A2 Biopsychology Flashcards
What does hemispheric lateralisation mean
Each hemisphere of the brain is specialised to perform different functions
What is the function of the occipital lobe
Proccess visual information
Contralateral
Where is motor cortex
Motor cortex found in frontal lobe
Contralateral
What is the function of the somatosensory cortex and where is it
In the parietal lobe
Separated from motor cortex by the central sulcus
Responsible for sensory information from skin
Where is the auditory cortex found
Found in near the temporal lobe
Controls auditory information
Damage my produce hearing loss
What is Broca’s area
Broca’s area
Responsible for speech production
left frontal lobe
Damage can lead to brocas aphasia (speech can sometimes lack fluency etc)
Where is wernickes area
And what is it’s function
In left temporal lobe
Responsible for being able to understand speech.
Damage leads to wernickes aphasia
No problem producing language but difficulty it. Language produced is fluent but meaningless
What is damage to both wernickes and brocas called
Global aphasia
Evaluation of localisation of function: Case studies
Strengths
Case studies like Tan, gage, show how loss of certain functions is due to damage caused in that area
Suggests that functions are localised
Counterpoint: use of case studies may be unscientific as when a modern MRI was done on Tans brain
Showed damage to more than Broca’s area
Shows how localisation is a limited explanation
Evaluation of localisation: evidence for neurosurgery
Strength
P: damage linked to mental disorders
E: Dougherty et al found 30% of 44 people had met critera for a full recovery
14% were partial when undergoing cingulomoty
Success shows that behaviours may be localised
Evaluation of localisation of function brains scans
Strength
Point: supports everyday functions are localised
E: buckner and Peterson found semantic and episodic memories are in different parts of prefrontal cortex
E: shows how parts of everyday life are localised, futher support from case studies
L:
Counterpoint: Lashley found that higher cognitive processes such as learning are not localised and memory are not localised. By the way he removed parts of rats brains and made them do a maze
Evaluation of localisation of function: is language really localised
P: language may not be localised
E: Dick and Tremblay found that only 2% of modern researchers think language is localised
E:shows how language may be distributed holistically across the brain
L: this contradicts localisation theory
Why is language lateralised
The language centres of Broca’s area is in the left frontal lobe
And wernickes in left temporal lobe.
So language is lateralised
What is contralateral wiring and give an example
The motor cortex is contralateral because the RH controls the left side of the body and the LH controls movement on the right
Other examples like vision and somatosensory areas appear in both hemispheres
What type of wiring does vison have
Ipsilateral and contralateral (so it’s opposite and same sided.
For example light is received the left visual field and the right visual field.
The LVF of both eyes is connected to the right hemisphere and the opposite is true for the RVF.
This enables the visual areas to compare slightly different perpectives which adds depth
.split brain research
What is it
Who done it
What was the procedure
What were the findings
What is it?
Surgical procedure to reduce epilepsy
When you cut corpus colosseum
Who done it
Sperry conducted a study on patients who had this done
Procedure
- 11 people were studied
- image was shown to a Ppts RVF and the same or different image would be shown to LVF. Participants were asked to pick up the image, say what the image was etc
Findings
When image was shown to RVF (linked to LH) ppt could describe what was seen but not when shown in LVF (linked to RH) because language centres are located in LH. Often they would say there’s nothing there
Ppts could select the object when it was shown LVF. They could select objects using left hand linked to RH.
Conclusion
Show how functions are lateralised
And how LH verbal and RH silent but emotional
.evaluation of lateralisation
Connected brains
Fink et al used PET scans to identify parts of brain that were active during a visual processing task
When looking at pictures of a whole forest RH was more active
When asked to focus on finer details LH tended to dominate
Suggest lateralisation is a feature of a connected brain as well as as split brain (?)
Evaluation of lateralisation
Right brain and left brain
Limitation is the idea that RH is synthétiser and LH is analyser may be wrong
Nielson et al suggests that people don’t have a dominate side
Analysed brain scans of over 1000 people and did find that people used different hemispheres for different tasks
But no evidence of a dominant side (so a mathematicians brain or an artists brain)
Evaluation of lateralisation
Lateralisation vs plasticity
Can be adaptive as two tasks can be performed simultaneously with greater efficiency
Rogers found that ‘lateralised chickens’ could find food whilst watching for predators but normal couldn’t
However neural plasticity could be seen as adaptive
Some functions can be taken over by non specialised areas. Language may switch sides (Holland et al)
Evaluation of split brain research
Support
Gazzinga showed split brain Ppts perform better than connected ones on certain tasks
For example they were faster at identifying the odd one out.
In normal brain LH cognitive strategies are watered down by RH (Kingstone)
-supports sperry findings of left and right brain
Evaluation of split brain research
Generalisation
-casual relationships hard to establish
Although behaviour was compared to a control group
None of the Ppts had epilepsy which was a major confounding variable
This means that unique features may have been due to the epilepsy
Evaluation of split brain research
Ethics
The trauma of the operation might have meant the Ppts did not understand the implications of what they had agreed to
They were subject to being tested over repeatedly which may have been stressful
However sperry did explain the procedure and did follow ethical guidelines. The patients had the opportunity to withdraw at any time. So perhaps sperry research would be considered ethical
What is plasticity
How the brain adapts change as result of experience or new learning
What are the reasons for plasticity
- learn new skills
- result of developmental changes
- direct trauma to area of brain
- due to indirect trauma such as a stroke
What is functional recovery
Healthy areas of brain compensate for lost neuronal pathways
What is synaptic pruning
Strengthen neuronal pathways
What happens in the brain when recovering
Axonal sprouting: growth of new nerve endings which connect undamaged nerve cells to form new neuronal pathways
Denervation supersensitivity: occurs when axons do a similar job but become aroused to higher level to compensate for ones lost (can be negative and cause pain)
Recruitment of homologous areas: Specific tasks can be performed but by other parts of the Brain
AO1 research about plasticity
Maguire et al
Found significantly more grey matter in hippocampus than in a matched control group
London taxi can drivers
Also found longer they been in job the more different hippocampus was
Supporting evidence
Draganski: took brain images of med students and found that changes occurred three months after exams as a result of learning
Evaluation for plasticity: Negative plasticity
P: negative behavioural consequences
E: médina et al found that adaption to prolonged drug use leads to poorer cognitive function in later life and risk of dementia
E2: phantom limb syndrome, 60-80% of amputees known to develop phantom limb syndrome, people develop pain due to cortical reorganisation in somatosensory cortex (hirstein)
E: shows how brains adaptions may not always be functional and can result in pain, or negative implications in later life
Evaluation for plasticity: Age
P: life long
E: bezzola et al found 40 hours of golf training produced changes in neural representation. Fmri showed increased motor cortex
E: shows how this gives hope for people
L: demonstrates of how plasticity can be positive
Evaluation of plasticity: real life application
P: can be used to help patients recover
E: constraint induced therapy Is used with stroke patients
E: can help healthcare professionals, makes people’s lives better, can help economy etc
L: shows how understanding plasticity can contribute to cultivating new neuroréhabilitation techniques
Evaluation of plasticity: supporting evidence for functional recovery
P: supporting evidence to for functional recovery
E: EB had a hemispherectomy on left side of brain (removed left side), fmri scans showered how left like a blueprint for language
E: shows how even in cases extreme trauma the brain can recover could argue things like age being a factor as children recover quicker
L:
Evaluation of plasticity: individual differences in recovery
P: limitation as level of education can affect recovery rates
E: schinder et al found more time people were in education the more cognitive reserve they had, greater chance of disability free recovery
CP: can be damaging to people’s recovery rates,
40% with DFR had 16 years of education
Link: implies people with less CR less likey to recover
What is spatial resolution
level of accuracy identifying exact location of brain structure in space (where it happened
What is temporal resolution
level of accuracy in identifying exact location of where a brain activity happened in time (when activity happened)
What is post mortum dissection and what are the advantages and disadvantages of it
What is it?
When you dissect brains of people who suffered trauma and mental disorders and compare them to neurotypical brains. Example brocas area
Advantages
- Spatail resolution: can study brain in microscopic detail down to neurons
- technique has significant historical development of psychs understanding language centers
- able to see deep brain structures like hypthalmus
Disadvantage
-Problem with causation, after death means that you can’t see the brain in action, hard to make a correlation to damage in brain to behaviour seen in life. There also may be confounding variables that caused a change in brain structure like drugs
Ethical issues: people may not be able to provide consent (like HM )
What is fMRI and what are the advantages and disadvantages
What is it
can detect blood flow in brain. When doing a task there will be more blood flow to part of brain that controls it (haemodynamic response)
This then produces a 3D image showing parts of brain involved
Advantages
- Has good spatial resolution, so it can identify areas of brain involved when doing a task
- non invasive as it uses magnets, so better than PET scans, beneficial to econmey as people can recover quicker
Disadvantages
- low temporal resolution: 1 image can be taken every few seconds, so it would be hard to study brain processes that are very fast
- as it only measures blood flow, it cannot tell you what individual neurones are involved, so hard to tell what’s being shown, may be misinterpreted
- machine is expensive to build and operate, EEG is cheaper and captures more
What is an EEG and what are the advantages and disadvantages
What is it
an electroencephalogram, you were a cap with electrodes that measures activity. EEG readings are used In sleep studies and can detect Alzheimer’s and epilepsy
Advantages
- has good temporal resolution
- Has medical applications as it can diagnose epilepsy and Alzheimer’
- non invasive as there are no instruments inserted into brain
- cheaper than fMRI and is able to use in experiments when subjects are moving
Disadvantges
- lack of spatial resolution: only detects activity of cortex and not brain structures deep within
- Lack of spatial resolution hard to pinpoint exactly which area is producing activity. Cannot notice differences in activity between 2 areas near each other
- uncomfortable for ppt, which could result in a reading that is unrepresentative due to the discomfort triggering a result
What is an ERP and what are the advantages and disadvantages
What is an ERP
ERP’s are small voltage changes in the brain triggered by specific events or stimuli measured using an EEG. Stimulus is shown repeaditly as voltages can be hard to pick out from electrical activity of brain.
Advanatages
- Allows for changes to the stimulus can be directly recorded, as there is a measure of neuronal activity
- Good temporal resolution
- non invasive
Disadvantages
- only monitor activity in outer layers of brain so poor spatial resolution
- hard to control variables electrical activity may not even be due to stimulus
- lack of standardisation in methodology
What is an endogenous pacemaker
Are the internal body clocks that keep biological processes to time
What is an exogenous zeitgeber
External cues that entrain internal body clocks, so they alter body clocks to match the environment
What is a circadian rhythm
A biological rhythm that lasts about 24 hours
Give examples of circadian rhythms
Sleep wake Hormones Body temp Blood pressure Etc
What is the endogenous pacemaker for the sleep wake cycle and what does it do
Called the superchiasmatic nucleus
- Also know as master clock
- Found in hypothalamus within the limbic system
- nerve fibres connected to eye cross an area called optic chiasm.
What does it do?
When light is detected by SCN it sends light to pineal gland
Stopping production of melatonin (hormone that makes us sleepy)
What research is there for the SCN
Animal studies
De coursey et al
- the de coursey et al destroyed SCN connection in 30 chipmunks
- the chipmunks were retuned to their natural habitat
- they were observed for 80 days
- sleep wake cycle of chipmunks disappeared and many chipmunks were killed
Ralph et al
- Bred mutant hamsters with 20 hour sleep/wake cycle
- when SCN of mutant hamsters were planted into brain of normal hamsters their sleep wake cycle was 20 hours
What is the role of the pineal gland
- The SCN passes info on the day and length and light that it receives to pineal gland
- based on this during the night melatonin is increased
What exogenous zeitgebers are involved in sleep wake cycle
Light
- Campbell and Murphy demonstrated that light may be detected by skin receptors sites on body
- Light was shone on back of their knees
- researchers managed to change sleep cycle by 3 hours in some cases
- this shows how light is a powerful exogenous zeitgebers and there are other light receptors in our body
Social cues
- at 6 weeks a babies sleep wake begin
- at 16 weeks a babies rhythm has been trained by schedules imposed by parents
- research into jet lag shows that adapting local times of eating and sleeping is an effective way of beating jet lag
What is a limitation of SCN research
Research has found that there are peripheral oscillators in organs such as the lungs pancreas and skin
- these are influenced by SCN but can act independently
Damiola et al found that changing feeding patterns in mice could alter circadian rhythm in cells by up to 13 hours
But the rhythm of SCN is unaffected
This suggests that there are complex influences of sleep wake cycle
What is another limitation of studies about endogenous pacemakers
- they can’t studied in isolation
- total isolation studies such as siffre are rare
- in every day life both EPs and EZs interact so it would make little sense to isolate them as it would affect the external validity of the research
What is a limitation of using animal studies
Animal studies can be justified as generalisations of the sleep wake cycle can be made to human as we both have SCN and the pineal gland
This is because of adaptive reason
But ethically it is wrong
The study put the chipmunks at risk of dying
In fact some did die
What is a limitation of research of EZs
- EZ don’t have same effect in all environments
- people who live in places that are dark all year round like the artic circle have similar sleep wake cycle
- this suggest that EPs have more of an influence than EZ
What is another limitation of EZs
Case study
Miles et al
- did a study with a man who was blind from birth, his CR was 24.9 hours
- despite exposure to social cues such as regular metal times his sleep wake cycle could be adjusted
- suggests that social cues alone aren’t effective when resetting a biological rhythm
Supporting evidence for EZs
Elderly
Duffy et al
Found 30% of people of 60 have chronic insomnia
-this may be due to natural changes in CR as we age
Hood et al found if management of insomnia was improved if people were generally more active and had exposure to more light
This suggest that EZs can influence biological rhythm
Siffre cave study
What did he do to
What did he find
What is a criticism of this study
What he did?
- deprived himself of exposure to natural light and sound, clocks etc
- spend 2 months in a cave
What he found
-his free running biological rhythm settled down to was that was about 25 hours, but he has a regular schedule
Criticism
Suggest artificial lights can disparut measurements of free running CR by acting as EZs
What evidence is there that light is an EZ
- 27 office workers were exposed to blue light
- they would shift their CR to match office lighting
- the control group would match it natural light
This suggest that both light and artificial light can disrupt EP by overriding natural light as primary EZ
What is a strength of studying circadian rhythm
Provides understanding of conséquences occur when CR is disrupted
For example bolvin et al found that night shift workers have a reduced concentration at 6am called a circadian trough.
Also knuston found that workers are 3x more likely to have heart attacks
Research like this can have a postive affect on the economy and business can adapt working hours to ensure max worker productivity
CP
Research on this is usually correlational, this means it can hard to establish whether the sleep wake cycle being adjusted is the cause of negative affects. There may be other confounding variables at play like stress at home. This suggests that biological factors may not be associated with consequences of shift work
What is a strength of research into circadian rhythms
Medical treatment
- can be used to improve medical treatments
- chronotheraputics is how medical treatment can be administered in way that corresponds to biological rhythms
- for example aspirin is effective when take at night as heart attacks are more likely in the morning (bonten et al)
- this shows how CR research can help increase the effectiveness of drug treatments
- help economy etc
What is a limitation of research into CR
- It can be hard to make generalisations
- studies like Siffre and ashcoff are based ok small samples of Ppts.
- this suggests that Sleep/wake cycles vary from person to person
Czeisler
-found that individual differences in sleep wake cycles vary from 13 hours to
Moreover Duffy found that some people are prefer going bed early and rising early whereas others prefer the opposite
This demonstrates how it can be hard to say how long your sleep wake cycle should be as it different for everyone
Evaluation of CR
School starting later
Wolfson et al suggested that school start a few hours later to fit a teenagers sleep wake cycle
Some research has shown how this can have a positive effect on academic and behavioural performance
However this may not be practical for parents or teachers even if it has benefits
What is an infradian rhythm
A biological rhythm which is less frequent that 24 hours
What type of rhythm is the menstrual cycle
Approx 28 days
Governed by changes in hormone levels
What research is out there to suggest That your menstrual cycle is influenced by exogenous factors
Stern and McClintock
Study 29 women with a history of irregular periods
Pheromones were gathered from nine of the women at different stages of the menstrual cycle via a cotton pad placed in there
The pad was rubbed on the upper lip of participants
Day one pads from the start of the menstrual cycle apply to or 20 women day to the pad was given on the second day of the cycle and so on
Stern and McClintock found that 68% of women experience changes in their cycle which brought them closer to the cycle of the odour donor
What is seasonal affective disorder
It is a recurrent major depressive disorder which is which has a seasonal pattern
Usually happens In winter when there is a lack of light
Leads to increased melatonin
Symptoms: insomnia, lethargic, guilt/dispair
Treated with light therapy
What is an Ultradian rhythm
Biological rhythm that occurs through 24 hours
Example stages of sleep
What are the stages of the sleep cycle
Stage one light sleep this is when a person can be easily woken up
brain waves have high frequency and short amplitude
avoid continue but there are occasional random changes could split second spindles
stage three and four deep sleep or slow asleep.
brainwaves are Delta waves with low frequency and high amplitude
-hard to wake someone up
stage five
(rem sleep)
-body is paralysed
-brain activity resembles that of awake brain
-rapid eye movement happens and dreams are experienced
What is a strength of menstrual synchrony
It may have an evolutionary basis
Could be advantageous for women to menstruate together and become pregnant at the same time
This is good social groups allow babies who lost mothers to access breast milk increasing survival
Alternative explanations include stops 1 male dominating group increases genetic diversity
What is the limitation of McClintock study
Although they have been replications of McClintock study like Russell that showed positive results
There is not that much supporting evidence
For example Trevathan then showing that cohabiting lesbian couples did not synchronise even though they had optimal conditions for possible synchronisation
This suggests that there may be other factors in play when it comes to the synchronisation of menstrual cycles
What is a methodological limitation of synchronisation studies
Factors like stress changes in diet and exercise can affect the menstrual cycle
This can act as confounding variables
Suggest that patterns of synchronisation could have just occurred by chance
So studies of synchronisation may be flawed
Real world application of SAD treatments
Sanassi
Light therapy refuses effects of SAD by 80% in some people
Light therapy preferred over ADs
What is the strength of research ultradian rhythms
Has improved understanding of age related changes in sleep
Scientist observes SWS reduces with age
Cauter et al
Sleep deficits may explain issues in old age like alertness
In order to increase SWE relaxation may be used
Suggests that knowledge of ultradian rhythms has practical values
What is the limitation of ultradian rhythms research
There is variation between people
Tucker et Al
Found differences between participants in terms of duration of each sleep stage particularly in stages three and four
Tucker suggests that these differences are biologically determined
What are the strengths and limitations of using a sleep lab
A strength is that you can control extraneous variables which increases internal validity
A limitation is that be being attached to complicating machinery can lead participants to sleep in the way that does not reflect their ordinary sleep patterns
This may be solved by conducting studies in peoples own homes
