BIOPSYCHOLOGY Flashcards
(23 cards)
THE NERVOUS SYSTEM AO1
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LOCALISATION OF FUNCTION AO1
- Holistic theory (all parts of the brain involved in processing thought and action) replaced by localisation theory (specific areas perform specific tasks)
- Lateralisation = Some functions are performed by specific hemispheres. E.g. the left side of the body is controlled by the right hemisphere and vice versa.
- Outer layer is the cerebral cortex, approx. 3mm thick, highly developed.
- Cerebral cortex is divided into 4 areas.
- MOTOR AREA = At the back of the frontal lobe (both hemispheres). Controls voluntary movement, damage may impact control of fine motor movements.
- SOMATOSENSORY AREA = At the front of the parietal lobes. Processes sensory information from the skin (i.e. touch, heat, pressure.
- VISUAL AREA = In the occipital lobe at the back of the brain. Left visual field goes to the right visual cortex and vice versa.
- AUDITORY AREA = In the temporal lobe. Analyses speech-based information, damage may produce partial to full hearing loss.
BROCA’S AREA = Speech production, located in the left frontal lobe. Damage causes Broca’s Aphasia which is characterised by slow, laborious speech that lacks in fluency.
WERNICKE’S AREA = Speech comprehension, located in the left temporal lobe. Damage causes Wernicke’s Aphasia, where they produce language but struggle to understand it, so they produce fluent but meaningless speech. They often produce nonsense words within the content of their speech.
LOCALISATION OF FUNCTION AO3
✔ = Support from neurosurgery - e.g. removal of the cingulate gyrus can be used to treat OCD, dysfunction of this area can be a cause of OCD. Dougherty et al - studied 44 people who had this treatment, 30% successful response and 14% partial response
✔ = Brain scan evidence - Petersen et al used brain scans to show activity in Wernicke’s area during listening task and activity in Broca’s during reading
✘ = Lashley removed areas up to 50% of brains in rats learning routes through a maze. Learning required all of the cortex instead of being confined to one area. Suggests higher cognitive processes, i.e. learning, are distributed in a more holistic way
✘ = Few researches still believe language is localised to Wernicke and Broca’s area, with fMRI being used to identify regions in the right hemisphere
FIGHT OR FLIGHT A01
- Involves the endocrine system and the autonomic nervous system working in parallel
- Stressor perceived by the hypothalamus which activates the pituitary gland.
- Sympathetic nervous system aroused
- Adrenaline (the stress hormone) is released from the adrenal medulla. Delivers the aroused state, i.e. increased heart rate, dilation of pupils.
- Parasympathetic nervous system takes over once the threat has passed. Returns the body to its resting state.
HEMISPHERIC LATERALISATION AO1
- The brain is ‘lateralised’, having two sides
- Some functions are localised, appearing in both left and right hemispheres (auditory, visual, motor)
- Some functions are lateralised to specific areas (Broca’s, Wernicke’s)
- Contralateral = in the motor area, the right controls the left and the left controls the right
- Ipsalateral - The left visual field of both eyes is connected to the RH, and the right visual field is connected to the LH
HEMISPHERIC LATERALISATION AO3
✔ = Evidence of lateralisation - Attention shown to global elements shows activity in the RH, while attention to finer details shows higher in the LH
✘ = Suggestion of analyser vs synthesizer brain is wrong - Nielsen found that people do use certain sections for certain tasks but there’s no dominance
SPLIT-BRAIN RESEARCH AO1
- Two hemispheres are surgically separated, i.e. by cutting the Corpus Callosum. Used to treat epilepsy
- Object presented to RVF = Participant can describe (language centres in LH)
- Object presented to LVF = Cannot name object (no language centres in RH), can select object closely associated with it. Pinup picture shown, participants laughed but reported seeing nothing.
- Shows that LH is verbal but RH is ‘silent’ but emotional
SPLIT-BRAIN RESEARCH AO3
✔ = Luck et al (1989) showed split-brain participants are better than controls at e.g. identifying the odd one out in similar objects. Supports left brain/right brain as LH is ‘watered down’ in normal brains by RH.
✘ = Causal relationship absent = Sperry compared the split-brain participants to neurotypical control, instead of epileptic ones. Any differences between the groups could be due to epilepsy.
PLASTICITY AO1
- The brain is ‘plastic’ - synaptic connections are formed and pruned.
- Rapid growth of synaptic connections in infancy. As we age, rarely-used connections are deleted and frequently-used ones are strengthened.
- MAGUIRE et al (2000) - Taxi drivers. Significantly more grey matter in the hippocampus of London taxi drivers than in a matched control group.
- DRAGANSKI et al (2006) - Medical students. Imaged brains three months before and after final exams. Hippocampus and parietal cortex changes, presumably brought on by learning.
PLASTICITY A03
✘ = Possible negative behavioural consequences: Brain’s ability to adapt to damage may not always be beneficial, e.g. 60-80% of amputees experiencing phantom limb syndrome
✔ = May not sharply decline with age: Ladina Bezzola et al (2012) demonstrated how 40 hours of golf training produced neural differences in pps. 40-60 years of age.
FUNCTIONAL RECOVERY OF THE BRAIN AFTER TRAUMA AO1
- Following trauma, healthy brain areas take over the function of damaged, destroyed or missing ones.
- Spontaneous recovery occurs quickly after the trauma, then recovery slows down, at which point the person may require rehabilitative therapy
- The brain rewires itself by forming new synaptic connections near the area of damage
- Secondary neural pathways that normally wouldn’t be used are activated to enable functioning to continue
- Changes may include axonal sprouting (growth of new nerve endings which connect with undamaged cells), or recruitment of homologous areas (the opposite side of the brain takes over specific tasks)
FUNCTIONAL RECOVERY OF THE BRAIN AFTER TRAUMA A03
✔ = Real-world application: It has permitted development of new therapies and neurorehabilitation. Helps medical professionals know when interventions can be made.
✘ = May be linked to cognitive reserve: Schneider et al (2014) found that patients with a higher cognitive reserve (spent longer in education) achieved disability-free recovery. Higher cog reserve determines how a brain will recover after trauma.
METHODS OF STUDYING THE BRAIN AO1
fMRI - Detects changes in blood oxygenation and flow that occur due to neural activity. Produces a 3D image that shows which part of the brain is active.
EEG - Measures electrical activity in the brain using electrodes in a cap. Scan recording shows brainwave patterns. Diagnostic tool.
ERP - Event-related potentials exclude all extraneous brain activity from EEGs. Only responses from a specific stimulus remain.
Post-Mortem Examinations - Analysis of a person’s brain following their death. Areas of the brain are examined to establish deficits or causes of death. Comparison with neurotypical brains.
METHODS OF STUDYING THE BRAIN AO3
fMRI -
✔ = Does not use radiation like e.g. PET scans
✔ = High spatial resolution, images by the mm
✘ = Expensive to perform compared to other techniques.
✘ = Poor temporal resolution, ~5 second delay between the activity and the image
EEG -
✔ = High temporal resolution, 1 millisecond
✘ = Produces a generalised signal from thousands of neurons, hard to know the exact source of activity.
ERP -
✔ = More specific measures of neural processes
✔ = Better temporal resolution than fMRI
✘ = Lack of standardisation makes it hard to confirm findings, and background noise is hard to fully eliminate.
Post-Mortem -
✔ = Use in research, e.g. Wernicke & Broca, HM’s memory deficits
✘ = Damage in the brain observed may not be linked to the behaviours under review.
✘ = Ethical issues of consent after death
BIOLOGICAL RHYTHMS - CIRCADIAN RHYTHMS AO1
- Governed by INTERNAL BIOLOGICAL CLOCKS (Endogenous pacemakers) and EXTERNAL CHANGES IN THE ENVIRONMENT (Exogenous zeitgebers)
- Circadian rhythms last around 24 hours - e.g. the sleep/wake cycle
SLEEP/WAKE CYCLE
- Exogenous zeitgebers - the fact that we feel drowsy at night and alert during the day indicates the influence of daylight
- Endogenous pacemakers - ‘free-running’ is the internal system left to its own devices without the influence of external stimuli. The SCN governs the basic rhythm, influenced by the input from the eyes about light levels
- French caver Siffre - spent 2 months then 6 months in a cave to examine the free-running sleep cycle. Settled to around 25 hour days.
- Aschoff and Wever - group of pps, all but one settled to a rhythm of 24-25 hrs.
- Folkard found endogenous was stronger - had participants go to bed when a clock said 11:45 and wake up at 7:45, but secretly sped the clock up to a 22 hour day. Only one pp was able to adjust
BIOLOGICAL RHYTHMS - CIRCADIAN RHYTHMS AO3
✔ = Application to shift work - creates a desynchronisation of biological rhythms, such as a lapse in concentration around 6am (circadian trough), and a link between shift work and poor mental health
✘ = Research is only correlational, may not be the cause of observed difficulties. Other factors, such as social influences like missing out on important family events (Solomon)
✔ = Use in timing medicine for the greatest impact on the body - Aspirin reduces heart attacks which most commonly occur in mornings, and is most effective when taken late at night.
✘ = Studies often use very small groups of pps, and cannot be effectively generalised to the population
BIOLOGICAL RHYTHMS - INFRADIAN RHYTHMS AO1
- Less than one rhythm in 24 hours
MENSTRUAL CYCLES - The human cycle is around 28 days, meaning less than one full rhythm occurs in 24 hours.
- Oestrogen causes release of an egg, progesterone thickens the womb lining, then the egg is absorbed and womb lining shed if pregnancy does not occur.
- Exogenous zeitgebers - Pheromones were taken from the armpits of women at different stages of their cycles and transferred to a ‘donor’. 68% of those donors experienced changes to their cycle
SAD
- Seasonal affective disorder has a seasonal pattern, with symptoms in winter when the daylight hours get shorter
- May be caused by melatonin - usually secreted until dawn when there is an increase in light, but less light in winter means secretion goes on for longer. This has a knock-on effect for serotonin production in the brain
BIOLOGICAL RHYTHMS - INFRADIAN RHYTHMS AO3
✔ = Evolutionary basis in research - female menstrual cycles may line up for a survival purpose, allowing babies to feed from several mothers if needed and improve chances of survival
✘ = Methodology used in synchronisation studies - variations in menstrual cycles can be caused by a variety of influences, including stress or diet. Lack of successful replications indicate this
FIGHT OR FLIGHT AO3
‘Tend and befriend’ - androcentrism
Freeze response
