biopsychology Flashcards
(16 cards)
NERVOUS & ENDOCRINE SYSTEM
Ao1
**NERVOUS SYSTEM **
to collect/process/respond to information from environment & coordinate organs and cells
Central nervous system (CNS)
brain& spinal cord
* cerebral cortex allows higher functioning
* spinal cord allows info between brain & body; responsible for simple reflex actions/arcs
Peripheral nervous system (PNS)
Somatic nervous system
* controls voluntary movement & external environment, causes movement
* sensory receptors (to brain) and motor pathways
Autonomous nervous system:
controls involuntary body responses & internal environment
Sympathetic nervous system:
* responses to percieved threats, fight or flight
Parasympathetic nervou system:
* homeostasis, rest and digest function
ENDOCRINE SYSTEM
- works w/ nervous system to maintain homeostasis, peripheral NS collects info and sends signal to CNS for anything abnormal
- signal sent to endocrine glands to release hormones into bloodstrem. slower than nervous system but wider and more powerful effects
Main endocrine glands:
- PITUITARY (main): 6 hormones, FSH LH TSH ACTH GH PRL
- OVARIES, TESTES, THYROID, PANCREAS, ADRENAL
THE STRESS RESPONSE
- physical & psychological response to as stressor. adaptive as aids survival.
- hypothalamus triggers sympatheic nervous system & immediate f or f response dealt with by SAM system (sympatho adrenal medullary), releases adrenaline
-shuts down unnecessary functions, stimulates heart rate etc. parasympathetic restores once danger passes
NEURONS & SYNAPTIC TRANSMISSION
Ao1
STRUCTURE OF A NEURON
- Dendrite (recieves electrical impulses, makes it positively charged)
- Nucleus
- axon (transmits action potentials)
- nodes of ranvier (gaps allow jumping)
- myelin sheath (insulate nerve fibres)
- axon terminal (electrical signal triggers neurotransmitter release)
TYPE OF NEURON
- Motor neuron: nucleus in dendrites
-Relay neuron: nucleus in axon
-Sensory neuron: nucleus sticking out
SYNAPTIC TRANSMISSION
1. action potential travels down axon and reaches terminal on pre-synaptic neuron
2. triggers neurotransmitters to move to the membrane of neuron & be released into synaptic cleft
3. cross the cleft and bind to receptors on post synaptic neuron, triggering electric signal
4. neurotransmitters left in synapse are reabsorbed/broken down and vesticles are refilled
EXCITATION VS INHIBITION & SUMMATION
- excitory neurotransmitter messages make it more likely that post synaptic neuron wilkl fire (e.g. adrenaline)
- inhibitory neurotransmitters make it less likely (increase negative charge) e.g. serotonin
- neuron integrates excitory/inhibitory inputs and results in all or nothing effect, wether it will fire or not.
BIOLOGICAL RHYTHMS
Ao1
patterns of changes in body activity in cyclical time periods. governed by exogenous zeitgebers/endogenous pacemakers
CIRCADIAN
- occur once every 24 hours, e.g. sleep wake cycle
- affected by sunlight and internal body clock (SCN), lies above optic chasm
Siffre cave study
- many periods of time living in caves in dark.
- 2 months in Alps, 6 months in Texas
- each time found his sleep/wake cycle defaulted back to 24-25 hours on a regular schedule. supports internal body clock
Folkard study
- pps lived in a cave for 3 weeks, went to bed and woke up at regular times by alarm clock.
- clock gradually sped up to 24 hours became 22
- natural biological rhythms were unable to adjustm, supports internal
core body temp cycle
varies by about 2 degreees C during day, lowest at 4am and highest at 6am. Folkard children who read stories 3pm = superior recall to at 9am.
INFRADIAN
takes longer, occurs less than once every 24 hours. for example menstrual cycle and SAD.
Menstrual cycle
- about 28 days, considerable variation
- rising oestrogen cause ovulation. progesterone thickens womb lining.
- no pregnancy = womb lining comes away.
McClintock
- wanted to test exogenous factors (other women’s hormones)
- 29 irregular period women, 9 gave pheromone samples
- pads rubbed against other pps each day
- found 68% experienced changes to cycle (closer)
Seasonal Affective disorder
-could also be ‘circannnual’.
-variation of mood, experience depression in the winter as daylight hours are shorter
-could be related to melanin production having knock on effect of reduced serotonin
ULTRADIAN
more than one cycle every 24 hours
Stages of sleep
- 5 distinct stages over roughly 90 mins
1. Light sleep , alpha waves, easily woken, muscles relax/twitch
2. also light & alpha waves or random changes to theta waves (sleep spindles). breathing, heart rate, temp fall
3&4. deep sleep, delta waves, all activity slows, difficult to wake
5. REM/dream sleep. body paralysed, brain active. theta waves
BIOLOGICAL RHYTHMS
Ao3
CIRCADIAN
STRENGTHS
- chronotheraputics - best time of day to deliver medicine, due to changes in body processes thoughout day. E.g. asprin late at night more effective for treating heart attacks than day
- understanding adverse effects of night shift work - experience reduced concentration around 6am, could cause accidents/mistakes (Boivin). Shift workers 3x more likely to develop heart disease due to disruptions
LIMITATIONS
- studies involves small numbers of pps, might not be representative. Schiffre body clock slowed with age, showing role of other factors
- individual differences - Czeisler found body clocks between 13-65 hours. Larks vs owls, and age factors. Averages may be meaningless.
ULTRADIAN
STRENGTHS
- led to phototherapy = one of most effective SAD treatments, strong lightbox in morning and evening thought to reset melatonin levels. Found improvement in 60% sufferers (Eastman).
- adaptive strategy of sycnchronised menstrual cycles, become pregnant as social group
LIMITATIONS
- Trevathan found no evidence of menstrual synchronisation. Many other factors affecting e.g. health, excersise, diet, stress.
-Tucker study found large differences in duration of sleep stages particularly 3&4. difficult to describe normal sleep in a meaningful way
EXOGENOUS ZEITGEBERS / ENDOGENOUS PACEMAKERS
Ao1
end. p.makers - internal mechanisms that govern biological rhythms
suprachiasmatic nucleus
primary endogenous pacemaker in mammals
- nerve cells located in hypothalamus above optic chiasm
-recieves information about light, passes on to the pineal gland
- influences production of melatonin, chemical which induces sleep
Animal studies
Decoursey chipmunks
-destriyed SCN connections in chipmunks, returned to natural habitat and observed for 80 days
-sleepwake cycle had disappeared, many had been killed by predators, awake and vulnerable to attack at wrong times
Ralph hampsters
-bred mutant hampsters with 20 hour sleep wake cycle
-transplanted their SCN cells into normal hampsters
-their cycles defaulted to 20 hours
ex. z.gebers - environmental factors that influence biologicl rhythms
work trough entrainment - adjustment of body clocks in line with environment, become synchronised
- light is a key EZ, resets SCN.
Cambell & Murphy
-tested wether light could be detected by skin receptor sites on body, even when not recieved by eyes
-15pps woken at various times, light pads shone on backs of knees
-managed to produce deviation on s/w cycle of up to 3 hours
social cues
-babies adapt to parents sleep cycle in about 6 weeks
ENDOGENOUS PACEMAKERS / EXOGENOUS ZEITGEBERS
Ao3
- total isolation cave studies very rare. IRL ex/en interact to set biological rhythms. makes little sense to separate them for research - could lower ecological validity
-generalising animal studies to humans, plus harm to chipmunks
-experience of people who experience different sunlight patterns to normal reduce effect of ex. zeitgebers - e.g. Arctic circle. have similar sleep patterns all year round
-peripheral oscillators - numerous circadian rhythms that operate in cells/organs of the body. Damiola showed feeding patterns could change liver rhythms by 12 hours, despite SCN. more complicated factors.
LOCALISATION OF FUNCTION
Ao1
-previous to 19th century holistic view of brain, then localisation. argued for by Brocca & Wernicke
Two hemispheres
-activity contralaterally wired
-cerebral cortex covers most of brain, much more developed in humans
Parts of brain
-frontal lobe (logic, planning, decisions, problems)
-parietal lobe (orientation, recognition, sensory info)
-temporal lobe (auditory info, speech analysis)
-occipital lobe (visual processing, back area visual cortex - eye info recieved)
-motor area (voluntary, fine motor movements)
-somatosensory (sensory info represented)
Brocca’s & Wernicke’s area
-Brocca’s area in left frontal lobe
-Brocca’s asphasia = can’t produce speech
-Wernicke’s area in left temporal lobe
-causes issues with speech comprehension
LOCALISATION OF FUNCTION
AO3
STRENGTHS
-Phinneas Gage - trauma to frontal lobe, changed personality and emotions. didn’t affect movement, speech, vision etc.
-Petersen brain scans - showed Brocca/Wernicke areas light up during reading/listening. modern scientific/objective evidence
LIMITATIONS
- Lashley’s rats - removed 10-50% of rats brains and taught maze. found no difference for specific area, learning too complex to be localised
-plasticity shows when area of brain damaged rest appears to reorganise to recover lost function. location not relevant
HEMISPHERIC LATERALISATION
AO1
idea that two halves of brain are functionally different.
Left and right hemisphere
- language localised to left (Brocca & Wernicke’s area)
- movement - not lateralised in general, but contralaterally wired.
- vision - not lateralised generally, contralaterally and ipsilaterally wired. all info from RVF goes to left hemisphere and vice versa.
Sperry
-study on 11 commissurotomy patients, had ‘separate’ brains, extent to which sides are specialised
- images / words projected to only one of the visual fields. pps focused on central cross
- when displayed to RVF could easily describe (left hem. responsible for language)
- when displayed to LVF couldn’t describe it, but could draw it or select with left hand
-tells us left hem. is verbal , right non verbal
-right processes emotions - racy images giggled, showing emotional response
HEMISPHERIC LATERALISATION
Ao1
STRENGTHS
- Fink PET scans during visual tasks. whole picture (holistically) right hemisphere, individual details (analysing) left hemisphere.
-Rogers found split brain chickens had better survival adaptations e.g. could find food & look for predators. adpative advantage
-Sperry study was highly scientific and standardised. Fixation point improved validity & lateralised pps.
LIMITATIONS
- lack of generalisability. only 11 and all had commissurotomies & epilepsy which could have caused further damage.
PLASTICITY & FUNCTIONAL RECOVERY
Ao1
plasticity = brain’s ability to adapt and change as a result of new learning.
growth spurt during infancy as well as synaptic pruning.
functional recovery = form of plasticity where brain can repair or redistribute functions to other areas
Maguire
-studied brains of taxi drivers who took ‘the knowledge’.
-used MRI scans and found significantly more grey matter in posterior hippocampus (spatial & navigational skills).
-more pronounced the longer they had the job.
processes in functional recovery
Never Sell A Dirty Rug
1. New synaptic connections made close to damage area
2. secondary neural pathways activated/unmasked to create similar functioning
3. axonal sprouting - grows new nerve endings which connect
4. denervation super sensitivity - remaining nerves become more sensitive to compensate
5. recruitment of homologous areas - similar opposite areas perform similar tasks
Jody
- showed functional recovery after trauma. due to epilepsy entire right hemisphere was removed
- within 10 days could walk, slight paralysis in left side but improved significantly over time.
-left side developed and adapted to take over role.
FUNCTIONAL RECOVERY
Ao3
STRENGTHS
-practical application - has led to development of neurorehabilitation. e.g. constraint induced movement therapy for stroke patients, limb strapped down
- Bezzola golf study, pps aged 40-60. 40 hours of golf training, found increased motor cortex activity. shows not limited to young brains
-Hubel & Wiesel sewed kittens’ eyes shut. Inactive part of brain refocused & processed info from other eye
LIMITATIONS
- correlation vs causation of the knowledge.
- phantom limb syndrome - 60-80% of amputees suffer, due to reorganisation of somatosensory area.
Studying brain - fMRIs
Ao1:
-functional magnetic resonance imaging
- uses magnets to determine haemoglobin (blood flow) to different areas.
- increased demand for oxygen whilst completing certain tasks in certain areas
- able to produce maps of areas used in certain functions
Ao3:
STRENGTHS
- doesn’t rely on radioactive tracer, risk free & non invasive
- produces high resolution images, accurate to the mm. clear images of localised functions
LIMITATIONS
- expensive machines, specially trained experts to operate
- temporal resolution - indirect measure, studying blood flow not firing - 5 second delay
ways of studying the brain - EEG
Ao1:
electroencephalogram
- measures electrical activity in brain through electrodes placed on scalp
- can be used to detect types of brain disorder (e.g. Alzheimers / epilepsy)
- diagnostic tool to recognise abnormalities
Ao3:
STRENGTHS
- useful/practical for making diagnoses, RWA
- high temporal resolution (can detect firing in milliseconds)
LIMITATIONS
- general measure of groups of neurons/areas. not specific locations
- doesn’t allow differentiation between different but adjacent areas
ways of studying brain - ERPs
Ao1
event related potentials
- EEGs too crude / general in raw form, way of isolating responses using statistical averaging, extraneous activity filtered out
- brainwaves left that are triggered by certain events. how these are linked to perception/cognition
Ao3:
STRENGTHS
- more specific than raw EEG
- excellent temporal resolution
LIMITATIONS
- differing procedures adopted by different institutions, not standardised
- all extraneous variables must be eliminated for it to work
ways to study the brain - post mortems
Ao1
- used to establish underlying neurobiology of brain / particular behaviour
- when someone displays interesting behaviour whilst alive, can later study brain abnormalities
- e.g. Brocca
Ao3
STRENGTH
-improve medical knowledge, vital in early days of psyschology before technology
LIMITATION
- doesn’t allow for study of functional activity
