian rhythms of ai travellers adjusted more quickly if they went outside more at their destination
• thought to be because they were exposed to the social cues of their new time zone- acted as a zeitgeber

Question 114

Exogenous zeitgebers- strengths

Answer 114

Practical applications:
- see endogenous pacemakers strengths- application of knowledge about the interaction of EPs and EZs

Age-related insomnia:
- evidence suggests that people have poorer quality sleep as they get older
- may be due to natural changes in te circadian rhythm as we age- means falling asleep earlier and broken sleep at night- Duffy et al, 2015
- however, studies have suggested that exogenous zeitgebers may be more responsible for the changes in sleep patterns amongst older people
- Hood et al (2004)- found management of insomnia was improved if elderly people were more active and had more exposure to natural light
- shows how knowledge of EZs can work to improve quality of life in the elderly

Question 115

Exogenous zeitgebers- weaknesses

Answer 115

Case study conflicting evidence:
- Miles et al (1977)
- recount study of a young man who had been blind since birth
- had an abnormal circadian rhythm of 24.9 hours
- despite exposure to social cues, such as regular mealtimes, his circadian rhythm couldn’t be adjusted
- suggests that social cues alone are not effective in resetting the biological rhythm

Conflicting research:
- Luce and Segal (1966)
- found light levels can be overridden
- In the Arctic circle, 6 months of the year is total darkness, and 6 months is total light
- found that people in these conditions tend to maintain a constant sleep pattern
- questions the importance of light as an EZ and suggests social cues can act to reset EPs instead
- suggests the sleep/wake cycle is primarily controlled by EPs that can override environmental changes in light

Question 116

Describe infradian rhythms, name examples

Answer 116

• duration longer than 24 hours
• may be cycles lasting days, weeks, months, or even annual
• examples- the menstrual cycle, seasonal affective disorder

Question 117

Describe the menstrual cycle

Answer 117

• governed by monthly changes in hormone levels which regulate ovulation
• cycle refers to the time between the first day of a women period, when the womb lining is shed, to the day before her next period
• typically takes 28 days to complete (but 24-35 normal)
• during each cycle, rising levels of the hormone oestrogen cause the ovary to develop and release an egg (ovulation)
• after ovulation, the hormone progesterone helps the womb lining to grow thicker, readying the womb for pregnancy
• if pregnancy doesn’t occur, the egg is absorbed into the body, the womb lining comes away and leaves the body (menstrual flow)
• endogenous system, but also may be influenced by exogenous zeitgebers such as other women’s cycles

Question 118

Name research into menstrual cycles

Answer 118

McClintock (1999)

Question 119

Describe McClintock’s research (menstrual cycles)

Answer 119

• studied 29 women with a history of irregular periods
• samples of pheromones were gathered from 9 of the women at different stages of their cycles- via a cotton pad placed on their armpit worn for 8+ hours so they were picked up
• pads treated with alcohol and frozen- rubbed on upper lips of te other PPs
• day 1- pads from start of menstrual cycle applied to all 20 women
• Day 2- given pad from 2nd day etc
• Stern and McClintock found that 68% of women experienced changes to their cycle that brought them closer to the cycle of their ‘odour donor’
• suggests exogenous zeitgebers affect our pacemakers in regards to the cycle

Question 120

Describe seasonal affective disorder (SAD)

Answer 120

• depressive disorder that has a seasonal pattern of onset
• described and diagnosed as a mental disorder in the DSM-5
• main symptoms are persistent low mood and a general lack of activity and interest in life
• triggered in winter when the number of daylight hours becomes shorter
• circanual rhythm- subject to a yearly cycle
• also circadian- may be affected by the disruption of the sleep/wake cycle- long periods of daily darkness in winter
• hormone melatonin implicated in the causes of SAD:
• during the night, the pineal gland secretes melatonin till dawn when there is an increase in light
• during winter, the lack of light means the secretion process carries on for longer
• thought to have a knock-on effect to the production of serotonin in the brain- a chemical that has been linked to the onset of depressive symptoms
• controlled by endogenous pacemakers (melatonin) ad zeitgebers (light)

Question 121

Describe research into seasonal affective disorder

Answer 121

• Terman (1988)- sound SAD was 5x more common in New Hampshire (northern USA state with less sunlight) than in Florida (sunnier climate)
• Golden et al (2005)- meta-analysis- found the use of a bright light as treatment for SAD was effective in reducing symptoms of SAD

Question 122

Infradian rhythms- strengths

Answer 122

Evolutionary basis:
- menstrual synchrony may be explained by natural selection
- for distant ancestors, may have been advantageous for women to menstruate together and become pregnant at the same time
- in a social group, this would allow babies who had lost their mother before or after childbirth to have access to breastmilk- thereby improving chances of survival
- suggests synchronisation is an adaptive strategy

Practical application:
- SAD treatment- phototherapy
- lightbox stimulates very strong light to reset the body’s internal clock (melatonin levels) in morning and evening
- studies show this reduces the effects of SAD in around 80% of people (Sanassi, 2014)
- Eastman et al (1998)
- also preferred over antidepressants as regarded as safe
BUT
- same study recorded a placebo effect of 30% when PPs given a ‘fake generator’ - told it was another form of treatment
- questions extent to which light is a factor in causing SAD if symptoms can improve without any changes to melatonin, and whether SAD is an infradian rhythm

Question 123

Infraradian rhythms- strengths

Answer 123

Evolutionary basis:
- menstrual synchrony may be explained by natural selection
- for distant ancestors, may have been advantageous for women to menstruate together and become pregnant at the same time
- in a social group, this would allow babies who had lost their mother before or after childbirth to have access to breastmilk- thereby improving chances of survival
- suggests synchronisation is an adaptive strategy

Practical application:
- SAD treatment- phototherapy
- lightbox stimulates very strong light to reset the body’s internal clock (melatonin levels) in morning and evening
- studies show this reduces the effects of SAD in around 80% of people (Sanassi, 2014)
- Eastman et al (1998)
- also preferred over antidepressants as regarded as safe
BUT
- same study recorded a placebo effect of 30% when PPs given a ‘fake generator’ - told it was another form of treatment
- questions extent to which light is a factor in causing SAD if symptoms can improve without any changes to melatonin, and whether SAD is an infradian rhythm
- further, light therapy can produce headaches and eye strain
- Rohan et al (2009)- recorded relapse rate of 46% over successive winters, compared to 27% in comparison group receiving CBT

Question 124

Infraradian rhythms- weaknesses

Answer 124

Methodological limitations:
- synchronisation studies
- many factors that affect the menstrual cycle- stress, changes in diet, exercise etc- may act as confounding variables
- means any supposed pattern of synchronisation is no more than what would’ve been effected due to chance
- may explain why other studies such as Trevathan et al (1993) have struggled to replicate the findings
- suggests menstrual synchrony studies are flawed

Conflicting evidence:
- Yang and Schank (2006)
- collected data on 186 Chinese women and their menstrual cycles over a year, who lived in a dorm together
- found that women living in groups did not synchronise theor cycles
- questions this particular infradian rhythm in terms of the influence of exogenous zeitgebers- suggesting the menstrual cycle may only be due to internal biological factors

Question 125

Describe ultradian rhythms

Answer 125

• last less than 1 day
• examples- sleep cycle, basic rest activity cycle (BRAC)

Question 126

Describe the sleep cycle

Answer 126

• 5 distinct stages of sleep- all together span 90 mins- cycle continues throughout course of the night
• each stage characterised by a different level of brainwave activity- can be monitored using an EEG
• stages 1 and 2- light sleep- easily woken
• 1- brain waves have high frequency and short amplitude, alpha waves
• 2- alpha waves continue but occasional random changes in pattern- sleep spindles
• stages 3 and 4- deep sleep (slow wave sleep, SWS)- delta brain waves, lower frequency and higher amplitutde- hard to wake someone
• stage 5- REM sleep- body paralysed but brain activity closely resembles that of the awake brain
• theta waves, eyes occasionally move aroun- rapid eye movement (REM)
• dreams most often experienced during REM, but may also occur during deep sleep
• sleep cycle alternates between rapid eye movement (REM) and non-rapid eye movement (NREM) sleep

Question 127

Describe basic rest activity cycle (BRAC)

Answer 127

• Kleitman- suggested the 90 minute ultradian rhythm continues during the day, even when awake
• rather than moving through sleep stages, we move from a period of alertness into a state of physiological fatigue approximately every 90 minutes
• research suggests the mind can focus for a period of bout 90 mins, and towards the end of these, the body begins to run out of resources, resulting in loss of concentration, fatigue and hunger
• not as obvious as the sleep cycle, but daily routines tend to match this
• e.g. the 10:30 break time for workers who start at 9am and finish at midday for lunch
• continues in the afternoon- cat naps more likely

Question 128

Strengths of ultradian rhythms

Answer 128

Research evidence:
- Demet and Kleitman (1995)
- monitored the sleep patterns 9 adult PPs in a sleep lab
- brainwave activity recorded on an EEG
- researchers controlled the effects of caffeine and alcohol
- found that everyone had periods of REM sleep during the night, and that if PPs were woken during REM sleep, they were more likely to recall dreans than in any other sleep cycle
- this study supports that the sleep cycle is an ultradian rhythm that goes through distinct stages with REM sleep

Age related changes:
- resrecah into ultradian rhythms has improved understanding of age related changes in sleep
- sleep scientists observed that SWS decreases with age
- growth hormone is mostly produced during SWS- therefore this is reduced in older people
- Cauter et al (2000)- the resulting sleep deficits in old age may explain various issues in old age, such as reduced alertness
- in order to increase SWS, relaxation and medication may be used
- suggests that knowledge of ultradian rhythms has practical value

High control:
- most research done in sleep lab
- leads to high control of extraneous variables
- means that a researcher can exclude temporary variables such as noise or temperature that may affect sleep
- BUT, lab studies involve being attached to complicated machinery- leading PPs to sleep in ways hat may not reflect their normal sleep patterns

Question 129

Ultradian rhythms- weaknesses

Answer 129

Individual diffrenecs:
- Tucker et al (2007)
- studied 11 PPs over 11 consecutive days and nights in a controlled laboratory environment
- researchers assessed sleep duration, time to fall asleep, and the amount of time spent in each sleep stage
- found large individual differences consistently in each of these characteristics
- for deep sleep (stages 3/4), the difference was particularly significant
- suggests that difrenecs between PPs were biologically determined and questions the sleep cycle that has been suggested to be innate in all humans