Electrophysiology is a field of research that deals with the electrical properties of cells and biological tissues. In many research applications probes are used to measure the electrical activity of individual cells, tissues, and whole specimens. Measuring the activity of cells at various membrane potentials can give valuable information about ion transport mechanisms and cellular communication. Varying ionic strength and membrane potential on cell populations can be used to study contractile movements of muscle cells, and diseases affecting the normal propagation of impulses. Using various stimulation techniques along with a selection of quality equipment and setup design can give rise to a wealth of applications in electrophysiology.