Ions, their transport across membranes, and their flow through specialized ion channels are central to the understanding of brain function, normal and pathological. The first part of this book deals with the regulation of ions in brain extra- and intracellular fluids. Regulation is effected by the blood-brain barrier, and by membrane ion pumps and other transport mechanisms of neurons and glial cells. Normally adjusted for optimal neural function, ion levels can change and alter the excitability of neurons and influence synaptic transmission in healthy and diseased brains. After an...