This month’s issue of Nature Neuroscience focuses on Learning and Memory, hitting a lot of nails on the head around this sprawling topic - from Brain Machine Interfaces, to links between pain processing and learning, to sleep, to development, neurogenesis, and mechanisms of memory retrieval. In our review paper with Joshua Johansen (Riken), we focus on the variety of roles that the neuromodulators acetylcholine, noradrenaline, and dopamine play in circuit function during aversive emotional learning. We discuss how these different neuromodulatory systems can increase the gain of a signal, improving signal-to-noise during learning, how their modular organization allows for context-dependent learning modes, and how their patterns of innervation can bind distal regions during learning, when circuit communication incorporates new patterns of activity.
