The neuronal cell membrane comprises a phospholipid bilayer and numerous embedded ion channels traversing the membrane. Embedded proteins transport charged molecules altering the electrochemical gradient across the membrane. In response to a stimulus, a voltage differential across the membrane crosses a depolarization threshold, resulting in an action potential.
Numerous studies have established that the neuronal cell membrane displays the electrical characteristics of resistance (R), derived from embedded ion channels, and capacitance (C), derived from the phospholipid bilayer structure, as a parallel-RC circuit. The parallel-RC circuit equivalent circuit of all cell membranes, including neurons, uses the resistance and capacitance of the phospholipid bilayer. Nerves are preferential electrical current conduction pathways through tissue, and their presence in living tissue makes the tissue anisotropic to electrical current flow. This anisotropicity and phenomenological inductance of the neuronal cell membrane may be demonstrated using externally applied fields.
The impedance neurography developments based on this anisotropicity of nerve conduction pathways, in combination with methods to develop a transmembrane current flow, have led to insights regarding the neuronal cell membrane electrical responses. As a result, a wide range of clinical applications may be advanced.