This volume provides an introduction to the general principles of neuromodulation--the key neurobiological process for understanding how the brain works. Emphasizing ion channels and biochemical mechanisms of protein phosphorylation, the book shows how neurons regulate their intracellular calcium concentration by modulating the activity of certain ion channels. It goes on to explain the function of intracellular calcium and describes some fascinating neuromodulatory phenomena in the mammalian brain that have long awaited the kind of mechanistic investigations possible in simpler systems. Bridging the gap between neurochemistry and neurophysiology, the authors make complex concepts and research approaches comprehensible to scientists in either field.