Adrenaline and norepinephrine from the brainstem alter frontal and hippocampal circuits to facilitate learning and memory.

“when norepinephrine is released from the locus cerus it has this tendency to elevate the levels of activity in other brain areas through this sort of sprinkling like mechanism what that means is that other areas of the brain such as your prefrontal cortex such as your hippocampus such as different areas of the hypothalamus and indeed lots of brain circuits all have a a greater capacity to be engaged this is what we're talking about when we talk about autonomic arousal”

“In fact, this little group of neurons in the back of our brain it's called the locus coeruleus, if you like, is churning out epinephrine all the time. If something stresses us out, it churns out more, and then it acts as an alertness signal for the whole brain. We also, of course, have adrenaline epinephrine released in our body, which makes our body ready for things. Think about epinephrine as a readiness signal.”