biopsychology (P2) Flashcards

Question

motor neurons | Neurons and synaptic transmission

Answer 1

connect the CNS to effectors such as muscles and glands short dendrites and long axons

Answer 2

**cell body** (soma) includes a **nucleus** (contains genetic material of cell) **dendrites** branch like structures that protrude from cell body. Carry nerve impulses from neighboring neurons towards the cell body **axon** carries impulses away from cell body down the length of the neuron **myelin sheath** fatty layer that protects axon and speeds up electric transmission of the impulse **nodes of Ranvier** gaps segmenting myelin sheath **terminal buttons** end of axon. Communicate with next neuron in chain across a gap (synapse)

Answer 3

aka soma includes **nucleus**

Answer 4

contains genetic material of cell

Answer 5

branch like structures that protrude from cell body. Carry nerve impulses from neighboring neurons towards the cell body

Answer 6

carries impulses away from cell body down the length of the neuron

Answer 7

fatty layer that protects axon and speeds up electric transmission of the impulse

Answer 8

gaps segmenting myelin sheath

Answer 9

end of axon communicate with next neuro in chain across a gap (synapse)

Answer 10

may be in CNS but have long axons that form part of PNS

Answer 11

in PNS in clusters known as **ganglia**

Answer 12

make up 97% of all neurons most found in brain and visual system

Answer 13

when neuron is in resting state inside of cell is negatively charged compared to outside. when neuron is activated by a stimulus inside of cell becomes positively charged for a split second causing an action potential to occur. Creates an electrical impulse that travels down axon towards end of neuron

Answer 14

process by which neighboring neurons communicate with each other by sending chemical messages across the gap (synapse) that separates them

Answer 15

groups in which neurons communicate with each other

Answer 16

signals **between** neurons are transmitted chemically across the synapse when electrical impulse reaches end of neuron (presynaptic terminal) it triggers the release of neurotransmitters from tiny sacks (synaptic vesicles)

Answer 17

brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function

Answer 18

chemicals that diffuse across the synapse to next neuron in chain once a neurotransmitter crosses the gap it's taken up by a postsynaptic receptor site on dendrites of next neuron chemical message is converted back into an electrical impulse and process of transmission occurs again

Answer 19

axon - to the synapse dendrites - away

Answer 20

one-way because neurotransmitters are released from presynaptic neuron terminal and received by the post synaptic neuron (at receptor sites)

Answer 21

several dozen typed identified in the brain, spinal cord and some glands each neurotransmitter has its own specfic molecular structure that fits perfectly into a postsynaptix receptor site

Answer 22

acetylcholine is found at each point where a motor neuron meets a muscle and upon release it will cause muscle contraction

Answer 23

adrenaline (both a hormone and neurotransmitter) causes excitation of the postsynaptic neuron by increasing its positive charge and making it more likely to fire

Answer 24

serotonin (neurotransmitter) causes inhibition in receiving neuron resulting in neuron becoming more negatively charged and less likely to fire

Answer 25

excitatory inhibitory

Answer 26

when a neurotransmitter increases positive charge of postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the electrical impulse

Answer 27

when a neurotransmitter increases negative charge of the postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse

Answer 28

whether a postsynaptic neuron fires is decided by process of summation excitatory and inhibitory influences are summed if the net effect on the postsynaptic neuron is inhibitory then the postsynaptic neuron is less likely to fire if the net effect is excitatory it is more likely to fire action potential of postsynaptic neuron is only triggered if the sum of excitatory and inhibitory signals at any time reaches the threshold

Answer 29

Electrical impulses (action potential) reach presynaptic terminal. Electrical impulses (action potential) trigger release of neurotransmitters (e.g. serotonin) from synaptic vesicles. Neurotransmitters diffuse across the synaptic cleft. Neurotransmitters bind to receptors on the postsynaptic membrane.

Answer 30

theory that different areas of the brain are responsible for specific behaviours, processes or activities thus if a certain area is damaged function associated will also be affected

Answer 31

all parts of brain involved in processing of thought and action

Answer 32

during 19th century scientists (Paul Broca, Karl Wernicke) discovered specific areas of the brain are associated with particular physical and psychological functions . Prior to this holistic theory was generally supported. Broca and Wernicke argued for localisation of function.

Answer 33

main part of brain (cerebrum) divided into 2 symmetrical halves called left and right hemisphere some physical and psychological functions controlled/dominated by specific hemisphere (lateralisation) activity on left-hand side of body is controlled by right hemisphere and vice versa

Answer 34

outer layer of both hemispheres subdivided into 4 lobes

Answer 35

back of frontal lobe (both hemispheres) contains voluntary movement in opposite side of the body damage may result in loss of control over fine movements

Answer 36

front of both parietal lobes. Separated from motor area by central sulcus where sensory information from the skin (related to touch, heat, pressure) is represented amount of somatosensory area devoted to a particular body part denotes its sensitivity e.g. receptors for our face and hands occupy over half of the somatosensory area

Answer 37

occipital lobe at back of brain **receives and processes visual information** each eye sends information from the right visual field to the left visual cortex and vice versa means damage to left hemisphere can produce blindness in right visual field of both eyes

Answer 38

temporal lobes **concerned with analysis of speech-based information** partial hearing loss. More extensive damage = more extensive loss

Answer 39

left frontal lobe responsible for speech production Broca's aphasia (characterised by slow, laborious and lacking in fluency speech) (difficulty with prepositions and conjunctions)

Answer 40

left temporal lobe responsible for understanding language Wernicke's aphasia - often produce nonsense words (neologisms) as part of content of their speech

Answer 41

strengths **evidence from neurosurgery** damage to areas of the brain have been linked to mental disorders neuorsurgery = last resort method for treating some mental disorders, targeting specific involved areas example - cingulotomy involves isolating a region called cingulate gyrus which has been implicated in OCD. Dougherty et al (2002) reported on 44 people with OCD who had undergone a cingulotomy. At post-surgical follow-up (after 32 weeks) about 30% had met criteria for successful response to surgery and 14% for partial response. Suggests behaviours associated with serious mental disorders may be localised **case study - Phineas Gage** whilst working on railroad 25-year-old Phineas Gage was preparing to blast a section of rock with explosives to create a new railway line. During the process Gage dropped his tamping iron onto the rock causing the explosive to ignite. Explosion hurled metre-length pole through gage's left cheek exiting his skull from the top of his head removing most of his frontal lobe. Gage survived but personality changed from calm and reserved to someone who was quick-tempered rude and 'no longer Gage'. Frontal lobe may be responsible for regulating mood. **counterpoint** problems with case studies. Difficult to make meaningful generalisations from the findings of a single individual. Conclusions drawn may depend on subjective interpretation of researcher **evidence from brain scans** petersen et al (1988) used brain scans to demonstrate how Wernicke's area was active during a listening task and Broca's area was active during a reading task. Tulving et al (1994) - study of LTM revealed semantic and episodic memories reside in different parts of the prefrontal cortex. Confirmed localised areas for everyday behaviours. Therefore objective methods for measuring brain activity have provided scientific evidence that many brain functions are localised **counterpoint** Lashley (1950) removed areas of cortex (between 10% and 50%) in rats that were learning route through a maze. No area was proven to be more important than any other area in terms of the rats' ability to learn the route. Process of learning seemed to require every part of cortex rather than being confined to a particular area. Suggested higher cognitive processes (e.g. learning) not localised, distributed in a holistic way in the brain limitations **language localisation questioned** language may not be localised to just Broca's and Wernicke's area. Review by Dick and Tremblay (2016) found that only 2% of modern researchers think language in the brain is completely controlled by Broca's and Wernicke's area. Advances in brain imagining techniques such as FMRI mean that neural processes in the brain can be studied with more clarity. Seems that language function is distrubuted holistically in 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 thalamus. Suggests language may be organised more holistically in the brain which contradicts localisation theory

Answer 42

idea that 2 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

Answer 43

vision visual area is in the left and right occipital lobe

Answer 44

left hemisphere ## Footnote Broca's area = frontal lobe Wernicke's area = left temporal lobe

Answer 45

Lateralised ## Footnote performed by one hemisphere rather than the other

Answer 46

can only produce rudimentary words and phrases but contributes emotional context to what is being said

Answer 47

synthesiser

Answer 48

cross-wired contralateral wiring ## Footnote right hemisphere controls movement on the left side of the body whilst the left hemisphere controls movement on the right

Answer 49

Vision is both contralateral and ipisilateral (opposite and same-sided) ## Footnote Each eye recieves light from the left visual field and the right visual field. Left visual field of both eyes is connected to the right hemisphere and the right visual field The left visual field of both eyes is connected to the right hemisphere The right visual field of both eyes is connected to the left hemisphere Enables visual areas to compare different perspectives from each eye and aids depth perception

Answer 50

a series of studies which began in the 1960s (still ongoing) involving people with epilepsy who had experienced a surgical separation of the hemispheres of their brain to reduce the severity of their epilepsy enabling researchers to test lateral functions of the brain in isolation

Answer 51

how the hemispheres function when they can't communicate with eachother

Answer 52

11 split-brain individuals

Answer 53

11 split-brain individuals were studied using a set up which an image or word could be projected to a participant's right visual field and the same or different image could be projected to the left visual field (processed by the right hemisphere) . ## Footnote In a typical 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 ment that the information cannot be conveyed from that hemispehre to the other

Answer 54

when a picture of an object was shown to a participant's right visual field (linked to the left hemisphere) the participant could describe what was seen They couldn't do this if the object was shown to the left visual field - they said nothing was there. Not possible in split-brain for the messages from the right hemisphere to be relayed to the language centres in the left hemisphere Participants couldn't give verbal labels to objects projected to the left visual field but could select a matching object out of sight using their left hand (linked to the right hemisphere) The left hand was also able to select an object that was closely associated with an object presented in the left visual field If a pinup picture was shown to the left visual field there was an emotional reaction (e.g. a giggle) but the participants usually reported seeing nothing or just a flash of light

Answer 55

show how functions are lateralised in the brain and support the view that the left hemisphere is berbal and the right hemisphere is silent but emotional

Answer 56

Research support - Gereon Fink et al (1996) ## Footnote used PET scans to identify which brain areas were active during a visual processing task. When 'normal' participants were asked to attend to 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 finder detail (e.g. indivdual trees) the specific areas of the left hemisphere tended to dominate Suggests that hemispheric lateralisation is a feature of the normal brain as well as the split-brain

Answer 57

idea that the left hemisphere as analyser and right hemisphere as a synthesiser may be wrong ## Footnote There may be different functions in the right hemisphere and left hemisphere but research suggests people don't have a dominant side of their brain which creates a different personality Jared Nelsen et al (2013) analysed brain sxans from over 1000 people aged 7 to 29 years and found people used certain hemispheres for certain tasks (evidence for lateralisation). But there was no evidence of a dominant side i.e. not artist's brain or mathmetician's brain suggests notion of righ or left brained people is wrong

Answer 58

Research support - Micheal Gazzaniga (Luck et al 1989) ## Footnote Showed that split-brain participants actually perform better than normal controls on certain tasks. For example they were faster at identifying the odd one out in an array of similiar objects than normal controls. In the typical brain the left hemisphere's better cognitive strategies are watered down by the inferior right hemisphere (Kingstone et al 1955) Support's Sperry's findings that the left brain and right brain are distinct

Answer 59

Generalisation issues - casual relationships are hard to establish ## Footnote The behaviour of Sperry's split-brain participants was compared to a neurotypical control group. An issue is that none of the participants in the control group had epilepsy. Any differences that were observed between the 2 groups may be the result of the epilepsy rather than the split brain Some of the unique features of the split-brain particpants' cognitive abilities might have been due to their epilepsy

Answer 60

ethics ## Footnote split-brain operation easn't performed for the purpose of the research so in that sense Sperry's participants were deliberately harmed. All procedures were explained to the split-brain participants and their full informed consent was 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 and this may have been stressful over time

Answer 61

Brain's tendency to change and adapt as a result of experience and new learning. This generallu involves the growth of new connections

Answer 62

During infancy the brain experiences a rapid growth in the number of synaptic connections it has Peaking at approximately 15,000 at 2-3 years old

Answer 63

process where as we age rarely-used connections are deleted and frequently-used connections are strengthened

Answer 64

yes ## Footnote synaptic pruning enables lifelong plasticity where neural connections are formed in response to new demands on the brain

Answer 65

Eleanor Maguire et al (2000) London taxi drivers ## Footnote found significantly more volume of gray matter in the posterioir hippocampus in London taxi drivers than in a matched control group. This part of the brain is assoicated wuth the development of spatial and navigational skills in humans and other animals As part of their training London taxi drivers must take a complex test called the knowledge which assess their recall of the city streets abd possible routes Found this learning expereince alters the structure of the taxi drivers' brains Longer the taxi drivers had been in the job the more pronounced the structural difference (a positive correlation)

Answer 66

Bogdan Draganski et al (2006) ## Footnote imaged the brains of medical students three months before and after their final exams. Learning-induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of the learning

Answer 67

A form of plasticity following damage through trauma, the brain's ability to redistribute or ransfer functions usually performed by a damged area(s) to to other undamaged area(s)

Answer 68

Neuroscientists suggest 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

Answer 69

Brain is able to rewire and reorganise itself by forming new synpatic connections close to the area of damage Secondary neural pathways that wouldn't typically be used to carry out certain functions are activated or unmasked to enable functioning to continue

Answer 70

1. Axonal sprouting 2. Denervation supersensitivity 3. Recruitment of homologus areas on the opposite side of the brain ## Footnote 1. the growth of new nerve ending which connect with other undamaged nerve cells to form new neuronal pathways 2. occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost. Can result in oversensitivity to messages such as pain 3. 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 side equivelant would carry out its function. After a period of time functionality may then shift back to the left side

Answer 71

Doesn't always decline sharply with age ## Footnote Plasticity reduces with age Ladina 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 increased motor cortex activity in the novice folgers compared to a control group suggesting more efficent nerual representations after training Shows that neural plasticity can continue throughout the lifespan

Answer 72

may have negative behavioural consequences ## Footnote evidence has shown that the brain's adaptation to prolonged drug use leads to poorer cognitive functioning in later life and increased risk of dementia (Medina et al 2007) 60-80% of amputees have been known to develop phantom limb syndrome (continurd experience of sensations in the missing limb as if it was still there). This is usually painful and thought to be due to cortical reorganisation in the somatosensory cortex that occurs as a result of limb loss (Ramachandran and Hirstein 1998) Brains ability to adapt to damge isn't always beneficial

Answer 73

real-world application ## Footnote Understanding the processes involved in plasticity has contributed to the field of neurorehabilitation Understanding that axonal growth is possible encourages new therapies to be tried. For example constraint-induced movement therapy is used with stroke patients whereby they repeatedly practice using the affected part of their body while the unaffected part is restrained

Answer 74

level of education may influence recovery effects ## Footnote Eric Schneider et al (2014) revealed that the more time people with a brain injury has spent in education (an indication of their cognitive reserve) the greater their chances of a disability-free recovery (DFR) 40% of those who achieved DFR had more than 16 years education compared to about 10% who has less than 12 years suggests people with brain damage who have insufficient DFR are less lievely to achieve a full recovery

Answer 75

Functional Magnetic Resonance Imaging works by detecting changes in both blood oxeygenation and flow that occur as a result of neural activity in specific parts of the brain When a brain area is more active it consumes more oxygen and to meet this increased demand blood flow is directed to the active area (haemodynamic response) Produces three-dimensional images (activation maps) showing which parts are involved in particular mental processes and this has important implications for our understanding of localisation of function

Answer 76

electroencephalogram measures electrical activity within the brain via electrodes that are fixed to an individual's scalp using a skull cap The scan recording represents the brainwave patterns that are generated from the action of thousands of neurons, providing an overall acoount of brain activity Often used by clinicians as a diagnostic tool as unusual arrhythmic patterns of activity (i.e. no particular rhythm) may indicate neurological abnormalities such as epilepsy, tumours or disorders of sleep

Answer 77

The electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data ## Footnote Within EEG data are contained all the neural responses associated with specific sensory, cognitive, and motor events that may be of interest to cognitive neuroscientists. Researchers have developed a way of teasing out and isolating these responses. Using a statistical averaging technique all extraneous brain activity from the original EEG recorded is filtered out leaving only those responses that relate to the presentation of a specific stimulus or performance of a specific task. What remains are event-related potentials - types of brainwave that are triggered by particular events

Answer 78

The brain is analysed after death to determine whether certain observed behaviours during the person's lifetime can be linked to structural abnormalities in the brain ## Footnote Technique involving the analysis of a person's brain following their death. Individuals whose brains are subject to post-mortem examination are likely to be those who have a rare disorder and have experienced unusual deficits in mental processes or behaviour during their lifetime. Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person experienced. This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference

Answer 79

1. risk-free 2. non-invasive 3. high spatial resolution ## Footnote 1. doesn't rely on use of radiation 2. 3. depicting detail by the milimetre and providing a clear picture of how brain activity is localised

Answer 80

1. expensive 2. poor temporal resolution ## Footnote 2. 5-second time-lag behind the image on screen and the initial firing of neruonal actvitity. Cannot represent moment-to-moment brain activity

Answer 81

1. Real world uses 2. high temporal resolution ## Footnote 1. helpful in studying the stages of sleep and in diagnosis of conditions such as epilepsy (characterised by random bursts if activity in the brain) 2. can detect brain activity at a resolution of a milisecond (less in some cases)

Answer 82

1. comes from 1000s of neurons, can't identify source ## Footnote 1. not useful in pinpointing exact source of neural activity

Answer 83

1. more specific than EEG 2. Higher temporal resolution than FMRI ## Footnote 1. bring more specificity to the measurement of neural processes than could be achieved using raw EEG data 2. frequently used to measure cognitive functions and deficits such as the allocation of attentional resources and the maintenance of working memory

Answer 84

1. not standardised method 2. background noise difficult to control ## Footnote 1. difficult to confirm findings 2. in order to establish pure data in ERP studies background 'noise' and extraneous material must be completely eliminated not always easy to achieve

Answer 85

1. early research (e.g. Broca) ## Footnote 1. vital in providing a foundation for early understanding of key processes in the brain. Broca and Wernicke relied on post-mortem studies in establishing links between language, brain, and behaviour decades before neuroimagining became possible. Case of HM

Answer 86

1. causation an issue 2. consent issues ## Footnote 1. observed damage to the brain may not be linked to deficits under review but to some other unrelated trauma or decay 2. participants may not be able to provide informed consent for example case of HM who lost his ability to form memories and wasn't able to provide consent but nevertheless post-mortem research has been conducted on his brain

Answer 87

Distinct patterns of changes in body activity that conform to cyclical time periods. Biological rhythms are influenced by internal body clocks (endogenous pacemakers) as well as external changes to the environment (exogenous zeitgebers)

Answer 88

Biological rhythms subject to a 24-hour cycle which regulate a number of body processes such as the sleep/wake cycle and changes in core body temperature ## Footnote examples are: sleep/wake cycle and core body temperature

Answer 89

The fact we feel drowsy when its night-term and alert during the day demonstrates the effect of dayligh (important exogenous zeitgeber) Also governed by an internal (endogenous) pacemaker (biological clock) called the suprachiasmatic nucleus (SCN) which lies just above the optic chiasm providing information from the eye about light Exogenous zeitgebers can reset the SCN

Answer 90

had spent several extended periods underground to study the effects on his own biological rhythms deprived of exposure to natural light and sound but with access to adequate food and drink Resurfaced in mid-September 1962 after 2 months in the caves of the Southern Alps believing it to be mid-August A decade later he did this again for 6 months in a Texan cave In each case his free-running biological rhythm settled to aorund 25 hours though he did continue to fall asleep and wake up on a regular schedule

Answer 91

Procedure - group of participants spent 4 weeks in a WW2 bunker deprived of natural light Findings - all but one participant displayed a circadian rhythm between 24 and 25 hours Conclusions - natural sleep/wake cycle may be slightly longer than 24-hour day but it is entrained by exogenous zeitgebers associated with our 24-hour day (such as the number of daylight hours, typical mealtimes etc)

Answer 92

Sample - 12 people procedure - 12 people agreed to live in a dark cave for 3 weeks, retiring to bed when the clock said 11:45pm and rising when the clock said 7:45am. Clock was gradually sped up (without participants' knowledge) so day only lasted 22 hours Findings - only 1 participant comfortably adjusted Conclusions - suggest an existence of a strong free-running circadian rhythm that cannot be easily overridden by exogenous zeitgebers

Answer 93

1. Shift work 2. Medical treatment ## Footnote 1. Provides an understanding of the adverse consequences that occur when they are disrupted (desynchronisation) . For example when night workers engaged in shift work experience a period of reduced concentration around 6am (a circadian trough) meaning mistakes and acciedents were more likely (Boivin et al 1996). Research alsp pointed to relationship between shift work and poor health with shift workers being 3x more likely to developheart disease than those with a typical work pattern (Knutsson 2003). Research into sleep/wake cycle may have real-world economic applications in terms of how best to manage worker productivity 2. Research into circadian rhythms is that it has been used to improve medical treatments. Circadian rhythms co-ordinate a number of the body's basic processes such as heart rate, digestion, and hormone levels. These rise and fall during the day leading to the field of chronotherapeutics. For example Aspirin reduces blood platelet activity and this can reduce the risk of heart attack. Heart attacks are more likely to occur early in the morning so the timing of taking aspirin matters (supported by reseach e.g. Bonten et al 2015). Help increase effectiveness of drug treatments

Answer 94

1. individual differences 2. counterpoint to shift work ## Footnote 1. Generalisations are difficult to make. Studies (e.g. Siffre) are based on very small samples of participants (just one in Siffre's research). It seems that sleep/wake cycles may vary widely from person to person. Research by Czeisler et a (1999) found individual differences in sleep/wake cycles varying from 13 to 65 hours. Study by Duffy et al (2001) revealed some have a natural preference for going to bed early and rising early while others prefer the opposite. Difficult to use research data to discuss anything more than averages that may be meaningless 2. studies investigating the effects of shift work tend to use correlational methods . This means it is difficult to establish whether desynchronisation of the sleep/wake cycle is actually a cause of negative effects. There may be other factors for example Solomon (1993) concluded that high divorce rates in shift workers might be due to the strain of deprived sleep and other influences such as missing important events . Suggests it may not be biological factors that create adverrse consequences associated with shift work

Answer 95

A type of biological rhythm with a frequency of less than one cycle in 24 hours ## Footnote Examples: menstruation cycle and seasonal affective disorder

Answer 96

an example of an infradian rhythm governed by monthly changes in hormone levels which regulate ovulation. The cycle refers to the time between the first day pf a period, when the the womb lining is shed, to the day before her next period. Typically takes approximately 28 days to complete (24-35 days generally considered as normal). During each cycle rising levels of the hormone oestrogen cause the ovary to develop an egg and release it (ovulation). After ovulation the hormone progesterone helps the womb lining to grow thicker readying the womb for pregnancy however if pregnancy does not occur the egg is absorbed into the body and the womb linin leaves the body (the menstrual flow)

Answer 97

Sample - 29 women with a history of irregular periods Procedure - samples of pheromones were gathered from 9 of the women at different stages of their menstrual cycle via a cotton pad in their armpit. The pads were worn for at least 8 hours to ensure pheromones were picked up. Pads were treated with alcohol and frozen to be rubbed on the upper lip of other participants. On day 1 pads from the start of the menstrual cycle were applied to all 20 women, on day 2 they were all given a pad from the 2nd day of the cycle and so on findings - 68% of the women experienced changes to the cycle which brought them closer to the cycle of their odour donor

Answer 98

Depressive disorder which has a seasonal pattern of onsent and is described and diagnosed as a mental disorder in the DSM-5. Main symptoms are persistent low mood, lack of activity and interest in life symptoms are triggered during the winter months when the number of daylight hours become shorter Particular type of infradian rhythm called a **circannual rhythm** as it's subject to a yearly cycle Can be classed as a circadian rhythm as it may be due to the disruption of the sleep/wake cycle and this can be attributed to prolonged periods of daily darkness during winter hypothesised that the hormone melatonin is implicated in the causation of SAD. During the night the pineal gland secretes melatonin until dawn when there is an increase in light. During winter the 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

Answer 99

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

Answer 100

stages of sleep ## Footnote Psychologists have identified 5 stages of sleep that altogether span approximately 90 minutes A cycle that continues throughout the night Each stage is characterised by a different level of brainwave activity Can be monitored using an EEG

Answer 101

This is light sleep where a person may be easily woken ## Footnote In stage 1 brain waves are high frequency and have a short amplitude. These are alpha waves In stage 2 the alpha waves continue but there are occasional random changes in pattern called sleep spindles

Answer 102

deep sleep or slow wave sleep ## Footnote brain waves are delta waves with lower frequency and higher ampitude difficult to wake someone at this point

Answer 103

REM sleep ## Footnote Body is paralysed yet brain activity closely resembles that of the awake brain During this time the brain produces theta waves and the eyes occasionally move around thus rapid eye movment (REM) Dreams are most often experienced during REM sleep but may also occur in deep sleep

Answer 104

menstrual synchrony may be explained by natural selection ## Footnote Synchronisation of the female menstrual cycle is thought to have evolutionary value. For our distant ancestors it may have been adventageous for females to menstruate together and become pregnant at the same time. In a social group this would llow babies who had lost their mothers during or after childbirth to have access to breast milk improving chance of survival. Adaptive strategy.

Answer 105

methodological shortcomings ## Footnote There are many factors that may effect change in a women's menstrual cycle including stress, change in diet, exercise etc. These may act as confounding variables which means that any supposed pattern of synchronisation is no more than would have been expected to occur by chance. May explain why findings are difficult to retest. Suggests menstrual synchrony studies are flawed

Answer 106

improved understanding of age-related changes in sleep ## Footnote Sleep scientisits have observed that SWS reduces with age. Growth hormonse is mostly produced during SWS therefore this becomes deficient in older people. According to Cauter et al (2000) the resulting sleep deficit may explain various impairments in old age such as reduced alertness. In order to increase SWS relaxation and medication may be used. This suggests knowledge of ultradian rhythms has practical value

Answer 107

significant variation between people ## Footnote Tucker et al (2007) found large differences between participants in terms of the duration each sleep stage, particularly stages 3 and 4. Tucker et al suggest that these differences are likely to be biologically determined Makes it difficult to descrive nrmal sleep in any meaningful way

Answer 108

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

Answer 109

A tiny bundle of nerve cells located in the hypothalamus of the prain One of the primary endogenous pacemakers in mammalian species Infleuntial in maintaining circadian rhythms such as the sleep/wake cycle Nerve fibres connected to the eye cross in an area called the optic chiasm on their way to the left and right visual area of the cerebral cortex. The SCN lies above optic chiasm recieving information about light directly from this structure. Continues even when eyes are closed enabling the biological clock to adjust to changing patterns of daylight constantly

Answer 110

sample - 30 chipmunks procedure - destroyed SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days findings - The sleep/wake cycle of the cipmunks dissapeared and by the end of the study a significant proportion of them had been killed by predators (because they were awake and vulnerable to attack when the should be asleep)

Answer 111

sample - hamsters procedure - bred mutant hamsters with a 20-hour sleep/wake cycle. Transplanted SCN cells from the foetal tissue of mutant hamsters into the brains of normal hamsters findings - cycles of the second group defaulted to 20 hours

Answer 112

SCN passes the information on day length and light that it recieves to the pineal gland. This is another endogenous mechanism guiding the sleep/wake cycle. During the night the pineal gland increases production of melatonin - a chemical that induces sleep and is inhibited during periods of wakefulness. Melatonin also suggested as a factor in SAD

Answer 113

1. may obscure other body clocks 2. endogenous pacemakers cannot be studied in isolation 3. ethical issues ## Footnote 1. Research has revealed that there are numerous circadian rhythms in many organs and cells in the body. These peripheral oscillators are found in the organs including the lungs, pancreas and skin. They are influenced by the actions of the SCN but also act independently. Damiola et al (2000) demonstrated how changing feeding patterns in mice could alter the circadian rhythms of cells in the liver by up to 12 hours whilst leaving the rhythm of the SCN affected. Suggests other complex influences on the sleep/wak cycle 2. Total isolation studies (e.g. Siffre's cave study) are extremely rare. Siffre made use of artificial light which could have reset his biological clock everytime he turned his lamp on. In everyday life pacemakers and zeitgebers interact meaning it may make little sense to seperate the 2 for the purpose of research. Suggests the more researchers attempt to isolate the influence of internal pacemaker, the lower the validity of the research 3. Animal studies - were exposed to risk when returned to their natural habitat resulting in a majority of the sample dying (DeCoursey et al)

Answer 114

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

Answer 115

1. Light 2. Social cues

Answer 116

It can reset the body's main endogenous pacemakers (the SCN) thus playing a role in maintenance of the sleep/wake cycle. Light also has an indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation.

Answer 117

Demonstrated that light may be detected by skin receptor sites on the body even when the same information is not recieved by the eyes 15 participants were woken at various times and a light pad was shone on the back of their knees Researchers produced a deviation in the participants' usual sleep/wake cycle of up to 3 hours This suggests that light is a powerful exogenous zeitgeber that doesn't rel y on the eyes to exert its influence on the brain

Answer 118

Newborn babies' initial sleep/wake cycle is pretty much random At about 6 weeks of age the circadian rhythms begin By about 16 weeks babies' rhythms have been entrained by the schedules imposed by parents including adult-determined mealtimes and bedtime

Answer 119

That 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 travellinh long distances

Answer 120

1. Environmental observations 2. Case study evidence ## Footnote 1. Do not have the same effect in all environments. The Inuits of the Arctic Circle are said to have a similar pattern all year round despite spending around 6 months in almost total darkness. Suggest sleep/wake cycle is primarly cotrolled by endogenous pacemakers that can override environmental changes in light 2. Miles et al (1977) recount the study of a young man, blind from birth, who had an abnormal circadian rhythm of 24.9 hours. Despite exposure to social cues (e.g. regular mealtimes) his sleep/wake cycle could not be adjusted. Suggests social cues alone are not effective in resetting the biological rhythm