Hemispheric lateralisation and split- brain research Flashcards
1
Q
what is hemispheric laterisation?
A
- two halves of the brain are functionally different
- mental processes and behaviours are mainly controlled by one hemisphere e.g. language
2
Q
what is split- brain research?
A
- studies in the 60’s which involve people with epilepsy
- they had surgical separation of the hemispheres of their brains to reduce severity of epilepsy
- seperating the corpus collosum
- able to test lateral functions of the brain in isolation
3
Q
what is localisation?
A
- some functions are governed by very specific areas in the brain
4
Q
what is lateralisation?
A
- there are two sides
- hemispheric lateralisation
- some functions appear in both hemispheres e.g. vision
- left and right visual area in the left and right occitipal lobe
5
Q
How is language lateralised?
A
- Brocas area is in the left frontal lobe
- Wernickes area is in the left temporal lobe
- RH can only produce rudimentary words/ phrases but contributes to emotional context
- LH is analyser while RH is synthesiser
6
Q
Which functions are not lateralised?
A
- vision
- motor
- somotasensory appear in both hemispheres
7
Q
how is the motor area contralaterally wired?
A
- RH controls movement on the left side of the body
- LH controls movement on the right side of the body
8
Q
How is the visual areas contralaterally and ipsilaterally wired?
A
- it is opposite and same sided
- each eye recieves light from the left and right visual field (LVF) (RVF)
- LVF of both eyes is connected to the RH
- RVF of both eyes is connected to the LH
- visual areas compare the slightly different perspective from each eye
9
Q
Hemispheric laterlisation Evaluation strength: Lateralisation is connected to the brain
A
- Fink et al. used PET scans to see which areas where active during a visual processing task
- those with connected brains who were asked to describe global elements, regions of the RH where more active
- when asked to focus on finer detail the LH dominated
- during visual processing hemispheric lateralisation is a feature of both the split brain and connected brain
10
Q
Hemispheric lateralisation Evaluation Limitation: One brain
A
- different functions of the LH and RH but research says peopledont have a dominant side that creates a diff personality
- Neilson looked @ brain scans of over 1000 people
-used different hemispheres for different tasks but no dominant side - no right or left brained people
11
Q
Sperry’s split brain research: procedure
A
- 11 people with a split brain
- imagine projected onto LVF (processed by LH) and the same or diff imagine projected onto RVF (processed by LH)
- ‘normal’= corpus collosum would share the info across creating a full image
- split brain= info cant be shared to the other hemisphere
12
Q
Sperry’s split brain research: findings (1)
A
- picture showed to RVF= could describe what was seen
- picture showed to LVF= nothing there
- in connected, messages from RH shared to language centres in LH
13
Q
Sperry’s split brain research: findings (2)
A
- couldnt give verbal description of object shown to LVF (RH)
- they could select the matching object that was out of sight using their left hand (RH)
- if a pinup picture was shown to the LVF there was an emotional reaction but they reported seeing nothing or just a flash
14
Q
Sperry’s split brain research: conclusion
A
- show how certain functions are lateralised
- support that the LH is verbal and the RH is ‘silent’ but emotional
15
Q
Split brain research evaluation: strength research support
A
- Gazzaniga showed split brain patients perform better than connected at certain tasks
- faster at identifying odd one out
- in normal brain LH’s better cognitive strategies are watered down by inferior RH
- left and right brain are distinct
