using touch as an example, when u touch something hot a nerve impulse is sent from your brain through the nerves in your arm telling it to let go of the object to avoid harm. using sight, light that has been reflected off of objects enters your eyes. they send nerve impulses to your brain transmitting this information. your brain then sends a message to what ever part of your body needs to respond eg if you see a car is coming quickly towards you your brain sends a message to your legs telling them to walk back to the pavement. Hope this was what you meant i wasn't too sure exactly what you were asking for
