a nerve 'impulse' [=a wave of electrical energy that is carried through the nerves to the brain]
Shopping with a credit card can lead to 'impulse buying'.
He had to resist the 'impulse' [='urge'] 'to shout'.
(..) I could tell by the way you both related there was no connection whatsoever. And I felt when I walked in that there was something between us. There was an impulse that we were both following. So that gave me the right to come in and talk to you. Otherwise, I never would have felt (..)1976 Taxi Driver