Biospsychology y1 and 2 Flashcards
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
4
Q
what is the function of the peripheral nervous system
A
carries messages to and from the CNS
(Sensory neurones take info to CNS and motor neurones take info away from CNS)
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
- autonomic nervous system - controls involuntary muscles ( not under our conscious control so can’t move them whenever we want to)
6
Q
what is the autonomic nervous system divided into and describe their functions
A
- sympathetic nervous system- increases bodily activity. Release of noradrenaline 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
- 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
- also promotes normal metabolism and maintains blood sugar levels
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)
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
- treated a patient unable to speak any other word but 'tan' even though he understood language
- studied 8 other patients with similar deficits along with lesions in the left frontal hemisphere
- patients with damage to right frontal hemisphere didn't have the same problems- showing language is from the left hemisphere and believed to be critical for speech production
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- frontal lobe
2) Broca’s area- frontal lobe
3) auditory area and Wernicke’s area- temporal lobe on the superior temporal gyrus
4) visual cortex- occipital lobe
5) somatosensory cortex- 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, the process appeared in every part of the cortex not just a particular area
2) 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 is known as the 'law of equipotentiality' whereby surviving brain circuits chip in
- this suggests that learning is too complex to be localised and requires the involvement of the whole brain
35
what is a strength of localisation
-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.
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 damage to the left hemisphere is far more detrimental to language than damage to the right
- however one patient known as J.W developed the capacity to speak out of the right hemisphere with the result that he can now speak about info presented to the left or right 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
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
43
what are strengths of split brain research and lateralisation
1) advantage of lateralisation- if only one hemisphere is used in a task, theoretically the other hemisphere is free to carryout another function
- it is argued by Roger that chickens have an enhanced ability to perform two tasks simultaneously e.g find food and be vigilant of predators
- therefore there is some evidence that lateralisation enhances brain efficiency in cognitive tasks that demand the simultaneous but different use of hemispheres
2) Sperry’s research was a well controlled experiment, involving a range of tasks
- standardised procedures mean that the research is replicable
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 Maguir's research into plasticity (studied brains of london taxi drivers)
- found significantly more volume of grey matter in the posterior hippocampus
- this part of the brain is associated with the development of spatial and navigational skills in humans and other animals
- as part of their training they take a complex test which assesses their recall of the city streets and possible routes
- it appears that this spatial learning alters the structure of the taxi drivers brains
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)
- where 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 to continue, often in the same ways as before
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
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
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, lacks spatial activity
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.
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
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 and found that without daylight the human has a 25hr body clock
- he had artificial light such as a lamp
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 the study by Folkard on circadian rhythms
- studied a group of 12 ppl who agreed to live in a dark cave for 3 weeks, going bed at 11:45pm and rising when it said 7:45am
- overtime researchers speeded up the clock so a 24hr day only lasted 22hrs
- no ppt was able to comfortably adjust to new regime
- suggests the existence of a strong free-running circadian rhytm that can't be easily overridden by changes in the external environment
- we are designed to have a 25hr body clock
65
what is a strength of research into circadian rhythms
- 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
- 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
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) 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
1) light sleep- muscle activity slows down, can be easily awoke (theta waves, slow frequency but high amplitude)
2) light sleep (45-55%)- breathing and heart rate slows down, body temp decreases
3) deep sleep begins- brain starts to generate slow delta waves
4) very deep sleep (15%) - rhythmic breathing, limited muscle activity
5) REM sleep (25%) - not deep sleep, brainwaves speed up, heart rate increases, breathing is rapid, DREAMING OCCURS, antonia-paralyses muscle, keeps you safe (delta waves similar to wakefulness however body is paralysed)
Cycle is repeated around 4/5 times each lasting 90 minutes
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
-Detemt 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
- 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 (DSM) with a seasonal pattern
- as with other forms of depression, main symptoms are low mood
- only occurs in winter months
-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 an 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
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)
- 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 from the PNS
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
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
- 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
