Biopsychology Flashcards
Robert suffered a stroke at the age of 55. After the stroke he was paralysed down his right side, though he could move his left arm and leg easily. Robert could clearly understand what was said to him, but was unable to produce any speech.
Discuss how knowledge of hemispheric lateralisation and language centres in the brain has helped our understanding of cases such as Robert’s.
Refer to Robert’s case in your answer
- different parts of the brain perform different functions
- functions are specific to individual parts of the parts
what two halves is the brain divided into
the left and right hemisphere which are divided by a small gap
what is localised to the left hemisphere
language
what is localised to the right hemisphere
spatial skills
what is hemispheric lateralisation
different sides of the brain perform different functions
Patient tan lost the ability to speak. Based on your knowledge of hemispheric lateralisation, where did Tan have damage
left hemisphere
what is Contralateral organisation
is when the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.
what are both hemispheres of the brain involved in
the 5 senses and controlling our movement
what does contralateral mean
opposite side
what functions are organised contralaterally
vision, movement, touch
how do the right and left hemisphere communicate
communicate by sending nerve impulses to each other using the corpus callosum.
what is the The corpus callosum
a bundle of axons that connect the hemispheres. It acts as a bridge between the two hemispheres
what does it mean if some functions are processes by only one side of the brain
they are hemispherically lateralised
Explain what is meant by contralateral brain organisation
Contra means ‘opposite’, and lateral means ‘side’, so contralateral means that some functions of the brain controls the opposite side of the body. Contralateral brain organisation means that the right hemisphere controls the left side of the body, and the left hemisphere controls the right side of the body.
Which two regions of the brain are involved in the fight or flight response?
Hypothalamus, pituitary gland.
what are split brain patients
patients whose corpus callosum has been cut
what happens when he corpus callosum is cut
the two hemispheres can no longer communicate
what is the procedure used in split brain research study
- patients are sometimes asked to respond to a stimulus that has been presented to them, by pointing at the stimulus that matches the one they were shown
- patients are sometimes asked to describe a stimulus that has been presented to them
what is the method used in split brain research
1) present stimulus to left or right side of brain
2) ask patient to respond to the stimulus
what are the results of split brain research
Sperry’s study:
he concluded that language is hemispherically lateralised to the left hemisphere
patients could match the pictures whether or not it was presented to the right or left hemisphere
In Sperry’s original study, he showed split-brain patients a stimulus, to either their right or left hemisphere. He then later asked patients to point to that same stimulus, when showed a choice of four different ones. Patients could point to the correct image. Explain why this happened.
The ability to visually process and identify the image isn’t hemispherically lateralised. Therefore regardless of which hemisphere the information was presented, the participant had still processed the information and was able to point to the correct stimulus from the choice of four.
When participants were asked to respond verbally to a stimulus, their response depended on which side the information was presented to. Explain why these results occurred in Sperry’s subsequent study.
The ability to say what was processed by the left hemisphere occured because language is hemispherically lateralised to the left hemisphere. If a stimulus is presented to the right hemisphere, a split brain patient is unable to identify or describe it, because language is not processed in the right hemisphere.
What are the limitations of split-brain research?
- the study contains confounding variables
- the study has not been consistently replicated
- the study lacks generalisability
- the participants brains were abnormal
what could Danelli conclude about hemispheric lateralisation from doing a case study on EB
hemispherically lateralised functions can be taken over by the other hemisphere in some conditions
Explain one issue of using patients who have undergone split-brain surgery to study hemispheric lateralisation of normal people’s brains.
Split-brain patients have had the surgery to split their brain because they were experiencing severe seizures. So, it’s possible that these patients’ brains are organised differently to other people’s brains. Therefore this is a confounding variable in the interpretation of the study, because it may actually be their different brains that cause any results rather than their corpus callosum being severed.
what is the cortex
the outer surface of the brain
what does the motor cortex do
controls body movement on the right side of the body
what does the somatosensory cortex do
processes the feeling of touch. the somatosensory cortex in the right hemisphere controls the left side of the body. and the somatosensory cortex in the left hemisphere controls the right side of the body
where is the somatosensory cortex located
behind the motor cortex
how does the auditory cortex process sounds
by receiving nerve impulses or impulses from sensory neurones that talk to sensory receptors in the ears
where is the auditory cortex located
behind and slightly below the somatosensory cortex
what does the auditory cortex do
processes sound. There is an auditory cortex in both hemispheres, but the auditory cortex is not organised contralaterally
where is the visual cortex located
right at the back of the brain
what des the visual cortex do
processes vison. Both hemispheres are involved in processing vison. The visual cortex works by receiving nerve impulses from sensory neurones that talk to sensory receptors in your eyes. Vison is organised contralaterally
where is the brocas area located
below and slightly in front the motor cortex
what is the function of brocas area
involved in producing language, so we can say it is hemispherical lateralised to the left hemisphere
where is the Wernickes area located
behind the auditory cortex
what is the function of wernickes area
- enables us to understand written language
- enables us to understand speech
- hemispherically lateralised to the left hemisphere
what is aphasia
- when people lose the ability to produce language
- when people lose the ability to understand language
what is brocas aphasia
inability to produce language
what is Wernickes aphasia
inability to understand language
Bella was in a terrible car crash and received severe damage throughout the whole cortex of her right hemisphere.
What symptoms would we expect Bella to exhibit?
- Loss of vision to the left of her body.
- Loss of movement to the left half of her body
- Loss of sensation of touch to the left half of her body.
In a conversation, Joseph listens and can understand what people are saying. However, he struggles to express himself verbally. His dad suggested that he writes down what he thinks, or acts it out, but he struggles with this too - his left hand and arm feel like they’re not doing what he wants them to do.
Using the information above, explain what areas of Joseph’s brain might be damaged and why.
Joseph’s Broca’s area could be damaged because he is struggling to create language - he can’t find the right words to express himself. His right motor cortex may also be damaged, because he is struggling to use his left arm and hand, and his right motor cortex controls the left side of his body. Joseph isn’t having any problems with touch sensations, right side of his body or understanding language, so his somatosensory cortex, left motor cortex and Wernicke’s areas seem to be ok.
what are the limitations of localisation of function
- may be over simplified because a complex function often requires more than one brain region/ area
- ignores the importance of communication between brain regions
- it ignores individual differences in brain organisation
what are the criticism of patients tan research
Dronkers found that patient tan had damaged other regions of his brain outside of Brocas area. Dronkers supports the idea that more than one region is responsible for language production
Explain why case studies of patients like Tan support the idea of brain localisation.
Tan displayed difficulties with producing language, and after he had died a post-mortem examination showed damage to his Broca’s area. This suggests that damage to that particular area had caused Tan’s symptoms, supporting that different areas have specific functions.
Explain what Dejerne’s study tells us about brain localisation.
The study demonstrates that the idea that only one brain region contributes to a function is over-simplified. It also shows that even the idea of multiple brain regions contributing to a function is over-simplified. The study illustrates the importance of communication between brain regions, rather than just looking at one area as important to a function.
what parts of the brain are important for memory
temporal lobe, frontal cortex and hippocampus
what regions are located on the brains surface
- somatosensory cortex ‘
- visual cortex
- wernickes area
what regions are located in the middle of the brain
- hypothalamus
- pituitary gland
- hippocampus
- cerebellum
what is a functional recovery
- when a function is regained after brain damage
- when a function is transferred from a damaged brain region to an undamaged brain region
what is synapse strengthening
first step of functional recovery
when the likelihood of of nerve impulses being transmitted during synaptic transmission increases
what is the role of synapse strengthening in functional recovery
after brain damage, synapse strengthening occurs, meaning that synapse is strengthened in brain regions near the damaged area
what is neural rewiring
second step for functional recovery
axons from brain regions that used to communicate with the damaged regions rewire to to form connections with nearby brain regions
does the case of Gage support the localisation of function theory or the holistic theory
the case of Gage supports the localisation of functions theory. it supports the idea that certain functions are associated with specific areas of the brain. in Gages case it was evident that the frontal lobe is associated with personality as Phineas changed
what does plasticity mean
refers to how flexible something is eg muscles in our body
what does brain plasticity mean
refers to the brains ability to change and adapt because of experience. Research has demonstrated that the brain continues to create neural pathways and alter existing ones in response to changing experiences
what is functional recovery
a form of plasticity, the brains ability to redistribute or transfer functions: following damage through trauma
what does pruning mean
where connections are lost due to lack of use
what does Bridging mean
where new connections are created due to use and new stimulus
what was Kuhn study about functional recovery and brain plasticity
got participants to play Mario games for 30 mins per day for two months and then compared their brain development to a control who didn’t. Found significant difference in grey matter of video game participants particularly in cortex
how does the plasticity of our brain change with age
with age gets rid of connections that we no longer use (synaptic pruning ) + adapts to create new connections for new learning
what did Maguire find in a study of taxi drivers ? How does this support plasticity
found significant amounts of grey matter in the post terior hippocampus than in the control group. This part of the brain is associated with spatial skills and navigational skills. This supports plasticity as it shows that the brain can permanently change in response to frequent exposure to a particular task
what did Draganski et al (2006) find about plasticity
imaged the brains of medical students three months before and after their final exams. Learning induced changes were seen to have occurred in the posterior hippocampus and the parietal cortex presumably as a result of the exam
what exactly happens during functional recovery after trauma? how does the brain quickly adapt
After trauma, such as stroke, unaffected areas of the brain are often able to adapt + compensate for those areas that are damaged. Neuroscientists suggest it is a spontaneous recovery then slows down after weeks/ months
what is synaptic pruning
as we age, rarely used connections are deleted and frequently used connections are strengthen end
what is axonal sprouting
undamaged axons grow new nerved endings to reconnect neurons whose links were injured or severed
what is the A03 for plasticity
+ evidence in animal studies
+ continues through age
+ practical application of neural rehabilitation
- potential negative consequences
what is the evidence of brain plasticity in animal studies
nubel and wise (1963) sewed one eye on a kitten shut and analysed the brains cortical response. this shows how loss of function leads to compensatory activity in the brain
what are the potential negatives consequences of brains plasticity
Ramachandran & hirstein found that 60-80% of amputees have developed phantom limb syndrome
what type of experiment was sperrys spilt brain experiment
a quasi experiment 11 participants who were epileptic and had their corpus callosum cut
what are FMRIs scans
A brain scanner which measures increased blood flow to brain sites when individuals are asked to perform cognitive/physical tasks. Increased blood flow indicates increased demand for oxygen in that area.
what are the strengths of FMRIs
Non-invasive – No insertion of instruments unlike PET and no exposure to radiation – Beneficial to the economy as there is no recovery time so people don’t have to be off work.
what are the limitations of FMRIs
Expensive –
fMRI only measures blood flow – it cannot home in on the activity of individual neurons therefore it’s hard to tell exactly what brain activity is being represented on the screen – High likelihood that the findings will be misinterpreted as it doesn’t show activity like EEG/ERP.
what are EEGs
Measures electrical activity in the brain using electrodes attached to the scalp, and measures how electrical activity in the brain varies over time/in different states (e.g. waking vs. asleep). EEG readings can detect epilepsy and Alzheimer’s.
what are the strengths of EEGS
- EEGs have medical applications in diagnosing disorders such as epilepsy and Alzheimer’s.
- Non-invasive - No insertion of instruments EEGs are virtually risk free and is avoidant of any danger to the brain itself.
- Cheaper than fMRI thus making them more available – Psychologists can gather more data on the functioning of the human brain thus contributing to our understanding of different psychological phenomena.
what are the limitations of EEGS
Not highly accurate – electrical activity detected in several regions of the brains simultaneously – Very hard to pinpoint exactly which area is producing this activity. therefore cannot distinguish differences in activity between 2 closely adjacent areas.
• Uncomfortable – Hard for the patients as electrodes are attached to their head – Could result in an unrepresentative reading as the patients discomfort could trigger cognitive responses to the real time situation.
what are ERPs
ERP’s are very small voltage changes in the brain triggered by specific events or stimuli which are measured using an EEG.
Measures small voltages of electrical activity when a stimulus is presented.
what are the strengths of ERPs
Non-invasive - No insertion of instruments no exposure to radiation – Virtually risk free and is avoidant of any danger to the brain itself.
what are the limitations of ERPs
- only monitors electrical activity in outer layers of the brain, therefore, cannot reveal electrical activity deep down in the brain
- poor spatial resolution
what are circadian rhythms
biological rhythms that occur over a 24 hour cycle
what are biological rhythms
patterns of changes in body activity over cyclical periods
what are ultradian rhythms
biological rhythms occur more than one in 24 hours
what are intradian rhythms
biological rhythms that occur less than one cycle in 24 hours
what are endogenous pacemakers
internal body clocks that regulate biological rhythms
what are exogeneous Zeitgebers
External cues that influence our biological rhythms
what does the brains circadian clock regulate
- sleeping + feeding patterns
- alertness
- core body temp
- urine production
what is affected by the circadian clock
melatonin= produced in pineal gland in brain, chemically causes drowsiness and lowers body temp cortisol = produced in the adrenal gland, and used to form glucose + enables anti stress
where is the circadian clock located
in the SCN in the hypothalamus of the brain one in each brain hemisphere
note when sleep wake cycles occur
core temp = 4:30-5:00 am
melatonin produced 8-9pm and stops at 7-8 am
sleepiness occurs 2-3am
what did Aschoff and weber (1976) find about circadian rhythms
found that participants placed in WW2 bunker underground with the absence of any environmental and social cues displayed circadian rhythms between 24-25 hours, with some as long as 29 hours
This shows that circadian rhythms operate in the absence of external cues
what did folkard (1985) find about circadian rhythms
isolated 12 participants from natural light for 3 weeks ( dark cave ) manipulating clocks so that only 22 hours passed a day
one of the Ps could adjust to the clock, showing the strength of circadian rhythms
what endogenous pacemakers and exogeneous Zeitgebers are likely to influence your sleep wake cycle? how?
pacemaker= SCN, the lack of light stimulates the SCN, which sends signals to the pineal gland to release melatonin, which in turn promotes wakefullness os sleep is triggered
light + Zeitgebers as demonstrated by campell + murphey who found that circadian rhythms were shifted when light was shone at the back of knees
AO3 for circadian rhythms
- support from cave study
- issues with cave study evidence
- poor control of studies
what is a silent synapse
a synapse that becomes inactive due to lack of nerve impulses
what is the 3rd mechanism to enable functional recovery
unmasking neural connections
what are mechanisms for brain plastcity
- rewiring
- synapse strenthening
- neural unmasking
Explain how neuronal unmasking contributes to learning
Neuronal unmasking is when silent synapses become active and so reveal hidden neuronal connections between brain regions. These hidden connections reactivate to help our brain to change and adapt to new experiences, which contributes to learning.
what is the method for maguire taxi study
- used a MRI scanner to investigate brain plasticity
- performed quasi experiment
- compared the brain of london taxi drivers to non taxi drivers
what are the limitations of maguire taxi study
- didn’t use random allocation because she couldn’t directly manipulate the IV
- couldn’t establish a cause and effect relationship, because she couldn’t directly manipulate the IV
- couldnt control the participant variable, because it was a quasi experiment
what are infradian rhythms
last longer than 24 hours and can be weekly, monthly and annually such as menstrual cycle and hibernation in animals
what happen occurs in the monthly infradian rhythm of menstrual cycles
- regulates hormones
- ovulation occurs half way through cycle when oestrogen cycles are highest
- after ovulation, progesterone levels increase, ready for possible embryo
what is sad
- seasonal affective disorder is an infradian rhythm, related to the seasons (yearly cycle)
- melatonin is secreted by the pineal gland at night
- longer nights= increased melatonin secretion
- linked to increase in depressive symptoms
what did Reinberg say about infradian rhythms
A03 examined a woman who spent three months in cave with only a small lamp to provide light. Reinberg noted that her menstrual cycle shortened from the usual 28 days to 25.7 days. This suggests that exogeneous Zeitgebers such as light helps regulate our menstrual cycle
what did Russel et find about infradian rhythms
A03 found that female menstrual cycle became synchronised with other females through odour exposure. In one study, sweat samples from one group of women were rubbed onto the upper lip of another group. Despite the fact that the two groups were separate their menstrual cycle was synchronised
what does Russel et al study suggest
this suggest that synchronisation of menstrual cycle can be affected by pheromes (exogenous Zeitgebers) which have an affect on people nearby rather than the person producing them
what are ultradian rhythms
fewer than 24 hours such as meal patterns and human sleep patterns
this also means that you can go through more than one cycle
what happens in stage 1 and 2 of human sleep patterns
- light sleep- brain patterns become slower ( starting with alpha waves, progression to theta waves
what happens in stage 3 and 4 of human sleep patterns
- deep sleep or slow wave sleep stage ( associated with delta waves)
what happens in stage 5 of human sleep patterns
- REM = rapid eye movement.
- body is paralysed: desynchronised brain waves
what is the randy Gardener study on ultradian rhythms
he remained awake for 264 hours
- after this experience, Randy slept for just 15 hours and over several nights has recovered only 25% of his lost sleep. Interestingly, he recovered 70% of stage 4 sleep and very little of other stages
what does the study on randy gardener show
the results highlight the large degree of flexibility in terms of the different stages within the sleep cycle and the variable nature of this ultradian rhythm
what did Tucker et al find about ultradian rhythms
AO3 found significant differences between participants in terms of the duration of each stage, particularly stage 3 and 4 ( just before REM)
what dies Tucker et al study demonstrate
demonstrates that there may be innate differences in ultradian rhythms which means that it is worth focusing on these differences during investigations into sleep cycles
what was the method used in Maguire’s study?
- quasi experiment
- IV = participants job, natural occurrence
- DV= volume of hippocampus
what are the limitations for Maguire study
quasi = couldn’t control participant variables, also couldn’t randomly allocate participants to either experimental or control group
