Please enable JavaScript.
Coggle requires JavaScript to display documents.
localisation of function in the brain and hemispheric lateralisation -…
localisation of function in the brain and hemispheric lateralisation
localisation of function
refers to the principle that specific functions (language, memory, hearing etc.) have specific locations within the brain
motor cortex
responsible for voluntary movements
located at the back of the frontal lobe
important for complex movement not basic actions; coughing, crying, gagging
brocas area
responsible for speech production
damages result in slow speech which lacks fluency (brocas aphasia)
located in left frontal lobe
auditory area
concerned with hearing, analyses speech-based information
located in temporal lobes
damage may produce hearing loss
wernickes area
located in left temporal lobe
responsible for language comprehension (understanding)
damage results in wernickes aphasia- produce nonsense words as part of speech
visual centre
located in the occipital lobe at the back of the brain
each eye sends information to the opposite side of the occipital lobe
damage in left hemisphere can cause blindness in the right visual field of both eyes
somatosensory area
found at front of parietal lobe
area where sensory information from skin (heat,pressue) is represented
evaluation
strength-case study of Phineas gage provided supporting evience. experienced damage to frontal lobe and became bad tempered and rude as this area thought to be for regulating mood. therefore provides evidence brain is localised with functions
limitation- relies on case studies which reflect unique experience of brain damage. patterns of brain damage can be different between individuals as well as differences in individuals brain organisation, therefore findings cannot be generalised to the general population
hemispheric lateralisation
split brain research
sperry and gazzangia
ptpts
11 individuals who had undergone commissurotomy (corpus collosum cut which connects the 2 hemispheres) to control epileptic seizures
findings
conclusion
language is lateralised to the left hemisphere
drawing and face recognition is lateralised to the right hemisphere
aim
to investigate the effects of severing the connection between the two hemispheres of the brain (corpus collosum) on functioning
task
patient either stated the word they had seen or wrote the word or matched the word with an object
procedure
2experimental situation set up with split visual field. image/word projected to patients right visual field (processed by left hemisphere) and same/different image projected to the left visual field (processed by right hemisphere). researchers blindfolded one eye and then flashing images/words on the screen for 1/10th of a second meaning patient wouldn't have time to move their eye across the image to spread the I formation across both visual fields
the theory that two halves or hemispheres of the brain are functionally different and certain mental processes and behaviour are mainly controlled by one hemisphere rather than the other
evaluation
strength- conducted in lab so highly controlled and high internal validity. used standardised procedures of presenting visual information to one hemispheric field at a time. means can be confident in the conclusions made
limitation- biased sample so finding cannot be widely accepted/generalised. disconnection was greater in some patients than others and some patients had received drug therapy for longer than others. could argue that findings may have been influenced by these unique changes in the brain, so not representative of lateralisation in all brains
plasticity and functional recovery of brain after trauma
brain plasticity
bridging
new connections are made due to use and new stimulus
synaptic pruning
rarely used connections are deleted and frequently used connections are strengthened
during infancy bumber of neural connections increases rapidly peaking at approximately 15,000 at the age of 2-3. this about twice as many as adult brain
video games increase brain plasticity. research found those who had played super Mario for 2 months had significantly increased their grey matter in the hippocampus, cerebellum and the cortex compared to a control group
originally thought changes in brain limited to childhood and that the adult brain having moved beyond critical period would remain fixed and static in terms of function and structure. more recent research suggests any time in life existing neural connections can change or new neural connections can be formed
evaluation
strength- research support by assessing hippocampus volume in london taxi drivers who sat knowledge test compared to control group. sig more volume of grey matter in hippocampus which is associated with the developent of spatial and navigational skills. suggests brain adapts with experience and provides insight into plasticity and functional recovery
limitation- is individual differences in ability of brain to change and adapt as found neural reorganisation is much greater in children than adults. research also shows women tend to recover more effectively than men as their function is not lateralised. suggests factors involved I'm determining plasticity of the brain and ability to recover depends on individual
functional recovery
unmasking/neural regeneration organisation
the brain is able to rewire itself through the growth of new neurons and/or connections (axons&dendrites) between neurons to compensate for damaged areas
axon sprouting
growth of new nerve endings to form new pathways
functional compensation
transfer of functions to undamaged areas
evaluation
strength- evidence to support from patient who had callostomy so 2 hemispheres can't communicate. after 15 years he was able to speak from right hemisphere. due to speech/language centres being on left, shows brain able to recover after injury and talk from right side
limitation- evidence suggests functional recovery isnt as simple as the brain repairing itself and is many factors involved in recovery. found recovery quicker when higher education level due to there being cognitive reserve in neural adaptation meaning those with higher education level more able to adapt/change after injury. suggests ability to recover depends on individual
factors affecting functional recovery= age, gender, educational attainment
functional recovery after trauma is an example of plasticity. following trauma unaffected areas of the brain are often able to adapt and compensate for damaged areas