biopsychology Flashcards
what is the nervous system made up of?
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
What are the subdivisions of the PNS
- Autonomic nervous system: controls involuntary vital functions of the body
e.g maintaining heart and breathing rate - Somatic nervous system: receives information from sensory receptors belonging to each of the 5 senses, and results in effectors being stimulated by the CNS by the motor neurones
What is the autonomic nervous system divided into?
-parasympathetic nervous system
-symapthetic nervous system
-work as an antagonist pair during the “rest and digest” response
-crucial in producing physiological arousal needed to maintain the fiight or flight response
Outline the role of the subdivisons of the autonomic nervous system
-sympathetic NS : increases heart and breathing rate and causes pupil dilation and vasoconstriction
-parasympathetic NS : decreases heart rate , breathing rate and causes pupil constriction and vasodilation
Outline the endocrine system
- main chemical messenger of the body
-hormones are secreted into the bloodstream from the glands to regulate bodily functions
-chemical system of communication via blood
Outline the role of the pituitary gland with an example
- “master gland” :
- controls the release of hormones from all other glands of the body
e.g : thyroid releases the hormone thyroxine, which increases heart rate and therefore increases the rate of growth.
Outline the role of the adrenal gland with an example
- releases adrenal from adrenal medulla
-creates the psychological arousal preceded by the flight or flight response - through increasing activity within the sympathetic branch of the NS
e.g : increase heart rate and increases respiration and sweating
Outline the flight or fight response
1) body senses and becomes aware of a change in the environment
(e.g sound of speeding car)
2) sensory receptors and sensory neurones in the PNS send this information to the hypothalamus in the brain , coordinating a response
3) This triggers an increase in levels of activity in thee sympathetic branch in the ANS
4) Adrenaline is released from the adrenal medulla in the adrenal glands and is transported to target effectors
(through the blood and through action of the Endocrine system)
5) Due to this , the rectum contracts ,saliva production is inhibited and breathing rate increases.
- this creates the psychological response needed to sustain the fight or flight response
6) When the stressor is no longer a threat , as part of the antagonist pairing the hypothalamus triggers less activity in the sympathetic branch and more in the parasympathetic branch of the ANS
(“rest and digest” response)
What is the purpose of the flight or fight response
has an adaptive purpose to enable us to escape the stressor and so increase the likelihood of our survival.
Why is the fight or flight response referred to as the “rest and digest” response
this is because the parasympathetic branch decreasing the activity which was originally increased through the action of the sympathetic branch.
Outline the role of synaptic transmission
the process of how neighbouring neurons communicate with each other by sending chemical messages across synapse gaps that separate them
Outline the full process of synaptic transmission
1) an electrical message travels down the axon of pre-synaptic neuron to the terminal button
2) vesicles (in pre-synaptic neuron) are activated to fuse with surface of the terminal button membrane and release neurotransmitters across the synaptic cleft
3) neurotransmitters diffuse (high to low conc) across synapse to post-synaptic cell , where it binds to complementary receptor sites on dendrite
4) post synaptic effects are either excitatory or inhibitory , depending on the result of summation
what is the excitatory effect of neurotransmitters?
- depolarisation
-increase likelihood of post- synaptic neuron firing
-causes action in post synaptic neuron
-message continues to move through neuron across brain/body
what is the inhibitory effect of neurotransmitters?
- hyperpolarisation
- decreases likelihood of post synaptic neuron firing
-causes inaction in the post-synaptic neuron
-message does not continue to other neurones
Outline the what summation is and its results
- influences of the excitatory and inhibitory effects of neurotransmission on the post-synaptic neuron added together
e.g if net effect on post-synaptic neurone inhibitory/excitatory
Outline an example of excitatory neurotransmission
Dopamine
- fires off a message in the neuron
Message is passed on
Outline an example of inhibitory neurtransmission
GABA
-they are the nervous system “off” switch in that they decrease the likelihood of neurons firing.
-makes receptor sites difficult to stimulate , reducing anxiety
What does the localisation theory suggest?
suggests that certain areas of the brain are responsible for certain processes,
behaviours and activities.
Outline the location and function of the motor area in the brain
Function :
involved in regulating and coordinating movements
- lesions or damage to such area results in an inability to control vital body movements
Location:
frontal cortex in both hemispheres
Outline the location and function of the auditory area in the brain
function :
responsible for processing auditory information and speech
-lesions/damage could lead to hearing loss or wernicke aphasia
location :
temporal lobe in both hemispheres
Outline the location and function of the visual area in the brain
function:
processes visual information (from eyes via retina)
location :
occipital lobe in both hemispheres
Location and function or Wernicke’s area
function :
language understanding such as speech comprehension
location : temporal lobe , in left hemisphere
what happens when there is damage to wernicke’s area?
- wernicke aphasia
- individuals ability to understand language is severely impaired
- inability to understand language in verbal or written form , however connected speech production not affected
Location and function of Broca’s area
function:
sentence creation and formation (speech production)
location:
frontal lobe - in left hemisphere only
what happens when there is damage to the broca area?
-broca’s aphasia
-speech production severely impaired
-difficulty forming complete sentences and understanding sentences, as well as
failing to understand the order of words in a sentence and who they are directed towards
What is the left hemisphere of the brain associated with?
-language production and comprehension
-language is an example of a cognitive ability which is both localised and lateralised (to the
left hemisphere).
Location and function of somatosensory area
function:
detecting sensory touches (5 senses)
location: parietal lobe in both hemispheres
-highly localised
Evaluate a strength of localisation of function theory (BRAIN SCANS)
P- brain scans provide evidence that many everday brain functions are localised
E- Peterson et al. used brains scans and demonstrated how wernicke’s area was active during a listening task & broca’s area active during reading task
E- strength : highly scientific methods that areas of brain have specific functions supporting the theory of localisation of function .
(Broca and Wernicke area explain)
-if this wasnt the case there would be no change in location of activity in the brain when completing different tasks
Evaluate a strength of localisation of function theory (PRACTICAL ISSUES)
P- research into functional localisation have practical applications
E- in cases of extreme OCD or depression the patient might have a cingulotomy (lesioning an area responsible for emotional processing and behavioural control)
-Dougherty reported 1/3 of patients were identified as having successful outcomes 32 weeks after surgery
E- strength : highlights how localisation research can work to improve the quality of life for patients with severe mental illness , which in turn benefits the economy
-surgery success also indicates that symptoms and behaviours associated with mental illness are localised
Evaluate a Weakness of localisation of function theory (language localisation)
P-Language localisation has been questioned
E- In a study of silence reading Bavelier et al (1997) found a large variability in individual patterns of activation of the brain across different individuals. They observed activity in the right temporal lobe as well as the left frontal temporal and occipital lobes
E-limitation : because it suggests that rather than being confined too a couple of key areas, language may be organised more holistically in the brain.
-This directly contradicts the localisation theory as it does not identify one specific location for language function
Outline the idea of hemispheric lateralisation
- the idea that the the two hemispheres of the brain function differently
certain behaviours , processes. and activities are mainly controlled by one hemisphere rather than the other
how are the two hemispheres split? + example
- they are connected through a bundle of nerve fibers such as corpus callosun
-corpus callosun allows the two hemispheres to communicate and send / recieve information from one another
Outline the role of the left hemisphere
- processing the right visual field
- understanding of language and reading
Outline the role of the right hemisphere
- processing the left visual field
-facial recognition
Outline an example of hemispheres sending messages (nerve impulses) to one another
-language and facial recognition are distributed between the two hemispheres
-e.g to be able to talk about facial recognition (right) we would need to use language (left)
-language more dominant in left and facial recognition more dominant in right
what do dominant hemispheres control
- dominant hand you use
-e.g right hemisphere dominant = left handed - this is called contra-latterly : left hemisphere controls right side of body
What is meant by “split brain research”?
- studies how the hemispheres function when they cannot communicate with eachother
-usually due due to surgical cutting of corpus callosum
-e.g epileptic patients : experienced surgical seperation of hemisphere of the brain
Outline Sperry et al (1968) research Aim and Procedure
Aim : conducted a split brain research to study how two seperate hemispheres deal with information
Procedure:
- Studied 11 people who had split brain research due to epilepsy (cutting of corpus callosum) and studied the function of both hemispheres in isolation
- participants asked to fixate on a dot in the centre of the screen while a word or image was presented to either the Left or right VF
-participants were asked to make responses with their :left hand (controlled by right HM)
-right hand (controlled by R HM)
-verbally ( left HM)
without seeing what their hand was doing
Outline Sperry and Gazzaniga split brain research findings
DESCRIBING OBJECT
- when picture was shown on the RVF the patient could easily describe what was seen (left HM)
- if the picture was shown on LVF patient typically reported that there was “nothing there”
- this is because , connected brain : messages from RH is relayed to language centres in LH
OBJECT
- could not give verbal labels to objects in LVF they could select matching object out of plain sight using their Left hand (RH) that most closely associated w/ LVF
MATCHING FACE
-when asked to match face with a series of other faces: picture presented on LVF was consistently selected and RVF ignored
BOTH VF WORD
- wrote the word in LVF (RH)
- say word in RVF (LH)
what does Sperry’s study conclude?
- certain functions are lateralised to specific locations within the brain
e.g LH is associated with the use of language and RH associated with facial recognition (silenced , but emotional)
Evaluate a strength into split brain research ( TAN)
- supported by case studies
-patient “tan” could only speak one word (tan) despite understanding speech had autopsy
-broca had substantial damage in frontal lobe , concluding this area was involved for speech production
- strength: left hemisphere alone (frontal lobe) is responsible for speech production
-CP: however this may not be representative of wider population : no certainty that tan represent typical pop
Evaluate a strength of split brain research of sperry (quasi)
P- Quasi experiment , high control over extraneous variables : can establish cause and effect
E-lab conditions , test administered in a controlled systematic manner e.g showing images at the same length of time (less than a desisecond)
E- cause and effect relationship between IV ( split brain vs control) and DV ( performance of tests)
-conclusions made will be off high internal validity : generalised
CP : can be argued : limited sample of only 11 split-brain participants and 11 control
- epilepsy could have also caused unique changes to the brain : lack validity& generalisability
Evaluate a limitation of split brain research
P- language may not be restricted to just the left hemisphere but may differ between individuals
E- for example , right handed individuals generally develop their language in the left hemisphere , whereas left handed individuals may have them on either side or both
E- limitation : wrong to assume that there is lateralisation of language centres in individuals ; decreases validity of conclusions
Outline what is meant by “brain plasticity”
refers to the brains tendancy to change or adapt (functionally and physically) in response to trauma , new experiences and learning
Outline a research conducted into brain plasticity
- Maguire et al
- studied the brain of london taxi drivers
- compared 16 male taxi drivers to 50 male (non drivers)
- found significantly more volume of grey matter in posterior hippocampus than in a matched control group
-this area in brain is associated with development of spatial and navigation skills in humans and animals
-“knowledge test” : recall of city streets&navigation : learning experience altered structure of taxi drivers brains
-longer the driver had been working : more pronounced the structural difference from control group (positive correlation)
Outline what is meant by “functional recovery”
- form of neural plasticity
-following a damage through trauma , it is the brains ability to transfer or redistribute functional working areas of the brain to damaged areas
-occurs quickly after trauma , slows down after months : would need rehabilitative therapy
Outline what happens in the brain during functional recovery
brain rewires and organises itself forming new synaptic connections close to area of damage
+ secondary neural pathways become activated to enable functioning to continue through structural changes in the brain:
axonal sprouting : growth of new nerve endings connecting with other undamaged nerve cells to produce new neuronal pathways
denervation supersensitivity: axons that do a similar job become aroused to a higher level to compensate for those that are damaged/lost . negative : oversensitivity :pain
requitment of homologous areas on opposite side of brain : specific tasks can still be performed (e.g broca damage : right equivilent take its place) temporarily
Outline a limitation of maguire et al’s study
- small sample : 16 participants of male taxi drivers
-not representivtive of wider population : cannot be generalised
-maguire conclusion may not be valid
-CP: no evidence to suggest that sample is unrepresentivtive
-but : sample consisted of only men and not woman (gender bias)
Outline a strength of plasticity and functional recovery (research)
P- there is research evidence to support plasticity of the brain
E- Jodi miller: all of left hemisphere removed in attempt to control epileptic seizures (hemispherectomy)
E- however through the mechanisms of neural plasticity , she was still able to control the right side of her body through the use of cerebral spinal fluid.
L- this demonstrates neuroplasticity - brain reorganised - discarding new neural pathways so that jodi could lead an effectively normal life - ** real life applications**
Outline a strength of plasticity and functional recovery (cognitive reserve)
P- level of education may increase rate of functional recovery (cognitive reserve)
E- cognitive reserve is the level of education an individual has attained and for how long.
research suggests that an increased cognitive reserve increases the likelihood of DFR ( disability free recovery) after trauma.
- Eric Schneider et al : 40% of those achievd DFR had more than 16 years of education compared to 10% who have had less than 10yrs
E- those who have been in edc longer may develop ability to form neural connections at a higher rate : higher levels of functinal recovery : positive plasticity
Evaluate strength of functional recovery (research real world)
- use of neurorehabilitation
-uses motor therapy and electrical stimulation of brain to counter negative effects and deficits in motor and cognitive functions following accidents injuries and/or strokes
-positive application of research in this area to improve cognitive functions of people suffering from injuries
what is the purpose of techniques for investigating the brain?
- medical purposes
-to identify and investigate localisation
Outline the function of fMRI scans?
- functional magnetic resonance imaging
- detects changes in oxygenated blood flow in the brain
-when brain area is active it consumes more oxygen - so increase blood flow indicates increase activity in that specific area of brain
-3D images produced
-assisting our understanding of localisation of function
strengths and weaknesses of fMRI
STRENGTHS
-3D image
-doesnt rely on radiation : safer
-high spatial resolution : abiility to locate function very accurately
-non-invasive
WEAKNESSES
-very expensive
-poor temporal resolution : actively has a delay , difficult to attribute activity to specific behaviour
Outline the function of EEG
- electroencephalogram
-measures the general electrical activity within the brain
-electrodes are fixed to a scull cap , recording activity represented as brain waves
-diagnostic tool for arrhythmic patterns of activity
USED FOR :
-investigating epilepsy , tumours sleep disorders
what are the strengths and weaknesses of EEG
STRENGTHS:
-helpful for diagnosis
-high temporal resolution (milliseconds oor less)
-non-invasive
WEAKNESSES:
-poor spatial resolution: not useful for pinpointing exact source of neural activity (so many neurons fire at once) thereforee difficult to attribute function to one specific area
Outline the function of ERps (and use)
- event related potentials
-uses EEGs and detects neural response to associated specific stimuli e.g high pitch sounds or facial expression
-original EEG recording adjusted to remove extraneous brain activity in order to isolate activity specific to event presentation
USED FOR:
- revealed information relating to cognitive processing e.g attention and perception
strength and weaknesses of ERps
STRENGTHS :
-helpful for measuring cognitive functions and cognitive deficits
-high temporal resolution
-non-invasive
WEAKNESSES:
-lacks standardisation: differences in methodology in ERP studies : difficult to confirm findings
-difficult to entirely remove extraneous variables
-can lack mudane realism/ecological validity
Outline post-mortem examinations
-analysis of brain after death
-are likely to have rare/specific condition
USED FOR :
compared to neurotypical brain
identifying areas damaged areas can create cause and effect relationship
strengths and weaknesses of post-mortem examinations
STRENGTHS
-vital in providing foundation knowledge regarding localisation of function
-identifying areas can create a cause and effect relationship
WEAKNESSES:
- causation issues - observed damage to brain may not be linked to defecits experienced in individual
-may lack informed consent
what are biological rhythms?
- cyclical patterns within biological systems that have evolved in response to environmental influences
they are governed by two things:
- endogenous pacemakers: bodys internal biological “clocks”
- exogenous zietgebers: external changes to the biological environment
what are the 3 types of biological rhythms?
-ciracadian rhythms: last for about 24hrs
-Ultradian rhythms: more than one cycle for 24 hours (shorter period and higher frequency than circadian rhythms)
-Infradian rhytms: less than one cycle in 24 hours ( last more than 24h)
Outline 2 examples of circadian rhythms
sleep-wake cycle:
- dictactes when to be awake/asleep
-dips and rises at different types in the day , circadian dips may be more intense when sleep deprived
e.g strongest sleep drive at 2-4am
-controlled by endogenous pacemaker: suprachiasmatic nucleus (SCN)
core body temperature:
- sleep occurs when core temp begins to drop and begins to rise during last hours of sleep ,promoting awareness feeling
Outline a study supporting circadian rhythms
- sleep-wake cycle
-conducted by Michael Siffre 1975 - isolated himself from all daylight by spending 2 months in the caves of southern Alps
-access to adequent food and drink & artificial light to help navigate
FINDINGS :
-internal biological clock was allowed to “free run” in the beginning of his experiment , erratic pattern
-Eventually settled into a sleep-wake cycle of aprox 25 hours , continuing to fall alseep and awake on a regular schedule
Evaluate a strength of Siffre’s study
-strength: supports the claim that humans have a circadian rhythm that lasts around 24h and is governed by endogeneous pacemakers
- siffre isolated from natural light: eventually settling down to 25h-30h body clock after erratic schedule
- strength of theory of endogenous pacemakers theory: suggests in the absense of exogenous zietgebers (e.g natural light sources) circadian rhythms are roughly maintained by internal body clock
-CP: articial lamp siffre took may have acted as a exogenous zeitgeber : results may not be as valid as originally suggested : limiting support of circadian rhythms
Outline another study into circadian rhythms
-
Aschoff and Wever
-55 participants were deprived of natural light whilst spending 4 weeks in an underground
bunker
-all individuals showed “free-running” circadian rhythms
-average periods of wakefullness and sleep ranged from 24h-50h
FINDINGS DEMONSTRATE:
although the free-running circadian rhythm is more than 24 hours long,
as a society we have specific exogenous zeitgebers which entrain the rhythm to
conform to a 24 hour cycle.
Evaluate a strength of research into circadian cycles (medical support)
P- used to improve medical treatments
E- circadian rhythms control vital bodily functions e.g heart rate , digestion&hormone levels
E- study of this rise and fall rhythm has lead to the field of chronotherapeutics , which is how medical treatment can be administered to respond to a persons rhythms
E- e.g aspirin -(reduces blood platelet activity) treatment for heart attacks is found to be best taken last thing at night as heart attacks usually happen in the morning (timing is important )
L- effective for drug treatment research
Evaluate a limitation of research into circadian rhythms (gsce grades)
P - individual differences betweeen circadian rhythms (Siffre and Aschoff and Wever on individual difference)
E - Circadian rhythms may not and do not always have to conform to cyclical 24 hour periods
E- For example , a medical professor at Oxford university found that delayed the starting time of a high school from 8am to later 10am.
-researchers found GSCE grades rose from 34% to 53% of scoring students gaining A*-C
L-this is a real-life example of how the circadian rhythms of teenagers specifically are not always in line with that of adults,
- appreciation of this can improve educational systems
Outline examples of infradian rhythms
mestural cycle
- duration of more than 24hrs , average of 28 days but can be betweeen 23-36 days
- when womb lining is shed to the day before her next period
-regulated by hormones such as oestrogen and progesterone , ovulation takes place roughly halfway through cycle
seasonal affective disorder
-a despressive disorder which has a seasonal pattern onset and is described and diagnosed as a mental disorder in the DSM-5
-symtomps are : presistant low mood alongside a general lack of activity and interest in events occuring in life
- can be caused by disruption to sleep-wake cycle : longer nights means more melatonin is secreted from the pitruity gland : changes to this hormone level leads to loneliness and depression
Outline a research conducted into the menstrual cycle
-Mcclintock and stern 1998
-29 woman with a history of irregular periods
-samples of pheromones were gathered from 9 woman at different stages of their menstrual cycle
-pad was worn for atleast 8 hours
-given new pads everyday to supply the samples of pheromones
FINDINGS:
- 68% of woman experienced changes to their cycle which brought them closer to the cycle of their “odour donor”
Evaluate a limitation of research conducted into mensural cycles (methological)
P- methodological issues
E- there are many factors affecting menstural cycles including stress,diet and excercise
E- may act as confounding variables : theerefore patterns observed by McClintock and Stern may be by change (etc)
E- conclusions drawn (explain the conclusion) may be invalid
- Therefore, this raises doubts aboutthe strength of the influence of pheromones, as an exogenous zeitgeber which can entrain infradian
rhythms.
Evaluate one advantage of research into SAD
P - has practical applications
E-most effectve treatment for SAD is phototherapy
E-this is a lightbox : stimulates very strong light in the morning and evening
-is thought to reset melatonin levels in people with SAD and relieve symptoms in up to 60% f sufferers as found by Eastman et al (1998)
L- is found to be more affective than CBT in some cases , therefore suggests in its apparent sucess that infradian rhythms are indeed affected by exogenous zeitgebers
Outline an example of ultradan rhythms
SLEEP CYCLES
- monitored brain activity by ECG
Stage 1&2
- light sleep: individual can easily be woken up
-alpha waves: brain patterns start to slow down
stage 3&4
-deep sleep: known as dead sleep or slow wave sleep
-delta waves: brain waves are slower than stage 1&2
-difficult to wake someone up at this point
stage 5
-REM sleep : rapid eye movement to denote for the fast jerky activity under the eyelids
-body paralysed but brain activity speeds up as if awake
Outline research support for ultradian rhythms (sleep cycle)
dement and kleitman 1957
- 9 participants 7M 2F
-caffiene and alcohol intake was controlled
- asked to report to labratory for bed time connected to EEG to monitor brain activity
FINDINGS:
-All participants experienced stage 5 (REM) activity every night
-high incidences of dream ree
call when particpants were awakened during REM periods of sleep
: dreaming was associated wit REM
-if awakened during other stages: low amounts of dreams were reported
Evaluate one disadvantage of ultradian rhythms (biological)
P- evdence to suggest that sleep patterns may be biologically determined
E- tucker et al discovered large differeence in sleeping patterns between individuals - was discovered in lab expermeent which consisted over 11 nights
E- sleep patterns may be particularly determned by genes
CP- limiited - extraneous variables: undergone labratory setting : indviduals sleep patterns may have differed in a different setting e.g lab and home bed :lacks ecological validity
Outline function and role of suprachiasmatric nucleus (SCN) in the sleep-wake cycle
- one of primary endogenus pacemakers in mammalian animals and is influential maintaining circadian rhythms (e.g sleep-wake cycle)
-bundle of nerve cells located in the hypothalamus in each hemisphere of the brain
- receives information about day light and
day length from the eyes,
processed by the visual area in the occipital lobe
- relayed to the SCN via the optic chiasm
(from one hemisphere to the other).
-SCN processing this information leads to different rates of release of melatonin from the pineal gland
night time - pineal gland releases production of melatonin : chemical that induces sleep and is inhibited during long periods of wakefulness
-day time : less melatonin : more serotonin
Outline research evidence for the SCN in the sleep-wake cycle (animal studies)
DeCoursey et al (2000)
-surgically lesioned the SCNS of 30 chipmunks and compared their circularity rhythms in their natural habitat with 17 controls
-found: vast majority of experimental group had been killed within the first 80 days after being returned to their habitat due to predation
Ralph et al
Ralph et al extracted SCN cells from hamsters which showed abnormal sleep-wake cycles, and inserted these cells into healthy hamster foetuses.
- found: cycle of second group defaulted for 20h instead of normal 24h
- basic period of the overt circadian rhythm therefore is determined by cells of the suprachiasmatic region
what are the roles of exogenous zeitgebers and the sleep/wake cycle
LIGHT
- demonstrated by Siffre et al
- can reset bodys main enodgenous pacemaker (SCN)
-indirect influence of key processes on the body that control functions such as hormone secretion and blood circulation
SOCIAL CUES
-These include set meal times and bed times, which signify when to wake up and when to fall asleep
-This meansthat in order to avoid jet lag, it is useful to accustom yourself to the set sleeping and eating times of your destination, to avoid desynchronisation of an already ‘pre-set’ circadian rhythm
Outline a study which supports the role of exogenous zietgebers on the sleep/wake cycle
Campbell and Murphy 1988
-Light as a key zietgeber in human body
- produced deviations of 3 hours in the participant’s sleep-wake cycle by shining light onto pads on the back of Their knees
- showing that light does not always need to be detected by the eyes in order to entrain
biological rhythms
Evaluate limitation of endogenous pacemakers. (isolation)
P - effect of endogenous pacemakers cannot be studied in isolation : decreased validity
E - total isolation studied (e.g Michael Siffre) are extremely rare - in addition to the fact that artificial light could have reset his biological clock
**E* pacemakers and zeitgebers interact in everyday life
L therefore it makes little sense to seperate the two for the purpose of research
-isolating lowers validity
Evaluate limitation of endogenous pacemakers. (ethics )
-Ethical issues associating with harming of animals
e.g - DeCoursey et al : breaching the BPS
ethical guideline of protection from psychological and physical harm
-cost benefit analysis REQUIRED
-secondly , generalising findings from animal studies to humans, particularly due to differences in physiology and
the number/types of circadian rhythms, thus limiting the ecological validity of such findings
CP: animal studies of sleep-wake cycles may be justified because similar mechanisms across species
limitaton of exogenous zietgebers
**Miles et al **
- cases of exogenous zeitgebers and endogenous pacemakers have failed to alter circadian rhythms
-man had a sleep-wake cycle of 24.9 hours that couldnt be changed by sedatives or stimulants
-suggests influnce of exogenous and endogenous factors may be overstimulated
Outline function of sensory neuron
-connects external and environment to internal NS
-processes information from 5 senses
- info from brain to spinal cord (PNS TO CNS)
- attached to receptor cells which provide info from environment
outline function of relay neuron
-recieves info from sensory neurons
-found in brain and spinal cord (cns only)
-pass messages on
outline function of motor neuron
- recieves messages from relay neurons and pass to organs and muscles
-messages sent from CNS to PNS to effectors
-info from brain to muscles -makes motions and actions happen
