A2 Biopsychology Flashcards
What are the strengths of localisation of function?
. Phineas gage ‘no longer gage’ after injury to frontal lobe
.brain scans- Peterson (1988) found only Broca’s area used in reading task and only wernickes area used in listening task
. Neurosurgical evidence- Dougherty (2002) put lesions in cingulate gyrus of OCD sufferers- 30% made full recovery, 14% made partial recovery
What are the limitations of localisation of function
Lashley’s rats- removed 10-50% of rats brains and no area affected them doing the maze more than others- shows their brains work holistically.
Plasticity- if brain undergoes trauma in some cases brain is able to reorganise itself to regain function- shows holism
Dick and Trembly- found only 2% of modern researches believe language is completely controlled by B and W areas- fMRI scans have showed language is holistic
What is hemispheric lateralisation
The idea that the two halves of the brain are functionally different and that each hemisphere has specific functions
Is language lateralised?
Yes- B and W areas are both in the left hemisphere
What side of the brain contributes to emotional context?
Right
RH is the synthesiser
LH is the analyser
Is movement lateralised?
No- but it is cross wired (contralateral wiring) RH controls movement on left and vice Versa
Is vision lateralised
No- it is both contralateral and ipsilateral each eye gets info from RVF and LVF and each is processed in the opposite side of the brain (LH or RH)
Outline Sperry’s experiment
Tested on 11 males with commissurotomy’s
Patients would stare at cross in the middle of a screen and either and image or a word would flash in the LVF and RVF
What were the findings of Sperry’s experiment
Describe what you see- when object or word was displayed in right RVF the patient could easily describe it as was processed in LH
Recognition by touch- although patients could not verbally say what they saw in LVF and processed in RH they could pick up the object they saw when presented with and array of different things- they could also select the most similar (cigarette- ashtray etc)
What were the findings of Sperry’s experiment
If word or object shown in RVF patient could easily say what it was as processed by LH. If object or word shown in LVF patient could not remember was they saw
Even though patients could not verbally describe stimulus in LVF they could pick up the object from behind a screen- they could also select object most similar to the one they saw (cigarette- ashtray etc)
What were the findings of Sperry’s research
If word or object shown in RVF patient could easily say what it was as processed by LH. If object or word shown in LVF patient could not remember was they saw
Even though patients could not verbally describe stimulus in LVF they could pick up the object from behind a screen- they could also select object most similar to the one they saw (cigarette- ashtray etc
What does Sperry’s research tell us about hemispheric lateralisation
RH is non verbal
LH is verbal
RH can still process information non verbally
When racy image showed in LVF patient would giggle even though they didn’t know what they saw
What are the strengths of hemispheric lateralisation
Highly scientific supporting evidence- Fink et Al (1996) identified with PET scans that during a visual task when an image was looked at holistically RH was more active but when asked to focus on details LH was more active
Real world applications- Gazzaniga found that spilt brain patients are better at identifying an odd one out in a group because LH has better cognitive abilities which are not interfered with by RH. Rogers showed chickens with spilt brains could feed and look for predators simultaneously.
High internal validity of evidence- Sperry’s experiment was highly controlled- cross used to focus on etc
What is a limitation of hemispheric lateralisation?
Sperry’s research lacks generalisability- only carried out on 11 men all who previously had severe epilepsy
What is the definition of plasticity
Your brains ability to change and adapt as a result of new experiences and learning. As a child you have thousands of synapses per neuron but these are cut by ‘synaptic pruning’ suggesting your brain can change during adulthood.
What is the definition of functional recovery
When brain adapts to trauma by getting other parts of brain to carry out function of damaged part
Outline maguires study
Compared brains of black cab drivers to control group chosen by matched pairs design
Significantly more grey matter in posterior hippocampus of black cab drivers
Posterior hippocampus is for spatial awareness
What are the strengths of plasticity
Maguires experiment highly controlled- used matched pairs design and MRI scans to gather data
Draganski observed 3 medical students before and after exam and all 3 had either larger or more connections in posterior hippocampus and parietal cortex
Michelli found that people who were bilingual had bigger parietal cortex’s than people who weren’t
What are the strengths of plasticity
Maguires experiment highly controlled- used matched pairs design and MRI scans to gather data
Draganski observed 3 medical students before and after exam and all 3 had either larger or more connections in posterior hippocampus and parietal cortex
Michelli found that people who were bilingual had bigger parietal cortex’s than people who weren’t
What is a limitation of plasticity
Maguires results may not be reliable- none of the taxi drivers were tested before they took their ‘knowledge test’
How does Jody support idea of plasticity and functional recovery
Had RH removed at 3
LH took up all the function of RH
Can function almost perfectly with only slight paralysis on left side
What happens to the brain during recovery
New synaptic connections
Secondary neural pathways created
Axonal sprouting
Denervation super sensitivity
Recruitment of the homologous area
What are the strengths of functional brain recovery
Real work application- help people recover from strokes etc. strapping hand behind back ( constraint induced movement therapy)
Supporting evidence- Bezzola gave people aged 40-60 40 hours of golfing lessons and their brain structures changed
Schneider found that people who stayed in education for 16 years had 40% chance of recovering from traumatic brain injuries- if in education for under 12 years 10% chance of recovery
What is a limitation of functional recovery
Not always a good thing- phantom limb syndrome occurs when somatoes sensory area remains idle for too long and another part of the brain takes up its function
What is a limitation of functional recovery
Not always a good thing- phantom limb syndrome occurs when somatoes sensory area remains idle for too long and another part of the brain takes up its function
How does an fMRI scan work
Measures changes of blood flow in brain using radio waves and a magnetic field. As a result of these changes in blood flow, researchers can produce a map showing which areas of the brain are being used
What are the strengths of fMRI
No radioactive tracer (risk free)
Clear, high resolution images
Shows where functions are localised
What are the weaknesses of fMRI
Very expensive
Patient must remain still for long period of time (bad for children, ADHD and the elderly)
Poor temporal resolution (5 second delay between event and imaging)
How does an EEG work
Measures electrical activity in the brain. Electrodes on the scalp pick up small electrical activity from functioning brain cells. When the signals from different electrodes are graphed over a period of time you get an EEG
What are the strengths of EEG
Can be used to diagnose epilepsy, sleep disorders, Alzheimer’s
High temporal resolution (detects electrical activity in under 1 second)
What are the weaknesses of EEG
General measure- only picks up on groups of neurons firing electrical impulses not individual
Researchers can find it hard to decipher when different but adjacent areas are firing
How does an ERP work
Using an statistical averaging technique researchers can tease out all extraneous brain activity from original EEG leaving only the brain activity related to the presentation of a specific stimulus.
What remains are event related potentials: types of brainwaves that are triggered by particular events. Research has revealed many different forms of ERP that can be linked to cognition or perception
What are strengths of ERP
More specific than EEG readings
Very good temporal resolution as derived from EEG
What are the weaknesses of ERP
To be successful all interference must be eliminated
Not standardised- lots of different ways it is done depending on the researches
How does a post mortem work?
Used to establish the underlying neurobiology of a particular behaviour. For example, researches study a person who displays interesting behaviour that could stem from brain damage. Then when the person dies they can examine their brain to see if they were right. An example of this is Broca and Tan
What are biological rhythms
Distinct patterns of changes in body activity that conform to cyclical time periods. For example the sleep-wake cycle. These cycles are influenced by endogenous pacemakers and exogenius zeitgebers.
What is a cycle that occurs ONCE every 24 hours called
Circadian rhythm
What cycle takes more than 24 hours to complete
Infradian rhythm
What is the name of a cycle that occurs more than once every 24 hours called
Ultradian rhythm
What is the sleep wake cycle
7.30 am melatonin secretion stops
9 pm melatonin secretion starts
What is the body temperature cycle
4.30 am lowest body temperature
7pm highest body temperature
What is Sieffre’s cave study and what did it find out
Lived in a cave in the alps for 2 months and a cave in Texas for 6 months with no natural light and no alarm clock. He found that his natural biological rhythm remained at 24-25 hours and he woke up and fell asleep on a regular schedule.
What does sieffres study tell us about EP and EZ
Our sleep wake cycle is mainly dictated by EP
What was Folkard’s study
People had to live in cave with no natural light for 3 weeks and go to sleep at 11.45 and wake up at 7.45. Clock on wall completed full cycle in 22 hours not 24
What were the findings of Folkards study and what did it show
Participants were unable to adjust showing EP are more influential
What are two strengths of circadian rhythms
Real world application- Boivin (1996) found that night shift workers lose concentration at around 6 am and are more prone to accidents so breaks and artificial sunlight can be used to help this
Real world application- chronotheraputics can be implemented- aspirin better at preventing heart attacks if given late at night than earlier in the day
What are two weaknesses of circadian rhythms
Lack of generalisability- people who volounteer to stay in caves for months or weeks are likely to be of a certain demographic and have similar characteristics- leaving many groups not represented
Differences- Czeiser found that people have different sleep cycles from 13-65 hours. Some people are ‘larks’ while others are ‘owls’ . Old people likely to have different sleep cycles (go to sleep early wake up early)
Summarise the menstrual cycle
Day 1 bleeding
Day 7 oestrogen increases
Day 14 ovulation
Day 21 progesterone increases
Day 28 end of cycle
Summarise the stages of sleep (ultradian rhythm)
Stage 1- 5 mins- change from wake to sleep, brainwaves are high frequency- alpha waves
Stage 2- 40-50 mins- light sleep- breathing and heart rate slow. spend half your sleep in this stage- alpha waves
Stage 3- 4- 15-20 mins- deep sleep moving to very deep sleep. Muscles relax, slow breathing, hard to wake. Waves have lower frequency and higher amplitude. Delta waves (slow wave sleep)
Stage 5 (REM)- rapid eye movement. Brain is very active so waves speed up. Dreaming occurs, hear rate and blood pressure increases, sleep paralysis may occur
Stage
what was McClintocks study into infradian rhythms
had 29 participants with irregular periods
9 of the participants acted as ‘donors’ and gave pheromone samples everyday by having a cotton pad under their armpit for 8 hours, the other 20 participants would then rub this pheromone on their top lip.
what were the findings of McClintocks study into infradian rhythms
68% of women saw a shift in their menstruaol cycles closer to their ‘odour donor’
what did McClintock find about infradian rhythms and university students
those who lived together in un diversity halls tended to synchronise their periods
how is seasonal affective disorder an example of infradian rhythm
depressed in winter and not so much in summer
Florida- effects 1.4% of population
Maine- effects 10% of population
correlation with sunlight levels as less light means melatonin secreted for longer which has an effect on melatonin
what is a strength of infradian rhythms
real world application- SAD led to the establishment of light therapy where a Lightbox is used to reset melatonin levels- Sanassi found this relieved symptoms in 80% of sufferers.
what are the limitations of infradian rhythms
Confounding variables- McClintock failed to control variables such as diet, stress and exercise which can impact timing of menstrual cycle
generalisability- McClintock only studied 29 women
poor real world application- Rohan found 46% of people who did light therapy relapsed the next winter compared to 27% of those who did CBT
what is a strength of ultradian rhythms
real world application- scientists discovered through observing slow wave sleep that it is less common in old age. this is when growth hormone is produced so explains things such as lack of awareness, medication then can be prescribed to treat this.
what is a limitation of ultradian rhythms
low external validity- research is m mainly done on people sleeping in an unnatural setting or knowing they will be observed, such as Dement and Kleitman’s experiment which observed 9 people in a sleep lab using an EEG.
what are endogenous pacemakers
internal body clocks that maintain many of our biological rhythms
what are exogenous zeitgebers
external factors which effect our biological rhythms
what is an example of an endogenous pacemaker
the suprachiasmatic nucleus (SCN)
what does the SCN do
bundle of nerve cells in hypothalamus
maintains sleep/wake cycle as nerve fibres from eye which detect light run just underneath it- SCN receives info about light and influences level of melatonin
what are two pieces of research into the SCN
DeCoursey’s chipmunks
Ralph’s hamsters
what was DeCoursey’s chipmunk experiment
Destroyed SCN in 30 chipmunks and returned them to wild
their sleep wake cycle was completely off and many were killed because of this
what was Ralph’s hamster experiment
bred ‘mutant’ hamsters with a 20 hour sleep wake cycle
SCN cells of mutant hamster put in normal hamster who were then on 20 hour sleep wake cycle
how is light an example of an EZ
reset the Bodie’s main EP the SCN and effects the sleep wake cycle
what was Campbell and Murphy’s experiment into light as an EZ
wanted to see if light could be detected by the without the eyes
woke 15 participants up at random times in the night and shone light on the back of their knees
there was deviation up to 3 hours of some participants sleep wake cycles
what are social cues (EZ)
external factors such as meal times and bed times which influence biological rhythms
what are the limitations of endogenous pacemakers
over simplified- Damiola found that cahnging feeding pattern of mice could alter circadian rhythm of liver by 12 hours while SCN remained the same- shows SCN may not be most important EP
animal studies- supported by chipmunks and hamsters. cannot be generalised to humans and ethical issues
what are the strengths of endogenous pacemakers
sieffre and folkard
chipmunks and hamsters
what are the strengths of exogenous zeitgebers
real world application- research showed that light exposure on people who do East-West flights recover from jet lag- good for economy as persuades more people to fly and people travelling on business can work. more effectively
what are the different lobes in the brain
frontal
parietal
temporal
occipital
what is a ‘lobe’
a part of an organ that differs from the rest
describe the somatosensory area
located at the front of the parietal lobes
separated from motor area by a ‘valley’
where sensory information from the skin is represented
the amount of the area dedicated to a body part denotes its sensitivity- face and hands take up over half of it
describe the motor area
back of the frontal lobes
controls movements on opposite side of the body
damage can lead to loss of fine movements
describe the visual area
in occipital lobe
left gets info from RFV
right gets info from LFV
damage to this area can result in partial blindness in each eye (dependant on side)
describe the auditory area
temporal lobes
analyses speech based info
the more severe the damage the more extensive the loss
describe the Broca’s area
located in left frontal lobe
for speech production
based off post mortum of Tan (only word he could say)
damage leads to Broca’s aphasia which is characterised by slow speech that lacks fluency
describe Wernicke’s area
located in left temporal lobe
for speech comprehension
damage leads to wernicke’s aphasia- characterised by fluent speech of nonsense words (neologisms)
what is contradictory evidence against lateralisation (ao3)
Nielsen analysed brain scans of 1000 people from 7-29 and found that while people did use different hemispheres for different tasks there was no evidence for a stronger side. notion of left brained and right brained people is therefore wrong
what is supporting research for lateralisation
Luck’s research into Michael gazzaniga found that people with split brains were better at things such as identifying an odd one out. supports Kingstone’s idea that the LH’s better cognitive strategies are ‘watered down’ by the RH
rogers chickens
what is the definition of plasticity
the idea that the brain has the ability to change throughout life.
what did Gopnick find
number of synapses per neutron peaks at 15,000 at 2-3 years old- twice as many in the adult brain.
what is synaptic pruning
when unused synaptic connections are deleted while frequently used ones are strengthened. this is how plasticity works
what are two studies that support plasticity
Maguire
draganski
what is functional recovery
when the brain recovers from trauma by other areas of the brain taking up the functions of damaged areas. this can happen rapidly (spontaneous recovery) before slowing down over the next few weeks and months when therapy may be needed for further improvement.
what is the evaluation for plasticity
bezzola
bi-lingual
what is the evaluation for functional recovery
constraint therapy
school
jody
what is contrasting evidence for exogenous zeitgebers (AO3)
blind man with 24.9 hour sleep wake cycle was exposed to cues such as regular mealtimes and waking times etc but this did not fix the cycle
inuits in the artic circle maintain regular sleep wake cycles despite spending six months in total darkness
what are newborn babies sleep wake cycles
random
when do babies develop circadian rhythms
around 6 weeks
what are babies biological rhythms like by 16 weeks
depends on the schedules imposed by the parents- meal times and bed times etc
what role does the pineal gland play in secretion of melatonin
the SCN passes information it receives on day length and light to the pineal gland. pineal gland then increases or decreases production of melatonin
describe the SCN
tiny bundle of nerves in hypothalamus in each hemisphere
nerve fibres connected to the eye cross in the optic chiasm
the SCN lies just above the optic chiasm and receives info from this structure about light levels
continues to work even when eyes are closed
