In a person with a complete corpus callosum
even if you grab an object with your right hand or see an object to the left of where you are looking
both hemispheres can respond to what you grab or see.
This is possible because the two hemispheres communicate with each other.
However, for medical reasons some people have had their corpus callosum cut
The effect of this procedure on patients has offered scientists a unique glimpse into the functioning of the brain.
If these patients grab something with their right hand, only the left hemisphere will feel that object.
If they see something to the left of where they are looking, only the right hemisphere will be able to perceive it.
These patients are said to have “split-brains.”
It is important to note here that only the corpus callosum has been cut
the pathways from the hand or eye to the brain are unaffected.