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56 Cards in this Set
- Front
- Back
What is localisation of function? |
- different areas of the brain responsible for different behaviours/processes/activities |
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What is the lateralisation of function in the brain? |
- physical/psychological functions mainly by one hemisphere - left side controlled by right hemisphere - right side controlled by left hemisphere |
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What is the cerebral cortex? |
- outer layer of both hemispheres |
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What are the four lobes of each hemisphere? |
-Occipital – vision - Parietal – higher senses and language functions -Frontal – reasoning, problem solving, judgement and creativity - Temporal – perception, hearing , memory and meaning. |
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What is the motor area? |
- back of frontal lobes - voluntary movement in opposite side of body - damage=lose control of fine movement |
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What is the somatosensory area? |
- front of parietal lobes - where sensory info from skin is represented - more area devoted=more sensitivity |
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What is the central sulcus? |
- the valley which separates the motor and somatosensory areas |
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What is the visual area? |
- in occipital lobes at back of brain - info from right visual field to left visual cortex - damage to left hemisphere=blindless in right visual field of both eyes |
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What is the auditory area? |
- in temporal lobes - analyse speech info - damage=hearing loss - damage to specific area=affect ability to comprehend language |
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What did Broca find about the localisation of language? |
- identified small area of left frontal lobe=speech production - damage=slow, laborious, lack frequency - Broca's area |
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What did Wernicke find about Wernicke's area? |
- area in left temporal lobe=language comprehension - patients difficulty understanding language, not producing - damage=produce nonsense words in speech |
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Evaluate localisation of function in the brain |
Strengths BRAIN SCAN EVIDENCE -Peterson Wernicke's area active in listening; Broca's active in reading=diff. functions - highly objective methods=scientific NEUROSURGICAL EVIDENCE Dougherty- remove parts of brain to control behaviour -44 OCD patient who had undergone cingulotomy - 32 weeks=1/3 success - demonstrates symptoms and behaviours associated with serious mental disorders are localised CASE STUDY Phineas Gage -pole through face/frontal lobe destroyed/personality change (calm to rude) - frontal lobe may control mood=support localisation Weaknesses PLASTICITY -brain damaged=rest of brain compensates for action - stroke victims recover lost abilities - more than one area control same function |
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What is brain plasticity? |
The brain’s tendency to change and adapt (functionally and physically) as a result of experience and new learning. |
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What is functional recovery ? |
A form of plasticity, the brain’s ability to redistribute or transfer functions: following damage through trauma. |
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What is synaptic pruning? |
As we age, rarely used connections are deleted and frequently used connections are strengthened. |
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What is the research into brain plasticity? |
Maguire et al - London taxi drivers had more grey matter in posterior hippocampus than matched control - longer in job=more defined structure difference |
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How does the brain functionally recover after trauma? |
- injury/trauma=unaffected areas adapt for damaged (functional recovery) - happens quickly after trauma (spontaneous recovery) - slows down after weeks or months =rehab therapy needed |
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What structural changes occur during functional recovery ? |
- Axonal sprouting: nerve endings grow/ connect=new pathways - Reformation of blood vessels - Recruitment of homologous areas- Regions on opposite sides of the brain take on functions of damaged areas. |
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Evaluate plasticity and functional recovery on the brain after trauma |
Strengths Practical application - contributes to neurorehabilitation - physical therapy after spontaneous recovery - brain can't fully heal alone Animal Studies - Hubel/Wiesel - sew one kitten eye shut -analyse brain response=visual cortex area of closed eye not idle -continued to process info from open eye Age and plasticity -Bezzola - functional plasticity reduces with age - showed 40 hours of golf training produced neural representation of movement in ppts aged 40-60 -using fMRI researchers observed reduced motor cortex activity in the novice golfers compared to a control group suggesting more efficient neural representation after training - neural plasticity continues throughout life span Weaknesses Negative plasticity - behavioural consequences e.g long drug use=cognitive function down - risk of dementia up - 60-80% amputees=phantom limb syndrome=unpleasant |
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What is hemispheric lateralisation? |
- two hemispheres are functionally different - specific processes/behaviours controlled by one hemisphere |
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What is split brain research? |
- 1960s onwards studies of epileptic patients with hemispheres surgically separated - investigate extent to which brain function is lateralised |
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What was Sperry's split brain study into hemispheric lateralisation? |
- epileptic group had corpus callosum cut to separate hemispheres=control seizures - see if hemispheres performed tasks independently |
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What was the procedure of Sperry's split brain research? |
- image/word shown in right visual field (left hemisphere) vice versa - normal brain=corpus callosume share info between hemispheres=complete picture - split brain patient=info not shared |
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What were Sperry's key findings |
What you see? - picture shown to right visual field, could describe - left visual field, nothing there - right hemisphere lacks language centres Recognition by touch - object shown in left visual field;could match object from grab bag behind screen using left hand - right hemisphere - selected closely related object Composite words - two words same time each visual field - write with left hand word in left visual field - right hem- visual - say the word in the right visual field as left hemisphere linked with language/speech Matching faces - right hemisphere dominant - shown face to each visual field; asked to match from series of faces, left visual field chosen and right hemisphere ignored the faces - composite picture, left hemisphere described, right matched |
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Evaluate split-brain research |
Strengths
Methodology strengths - highly standardised procedures - one eye blindfolded;image 1/10th sec=no time to spread info to both visual fields - well controlled procedure Demonstrated brain lateralisation - left hemisphere=analytic/verbal tasks - right hemisphere=spatial/music tasks/emotion to language - left=analyser;right=synthesiser Weaknesses Cant Generalise - unusual/small sample, all had epileptic seizure history - influence findings;some more disconnection than others Difference in function overstated - labelling hemispheres=oversimplifying=less clear cut - normal brain=constant communication performing everyday tasks - many behaviours of one hemisphere done by other |
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What is functional magnetic resonance imaging (fMRI)? |
-Measures brain activity in specific areas by detecting associated changes in blood flow - detect radio waves from changing magnetic fields - 3D images/helps understanding of localisation of function |
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What are strengths and weaknesses of fMRIs |
Strengths - doesn't rely on radiation=virtually risk-free - non-invasive - high resolution Weaknesses - expensive compared to other techniques - poor temporal resolution - only measures blood flow not neurone activity |
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What is electroencephalogram (EEG)? |
- measure electrical activity in the brain via electrodes - A record of the brain wave patterns produced by millions of neurons, -producing characteristic patterns. |
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What are strengths and weaknesses of EEGs? |
Strengths - diagnose brain conditions - contributed to understanding of sleep stages - high temporal resolution Weaknesses - information too general - can't pinpoint source of neural activity - can't distinguish activities in different adjacent locations |
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What are event-related potentials (ERPs)? |
- The brains electrophysiological response to a specific sensory, cognitive or motor event can be isolated through statistical analysis of EEG data |
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What are strengths and weaknesses of ERPs? |
Strengths - more specific measure of neural processes - excellent temporal resolution compared to other techniques - used to measure cognitive functions/deficits Weaknesses - methodology lacks standardisation=difficult to confirm finding - pure data=background noise/extraneous material eliminated=not always achieved |
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What are post-mortem examinations ? |
-Correlating behaviours before death with brain structures after death. -brains that are left after post-modern usually have some sort of disorder |
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What are strengths and weakness of post-mortem examinations ? |
Strengths - foundation of understanding key brain processes - used by Broca/Wernicke - improve medical knowledge=generate hypotheses Weaknesses - causation issues=damage from unrelated trauma - ethical issues (consent of patients) |
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What are biological rhythms? |
Distinct patterns of changes in biological activity that conform to cyclical time periods |
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What are the two factors which control biological rhythms? |
- endogenous pacemakers (internal clocks) - exogenous zeitgebers (external changes) |
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What are circadian rhythms ? |
- biological rhythm last for around 24 hours - regulates body processes e.g. sleep/wake cycle and core body temperature |
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What else controls our sleep/wake cycle? |
- light=important exogenous zeitgeber - makes us drowsy at night and alert in the morning |
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What was Siffre's cave study on circadian rhythms ? |
- spent extended time underground= to study effects on biological rhythms - deprived of natural light/sound - 2 months in Southern Alps, resurfaced in September 1962;thought it was mid-August - endogenous pacemaker slowed to 25 hours cycle |
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What was Aschoff and Wever's research into circadian rhythms? |
- participants 4 weeks in WWII bunker=no sunlight - all but one showed 24-25 hour circadian rhythm- natural cycle longer;entrained by exogenous zeitgebers |
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Evaluate circadian rhythms |
Strengths Practical Application- Shift Work - understanding consequences of disrupting circadian rhythm - night workers=down concentration at 6am= mistakes - shift workers 3x likely develop heart disease= adjust sleep/wake cycle - implications=manage worker productivity Practical app- Drug treatments - circadian rhythms co-ordinate heart rate, digestion and hormone levels - effects action of drugs on body;peak times when most effective - guidelines on timing for some meds Weaknesses Poor control - Siffre still had access to artificial light (lamp)= assumed no effect -Czeisher: Adjust circadian rhythms 22 to 28 hrs using dim light - artificial light affected Siffre's findings Individual differences - sleep/wake cycle can vary in people from 13 to 65 hours -Duffy: some prefer early rise vs some prefer opposite - age differences in sleep/wake patterns |
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What is an infradian rhythm? |
Frequency of less than one cycle in 24 hours, such as menstruation and seasonal affective disorder |
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What is the menstrual cycle? What occurs during the cycle? |
- typical cycle lasts about 28 days - oestrogen levels up=release egg;progesterone thickens womb lining - no pregnancy=egg absorbed - womb lining leaves body |
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What was McClintock's research into the menstrual cycle? |
- 29 women irregular periods - pheromones from 9 women at different stages on cotton pad (8 hrs) - rubbed on upper lip of 20 women - 68% women cycles changed to match 'odour donor' |
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What is seasonal affective disorder? What are the possible causes? |
- Depression associated with seasonal changes, usually the onset of winter and decreased darkness. - symptoms triggered in winter months=daylight hours shorter - hypothesised melatonin implicated - night=pineal gland secretes melatonin until dawn (light up) - lack of light=longer secretion=effect serotonin production |
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What is an ultradian rhythm? |
Frequency of more than one cycle in 24 hours, such as the stages of sleep. |
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Describe the stages of sleep |
Stage 1 and 2 - light sleep=easily woken - beginning of sleep, brainwaves slower/rhythmic (alpha waves), then slower (theta waves) as sleep gets deeper Stage 3 and 4 - delta waves=slower/greater amplitude - deep sleep/slow wave sleep=difficult to wake someone Stage 5 (REM sleep) - body paralysed - brain activity speeds=awake brain - REM=rapid eye movement - REM activity highly correlated to dreaming |
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Evaluate the ultradian and infradian rhythms |
Strengths Evolutionary bass of menstrual cycle - past=advantageous to menstruate together=pregnant together=newborns raised in group=increase survival Evidence supporting stages of sleep - Dement/Kleitman: 9 adult sleep patterns in lab;EEG;control effects for caffiene/alcohol -REM highly correlated to dreaming; -brain activity varied according to how vivid dreams were - replicated;small sample size Weaknesses Methodological limitations in syncronisation studies - confounding variables e.g. stress/diet/exercise not controlled - patterns in synchronisation may due to chance - small samples;self report Animal studies - knowledge of pheromone effect on behaviour derived from animal studies - evidence for effect in human behaviour speculative/inconclusive - can't fully generalise animal study findings |
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What are endogenous pacemakers? |
Internal body clocks that regulate many of our biological rhythms. |
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What is the suprachiasmatic nucleus (SCN)? |
- nerve bundle in hypothalamus - primary endogenous pacemaker of mammal - maintains circadian rhythm e.g. sleep/wake cycle - nerve fibres connected to eye cross optic chiasm to visual area of cerebral cortex - SCN above optic chiasm=receives light info; continues when eyes closed |
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What was Decoursey's animal study into the SCN? |
- destroyed SCN in 30 chipmunks - returned to natural habitat/observed for 80 days - significant portion killed (awake when should've been asleep) |
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How are the pinal gland and melatonin affected by the SCN? |
- SCN passes info on light to pineal gland - night=increases melatonin production (induces sleep) |
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What are exogenous zeitgebers? |
external cues which affect biological rhythms e.g. light on sleep/wake cycle |
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How does light work as an exogenous zeitgeber? |
- resets SCN=maintain sleep/wake cycle - indirect influence on hormone secretion/blood circulation |
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What was Campbell and Murphy's research into light as an exogenous zeitgeber? |
- light detected by skin receptors when not received by eye - 15 participants woken diff. times - light shone on back of knee - deviated sleep/wake cycle up to 3 hrs- don't necessarily rely on eyes to influence the brain |
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How do social cues act as an exogenous zeitgeber? |
- 6 weeks=circadian rhythm;16 weeks=most babies entrained - influenced by parents schedules (mealtimes/bedtimes) - adapting to local time for eating/sleeping=beat jetlag |
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Evaluate endogenous pacemakers and exogenous Zeitgebers |
Strengths Beyond the master clock - many circadian rhythms in organs/cells (peripheral oscillators) - highly influenced by SCN, act independently -Damiola: change mice feed pattern alter liver cell circadian rhythm by 12 hours/SCN unaffected - other complex influences on sleep/wake cycle Weaknesses Ethical issues - cannot generalise findings from animal studies to humans - animals exposed to harm/risk when returned to natural habitat Methodological issues - Campbell and Murphy study not replicated - limited light exposure to eyes=major confounding variable - isolating light doesn't give insight to other zeitgebers influence Influence on EZ overstated - Miles: young man blind from birth;circadian rhythm 24.9 hrs;despite social cues, sleep/wake cycle not adjusted - occasions EZ little effect on internal rhythm Concusion Interactionist approach - free-running endogenous pacemakers exceptional circumstances - total isolation extremely rare=lack validity - pacemakers/zeitgebers interact |