Brain

• define lateralisation

  the idea that the 2 halves of the brain are functionally different and certain processes/behaviours are controlled by 1 hemisphere
• which side of the brain processes right/left side of the body

  RIGHT side of the brain processes info from the LEFT half of the body - e.g visual info from the left eye

  LEFT side of the brain processes info from the RIGHT half of the body - e.g visual info from the right eye
• what type of research was performed into lateralisation

  split brain research
• who are split brain patients

  a unique grouo of patients who had a corups callostomy to control their frequent and severe epileptic fits
• what is a corpus callostomy

  the corpus callosum is severes so separates the two hemispheres in the brain so they don't communicate with each other
• who performed research into split brain patients

  Sperry (1986)
• what was the aim of Sperry's research

  to investigate what functions of the brain are lateralised
• what was the procedures for this study - what were the 2 types of tasks

  compared split brain patients with controls that had no hemisphere separation, different activities were tried with the patients to see how different sides performed

  VISUAL tasks: a word/picture is presented into the left or right hemisphere and patient is asked something about the stimuli

  TACTILE tasks: using objects with the p's handss underneath a screen so they couldn't see, so had to use touch only
• what 4 functions did Sperry investigate

  1. describing what they see in the visual field

  2. recognition by touch

  3. drawing

  4. face recognition
• what were the findings of describing what they could see when shown to left or right visual field

  shown to LEFT visual field = unable to describe it, often reported nothing there

  shown to RIGHT visual field = could easily name/describe the picture shown
• what were the findings of recognition by touch when asked to pick up an object shown the their left eye

  shown an object to LEFT visual field and asked to pick it up = capable of selecting the object, as it was processed by RIGHT hemisphere which controls the LEFT hand - but unable to say anything about it
• what were the findings of recognition by touch when 2 different objects were placed in each hand then hidden for retrieval in a pile of items

  EACH hand searches for its own object, but if the LEFT hand picks up the object that the RIGHT hand is searching for, the object would be rejected
• what were the findings of drawing ability when a picture is shown to left or right visual field and asked to replicate it - which side was better

  the drawings were consistently better when drawn by the LEFT hand and controlled by the RIGHT hemisphere, despite all p's being right handed
• what does this suggest about the right hemisphere

  the right hemisphere has a superior drawing ability, compared to the left
• composite words - when a patient was shown 2 different words to their left and right visual field (left = ring, right = key) what would they say and what would they pick up with their left hand

  they would say key as it was processed by the LEFT hemisphere but would pick up the ring with their left hand as it was processed by the RIGHT hemisphere
• what do these findings show about the hemispheres

  the hemispheres function independantly
• what were the findings of face recognition when they were shown a picture with the left half a woman and right half a man (each visual field could only see 1 half) and asked to name who they saw

  LEFT hemisphere deals with language so they would say man, as that side was seen by the RIGHT eye so processed by the LEFT hemisphere
• what was concluded about lateralistion from these studies

  the hemispheres of the brain process info seperately and they have different functions which supports lateralisation

  also p's seem to have seperate streams of consciousness, with their own memories and perceptions
• what does the right hemisphere deal with

  spatial orientation, drawing ability, face recognition, visual imagery
• what does the left hemisphere deal with

  language ability, logic, maths
• what advantage is assumed about having a lateralised brain

  it increases neural processing capcity, as each hemisphere can engage in different functions
• give an example of evidence that supports this assumption

  in chickens brain, lateralisation was associated with enhanced abilities in finding food and simultaneaously staying vigilant for predators
• how does this support the advantages of lateralisation - however?

  this supports that brain lateralisation enhances brain efficiency in cognitive tasks that demand simultaneous, but different uses of both hemispheres

  However, the findings from chicken behaviour may not generalise to human brain functioning

  Also there is little empirical evidence to show the advantages of lateralisation for functions of the brain
• what research supports that lateralisation can change over time

  research found that language became more lateralised to the left hemisphere with increasing age in children and adolescents, but after 25 it can decrease with each decade
• why do they suggest that age can be a factor that affects brain lateralisation

  one possibility is that using the extra processing resources of the other hemisphere can compensate for age-related declines in functioning
• what early claims about lateralisation have now been disputed with evidence

  split brain research suggested that the right hemisphere was unmable to handle any language, However case studies such as J.W go against this - he developed the capacity to speak out of his right hemisphere
• what does this suggest

  lateralisation may not be the same for everyone
• give an evaluation of Sperry's split brain research involving the tyoe of method used

  the method was a Quasi experiment in controlled conditions

  + controlled conditions = standardised procedures that are the same for everyone, so high internal validity

  - in real life patients can adjust their visual position so information can go into both hemispheres, so lacks ecological validity
• what can be said about the population validity and generalisations

  the sample used 11 split brain patients, so has low population validity as you may not be able to generalise findings

  ALSO it may be inappropriate to make generalisastions about non-epileptic brain patterns from split brain patients, as their previous epileptic seizures could have caused changes to their brains, which could be a counfinding variable and affect the findings
• define plasticity

  the brains ability to change and adapt (functionally and physically) as a result of normal experiences/learning

  
• define functional recovery

  a form of plasticity where the brain can regenerate or transfer functions, usually performed by a damaged area to another area of the brain

  
• why does synaptic pruning occur - what is it

  during infancy the brain rapidly grows in synaptic connections, these connections go through synaptic pruning: deleting those that aren't used and strengthening those that are used through myelination
• what are the 2 examples of evidence for synaptic pruning

  + Maguire:

  compared taxi drivers to non-taxi drivers in an MRI scan

  + Kuhn et al: Super Mario

  compared a control group to one that was trained for 2 months on the game super mario
• what were the findings of Maguire's experiment - what does this show/support

  findings: more grey matter in hippocampus of taxi drivers than controls, there was a positive correlation between length of time in the job and the size of differences

  This supports plasticity as there were changes in the brain due to spatial knowledge/memory changing

  
• what are 2 strengths of this research on plasticity

  + control groups: significant difference between taxi drivers and other

  + scientific methods: objective measurements, MRI
• what is a weakness of Maguire's plasticity research

  - cause and effect: they weren't tested before so ca't be sure the difference is due to knowledge, e.g they could've become taxi drivers because their memory is good
• what were the findings of the super mario experiment - what does this show/support

  findings: increase in grey matter in cortex/hippocampus/cerebellum compared to controls

  This shows that game training results in new synaptic connections in areas involved in spatial navigation, working memory and motor performance, so supports plasticity as these areas are used in game training and changed over time - potential cause and effect, control didn't change

  
• what does recovery from brain trauma involve - what happens to damaged areas of the brain

  following brain trauma (e.g stroke), the unaffected areas of the brain adapt and compensate for those that are damaged
• what is functional recovery a form of - why

  it is a form of plasticity as healthy brain areas take on functions damaged by trauma
• how does the brain recover

  neural reorganisation: transfer of functions to undamaged areas

  neural regeneration: growth of new neurons/connections to compensate for damaged areas