The birth and discovery of electrophysiological science took place in the 18--th century laying the path for our understanding of nerve membrane ionic currents. The pore-forming proteins, ion channels, are involved and play critical roles in very important physiological and pathological processes, such as neuronal signaling and cardiac excitability, therefore, they serve as therapeutic drug targets. The study of physiological, pharmacological and biophysical properties of ion channels can be done by patch clamp, a gold standard and powerful electrophysiological technique. The current review, in addition to highlight and cover the history of electrophysiology, patch clamp (conventional and automated) technique, and different types of ion channels, will also discuss the importance of ion channels in different neurological diseases and disorders. As the field of neuroscience is growing, this manuscript is intended as a guide to help in understanding the importance of ion channels, particularly in neuroscience, and also in using the patch clamp technique for the study of molecular physiology, pathophysiology, and pharmacology of neuronal ion channels. Importantly, this review will spotlight on the therapeutic aspect of neuronal ion channels. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.