Bioelectromagnetism

Bioelectromagnetism is the interdisciplinary field that studies the interactions of electromagnetic fields with biological tissue and the electrical phenomena that arise in living systems. It covers how cells generate, propagate, and respond to electrical signals, as well as how external electric and magnetic fields influence physiology.

Endogenous bioelectricity includes resting membrane potentials and action potentials in neurons, muscle cells, and other tissues. The movement of ions through channels creates propagating signals that underlie nervous signaling, heartbeat, and muscle contraction. Bioelectric fields also play roles in development, wound healing, and cellular orientation.

Measurement and imaging techniques such as electroencephalography (EEG), electromyography (EMG), and electrocardiography (ECG) record endogenous bioelectric signals. Noninvasive imaging methods like magnetoencephalography (MEG) and approaches combining MRI with electrical or magnetic measurements reveal spatial patterns of activity.

External electromagnetic fields are used both diagnostically and therapeutically, through devices such as pacemakers, defibrillators, deep brain stimulators, transcranial magnetic stimulation (TMS), and electrical stimulation for nerve or wound healing. Safety guidelines from bodies like ICNIRP and IEEE address exposure limits.

Theoretical foundations rest on Maxwell's equations and tissue electrodynamics, including conductivity, permittivity, and magnetic susceptibility. The field spans scales from ion channels to organ systems and informs medicine, neuroscience, and bioengineering.