hemispheric lateralisation Flashcards
what is hemispheric lateralisation
® The idea that the two hemispheres of the brain are functionally different, and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other, as in the example of language (which is localised and lateralised)
® The two hemispheres are connected through nerve fibres called the corpus callosum which facilitates inter-hemispheric communication.
what is split brain
o A ‘split-brain’ operation involved severing the connection between the right hemisphere and left hemisphere, mainly the corpus callosum
o This is a surgical procedure to reduce epilepsy
split brain research
Sperry conducted research on 11 people who had undergone split-brain operations meaning information could not be transferred from one hemisphere to another as their corpus callosum was severed, preventing any communication
- When a picture of an object was shown to a participant’s RVF (linked to LH), the participant could describe what was seen. But they could not do this if the object was shown to the LVF (RH) - they said there was ‘nothing there’. This is because, in the connected brain, messages from the RH are relayed to the language centres in the LH, but this is not possible in the split brain.
- Although participants could not give verbal labels to objects projected to the LVF, they could select a matching object out of sight using their left hand (RH), as well as the right hand. If a pinup picture was shown to the LVF there was an emotional reaction (e.g. giggle) but the participants usually reported seeing nothing or just a flash of light.
- These observations show how certain functions are lateralised in the brain and support the view that the LH verbal and the Rh is ‘silent’ but emotional
