Two sources of dopamine for the hippocampus.
This article describes three recent papers that together suggest that novelty signalling in the brain's memory centre arises from two different brain pathways, whereas up until recently it was thought to originate from only one. Both pathways use a chemical messenger called dopamine.
Dopaminergic signalling is established as playing an important role in novelty related modulation of hippocampal memory. Two recent studies have identified the noradrenergic fibres originating in the locus coeruleus as an additional source of neurotransmitter acting on dopaminergic receptors in the hippocampus.