A statistically significant drop in the level of norepinephrine occurred in all assessed patients after sympathectomy - the 'lobotomy' effect
http://icvts.oxfordjournals.org/content/5/4/464.full
As a stress hormone, norepinephrine affects parts of the brain where attention and responding actions are controlled.
Along with epinephrine, norepinephrine also underlies the fight-or-flight response, directly increasing heart rate,
triggering the release of glucose from energy stores, and increasing blood flow to skeletal muscle.
Norepinephrine is also released from postganglionic neurons of the sympathetic nervous system, to transmit the
fight-or-flight response in each tissue respectively. The adrenal medulla can also be counted to such postganglionic
nerve cells, although they release norepinephrine into the blood.
Norepinephrine system
The noradrenergic neurons in the brain form a neurotransmitter system, that, when activated, exerts effects on large
areas of the brain. The effects are alertness and arousal, and influences on the reward system.
www.caam.rice.edu/~cox/wrap/norepinephrine.pdf