Electrophysiology

Electrophysiology is the branch of physiology that studies the electrical properties of biological cells and tissues. It focuses on how cells generate and propagate electrical signals through membrane potentials and ionic currents. The central concepts include resting membrane potential, action potentials, and the role of ion channels and pumps in establishing electrochemical gradients. Electrophysiology is essential in neuroscience, cardiology, and muscle physiology, and it underpins both basic research and clinical diagnostics.

Common methods range from invasive to non-invasive. Intracellular and patch-clamp recordings measure the voltage or current inside a single cell, revealing unitary currents through ion channels. Extracellular microelectrode recordings capture spikes and field potentials from populations of cells. Clamp techniques (voltage clamp, current clamp) control the membrane potential to study channel behavior. Modern approaches include multi-electrode arrays, which monitor activity from many neurons, and optical methods such as voltage-sensitive dyes and genetically encoded reporters. Non-invasive techniques include electroencephalography (EEG) for brain activity, magnetoencephalography (MEG), and electrocardiography (ECG) for cardiac activity; intracardiac electrograms are used clinically to map arrhythmias.

Applications span fundamental physiology, drug discovery, and medical device development. The patch-clamp technique, developed by Erwin Neher and Bert Sakmann, significantly advanced ion-channel research. Early work on neuronal signaling by Hodgkin and Huxley and on membrane potentials laid the groundwork for quantitative models of excitability. Electrophysiology informs the design of pacemakers, neural prosthetics, and brain–computer interfaces, and it supports diagnostics and monitoring in neurology and cardiology.