A2 biopsychology Flashcards
what is localisation theory?
different parts of the brain perform different tasks and are involved with different parts of the body
what is lateralisation?
physical and psychological functions are controlled by a particular hemisphere
give detail on the motor area
located in the back of the frontal lobe and controls body movement on the other side of the body
damage results in a loss of control over fine movements
give detail on the auditory area
located in the temporal lobe and analyses speech based production
info from the left ear goes to the right hemisphere
damage may result in hearing loss
give detail on the somatosensory area
at the front of the parietal lobes where sensory info from the skin is represented
the amount of somatosensory area given to a particular body part indicates how sensitive it is
e.g face and hands occupy over half of somatosensory
give detail on the visual area/cortex
in the occipital lobe
the eye sends info from the right visual field to the left visual cortex and vice versa
damage to the hemisphere can produce blindness in the opposite eye
What are brain imaging techniques
These allow doctors to research and view activity in the human brain
explain fmri
used to measure brain activity whilst someone performs tasks
regions of the brain that are rich in oxygenated blood are active
these 3D images show which part of the brain is responsible for a task
explain EEG
tracks brainwave patterns by putting electrodes on the scalp
detects problems with electrical activity that may be responsible for certain brain disorders
explain ERP
stimulus is presented to participant and the researcher looks for activity triggered by the stimulant through electrodes on the scalp
ERPs are linked to cognitive processes like attention and memory
explain post mortem examinations
brain is analysed after death to determine if certain behaviours were due to brain abnormalities
often conducted on people with rare disorders#
what is the difference between temporal resolution and spatial resolution
temporal: measurement w respect to time
spatial: the size of the smallest object that can be detected in an image
weakness of FMRI?
doesnt provide a direct measure of neural activity, just measures blood flow.
cant infer causation and say that part of the brain is responsible for a particular function
strengths of fmri
good spatial resolution (1-2mm),greater than others
can determine activity of regions with greater accuracy
non invasive. does not use radiation or involve instruments directly into the brain, its risk free so more patients can undertake and more data can be found
weaknesses off ERP
Erp has poor spatial resolution
only detect activity in superficial regions of the brain, not deeper regions
erp is uncomfortable as electrodes are attached to the scalp. discomfort may affect cognitive response
strengths of erp
good temporal resolution because it has readings every millisecond, accurate measurement of electrical activity when doing a task
non invasive. no radiation or instruments directly in the brain
strength of eeg
important in diagnosis of epilepsy, random burst in brain activity
good temporal resolution, readings every millisecond
weakness of EEG
electrical activity is detected in several regions of the brain simultaneously. difficult to pinpoint exact region and draw causal relationship.
post mortem strength
improve medical knowledge, broca and wernicke relied on pms
can access areas like the hypothalamus and hippocampus, which scanning techniques cannot, insight into deeper regions of the brain
weakness of post mortems
issue of causation, deficit a patient displays during their life may not be linked to the brain but another illness like mental health problems
ethical issues patients may not be able to provide consent
explain Brocas area
left hemisphere, makes up part of the language centre.
areas in the frontal lobe responsible for speech production
damage causes brocas aphasia: speech that is slow, laborious and lacks fluency
explain wernickes area
in the temporal lobe responsible for language comprehension
damage produces wernickes aphasia where patients can produce language but their speech is meaningless and they produce nonsense words
studies against localisation
evidence against localisation, lashley removed parts of rats brains (10-50%) whilst they learnt a maze. no area was more important, the learning process required every part of the cortex and wasnt localised. however rats learning a maze cant be compared to the complex learning we see in humans
study to support localsisation
phinneas gage had a metal rod forced through his head when dynamite exploded at his job, permanent damage to left frontal lobe, His friends believe his personality changed so personality is localised to the left frontal lobe. HWVER, this is too unique to generalise and the trauma of the incident could’ve been what caused the change
what is plastcicty
the brains ability to change and adapt as a response to new learning and experiences
AO1 brain plastcity
in infancy the brain has rapid growth in the number of synaptic connections with 15,000 at 2-3 as children are constantly taking in new information which is twice as much as adult brain
synaptic pruning: rarely used connections are deleted whereas frequently used connections are strengthened
neural connections can change or be formed at any time in life
exp-lain AO2 research into plasticity
maguire et al studied the brains of london taxi drivers and found more volume of grey matter in the posterior hippocampus than the matched control group
this part of the brain is associated with development of spatial and navigational skills
their brain adapted as a result of new learning
AO3: strength of plasticity
its may be a lifelong ability
bezzola et al shows how 40hrs of golf training leads to changes in the neural representation of movement in participants age 40-60. Fmri showed increased activity in motor area than a control group. suggesting NP is lifelong
however adults may find it harder to learn than children as albert et al suggests that general NP is much stronger in children (more synaptic connnections)
A03 : negative of plasticity
plasticity has maladaptive behavioural consequences. evidence has shown the brains adaptation to prolonged drug use leads to poorer cognitive functioning later in life as well as an increased risk of dementia.
shows the brains ability to adapt to damge may not always be positive but still supports the fact that it can adapt.
what is functional recovery?
a from of plasticity
after damage the brain is able to redistribute functions that are usually performed by the damaged area to a non damaged area of the brain
A01 for functional recovery
after damage unaffected areas can adapt and compensate for damaged areas
this can occur spontaneously then slow down after weeks or months
the brain rewires and reorganises itself by forming new synaptic connections close to the area of damage. secondary neural pathways that wouldn’t typically be used are activated to allow functioning to continue
What is reformation of blood vessels?
brain deals with indirect physical effects of trauma e.g damaged blood vessels
what is axonal sprouting?
the growth of new nerve endings which connect with undamaged nerve cells to form new pathways
what is recruitment of homologous areas?
areas on the opposite side of the brain carry out functions of the damaged area
weakness of functional recovery?
individual differences like education level influence recovery.
Schneider et al found that the more time people with brain damage spent in education the greater their chance of disability free recovery.
40% of people who achieved DFR had more than 16 years in education.
not everyone benefits from functional recovery equally.
strengths of functional recovery?
evidence to support from animal studies.
Tajiri et al found stem cells given to rats after brain trauma show a clear development pf neuron like cells in the area of injury. shows the ability of the brain to form new connections.
real life application in development of neuro rehabilitation. uses motor therapy and electrical stimulation to counter the deficits in motor and cognitive functions following accidents and strokes. e.g constraint induced movement therapy for strokes (practice using the affected part of the body whilst the other side is constrained)
what is hemispheric lateralisation?
the idea that two hemispheres of the brain are functionally different and certain mental processes are mainly controlled by hemisphere than the other
what does the corpus collosum do?
allows info received from one hemisphere to be sent to the other
explain sperrys procedure
image or word is shown to the right eye with left eye closed. and then the same image/word is shown to the left eye with the right eye closed.
in the normal brain the corpus collosum would share any info between hemispheres
in split brain patients info couldn’t be conveyed from one hemisphere to another
explain sperrys results
when an image was shown to the right eye they could easily describe what was seen.
when shown to the left eye they couldnt describe it. this is due to lack of language centres in the right hemisphere and no corpus collosum to relay information
weaknesses of lateralisation and split brain research
differences in function may be overstated. Sperry says left =speech and right = recognition and drawing. however functional recovery suggests functions of the damaged area may be taken over by non specialised areas in the opposite hemisphere e.g lang controlled by right
cant establish causal relationship w/ sperry. compared 11 split brain patients w epilepsy to neurotypical control group who had no epilepsy. having epilepsy is a confounding variable and any differences could be a result of this
strengths of split brain and lateralisation
research: in connected brains 2 hemispheres process info differently. fink et al pet scans to see what areas of the brain were active during a visual processing task. ptps w connected brains had to attend to global elements of an image(e.g a whole forest), regions of the right hemisphere were much more active. when focusing on finer details (individual trees)the specific areas of the left hemisphere dominated
support from more split brain research. split brains performed better than connected controls on certain tasks e.g faster identifying the odd one out than controls. in a normal brain the left hemispheres better cognitive strategies were weakened by the inferior right hemisphere
what is a circadian rhythm ?
patterns of behaviour that occur every 24 hours and is set and reset by environmental light levels
name 3 types of circadian rhythms?
the sleep wake cycle
core body temperature
hormone production
how do the circadian rhythms work?
circadian rhythms are driven by our body clocks and synchronised by the SCN in the hypothalamus.
how does light affect circadian rhythms
light provides the primary input to this system, setting the body clock to the correct time which is photoentrainment.
in mammals light sensitive cells in the eye act as brightness detectors and send messages about environmental light levels to the scn.
the SCN uses this to coordinate activity of the whole circadian rhythm.
what is the SCN?
an endogenous (internal) pacemaker in the hypothalamus of each hemisphere of mammals, acts as a master clock
explain Siffre’s cave study
he spent time underground to study his bio rhythms
he was deprived of exposure to natural light and sound but had access to food and drink. he resurfaced in mid September and believed it was mid august. a decade after he spent 6 months in the cave again. his free running bio rhythms was just beyond 24 hrs he fell asleep and woke up on a regular schedule.
this suggests we need external factors like light
ao3 evaluation of circadian rhythms
practical application shift work and the adverse affects. reduced concentration in the morning and more mistakes. poorer health e.g 3x more likely heart disease. economic implications
PA: education, shift in the timing of the school day. researchers recommended school day start later as its harder for hormonal teens to get sleep theyre sleepier in skl. schools aiming to improve performance will take circadian rhythms into account
used to improve medical treatments. CR coordinate a number of the bodys basic processes like heart rate. they rise and fall during the day so treatments are administered to fit a bio rhythm. E.g asprin for heart issues is best taken at night as heart problems occur in the morning so this timing matters
what is an exogenous zeitgeber
external cues that may affect or entrain our biological rhytms such as the influence of light on the sleep cycle
what is an endogenous pacemaker?
the internal body clocks that regulate our biological rhythms such as the influence of the SCN on the sleep cycle
Explain the process of melatonin being released or induced
the SCN receives info on light levels via the optic nerve.
the SCN signals to the pineal gland to increase production of melatonin at night and decrease it as light levels increase in the morning
how does melatonin induce sleep
by inhibiting the brain mechanisms that promote wakefulness
What happens to the body clock in the absence of external cues?
the free running biological clock that conrols the sleep cycle continues to tick in a distinct cyclical pattern, its then brought into line in environmental cues
state and explain 2 types of exogenous zeitgebers
light - it can reset the SCN and plays a role in the maintenance of sleep cycle
social cues - all babies start with a random sleep cycle, schedules are then imposed by people like meal times and bed times
A03 weakness of EP and EZ
influence of exogenous zeitgebers is overstated. miles studied man blind from birth who had an abnormal circadian rhythm of 24.9 though hes exposed to social cues like sleep and meal times.
exogenous zeitgebers dont have the same effect in all environments. people in the arctic circle have similar sleep patterns all year round. though they spend 6 months in total darkness. sleep cycle is controlled by endogenous p that override exz
A03 strengths of EZ and EP
research to support exogenous zeitgebers on sleep wake. Campbell and murphy found lights detected by skin receptor sites. had 15 ptps woken at diff times and light shone on the back of knees. produced deviation in ptps usual sleep cycle of up to 3 hrs. Light is a powerful zeitgeber on not j eyes.
research to support animal studies. DeCoursey destroyed SCN in brains of chipmunks and put them back in the wild, observed for 80 days. their sleep cycle dissapeared so they were killed by predators. SCN is important. No SCN = no sleep cycle. HWVR unethical do findings outweigh procedure?
What is an infradian rhythm?
type of biological rhythm w a frequency of less than one cycle in 24 hours e.g menstruation and seasonal affective disorder
what is an ultradian rhythm?
type of biological rhythm with a frequency of more that one cycle in 24 hours e.g stages of sleep
how is the menstrual cycle an infradian rhythm?
Its an endogenous system thats governed by the monthly changes in the hormone levels
typical cycle takes 28 days to complete
how is the menstrual cycle affected by other exogenous factors?
diet
stress
what is SAD and what are the symptoms
It is a depressive disorder which has a seasonal pattern of onset.
persistent low mood and lack of activity and interest in life
How may SAD be classed as a circadian rhythm?
SAD is triggered during winter where theres less daylight hours. during winter lack of light in morning and evenings means secretion of melatonin is extended which has a knock on effect on the production of serotonin in the brain.
A03 evaluation 2 strengths of infradian rhythms
SAD has practical application in creating light therapy. light box shines light in the morning and evening to reset melatonin levels in people w SAD, works in 60%. shows external cues affect melatonin which affects sleep wake. HWVER, higher relapse rate than those recieving CBT.
Menstrual cycle can be explained by natural selection. synchronisation of cycles has an evolutionary value. in ancestors time it may have been good for women to menstruate together because babies who lost the mother in childbirth can access milk and survive.
A03 weakness of infradian rhythms
studies support the menstrual cycle is influenced by exogenous factors like synchronisation. confounding variables like diet and stress affect the cycle. weakness as synchronisation may have been due to chance.no causal relationship
what does stage 1 and 2 of the sleep cycle consist of?
light sleep, easily awoken, brain wave patterns are slower
what happens at stage 3 and 4 of the sleep cycle?
deep sleep or slow wave sleep, more difficult to rouse someone at this point.
what happens at stage 5 and REM sleep?
body is paralysed but brain activity speeds up. rapid eye movement which is associated with dreaming
A03 evaluation one strength of ultradian rhythms
improved understanding of age related changes in sleep. sleep scientists have observed slow wave sleep(when growth hormone is produced) reduces with age.
sleep deficit explains issues with old age like reduced alertness. this led to the use of relaxation medication
A03 evaluation one weakness of ultradian rhythms
significant variations between research. Tucker found big differences between ptps in terms of duration of each sleep stage specifically 3 and 4 which are possibly biologically determined suggesting its difficult to describe ‘normal sleep’ in a meaningful way.
