BioPsych

Question 1

NERVOUS SYSTEM

Answer 1

specialised network of cells in body and based on electrical signals

main functions:
- collect, process and respond to environmental stimuli
- coordinate body

2 divisions:
- central NS
- peripheral NS

Question 2

Central NS

Answer 2

CNS is body’s master control unit and made of the brain n spinal cord(collection of nerve cells attached to brain)

• it is a network of cells specialised for internal communication
• and regulates/controls behaviour n physiological processes

sensory receptors send info to brain and the brain responds w msgs to effectors (muscles/glands)

Brain is divided into diff lobes that have diff functions
85% brain mass is cerebrum (forebrain)

Question 3

Peripheral NS

Answer 3

PNS is body’s link to outside world and it’s main function is to connect the CNS and rest of body

Has 2 divisions:

• Somatic NS:
  governs voluntary movement and involved in reflex actions
  Info from sensory receptors bought to CNS by electrical impulses to deal w stimuli and it then relays this to the motor neuron to control body movements via muscles
• Autonomic NS
  Regulates involuntary movements eg heart rate and is composed of 2 parts:

• Sympathetic NS:
deals w emergencies by slowing down bodily processes not needed in emergency during fight/flight response eg inhibits digestion/ stops saliva prod
It increases heart rate, breathing n blood pressure, causes pupil dilation, inhibits digestion etc and secrets adrenaline

• Parasympathetic NS:
relaxes body once emergency passes by resuming normal bodily functions eg slows heart rate, breathing, resumes digestion etc
aka rest n digest part of ANS

Question 4

Nervous system: Brain

Answer 4

Diencephalon contains 2 structures:

• Thalamus: is concerned w relaying sensory info to brain via electrical impulses
• Hypothalamus: regulates basic bodily functions eg thirst/hunger
  and controls pituitary gland (releases hormones)

Cerebrum: subdivided into 4 lobes n 2 hemispheres
eg frontal lobe which’s involved in speech/thght production. Cerebrum controls higher lvls of cog/emotional processes

• Limbic system involved in learning,memory,emotions
• Basal ganglia involved in motor activities/movement
• cerebral cortex only found in mammals n involved in planning, problem-solving, lang, consciousness n personality

Hindbrain contains:

• Medulla
• Cerebellum:
  controls movement/motor coordination n balance
• spinal cord:
  is extension of brain n links to bottom of brain (brain stem)

responsible for passing msgs to n from brain, connects nerves to the PNS n responsible for reflex actions
eg auto pulling hand away from hot object

Question 5

the structure of a Neuron

Answer 5

• neurons transmit info around body as electrical impulses
• cell body has dendrites that receives info from other neurons
• info travels along axon in form of an electrical impulse
• myelin sheath protects axon and speeds up the transmission.
• myelin sheath is segmented by gaps aka nodes of ranvier which speeds up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon
• at end of axon, impulse reaches the synaptic knob. there’s a small gap bw this neuron and the next aka synapse
• neurotransmitters are chemicals released form the synaptic knob n pass thru the synapse to carry the signal to the dendrites of the neighbouring neuron

Electrical transmission- the firing of a neuron
•when a neuron in resting state, inside of cell= neg charged. When neuron activated by a stimulus, inside of cell becomes pos charged for split sec which causes an action potential to occur. This produces an electrical impulse which travels down axon to end of neuron

Question 6

Neurons 2

Answer 6

Transmission of info to n from CNS:

Stimuli -> Receptor -> CNS -> Effector -> Response

• Receptors detect a change in the env stimuli.
• sensory neuron transmits electrical impulse from receptor to CNS
• relay neurons at CNS transmit the impulse to motor neuron
• motor neuron transmits impulse to effector which produces response

REFLEXES are fast/involuntary responses to stimuli that pass thru spinal cord and avoid conscious part of brain completely to speed up response n act as survival mechanism

Question 7

Synaptic transmission

Answer 7

Electrical transmission- the firing of a neuron
•when a neuron in resting state, inside of cell= neg charged. When neuron activated by a stimulus, inside of cell becomes pos charged for split sec which causes an action potential to occur. This produces an electrical impulse which travels down axon to end of neuron

• a synapse is junction bw a neuron n neighbouring neuron/ effector (muscle/gland)
• tiny gap bw cells at synapse is synaptic cleft
• presynaptic neuron has a swelling (synaptic knob) which contains synaptic vesicles that’s filled w neurotransmitters
• when an electrical impulse reaches the end of a neuron it causes neurotransmitters to be released into synaptic cleft and it diffuses across postsynaptic membrane and binds to specific receptors
• when neurotransmitters bind to receptors it may trigger an electrical impulse in postsynaptic neuron by process of summsation causing a muscle contraction (in muscle cell) or secretion of a hormone (from gland cell). This depends on if neurotransmitter’s excitatory/inhibitory
• Bcz receptors only on postsynaptic neuron, synapses ensure impulses are unidirectional(1 direction)
• the neurotransmitters are removed from the cleft so the responses don’t keep happening eg taken back to presynaptic neuron/ broken down by enzymes n products r taken back into neuron

Question 8

Typa neurotransmitters/excitatory/inhibitory n summation

Answer 8

Neurotransmitters can be either:
Excitatory: increase likelihood of an electrical impulse being triggered in postsynaptic neuron
Inhibitory: decrease likelihood of an electrical impulse being triggered in a post synaptic neuron

• Acetylcholine:
  Excitatory
  involved in Involuntary movement, learning, memory & sleep
  much= depression
  lil= dementia
• Dopamine:
  involved in Movement, attention, Learning
  much= schizo
  lil= Depression n Parkinson’s disease
• Noradrenaline:
  Excitatory
  Closely related to adrenaline
  Involved in fight/flight response.
  much = schizo
  lil = depression
• Serotonin:
  inhibitory
  involved in emotion, mood, sleeping, eating
  lil = depression
• GABA:
  Inhibitory.
  lil = anxiety disorders

Summation
is process which decides if postsynaptic neuron fires.
excitatory n inhibitory influences are summed:
if net effect on postsynaptic neuron is inhibitory, postsynaptic neuron less likely to fire
if net effect is excitatory, then likely to fire
(ie inside of postsynaptic neuron become pos charged for split sec n electrical impulse created n travels down the neuron.
therefore, the action potential of postsynaptic neuron only triggered if sum of the excitatory n inhibitory signals at any one time reaches the threshold

Question 9

Endocrine system

Answer 9

• Endocrine system
  is a network of glands throughout the body that manufactures and the secrets hormones
• Glands:
  Special groups of cells Within the endocrine system whose function is to produce and secrete hormones
• Hormones:
  Chemical messengers that travel through the bloodstream and only affect target organs. They influence different processes eg stress response and mood
• pituitary gland:
  master gland whose function= influence release of hormones from other glands

Question 10

endocrine system 2

Answer 10

• Endocrine systems work alongside NS
• It affects the body over a long period of time and hormones travels through blood instead of nerves
• Hormones generally affect cells in more than one organ which leads to different types of responses
  eg THYROID secretes THYROXINE which increases heart rate and body’s metabolic rate and influences growth
• Pituitary gland is controlled by hypothalamus with receives information about basic body functions and then uses this information to regulate functions
  other endocrine glands can release own hormones that can stop hypothalamus and pituitary gland- prevents hormone lvls getting too high aka NEGATIVE FEEDBACK
• OVARIES responsible for producing eggs n OESTROGEN/PROGESTERONE refer to Manner n Miller 2014 (found progesterone increased sensitivity to social cues which helps F protect unborn child from danger)
• TESTES prod TESTOSTERONE n sperm prod n responsible for male characteristics

Question 11

Role of adrenaline

Answer 11

Adrenal glands sit on top of the kidneys and secrete adrenaline which is crucial in fight or flight response.

adrenaline increases heart rate pushing blood to muscles therefore increasing blood pressure.
Breathing is also rapid to take in oxygen as much as possible
blood sugars and blood fats also increase to supply energy to the part of the body associated with the fight or flight response

• when threatened, the hypothalamus activates the pituitary gland which triggers Sympathetic NS
• when the sympathetic ANS triggered, preps body for action needed for fight/flight.
  it signals Adrenal Medulla to release adrenaline
• Adrenaline increases heart rate breathing rate, dilates pupils, inhibits digestion/saliva prod, contracts rectum
• when threat passes, Parasympathetic NS returns the body to the normal state by reducing heart/breathing rate reactivating digestion/saliva prod, constricting the pupils and relaxes rectum

Question 12

Localisation of function

Answer 12

Localisation of function is where diff areas of brain are responsible for diff functions so damage to an area will damage a particular body function
eg damage to certain area can distort memory

The brain is divided into left and right hemisphere which are contralateral (right hemisphere controls left body n vice versa)

• Motor cortex:
  controls voluntary movement. parts of motor cortex controlling diff body parts are amazingly arranged.
  Eg part controlling leg is near part controlling foot
• Somatosensory area: detects sensations from all over body
  eg skin receptors produce sensations related to pressure,pain, temperate etc
• Visual centre:
  processes visual info. light hits retina and this travels as impulse along optic nerve which then reaches the thalamus and relays it to the visual cortex in hindbrain. Visual cortex parts specialised for colour shape etc
• Auditory centre:
  Processes auditory info. Cochlea in inner ear converts sound waves into nerve impulses which travel along auditory nerve to the brain stem(decodes duration/intensity) and then info passes to auditory cortex which may recognise and respond to the sound

LANGUAGE CENTRES:

• Broca’s area:
  centre of speech production. Broca found that p(s) w speech problems had lesions in the Broca’s area in left hemisphere but lesions in the right hemisphere causes no speech problems
• Wernicke’s area:
  in left hemisphere and responsible for speech comprehension. Wernicke found ppl w lesions in this area could produce speech but not understand language.
  Wernicke’s area divided in 2
  parts:
  •Motor region: controls movement of mouth, tongue, vocal cords
  •Sensory area: associates meaning w language

There is a loop that connects the Broca’s and Wernicke’s area so lang prod and comprehension are tied together

Question 13

Evaluate localisation of function

Answer 13

FOR:

• IRL research support:
  • Phineas Gage lost part of his frontal lobe bcz a metal pole went thru his skull. This had affected his personality eg loss of inhibition. Suggests that frontal lobe may have part to play in mood regulation
  • Peterson found thru brain scans that Broca’s area is active during reading and Wernicke’s area active when listening. Shows that diff areas have diff functions and control diff bodily aspects
• Support from aphasia studies:
  •Damage to Wernicke’s area leads to Wernicke’s Receptive aphasia so p(s) can’t understand lang n produce nonsense words
  •Damage to Broca’s area leads to Broca’s expressive aphasia so p(s) lack fluency in speech
  • Broca studied a stroke patient who can only say Tan. B found damage in his Broca’s area meaning that he had speech distortion due to Broca’s expressive aphasia. However as B used post-mortem examination, this means that inferences were made and it maybe possible that the Broca’s area is not entirely responsible for speech production. So weakens localisation theory

AGAINST:

• Equipotentiality theory- •proposed by Lashley who a argued that tho basic brain functions (eg motor cortex) is controlled by localised brain areas, higher cog functions (eg problem-solving/emotional processes) are not.
  •based on research that found brain compensates for damaged brain areas by taking control of its functions. Suggests that area of damage isn’t important n rather severity of damage is.
• Connection bw areas maybe more important than location of areas:
  Sites are interdependent so damage to connections can b v serious
  Dejerine 1882 found damage to connection bw visual cortex and Wernicke’s area led to inability to read as it requires visual and language comprehension. weakens localisation theory showing that one area may not control a specific function and rather diff areas may contribute

Question 14

Hemispheric lateralisation

Answer 14

Hemispheric lateralisation refers to the 2 hemispheres having diff functions
left= speech/language
right= visual/motor
Broca found that damage to area in left hemisphere impaired language but damage to same area in right hemisphere didn’t.

•Hemispheres connected by Corpus Callosum which allows them to communicate
• in some cases of epilepsy p(s), corpus callosum had to be cut so effects of 2 unconnected hemispheres were studied to c effects of this;

Sperry 1968- effects of split brain surgery:

• AIM:
  assesses abilities of separated hemispheres
• METHOD:
  participants were asked to sit in front of a board and asked to stare at middle of it and lights flashed across their left n tight visual field
• FOUND:
  when right eye covered, they were unable to report lights flashing on the left side of the board. When left eye covered, they were able to verbally acknowledge lights on right side of board. But, when asked to point to which lights lit up, they pointed to both which shows lights seen in both hemispheres
• as light seen in left eye was processed by right hemisphere, couldn’t verbally acknowledge it as right hemisphere has no language centre. They were able to point it out suggesting right hemisphere has visual-motor centres
• proves that so say 1 seen suin, area of brain responsible for speech must b able to communicate w area responsible for visual processing

Question 15

Evaluate hemispheric lateralisation

Answer 15

AGAINST:

• Small sample size bcz split brain patients are rare. p(s) also had varying degrees of splitting n may’ve had other neurological problems that acted as an CV, hence results may not be valid n generalisable
• Mixed research evidence:
  • case study of JW showed after split brain procedure he developed ability to speak out of right hemisphere meaning he can speak about info presented to left/right visual field
  •Also age reduces lateralisation- possible as we age n face declining mental abilities the brain allocates more resources to cog tasks
  • suggests further research is needed to explore brain lateralisation b4 conclusions can be made

Question 16

Plasticity

Answer 16

•plasticity refers to neurological changes as a result of learning n experiences.
•this was traditionally associated w changes in childhood but recent research showed mature brains show plasticity too as a result of learning.
• env factors (eg learning n new experiences) cause ’synaptic pruning’ to occur as new neural pathways are formed, used pathways are strengthened n infrequently used pathways become weak n die

pros:

• Kempermann 1998 found rats housed in a complex env showed increase in neurons compared to rats in a cage.
  changes esp in hippocampus (associated w memory n spatial navigation).
  shows complex env encouraged learning in rats with led to physical changes in brain
  However can he criticised as animals were used n questionable if can be applied to humans as more complex etc but counter w below
• Maguire 2002 showed Ldn taxi drivers had more grey matter in their posterior hippocampus than control grp (area linked w spatial awareness/navigation).
  Amount of change in brain also pos correlated to how long they were ldn taxi driver
• Boyke 2008 found plasticity can b lifelong even at 60+ as learning juggling led to increase of growth in visual cortex
  Thus brain continually adapts to changed envs/experiences so indicates plasticity

Question 17

Functional recovery

Answer 17

Functional recovery refers to transfer of functions from damaged brain area after trauma to undamaged area

2 main forms:

1) Neuronal unmasking:
in 1960s researchers found stroke victims were able to regain some brain functions as brain ‘rewired’ itself so neurons next to damaged area could form new circuits to resume some lost functions

2) Stem cells:
•unspecialised cells that may become specialised to conduct distinct tasks
eg assuming role of damaged brain neurons
Current research is examining ways which stem cells can b used to aid recovery from brain trauma eg implanted to replace dead cells

• Tajiri et al 2013 transplanted stem cells in parts of rats’ brains affected by trauma n compared it to control grp. 3month later found newly developed neuron cells in injured areas of rats brains that were implanted
Shows evidence stem cells useful in recovery

Question 18

evaluate functional recovery

Answer 18

FOR:

• contribution to neurorehab:
  research n understanding into plasticity n functional recovery led to neurorehab which uses motor therapy n electrical stimulation of brain to counter neg effects on motor n cog functions after accidents n strokes
  •shows research in this area helped improve cog functions in ppl w injury

AGAINST:

• Individual differences:
  •unlike plasticity, functional recovery declines w age. Elbert et al found the capacity for neural reorganisation is greater in kids than adults. this shows neural regeneration is less effective in adults- may explain why adults find change more demanding than kids
  • Schneider found edu lvls is positively correlated w recovery speed from brain injury as their brains more active
  • therefore altho scientific evidence for this concepts apparent, suggesting a nomo approach maybe sufficient n findings maybe generalisable to an extent, idio approach maybe better when looking at effectiveness of plasticity n functional recovery w individual patients n expectations of recovery should be set on case-by-case basis

Question 19

Ways of studying the brain

Answer 19

1) fMRI (functional magnetic resonance imaging)
2) EEGs (electroencephalogram)
3) ERPs (event-related potentials)
4) post-mortem examination

Question 20

outline fMRI (functional mirroring resonance imaging)

Answer 20

• There is an increase in need of oxygen in part of the brain being used. Therefore blood flow increases to the area
• A brain scan can be used to measure this blood flow to the brain sites when participants were asked to perform a task
• 3D images of produce showing which part of the brain has been used perform the task
• This is important for understanding of localisation,
  eg in memory, participants may be asked to learn list of words and recall them. such a task with allow psychologists to determine which part of the brain has been used for memory recall, therefore increases our understanding of LTM.

Question 21

evaluate fMRI

Answer 21

FOR:

• non-invasive:
  no insertion to brain or exposure to radiation so is safe n ethical
• more reliable than verbal reports
  eg blood volume is accurately measured to c which brain part used in task rather than relying on p(s) self-reporting
  therefore, fMRI can investigate psychological phenomenas that ppl can’t. also removes chance of bias

AGAINST:

• may overlook interconnection bw brain sites n how they work together as it only focusses on where extra blood flow going. hence gives an incomplete understanding of the brain functions
• Expensive:
  due to this only a small sample is used. Also it requires specialists so not readily available for research so any conclusions based on fMRI has low population validity and does not represent population as much

Question 22

EEG (electroencephalogram)

Answer 22

• Electrodes are attached to the brain And continuously measure electrical activity in the brain. It can measure activity at different times/states,
  eg sleep or wake.
• EEGs detect epilepsy n alzheimer’s.
• there are 4 basic brainwave patterns:
  •Alpha- awake n relaxed
  •Beta- awake n highly aroused(or in REM)
  •Delta- deep sleep
  •Theta- light sleep

Question 23

Evaluate EEGs

Answer 23

FOR:

• brain activity recorded over time n changes are monitored as they happen w/o delay (high temporal resolution. Makes it easier for researcher to observe brain at certain times
  eg as person goes from task to task or 1 state to another eg sleep-wake.
• Can help w clinical diagnosis of conditions that affect the brain eg epilepsy/alzheimer’s therefore has medical applications. Useful to predict seizures n understand brain conditions

AGAINST:

• Only measures electrical activity in the outer layer of brain so cannot reveal electrical activity in deeper parts of the brain. Meaning info from EEGs are limited and deeper invasive methods may be required for more info
• Electrical activity is detected in several brain regions simultaneously so EEGs are not precise, means low spatial resolution. It is hard to pinpoint exactly which area is producing activity, especially if the activity is in adjacent areas

Question 24

outline ERPs (Event-related potentials)

Answer 24

• ERPs r a small voltage changes in brain triggered by specific stimuli that r measured by EEGs. As these voltages r small, hard to pickup from other electrical signals in brain, so stimulus is repeatedly presented n signals occurring w this presentation of stimulus is only considered.
• ERPs of 2 types:
  • Sensory ERPS:
  those that occur w/i 100milliseconds of stimulus presentation. represents recognising the stimulus
  • Cognitive ERPs:
  those that occur 100+ milliseconds after stimulus presentation. This represents processing of stimulus

Question 25

Evaluate ERPs

Answer 25

FOR:

• Can measure processing of stimuli even w/o verbal report so psychologists can understand brain functions better without relying on self-report
• Can see which part of the brain is affected by different stimuli so can learn a lot from this

AGAINST:

• low spatial resolution:
  Signals can’t pinpoint exact place of brain activity
  eg Electrical activity in every brain side, so it’s hard to distinguish in adjacent areas
• output can only b interpreted by trained professionals
  pricey training needed to fully appreciate activity measured from ERPs so limits usefulness as this can minimise use of ERPs in attempt to save p

Question 26

Outline post-mortem examination

Answer 26

• Deceased people with cognitive abnormalities of the brain dissected to assess if they had structural damage eg Broca found damage in Tan’s brain using post-mortem examination.
• neurological abnormalities have been linked w schizo n depression

Question 27

Evaluate post-mortem examination

Answer 27

FOR:

• allows deep/detailed examination of brain structures than would be possible w non-invasive methods eg EEGS.
  Allows psychs to get deeper understanding of role of brain in many aspects eg abnormalities n behaviour
• medical application:
  It played a central role in understanding schizo. Harrison 2000 suggests bcz of post-mortem exams, it was found abnormal brain structures n neurotransmitters are associated with schizo. Strength bcz it increased understanding of schizo development n treatment towards it

AGAINST:

• Issue of causation:
  Deficits displayed in the p(s) lifetime may not be linked to the damage in the brain so causation can’t be established. various factors may act as confounding variable, so may confuse findings eg age of death. This makes it difficult to conclude anything as no further tests can be followed up as patient is deceased
• ethics:
  deceased ppl can’t give consent

Question 28

Biological rhythms

Answer 28

There’s 3 types of cyclical bodily rhythms that affect behaviour, emotion, mental processes of living things:

1. Circadian rhythms:
   follows a 24hr cycle eg sleep-wake cycle
2. ultradian:
   occurs more than once a day eg cycle of NREM n REM in single nights sleep
3. Infradian:
   occurs less than once a day eg menstruation cycle

Endogenous Pacemakers (EPs): internal biological structures that control/regulate the rhythm

Exogenous Zeitbergers (EZs): external env factors that influence the rhythm

Question 29

Circadian rhythms

Answer 29

• •EP controlling sleep wake cycle in hypothalamus.
  •patterns of light and darkness (EZs) are registered by retina then travel along optic nerve to where the nerves join and then pass into suprachiasmatic nucleus (SCN in hypothalamus.
  • Pineal gland triggered by SCN and produces melatonin
  • This stimulates the shutting down of reticular activating system (RAS-associated w brain activity) so we fall asleep
  • if this nerve connection’s severed, circadian rhythms become random
  • suggests both EPs and EZs important in sleep-wake cycle

circadian rhythms seen as largely controlled by EPs
• homeostasis is circadian rhythm that affects sleep
• Human body temperature is lowest in early hours of the morning n highest at early evening
• Sleep usually occurs when body temp begins to drop. Temp begins to rise at the end of sleep cycle promoting alertness in morning
• Heart rate, breathing rate metabolic rate , reach max values in late afternoon or early evening and min values in early hours of morning
• if we reverse our sleep-wake cycle these rhythms persist. the internal cycle is therefore free-running regardless of external cues
• indicates human bodies evolved for day work and night rest so being nocturnal is highly stressful for physiological n psychological health

Question 30

Support for EPs affecting circadian rhythms

Answer 30

• Yakazaki found isolated lungs, livers n other lab grown tissues persist in showing circadian rhythms. suggests cells r capable of maintaining a circadian rhythm even when not controlled by brain structures n most bodily cells are tuned into following a circadian rhythm.
• Morgan 1995 bred hamsters to have abnormal circadian rhythm of 20hrs. took SCN of these hamsters and implanted into normal hamsters which then displayed 20hr rhythm. shows pattern imposed in recipients brain.
  other studies showed the reverse when normal planted into abnormal, rhythm became normal. therefore supports EPs affecting cycle n shows circadian primarily controlled by bio structures that have strong influence on us to maintain normal sleep-wake cycle.

Say how this study can’t generLize n stuff cos human complex etc

Question 31

Support for EZs affecting circadian rhythm

Answer 31

however research n everyday occurrences show circadian rhythms also influenced by EZs:

• Siffre spent 6month underground away from all EZs eg clocks n daylight. altho he organised his time in regular patterns of sleep n wake his body preferred 25hr cycle over 24 suggesting 24hr cycle increased cos of lack of external cues. as so, he thought it was a month earlier when he came out showing importance of EZs on circadian rhythm. however study criticised for assuming artificial light can’t act as EZ
• Light being only EZ= Reductionist
  buhr et al 2010 found fluctuations in temp important in setting timings of cells in body n caused organs n tissues to become active or inactive. shows circadian rhythm controlled n affected by many diff factors not j light so holistic approach in research more appropriate
• individual differences important in circadian rhythms
  Duffy et al 2001 found morning ppl prefer to sleep n wake up early n evening ppl prefer to sleep n wake up later.
  demonstrates there’s innate individual differences in circadian rhythms suggesting researchers should focus on these differences in research n take idio approach than nomo when studying sleep-wake cycles as not everyone operates same way

Question 32

Ultradian rhythms

Answer 32

EEGs measures electrical activity in brain n there’s also equipment that measures eye movement n muscle tension. these equipment indicates during a single nights sleep we experience a cyclical ultradian rhythm of diff stages n types of sleep which can be divided into NREM (non-rapid eye movement) n REM (strongly associated w dreaming

Question 33

NREM

Answer 33

NREM can be divided into 4 stages

1. light sleep- muscle activity slows down w occasional muscle twitches
2. breathing/heart rate slows down slight decrease in body temp
3. deep sleep begins- brain releases slow delta waves
4. V deep sleep- rhythmic breathing, limited muscle activity n brain produces delta waves
5. REM brain waves speed up, dreaming occurs. muscles relax. heart rate increases n breathing is shallow/rapid

when asleep, we enter stage1 and rapidly descend thru 2,3,4 n 5(REM). body progressively relaxes w muscles relaxing, EEGs less active, pulse, respiration, blood pressure slowing n becomes progressively harder to wake sleeper.
after some time in stage 4, NREM cycle reverses n we ascend back thru stages 3,2,1. but instead of waking up, we enter our first period of REM sleep (stage5).

cycle is total 90m and we go thru 4-5cycles a night

Question 34

REM

Answer 34

• during REM, pulse, respiration, blood pressure fluctuates n EEGs resemble those of waking
  person(shows brain active). major characteristic of REM is rapid eye movement behind closed eyelids n brain shows spontaneous activity associated w dreaming:
  • firstly as hind n midbrain (associated w visual n auditory processing) spontaneously generate signals (brain acts like seeing n hearing things)
  • secondly motor cortex (responsible for body movement) spontaneously generates signals (these r ‘cut off’ at top of spine so we’re effectively paralysed from neck down)
  •generally assumed we dream in REM n not NREM but possible we dream in both but can’t recall dreams from NREM as we in ‘deep’ sleep
• patterns of REM n NREM decrease as we age (need more REM n sleep as baby n only 8hr sleep as adult)
• bcz the pattern changes researchers believe a function of REM is growth n repair as we need more sleep when young n less w age so is important for memory.
• EP controlling REM is located in patch of cells in pons. damage to these cells causes REM to disappear. if neurons in diff parts of pons damaged, REM remains but muscle paralysis in REM disappears. this may’ve reason for “behavioural sleep disorder” where human sleepers may act out their dreams

Question 35

Evaluate ultradian rhythm

Answer 35

AGAINST

• Individual differences:
  Tucker et al 2007 found sig differences bw p(s) in terms of durations during stage 3&4. suggests there maybe innate individual differences in ultradian rhythms. means it worth focussing on these differences during investigations into sleep cycles
• Low eco validity:
  sleep is monitored in lab settings which isn’t how we’d naturally sleep. also, electrodes on head would interfere w sleep n not natural. also must consider consider situ variables affecting quantity n quality of sleep eg illness drugs exercise etc

Question 36

Effects of sleep deprivation

Answer 36

• Head:
  •memory loss
  • hallucinations
• heart:
  •increased heart rate variability
• Immunity:
  •weak immune system
• increased reaction time
• increased risk of obesity
• low body temp

Question 37

Infradian rhythms

Answer 37

occurs less than once a day eg female menstruation cycle

• menstruation cycle is monthly infradian rhythm which is regulated by hormones that either promote ovulation or stimulate uterus for fertilisation
• ovulation occurs halfway thru cycle when oestrogen is at highest
• after ovulation, progesterone lvls increase in preparation for possible embryo in uterus
• important to note menstrual cycle roughly 28d but can vary considerably for some women eg short cycle 20d or long cycle 40d

Question 38

evaluate infradian rhythms

Answer 38

AGAINST:

• there is evidence to suggest EZs affect infradian rhythms.
  Russel et al 1980 found female menstrual cycle become synched w other females thru odour exposure. sweat samples from one grp of women were rubbed on top lip of another grp. found that despite grps were separated, their menstrual cycles synched. suggests synchrony of menstrual cycles can be affected by pheromones which have an affect on ppl nearby rather than on person producing them. findings indicate external factors must be considered when investigating infradian rhythms n holistic approach should be taken as reductionist approach only considered endogenous influences

FOR:

• Research to suggest infradian rhythms are important regulator of behaviour
  Penton-Volk et al 1999 found women preferred feminine faces at least fertile stage of cycle n preferred masculine face at most fertile stage. shows women’s sexual behaviours influenced by their infradian rhythms so highlights importance of studying infradian rhythms n benefits it brings in terms of understanding human behaviour