A nerve relays messages to the brain.

Jesus, I think Oscar's voice and shrieking may go through my brain.  He has one of those annoying 'noises' for when things aren't going his way.  Shame said noise grates on my sodding brain.  Told them yesterday that they were playing on my last nerve - they're now fascinated with nerves.  As in 'mammy, if a nerve is something that sends messages to your brain how can we be playing on it?  I mean, it's not like a slide or a swing is it?  Or a football pitch.  What do you mean Mam??'  Etc. etc.