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