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Biopsychology, Broca & Wernicke found that different brain parts -->…
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- Broca & Wernicke found that different brain parts --> cause different physical/psychological functions --> to do with different body parts
- If certain brain part gets damaged ONLY the function associated is affected
- But, before scientists holistically believed all brain parts processed thoughts & action
- Has a right & left hemisphere, where right controls the left of body vice versa (lateralisation = certain hemisphere controls functions)
- Outer layer cerebral cortex (3mm thick) that's grey due to cell bodies location
- All lobes separated by central sulcus
- Frontal lobe = motor area that controls movement in opposite sides of body, damage affects movement
- Parietal lobe = somatosensory area processes sensory info from skin e.g. touch, of sensitivity of body parts like hands & skin
- Occipital lobe = visual area (visual cortex) receives/processes visual info where eyes send info from right visual field to left visual cortex vice versa, damage to hemisphere causes blindness in opposite visual field
- Temporal lobe = auditory area analyses speech info, damage can cause hearing loss/affect understanding of languages
- Broca's area in left frontal lobe responsible for speech --> damage caused Broca's aphasia --> slow speech lacking fluency
- Wernike's area in left temporal lobe responsible for language comprehension --> damage caused Wernike's aphasia --> where they could speak yet it was nonsense words (neologism)
- Peterson showed different brain parts --> different functions (localisation), through brain scans the Wernike's area was active when listening & Broca's was active when reading
- Tulving for LTM shows that semantic & episodic memories are in diff brain parts too
- More objective (when a study isn't biased & not affected by researcher) methods --> for measuring brain activity --> giving scientific evidence for localisation
- Surgery for removing brains parts --> used to control behaviour e.g. Freeman developed lobotomy a frontal lobe surgery to control aggression
- Neurosurgery occurs today e.g. Dougherty found in 44 OCD patients who had cingulotomy, a few weeks later they all showed signs of improvement, showing behaviours of mental disorders are localised too.
- Phineas Gage in a explosion had a pole through the left temporal lobe & face, where he survived but personality changed
- Where frontal lobe was responsible for mood, supporting localisation
- Measures change in brain activity as more 02 and blood flows to active area (haemodynamic response), forming 3D image of which brain parts --> activity (localisation)
- Uses MRI detects radio waves from changing magnetic fields
- Measures electrical impulses from neurons to see brain activity through brain wave patterns, by electrodes attached to scalp by skull cap
- For diagnosis of arrhythmic patterns (no rhythm) --> shows conditions like tumours or epilepsy
- After death analysis of brain where a person may have had rare disorder --> with unusual mental processes
- Damaged areas examined to find cause the person suffered & compared to neurotypical brain for difference
- EEG data has neural responses linked to sensory, cognitive & motor events, that researchers can individually isolate
- So the remaining response is the ERP that's the brain wave triggered by a specific response e.g. could link to cognitive processes of attention
- +ve Non-invasive and risk free as it avoids use of radiation, easy to use & high spatial resolution producing localisation of brain activity clearly in detail
- -ve Expensive, only gets clear image if patient is still, poor temporal resolution due to 5sec lag when image on screen and neuron activity is shown & only measures blood flow not neuron activity making it difficult to identify brain activity
- +ve Diagnosis of conditions e.g. epilepsy that has random bursts of activity that can be easily detected and understanding stages in sleep & high temporal resolution that detects brain activity quickly in milliseconds
- -ve Difficult to distinguish neural activity between adjacent brain parts as info received from thousands of neurons
- +ve ERP's for specific neural processes obtained from EEG measurements with a high temporal resolution, as different ERP's have been found for different functioning's
- -ve Research studies for ERP lack standardisation making it difficult to confirm findings & difficult to obtain pure data in ERP studies due to background noise and extraneous material
- +ve This was the foundation for understanding brain functions before neuroimaging e.g. used by Broca & Wernicke & help to improve medical knowledge
- -ve Causation isn't true, as damage seen in brain may not be to what thought instead to trauma/decay & these studies lack consent from patient before death ethical issues
- As an infant the synaptic connections grow a lot more than an adult has, yet the connections that aren't used are deleted & used strengthen = synaptic pruning
- Changes in brain development occur in critical period of childhood, but research found connections can change as an adult due to learning/experience*
- Maguire found in taxi drivers more grey matter in hippocampus (spatial/navigational skills) than control group, as a test on recalling routes --> learning experience --> altering their brain
- +ve correlation between longer they've been in job & brain difference
- Draganski found changes in hippocampus and parietal cortex of med student before/after exams & Mechelli found large parietal cortex of bilingual than monolingual people
= Is an e.g. of neural plasticity, where healthy brain areas take over the functions of the damaged areas
- After trauma e.g. stroke this quickly occurs for recovery, then slows down where further therapy for treatment may be needed
- New secondary synaptic connections form near the damaged area, so normal functions can continue as before (Doidge)
- Structural changes occur: Reforming blood vessels, growth of new nerve endings to undamaged nerves for new connections & recruitment of homologous areas on opp side of brain to carry out certain tasks
- Once functional recovery occurs, it may slow where physical therapy is needed to improve functions
- E.g. movement therapy or electrical stimulation to help motor/cognitive functioning, showing brain can fix itself yet further intervention is needed to be complete
- Rewiring of the brain = behavioural consequences e.g. drug use --> poor cognitive functioning --> dementia (Medina)
- People who have lost a limb experience phantom limb syndrome, sensations as if the limb is still there that can be unpleasant & painful due to reorganisation in somatosensory cortex (Ramachandran & Hirstein)
- It's said functional plasticity reduces with age, as children have more reorganisation due to experience
- Yet, Bezzola found in 40hrs of gold training in older people neural changes occured due to movement
- As fMRI found a reduced motor cortex activity in golfers than control group showing plasticity is in a whole lifespan
= Patterns of change in body activity at cyclical time periods, influenced by endogenous pacemakers (internal biological clocks) & exogenous zeitgebers (external environmental changes)
- Circadian rhythms = Rhythm that occurs every 24hrs to regulate body processes
- We are drowsy at night & alert during the day due to exogenous zeitgeber of daylight
- Yet, with only internal biological clocks & no external changes this affects circadian rhythm
- Siffre did a study underground with food/drink, but without exogenous zeitgebers (light/sound) where his biological rhythm was affected (not in 24hrs), yet he could form a sleep/awake pattern
- Aschoff & Wever got similar results, both studies showed a circadian rhythm a bit longer but support that EZ are important too
- Folkard found in study where pp's in a dark cave who's circadian rhythm was shortened to 22hrs were affected due to external changes of the clock they read
- Circadian rhythms affect pharmacokinetics (how well drugs are absorbed/distributed in body)
- Research found certain times in the day --> when drugs are most effective --> allowing guidelines for when medication should be taken e.g. anticancer (Baraldo)
- Research has found link between shift work & poor health (heart disease) --> as stress due to affected sleep/wake patterns & lack of sleep
- Night workers have circadian trough where around 6am they are likely to make more mistakes
- +ve as sleep/wake cycle can economically help to produce better work productivity
- Sleep/wake studies lacked representation & generalisation to the wider population due to few pp's
- E.g. Siffre found his internal clock was slower at 60 than younger, so even in an individual general conclusions can't be drawn
Hemispheric lateralisation = Each hemisphere of the brain is functionally different, controlling certain processes e.g. language is only in one hemisphere
= Studies by Sperry on patients who had surgical separation on the hemispheres to see lateralisation of brain function & if hemispheres performed task independently/together
- As the individuals had commissurotomy where corpus callosum & tissues connecting the hemispheres were cut to control seizures
- An image shown to patients light/right visual field --> processed by right/left hemisphere
- In normal brain corpus callosum would share info between both hemispheres for whole pic, but to the patient the info couldn't be shared
- Patients shown an object to their left visual field couldn't describe the object seen, as the right hemisphere couldn't process language, in a normal brain messages would relay from R to L H
- Patients could select a matching object with left hand linked to RH, so verbally they couldn't identify object seen but could understand it
- When 2 words shown to both visual fields, left hand selects key (as left visual field links to RH) & they'd say ring (as right VF links to LH responsible for language)
- When asked to match faces, the RH selected pics due to LVF than LH ignoring it & showing halves of a face to each hemisphere the L verbally described than R which matched
- From lots of research it concluded that left H for verbal/analytic tasks & right H for spatial tasks/music/emotion
- Where LH analyser & RH synthesiser, +ve for understanding brain processes
- Sperry used standardised methods by showing visual info to each hemisphere at a time
- Usually SB patients would be told to stare at an image & it then flashed --> so info doesnt spread across both VF/sides of brain
- From this Sperry made sure in his study only 1 hemisphere got info at a time & gave him a controlled procedure
- Sperry's research created a debate between functioning of the 2 hemispheres
- Pucetti said as the 2 hemispheres function differently --> duality in brain --> we all are two minds
- But, others said the 2 hemispheres are integrated both involved in everday tasks
= Rhythm with frequency of less than one cycle in 24hrs
- Menstrual cycle: Monthly changes in hormones for ovulation from 1st day of period, shedding of womb lining, day before next period. In each cycle oestrogen increases to form & release an egg and progesterone thickens womb lining for pregnancy. If not pregnant the egg is absorbed into body & womb lining leaves
- Menstrual cycle is endogenous, but exogenous factors affect it e.g. cycles of other women
- McClintock used women with irregular period & samples of their pheromones taken whilst in diff stages of their cycle
- Used cotton pad underarm alcohol added & frozen so other women could rub on lips, women were given pads of cycle order where 68% had changes to their own cycle
- E.g. of IR occurs at certain seasons (Circannual rhythm- yearly) & depressive disorder with low moods/activity
- Occurs in winter when daylight hours get shorter & type of CR as sleep cycle disruption too
- Melatonin causes it too, its usually released until increase in light in morning, but in winter takes longer for light to come = affecting serotonin in brain = depressive symptoms
= Rhythm with frequency of more than one cycle in 24hrs
- E.g. sleep cycle takes 90mins with diff brainwave activity using EEG
- Stage 1&2 = Light sleep, person easily woken as brainwave activity and rhythm slows alpha --> theta waves
- Stage 3&4 = Delta waves here slower but with greater amplitude, deep sleep that's difficult to wake one
- Stage 5 = REM (rapid eye movement) sleep, body paralysed here yet brain activity speeds & is awake, REM activity correlates with dreaming
- Menstrual synchrony in past would be an +ve, as females could fall pregnant together & new borns would have social group together --> survival of offspring
- But, Shank opposed females in synchrony can create competition for males with high quality --> lowers fitness of offspring (avoidance of synchrony = survival of fittest offspring)
- Confounding variable e.g. stress/diet affect menstrual cycle, so synchrony in McClintock's study may be by chance
- Also, these studies include small groups & women reporting of their cycles, yet others (Trevathan) may not have been able to support this evidence lack generalisability to all women
- Dement & Kleitman recorded brain wave activity of 9 pp's in sleep lab, where caffeine & alcohol effects were controlled
- REM activity in sleep correlated with dream & when woken they could recall the dream
- Replication found similar results, supporting REM sleep is important in ultradian sleep cycle
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= External cues that affect our biological rhythms, resets our biological clocks by entrainment
- Are nerve cells in hypothalamus that maintains sleep/wake cycle
- Nerves that connect to the eye cross (optic chiasm) is where SCN lies above before visual cortex, receives light info to control our biological clock of daylight patterns
- SCN passes info received from light to pineal gland increasing melatonin
- Melatonin helps us to sleep & inhibited when awake
- DeCoursey destroyed SCN connection in chipmunks, when returned to their habitat their sleep/wake cycle disappeared & most were killed by predators as they were awake at night
- Ralph bred mutant hamsters with 20hr sleep/wake cycles, SCN cells from them transplanted into normal hamsters where their cycle became 20hrs too
- Light resets the SCN & control processes like hormone secretion/blood circulation
- Campbell & Murphy showed how light can be detected on skin receptors, knees when same info isn't received by eyes. As shining light on knees at diff times changed a pp's sleep/wake cycle
- Parents determining meal & bed times for infants can help to entrain a circadian rhythm for sleep/wake cycle & maintain can help in jet lag too
- Animals in the studies were exposed to harm & risk when returned to their environment, creates debates about these unethical procedures
- We have many circadian rhythms in body e.g. in skin/lungs (peripheral oscillators) which are influenced by SCN, but can work alone
- Damiola found change in mice feeding --> altered liver cells circadian rhythm --> yet SCN rhythm unaffected. So other than SCN can influence sleep/wake cycle
- Miles found in a blind man his sleep/wake cycle involved him taking sedatives at night & stimulants in morning to keep on track of the 24hr day
- People in artic area where sun doesnt set quick in summer had normal patterns despite the light
- So these zeitgebers we can sometimes bear
Specific stimulus/task used to isolate specific response of neurons e.g. cognitive task of memory may isolate only neurons involved in attention to learn words
EEG data of many neurons receiving info --> narrowed down to only those neurons specific to a stimulus