Biospsychology y1 and 2 Flashcards
(116 cards)
1
Q
what is the nervous system
A
a complex network of nerves and cells that carry electrical impulses to and from the brain and the spinal cord to various parts of the body
2
Q
what are the two systems the nervous system is made from
A
the central nervous system and peripheral system
3
Q
what is the central nervous system made up from
A
the brain for conscious and unconscious processing
spinal cord which receives and transmits information
- brain functions: regulates body temp, heart rate and breathing, language and movement
- cerebral cortex (outer layer of brain) carries out essential functions such as memory, thinking, learning, problem solving, consciousness
- spinal cord ensures signals from the brain are transmitted to the rest of the body via PNS
4
Q
what is the function of the peripheral nervous system
A
- contains huge network of spinal nerves
- these nerves link to the brain and spinal cord
- sensory receptors in the PNS process internal and external changes
- information is then sent to the CNS via sensory nerves
5
Q
what are the subdivisions of the peripheral nervous system and describe their functions
A
- somatic nervous system- controls voluntary muscles (under our conscious control so can move them whenever we want to) also responsible for reflex arc as it involves muscles movement, directs muscles to move appropriately
- autonomic nervous system - involuntary ( not under our conscious control so can’t move them whenever we want to)- transmits and receives information from organs e.g heart rate, breathing, stress response, digestion
6
Q
what is the autonomic nervous system divided into and describe their functions
A
- sympathetic nervous system- increases bodily activity. Prepares body for physical activity when hypothalamus detects stimulus which requires action. SPNS is triggered when body is in an alert state. Release of adrenaline for fight or flight, increased heart/sweat/breathing rate, dilated pupils
- parasympathetic nervous system - known as the ‘rest and digest’ system, calms body to preserve and maintain energy, decreased heart/sweat/breathing rates, constricted pupils, regulates bodily functions, more time spent in this state, the healthier a person is likely to be
- usually homeostasis is maintained, means regulated by a balance between the sympathetic and parasympathetic systems
7
Q
what are the functions of the cerebrum (largest part of brain at front)
A
- responsible for personality, speech, vision, motor ability and regulates body temperature
8
Q
what is the function of the cerebellum
A
controls posture and balance
9
Q
what is a dendrite
A
- tree like branches which carry the electrical charges from one neuron to the next
10
Q
what is an axon
A
-neuron carrying impulses away from the cell body
- carries electrical charge down the length of the neuron and is covered in a protective fatty myelin sheath
11
Q
what is an action potential
A
the small amount of energy needed for an electrical impulse to be sent
12
Q
what are the two types of neurotransmitters and explain their role
A
1) Excitatory- making it more likely the post synaptic neuron fire (e.g glutamate, adrenaline) as they cause positively charged particles to enter (process called depolarisation)
2) Inhibitory- make it less likely the post synaptic neuron will fire (e.g GABA and serotonin) as they cause negatively charged particles to enter both occur in the action of the neurotransmitter at postsynaptic receptor (process called hyperpolarisation)
13
Q
Explain the process of summation on excitatory and inhibitory neurotransmitters
A
- an excitatory neurotransmitter will produce EPSP (excitatory post-synaptic potential) whereas inhibitory neurotransmitter will produce IPSP ( inhibitory post-synaptic potential).
- whether or not the post synaptic neuron will fire or not depends on EPSP and IPSP
- If EPSP is greater than IPSP then the neuron will fire
- If IPSP is greater than EPSP threshold is not reached, therefore postsynaptic neuron will not fire
- this process is called summation
14
Q
what is the role of the pituitary gland
A
-produces hormones to influence the release of hormones from other glands
- controlled by the hypothalamus, a region of the brain above the pituitary gland
15
Q
what does the anterior (front) of the pituitary gland produce
A
ACTH- a response to stress
16
Q
what does the posterior (back) of the pituitary gland produce
A
oxytocin- important for mother-infant bonding
- secreted during child birth, encourages attachment between mother and baby
17
Q
what are the two parts of the adrenal gland (inner and outer region) and what does each part do
A
inner region- adrenal medulla, releases hormones not necessary to live
outer region- adrenal cortex, releases hormones necessary to live
18
Q
what hormone does the adrenal cortex release and describe its functions
A
cortisol- a stress hormone, has functions such as cardiovascular and anti inflammatory functions
- released from adrenal cortex, maintains blood pressure and metabolism during stress, keeps body alert during prolonged stress
- does this by maintaining levels of glucose in the body, therefore helps the body deal with stress
19
Q
what hormone does the adrenal medulla release and describe its functions
A
adrenaline and noradrenaline- prepares body for fight or flight
- helps the body respond to a stressful situation (e.g increasing heart rate and blood flow to muscles and brain)
- noradrenaline restricts blood vessels so blood pressure increases
- adrenaline causes physiological responses
20
Q
what are the ovaries responsible for
A
production of eggs and for the hormones oestrogen and progesterone
21
Q
what are the testes responsible for
A
-male productive hormone that produces the hormone testosterone
-testosterone causes the development of male characteristics such as growth of facial hair, deepening voice and growth spurts
-testosterone plays a role in sex drive, sperm production and maintenance of muscle strength
22
Q
describe the meaning of localisation of the brain
A
specific functions of the brain have specific locations in the brain
23
Q
where are the visual centres located
A
-in the visual cortex in the occipital lobe
-spans both hemispheres (left and right)
24
Q
describe the visual process (how light travels and enters etc)
A
-light enters and strikes the photoreceptors in the back of the eye
-creates a nerve impulse from the retina, travels to areas of the brain via the optic nerve
25
where are the auditory centres located
- in temporal lobes on both sides of brain where the auditory cortex is
- processes sound info from ears
26
describe the auditory process (how sound travels and enters etc)
- begins in cochlea in the inner ear, sound waves are converted to nerve impulses
- travel via the auditory nerve to auditory cortex
- pit stop at brain stem where basic decoding happens
- last stop is auditory cortex
- sound has already been largely decoded at this point, in auditory cortex it is recognised and may result in an appropriate response
27
what are the two language centres and describe their function
1) Broca's area (left hemisphere only) , left frontal lobe responsible for speech production
2) Wernicke's area (left hemisphere only), top of temporal lobe, responsible for speech comprehension
28
explain Paul Broca's study on patient Tan
- patient who had suffered from epilepsy throughout childhood
- hospitalised at age 30
- became known as ‘tan’ as he could only produce the word tan
- suffered from complete paralysis down right side of body but able to use left arm and leg
- after death, Broca performed brain autopsy and found a lesion of the left frontal lobe
- concluded that this area is responsible for speech production
- Broca’s aphasia now used as a diagnosis for pp; who have difficulty producing speech
29
what did neuroscientists find out about the two regions of the Broca's area
- when people perform cognitive tasks (nothing to do with lang) their Broca's area is active.
- Fedorenko (2012) discovered 2 regions of Broca's area- one selectively involved in lang, other involved in responding to many demanding cognitive tasks (maths problems)
- located in the frontal lobe
30
explain the role of the Wernicke's area
- involves understanding language
-located in the temporal lobe
31
describe the roles of the motor cortex
- responsible for voluntary motor movements
- located in frontal lobe
- different parts control different parts of the body
- arranged logically, the region that controls the foot is near the region that controls the leg
- in both hemispheres, left + right
32
describe the roles of the somatosensory cortex
- detects sensory events
- located in the parietal lobe
- uses sensory info from skin to produce sensations e.g pain and temperature which it then localises to specific body regions
- in both hemispheres, left + right
- cortex on one side of the brain receives sensory info from the opposite side of the body
33
localisation theory suggests certain areas are responsible for certain processes. what are the areas and where are they located
1) motor cortex (in both hemispheres) - frontal lobe
2) Broca’s area (left hemisphere only) - frontal lobe
3) auditory cortex- temporal lobe
4) wernicke’s area (left hemisphere only) - posterior temporal lobe
4) visual cortex (both hemispheres) - occipital lobe
5) somatosensory cortex (in both hemispheres) - parietal lobe
34
what are the weaknesses of localisation
1) Lashley suggests processes such as learning are not localised but distributed in a more holistic way.
- Lashley removed areas of the cerebral cortex (between 10% and 50%) in rats that were learning a maze. He found that no area was proven to be more important than any other when learning the maze, it was about the size of the brain area damaged
- lead to idea of ‘law of equipotentiality’ idea that rather than functions such as memory and learning being localised to one area, the whole cortex has the ability to perform this function
- links to plasticity- when the brain has become damaged and a particular function has been comprised or lost, the rest of the brain recognises this and attempts to recover the lost function
- this suggests that learning is too complex to be localised and requires the involvement of the whole brain
2) biologically reductionist- tries to reduce very complex behaviour + cognitive processes to one specific brain region, critics suggest a more thorough understanding of the brain is required to truly understand complex cognitive processes like language
- more research should be conducted in order to enhance and improve our understanding of localisation
3) - when people perform cognitive tasks (nothing to do with lang) their Broca's area is active.
- Fedorenko (2012) discovered 2 regions of Broca's area- one selectively involved in lang, other involved in responding to many demanding cognitive tasks (maths problems)
- located in the frontal lobe
35
what are the strengths of localisation
1)Tulving et al demonstrated, using PET scans,
that semantic memories were recalled from the left prefrontal cortex, whilst episodic memories were
recalled from the right prefrontal cortex. This shows that different areas of the brain are responsible
for different functions, as predicted by localisation theory. This idea was further supported by
Petersen et al (1988) , who found that Wernicke’s area activation is required for listening tasks,
whereas Broca’s area is required for reading tasks. This confirms the idea that Wernicke’s area is
involved in speech comprehension, whilst Broca's area is responsible for speech production.
2) Supporting case studies- Phineas Gage- whilst working on railroad, tamping iron went through his left cheek, passing behind his left eye, and exiting his skull from the top of his head taking a portion of his brain with it- most of his left frontal lobe
- he survived but he had turned from someone who was calm and reserved to someone who was quick tempered, rude suggesting the frontal lobe may be responsible for regulating mood
HOWEVER- problems with case studies- difficult to make meaningful generalisations from the findings of a single individual, also conclusions drawn may depend on the subjective interpretation of the researcher
36
what does hemispherical lateralisation mean
- two halves of the brain are functionally different and each hemiphere has functional specialisations e.g left is more dominant for language and right excels at visual motor
37
what is corpus callosum
- bundle of nerve fibres that join the two halves of the brain
- acts as a bridge between the two hemispheres and allows them to send messages and work together
38
what is corpus callosotomy
- division of the two hemispheres by surgery which has been occasionally done to improve epilepsy
39
features of the left hemisphere
- lang centre of brain (Broca’s and Wernicke’s)
- controls right hand
- recieves info from right visual field
40
features of the right hemisphere
- can't process language
- focuses on visual spatial tasks
- controls the left hand
- recieves info from the left visual field
- ability to detect faces
- excels at visual motor tasks
41
explain Sperry's split brain research
- quasi experiment, 11 ppts
- ppts were all epileptics who couldn't be treated with drugs
- they already had their corpus callosum split
- ppts gazed at a fixation point on screen, images are projected either side of projection point ( into either visual field)
- there were 4 variations:
1) describing what you see- when object was shown to right visual field they could easily describe what was seen, when seen on left visual field they couldn't describe it as right hemisphere can't process lang
2) recognition by touch- when shown an object on left visual field they could pick up the object with left hand however couldn't verbalise what they were selecting
- two different objects were placed in each hand then hidden, if left hand picks up something the right hand is looking for, the object is rejected and other hand continues to search
3) drawing- drawings were consistently better when drawn with left hand as right hemishere contains visuo spatial tasks
4) face recognition- shown a split face (woman on left, man on right), when asked what was shown they would say man as left hemisphere is able to produce speech. If asked to pick matching pic of what they saw they would select image of woman as right hemisphere specialises in face recognition
42
what are the weaknesses of split brain research and lateralisation
1) language may not be restricted to one hemisphere
- previous research suggested that the right hemisphere was unable to deal with any language at all
- however Turk et al (2002) found one patient known as J.W who suffered damage to the left hemisphere, but developed the capacity to speak in the right hemisphere, leading to the ability to speak about the info presented on either side of the brain
- this challenges the notion that language is exclusive to the left hemisphere, plasticity and functional recovery allow the brain to compensate, so research understated the importance of plasticity
2) problem of case studies- studies have as few as one or two patients making up the study
-confounding variable, ppts taking part all had epilepsy, and had been taking medication that could have affected their abilities, therefore conclusions are based on potentially unreliable information and there is too little research on people who don't have any confounding variables
3) issue with replicating Sperry’s research as he was working with a small highly specific sample
- people who had corpus callosotomy represent a restricted population
- this means Sperry’s findings are difficult to generalise beyond this very limited demographic
4) may not be fixed- changes with age, lateralised patterns found in younger patients become more bilateral in older people. Saflarki et al found that language became more lateralised to the left hemisphere with increasing age in children and adolescents, but after the age of 25, lateralisation decreased with each decade of life. Therefore it’s too simplistic to state lateralisation is fixed as this shows age influences the extent of lateralisation
43
what are strengths of split brain research
1) has provided a unique way of testing the functions of each hemisphere and has led to a wide body of research, helping our understanding of lateralisation. Concluded that left hemisphere gears language and our right gears spatial knowledge and face recognition. Strength as it provides us evidence to show split brain research has developed our understanding of human brain where there are clearly lateralised functions. Led Sperry to being awarded a Nobel prize for his contributions to research
2) Scientific and well controlled, involved standardised procedures that allowed Sperry to vary different aspects each time whilst ensuring only one hemisphere was receiving info at a time. E.g use of fixation point ensured only one hemisphere was receiving info. Allowed Sperry to vary aspects in a well controlled way
44
what is meant by brain plasticity
- our brain can change and adapt over time
- in infancy the brain experiences growth in the many synaptic connections peaking at around 15000 at the age 2-3 (twice as many than the adult brain)
- as we age, rarely used synaptic connections are deleted and frequently used connections are strengthened in a process known as synaptic pruning
- the younger you are the more plastic your brain is therefore changes rapidly
- brain is not a static, concrete mass, it’s a flexible organ that adapts to environmental stimuli
45
what is meant by bridging in plasticity
- where new connections are created due to use and new stimulus
46
explain Maguire's (2000) research into plasticity (studied brains of london taxi drivers)
- examined whether structural changes could be detected in the brain of people with extensive experience of spatial navigation
- MRI scans obtained of 16 male London taxi drivers (driving for 1.5 years), control group of 50 healthy men (age didn’t differ)
- found increased great matter (more synaptic connections) in taxi drivers compared to the other men
- found in the posterior hippocampus (associated with development of spatial and navigational skills), correlation between amount of time being taxi drivers and volume of grey matter (more changes/synaptic connections)
- provides evidence for structural differences, suggesting that extensive practice with spatial navigation affects the hippocampus (supporting idea of brain plasticity)
47
explain Kuhn's research into plasticity (video games)
- got ppts to play super mario for at least 30 mins per day over a 2 month period.
- they compared the brain development to a control group who didn't play
- they found significant differences in the grey matter of the video gaming ppts particularly in the cortex, hippocampus and cerebellum
- hippocampus: memory
- cerebellum: balance, motor movements
48
what are the 3 functional recoveries of the brain after trauma
1) neural unmasking
2) axon sprouting
3) recruitment of homologous areas
49
what is neural unmasking (functional recovery of brain)
- in brains there are ‘dormant synapses’ where their connections exist but their function is blocked as they don’t receive neural input
- when a brain is damaged the rate of inputs to these dormant synapse increases meaning the synapses can open and become unmasked
- can open connections to regions of the brain that are not normally active, in time will cause new structures
50
what is axon sprouting (functional recovery of brain)
- growth of new nerve endings which connect with other undamaged nerve cells to form new nerve pathways
- at a younger age, recover from trauma is more likely
51
what is recruitment of homologous areas (functional recovery of brain)
- when a homologous (similar) area of the brain on the opposite sides is used to perform a specific task
- one example would be if the broca's area was damaged (left side of the brain) the right-sided equivalent would carry out it's function
- enable a route to be used without having to build new networks
52
what are strengths of functional recoveries of the brain and brain plasticity
1) strength of recruitment of homologous areas
- story of Judy, real life case study- entire hemisphere removed however still had the ability to function normally as the left side took over the functions of the right side
2) research support from animals (plasticity)
- found increased numbers of neurons in brains of rats housed in a maze environment than rats in a cage
- had more neurons in hippocampus for memory and ability to navigate
- evidence of the brains ability to change
3) further support from animal studies
- Hubel and Weisel sewed one eye of a kitten shut and analysed the brains responses
- area of visual cortex associated with the shut eye was not idle but continued to process information from the open eye
- study demonstrates how loss of function leads to compensatory activity in the brain- evidence of neural plasticity, however unethical and hard to extrapolate findings to humans
4) educational attainment and functional recovery
- patients with college education are 7 times more likely to be disability free after brain damage than those who didn't finish high school
- resilience to neuropathological damage is associated with educational attainment
- therefore this has useful application encouraging pupils to build up cognitive reserve through attending school
53
what are the 3 ways of investigating the brain
1) fMRI scans
2) EEGs
3) ERPs
54
what is an fMRI scan and what does it do
- detects change in blood oxygenation and flow that occurs as a result of brain activity in specific brain parts
- produces 3d images that show which parts of the brain are using larger amounts of oxygen and are therefore more active
- deoxygenated blood is present in less active areas
55
what are the strengths and weaknesses of fMRI scans
strengths: unlike PET scans they don't rely on use of radiation
-virtually risk free, non-invasive and straightforward to use
- produces images that have very high spatial resolution, giving detail by the millimetre - produces clear data
weakness: Fmri is expensive compared to other neuroimaging techniques and can only capture a clear image if the person stays perfectly still
- has poor temporal resolution because there is around a 5 second time lag behind the image on the screen and the firing of the neurons.
56
what is an EEG and what does it do
-measures electrical activity within the brain via electrodes that are fixed on the scalp, usually using a scull cap
- scan recording represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity
- often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity may indicate abnormalities such as epilepsy, tumours or disorders of sleep
57
what are the strengths and weaknesses of EEG'S
strengths: are able to diagnose conditions such epilepsy, a disorder characterised by random burst of activity in the brain that can easily be detected.
- similarly it has contributed to understanding of the stages involved in sleep
-unlike Fmri, EEG technology has extremely high temporal resolution
- today's EEG technology can accurately detect brain activity at a resolution of one millisecond
weakness: EEG'S tend to produce very generalised information so it is not useful for pinpointing the exact source of neural activity
- placed on scalp so can’t penetrate into deeper regions of the brain, so has poor spatial resolution
58
what is an ERP and what does it do
- ERP'S are a way of teasing out and isolating specific neural responses associated with sensory, cognitive and motor events
- these are of interest to cognitive neuroscientists
- ERP'S work by using a statistical averaging technique (showing same stimulus repeatedly) that filters out extraneous brain activity from the original EEG recording, leaving only the responses that relate to say, the presentation of a specific stimulus or performance of a specific task
- event related potentials remain; types of brainwave that are triggered by particular events
59
what are the strengths and weaknesses of ERP'S
strengths: partly address the limitations of EEG
- ERP'S allow researchers to isolate and study how individual cognitive processes take place in the brain, while EEG’S record general brain activity.
weakness: an issue is that in order to establish pure data in ERP studies, background noise and extraneous material must be completely eliminated, which is not always easy to do.
- important electrical changes happening deep inside the brain cannot be picked up and recorded, so poor spatial resolution
60
explain what a circadian rhythm is
- type of biological rhythm that operates along a 24hr cycle e.g sleep wake cycle
- driven by our internal body clock
- light provides the primary input, allowing our internal body clock to be set to the correct time- a process called photoentrainment
- circadian clock is located in the suprachiasmatic nucleus (SCN) in each brain hemisphere
- SCN is the endogenous pacemaker for the sleep wake cycle
- it has the responsibility for sending signals to several other parts of the brain to regulate the daily sleep-wake cycle
- endogenous pacemaker is also melatonin production form the pineal gland playing a role in triggering sleep responding to a decrease in the levels of light
- environmental cues can reset the body clock (exogenous zeitgebers) e,g light levels
61
explain how sleep and body temperature is linked to our circadian rhythm
-most important hormone effected by circadian clock is melatonin- affects sleep (produced in pineal gland, chemically causes drowsiness and lowers body temperature)
- core body temp usually reaches minimum at 2-4am
- melatonin typically produced around 8:00-9:00 pm then stops at around 7:00-8:00am
- 24 hr circadian rhythm is one of 2 factors that determine sleep
- the second is sleep pressure, a chemical called adenosine is building up in your brain and will continue to do so during the day
- adenosine causes feelings of tiredness, the concentration increases throughout the day and works alongside the circadian rhythm
62
what was the Michael Siffre cave study and what did it show about our circadian rhythm
- he spent 7 months in a cave deprived of all natural light and found that without daylight the human has a 25hr body clock
- suggests the endogenous pacemaker for the sleep wake cycle is free running but needs entrainment to keep to the 24hr day night cycle, who’s how light is a key exogenous zeitgeber for the sleep wake cycle
- he also believed the date to be a month earlier than it was, due to resurface on the 17th September and he believed date was 20th August
- suggests his 24hr sleep wake cycle was increased by the lack of external cues, making him believe one day was longer than it was
- shows EZ’s are important at helping to ‘entrain’ our body clock to keep a 24hr sleep/wake cycle
63
what was the Aschoff and Wever study and what did it show about our circadian rhythm
- ppts spent 4 weeks in a WW2 bunker deprived of natural light
- all but one of the ppts displayed a circadian rhythm between 24-25hrs
64
explain Morgan’s hamster study, representing the importance of the SCN on the sleep/wake cycle
- he bred ‘mutant’ hamsters so that they had a circadian rhythm of 20hrs instead of 24hrs
- then transplanted neurons from the mutant hamster’s SCN into a normal hamster
- these normal hamsters then also displayed the circadian rhythms of 20hrs
- shows the SCN is responsible for the sleep/wake cycle
65
what is a strength of research into circadian rhythms
1) real world application
- use of chronotherapeutic can be life saving to patients who need to take drug medication
- the specific time a patient takes a drug is crucial to its effectiveness, for example heart attacks are more common during the early hours of the morning
- new drug system using chronotherapeutic has been invented, the patient takes the drug at 10pm but the drug is not actually active until 6am the most likely time a heart attack would occur e.g aspirin
- our predictable circadian rhythm has allowed this treatment to be successful as we know that people biologically will wake up at around that time with little variation
2) provides understanding of consequences that occur when rhythm is disrupted, e.g night workers engaged in shift work experience a period of reduced concentration at around 6 in the morning where mistakes are likely to occur
- research also pointed out a relationship between shift work and poor health, shift workers are three times more likely to develop heart disease than people who work more typical hours, shows research may have real world economic implications in terms of how best to manage worker productivity
66
what are the weaknesses of research into circadian rhythms
1) confounding variables- although they were deprived of natural light, TV, clocks and radios, they weren't deprived of artificial light because at the time, researchers did not believe artificial light would interfere with the circadian rhythm
- however later research has suggested this may not be true, with artificial light able to change ones circadian rhythm down to 22hrs and up at 28hrs
2) use of case studies, although Siffre provided good research, not everyone’s the same so its difficult to generalise from one person, perhaps larger sample over longer time period would be more beneficial towards the research
2) temperature may be more important than light in setting out circadian rhythm
- Buhr argues that temperature controls our body clock rather than light
although light is undoubtedly the trigger, the SCN transforms this info into neural messages that set the body temp
- even the smallest change to our body temp can be enough to massively influence our internal body clock, our body temp fluctuates all the time
- this suggests that temp may be more important than light in setting circadian rhythms
67
what is an ultradian rhythm
biological rhythm with a cycle shorter than 24hrs
68
what is an example of ultradian rhythms
- sleep cycle
- 5 distinct stages of sleep, each lasting around 90mins. This cycle is continuous throughout the course of night
- each stage is characterised by a different level of brainwave activity that can be monitored using an EEG
69
explain the 5 stages of sleep
Cycle is repeated around 4/5 times each lasting 90 minutes
1) stages 1 and 2, easily woken however muscle activity begins to slow down- (theta waves, slow frequency but high amplitude)- may experience sensations of falling (hypnick jerks)
2) stages 3 and 4- delta waves are slow, greater amplitude- very difficult to wake body temp decreases, breathing and heart rate decrease
3) stage 5 is REM sleep- stage that dreaming occurs, eyeballs are active ‘rapid eye movement’, antonia paralysis, prevents petiole acting out in their dreams, brain activity speeds up, similar to wakefulness
70
explain brain waves during sleep (beta, delta and theta)
1) beta waves- during wakefulness high frequency, no reliable pattern as environment is constantly changing
2) delta waves- deep NREM sleep, activity dramatically decelerates, ten times slower than wakefulness, high predictable patterns
3) theta waves- almost identical to the frequency during wakefulness- brain seems awake but body is asleep, emotions, motivations and memories are played out like a movie in your brain. Hence dreaming occurs- produced in REM sleep
71
what are the roles of wakefulness, NREM and REM
1) wakefulness- reception, receiving information
2) NREM- reflection, reflecting on non useful and useful info received, keeps/gets rid of, helps the brain during synaptic pruning
3) REM- integration, stuff that's kept in store somewhere, helps brain with synaptic bridging
72
what is a strength of research into ultradian rhythms
- Dermot and Kleitman monitored the sleep patterns of 9 adult participants in the sleep lab
- they found that REM activity was highly correlated with the experience of dreaming, brain activity varied according to how vivid the dreams were and participants woken during their dream reported very accurate recall of their dreams
- suggests that the REM stage of sleep is associated with dreaming and that it is distinct from other stages in the ultradian sleep cycle
- they found the nature of their dreams was matched by their eye movements e.g vertical eye movement when climbing ladders/throwing basketballs, horizontal eye movements occured with dreams of watching ppl throw tomatoes
- further strength of this is the use of EEG is objective, therefore scientific and there is no demand characteristics
- however a weakness is there was only 9 ppts so a small simple size decreases generalisability as there may be different results from a wider range of individuals
73
what is a weakness/limitation of research into ultradian rhythms
- been found that not all dreams happen during the REM sleep stage of the cycle
- hypnogogic dreams occur during stages 1 and 2, softly after drifting to sleep, and those are the dreams in which we experience a feeling of being out of control or falling
- these dreams are significant for the fact that we often wake with a jolt
- this may suggest that the stages are less distinct than Dement and Klietman suggested
74
what is an infradian rhythm
-frequency of one complete cycle occurring longer than 24hrs
75
what are examples of infradian rhythms
-the menstrual cycle
- seasonal affective disorder
76
explain the menstrual cycle
- average cycle lasts 28 days
- day 1 is the first day of 'bleeding' (when the thickened lining of womb starts to shed)
- during the menstrual cycle, rising levels of the hormone oestrogen cause the ovary to develop and then release an egg (ovulation)
- after ovulation progesterone helps the uterus lining to grow thicker, readying the body for pregnancy
-progesterone and oestrogen act as endogenous pacemakers keeping the biological processes to time, acting as an internal body clock
- if pregnancy does not occur the egg is absorbed and the womb lining comes away and leaves the body
- this is known as the menstrual flow
77
what is season affective disorder
- depressive disorder (DSM5) with a seasonal pattern
- as with other forms of depression, main symptoms are low mood
- only occurs in winter months where number of daylight hours become shorter
-why?- the hormone melatonin is implicated in the cause of SAD
-during the night, pineal gland secretes melatonin
-during winter, lack of light in the morning means this secretion process continues for longer
- thought to have a knock on effect on the production of serotonin in the brain, which is the neurotransmitter linked to the onset of depressive symptoms
78
what is a strength of infradian rhythm (understanding the cause of SAD)
- research produced practical application for sufferers
- for example, phototherapy works by stimulating a very strong light in the morning and evening
- it resets melatonin levels and relieves symptoms in up to 60% of sufferers of SAD
- major strength as understanding of the role of melatonin has helped to produce therapies to aid suffering of many SAD patients
79
what are endogenous pacemakers
- part of the internal organism. Internal body clocks that regulate biological rhythms such as the sleep wake cycle and circadian rhythm
-primary endogenous pacemaker is a pair of tiny clusters of nerve cells called the SCN
80
what are exogenous zeitgebers
- external cues in the environment that may affect our biological rhythms, e.g the influence of light on the sleep/wake cycle
- responsible for resetting the biological clock
- social cues also act as exogenous zeitgebers e.g timing of meals, work schedules, exercise sessions
- alignment of behaviours such as walking, eating to regular sleep-wake cycle is known as entrainment
81
explain light acts as an endogenous pacemaker
- even when our eyes are shut the SCN gets info on light from the optic nerve, light can penetrate the eyelids and special photoreceptors in the eye transfer light signals to the SCN
- if our endogenous clock is running slow (really tired) the morning light automatically shifts the clock ahead so it's in synchrony with the world outside.
- the SCN sends the signal to the pineal gland
82
explain the studies to find the influence of the SCN (animal studies)
- Decoursey et al destroyed the SCN connections in the brains of 30 chipmunks who were the returned to their natural habitat and observed for 80 days
- the sleep/wake cycle of the chipmunks disappeared and by the end of the study a significant portion of of them had been killed by predators (they were awake, active and vulnerable to attack when they should have been asleep)
- another study by Ralph et al, he bred hamsters with a 20hour sleep/wake cycle. Took out their SCN and put it into normal hamsters. Normal hamsters then had a 20hr day. Therefore SCN is controlling our sleep and circadian cycle.
-however these were animal studies so we can't be sure it would be applicable for humans
83
what is another endogenous pacemaker that works with the SCN
the pineal gland
84
explain the features of the pineal gland linking to the SCN
- contains light sensitive cells
-when light is sensed, melatonin production is inhibited (decreases)
- when light levels fall, melatonin production increases
- this induces sleep by inhibiting brain mechanisms that promote the awake state
- another mechanism guiding the sleep/wake cycle
85
what is the process entrainment
- when biological clock resets each day by cues in the environment (sunrise and sunset)
- this is called entrainment (opposite of free-running where the biological clock works free of any exogenous cues, including social cues like clouds)
86
explain how light is a key zeitgeber in humans
- it can reset the body's main endogenous pacemaker, the SCN, therefore plays a role in the maintenance of the sleep/wake cycle
- a protein called melanopsin is critical, it detects natural light and carries signals to the SCN to set the daily body cycle
87
what is research support of light being a powerful exogenous zeitgeber
- Campbell and Murphy shone a light on ppts kneecaps, that alone can shift the sleep/wake cycle.
-researchers managed to produce a deviation in the ppts sleep/wake cycle of up to 3 hours
-suggests light doesn't have to go through the eyes for the sleep/wake cycle to shift and to reach the SCN. Light travels to the blood through to the SCN
88
explain how social cues such as a babies sleep/wake cycle can be entrained
- in infants the sleep/wake cycle is initially random, but by 6 weeks the circadian rhythms begin and by 16 weeks most babies are entrained
- schedules and social cues are determined by the parents e.g meal times and bed time
89
what research was done to link social cues with an entrained circadian rhythm (jet lag)
- research on jet lags suggests that by adapting to local times for eating and sleeping (rather than responding to one's own feelings of hunger and fatigue) is an effective way of entraining circadian rhythms and beating jet lag when travelling long distances
90
A01
Explain why neurons can only transmit information in one direction at the synapse
- neurotransmitters diffuse from a high to low concentration at the synapse
- there are only receptors at the post synaptic neuron meaning they can only travel towards that
- the pre synaptic neuron is the only neuron that holds the vesicles containing neurotransmitters
91
Explain the process of synaptic transmission
1) action potential arrives at pre synaptic neuron
2) vesicles containing neurotransmitters merge with the cell membrane and release neurotransmitters into the synaptic cleft
3) neurotransmitters diffuse from a high to low concentration across the synapse, binding to the receptors with a lock and key mechanism of the post synaptic neurone
4) if the charge inside post synaptic neurone passes a threshold (excitatory/ inhibitory) a new action potential forms
92
Explain the process of the flight or fight response
1) Amygdala sends signals to the hypothalamus when a stressor is detected and activates the SAM (sympathomedullary pathway)
2) hypothalamus sends a stress signal to the sympathetic nervous system, which then sends a signal to the adrenal medulla, activating it
3) adrenal medulla releases the hormone adrenaline into the blood stream, adrenaline binds to receptors on target cells causing cells to produce bodily reactions which are physiological changes e.g increased heart rate, dilated pupils etc
4) when threat has passed, hypothalamus alerts the parasympathetic nervous system which brings body back to normal again through rest and digest
- once threat or danger has passed it is possible that someone may feel exhausted, sick or ravenously hungry due to the energy that has been released during the response
- if energy is not used via exercise/action then it can ‘sit’ in the body, possibly leading to stress and other long term health conditions
93
What does damage to Wernicke’s area cause
- Wernicke’s aphasia, difficulty in understanding speech or written language, speech sounds fluent but lacks meaning
94
What does damage to the Broca’s area cause
- Broca’s aphasia, difficulty producing fluent speech, speech is slow, has missing worlds leading to poor grammar
95
What is meant by spatial resolution
- level of accuracy in identifying the exact location of a brain structure or brain activity
96
What is meant by temporal resolution
- level of accuracy in identifying the exact location of a brain activity in time (when activity happened)
97
What is the endogenous pacemaker for the sleep wake cycle
SCN (suprachiasmatic nucleus)
- when light is detected by SCN it sends light to the pineal gland, stopping the production of melatonin
98
Explain what McClintock found as an exogenous zeitgeber for the menstrual cycle
- 20 women were given a pad to wipe their top lip, taken from the armpits of 9 donor women at varying stages of their menstrual cycle
- found that women would either shorten or extend their menstrual cycle to match the donor, depending on when in the donor the women’s menstrual cycle the pad had been collected
- found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’
- suggesting synchronisation due to the presence of pheromones acting as an external cue for the timing of the infradian rhythm
99
What is a counterpoint for pheromones being exogenous zietgebers for the menstrual cycle
- Travathan noted that he found no evidence of menstrual synchronisation in the all female ppts used, suggesting there are other external variables which may affect the timing and duration of their cycles
100
A01
What is the cerebral cortex
- outer layer of brain
- carries out essential functions such as as memory, thinking, learning, problem-solving
- key marker that distinguishes humans from animals
101
A01
What are examples of hormones
- melatonin- regulates the sleep/wake cycle and is sensitive to light levels
- cortisol- stress hormone, secreted during times of anxiety, tension
- adrenaline- active during the fight or flight response to danger
- insulin- helps blood sugar enter the body’s cells so it can be used for energy
102
What physiological changes occur during a fight or flight response
- increased muscle tension
- increased heart rate
- decreased salivation
- increased sweating
- dilated pupils
- increased breathing rate
- decreased food digestion
103
Explain the role of sensory neurons
- sends information from the peripheral nervous system towards the central nervous system
- keep the brain informed about the external and internal environment information coming from the sense organs
- can only transmit messages one way, can’t receive messages
- has long dendrites and short axons
- cell body is to the side of the cell
104
Explain the role of motor neurons
- carry signals from the central nervous system towards organs, muscles and glands to the peripheral nervous system
- can transmit and receive messages
- control physical movements such as contraction/relaxation of muscles
- have short dendrites and long axons
105
Explain the role of relay neurons
- connect sensory neurons to motor neurons
- relay neurons are located in the CNS and carry signals/messages across this part of the nervous system
- messages can be transmitted and received
- have short axons and short dendrites
106
Explain the ‘Tan’ case study that Paul Broca did
- Tan was one of his patients who suffered from epilepsy throughout childhood
- he was hospitalised at 30 and died at 51
- was known as ‘Tan’ as he could only pronounce one spoken word which was ‘tan’
- had complete paralysis down right side of body but was able to move left arm and leg
- after he died, Paul Broca performed brain autopsy and found a lesion on the left temporal lobe of Tan’s brain, all other areas intact
- Broca concluded that this was the area that is responsible for speech production, and Broca’s aphasia is now used as a diagnosis for those who have difficulty producing speech
107
What is meant by the brain being contralateral
- refers to fact that right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body
108
What is functional recovery
- the brain’s ability to replace lost or damaged functions by using existing brain regions in their place
- enabled through the law of equipotentiality where secondary neural circuits surrounding damaged area become activated
109
A03
What are the weaknesses of the fight or flight response
1) human behaviour isn’t limited to just 2 responses, Gray (1988) suggests that the first response to danger is a ‘freeze’ response where humans appraise the situation to decide the best course of action for the threat
- therefore explanation is limited and doesn’t fully explain the complex behaviours of humans
2) doesn’t fully explain stress response in females. Taylor et al suggests females adopt a ‘tend a befriend’ response in stressful situations, where they are likely to protect their offspring but befriend other women rather than fight
3)detrimental effect on health in modern day life. May have been useful for ancestors in life threatening situations but modern life rarely requires intense biological responses. Activation of the fight or flight response can increase blood pressure and contribute to heart disease, suggesting it’s a maladaptive response in modern day life
110
What is meant by synaptic pruning
- as we age, rarely used connections are deleted and frequently used ones are strengthened
111
Explain how research into exogenous zeitgebers provides information on how the effects of jet lag could be reduced
- Burgess (2003) jet lag study
- exposure to bright light before a long flight decreased the time needed to adjust to local time
- ppts were exposed to either a bright light, intermittent light, or a dim light before flight
- those exposed to bright light shifted their rhythm by 2.1hrs
- provides practical suggestion as to how jet lag could be reduced, through exposing travellers to bright light before an east-west flight
- shows how effect of jet lag could be reduced by light
112
What is meant by a study suffering from anthropomorphism
- the idea that findings from animal studies can’t be extrapolated due to animals and humans being different and having different brain structures
113
Explain the steps that occur when stress is perceived as a threat (6 marker)
1) hypothalamus alerted and activates the SAM pathway
2) this causes the sympathetic nervous system to become activated
3) this leads to the stimulation of a part of the adrenal gland (found above kidneys) called adrenal medulla
4) when adrenal medulla is stimulated, it releases adrenaline
5) adrenaline prepares body for fight or flight by causing many physiological changes
6) when the stressful thing has gone, the parasympathetic branch of autonomic nervous system, is automatically activated to return the body to it’s normal state
114
Explain research by Folkard on the circadian rhythm ( as a way to argue against exogenous zeitgebers being important for circadian rhythm)
- studied a group of 12 people who agreed to live in a dark cave for three weeks, retiring to bed when the clock said 11:45pm and rising when it said 7:45am.
- over the course of the study the researchers gradually speeded up the clock (unknown to the participants) so an apparent 24hr day eventually lasted only 22 hours. Only one of the participants was able to comfortably adjust to the new regime. This would suggest the existence of a strong free running circadian rhythm that cannot be easily overridden by exogenous zeitgebers
115
A03
What is a strength for research into infradian rhythms
1) may be evolutionary advantage - synchronisation may be a way to stop one male dominating a group and having all the children, being unable to impregnate all the women at once due to synchronisation, leading to genetic diversity in small human groups
116
What are strengths and weaknesses of research into endogenous pacemakers
Strengths:
- controlled conditions and remove of SCN mean the study has good internal validity, researcher was able to direct observe effect of circadian rhythm disruption in a way which would have been impossible with human research
Limitations:
- use of animals- humans are very different biologically, cognitively and socially, so research is not generalisable to humans
- biologically reductionist- narrow explanation when considering something as complex and prone to variation as the patterns and habits involved in the sleep wake cycle
- there are likely to be an array of other factors which also contribute, e.g high stress levels may interfere with regular sleep, some people can also fall asleep in bright light or during daylight hours meaning that light may not be as important to the sleep wake cycle as some research suggests
