View source for Biology:Extracellular field potential

The '''extracellular field potential''' is the electrical potential produced by [[Biology:Cell|cell]]s, e.g. [[Biology:Neuron|nerve]] or muscle cells, outside of the cell.  [[Biology:Electrophysiology|Electrophysiological studies]] investigate these potentials using extracellular [[Biology:Microelectrode|microelectrode]]s. In these experiments the extracellular field potential will be detected as an electrical potential whose source and composition is often ambiguous, making its interpretation difficult. Individual nerve cells [[Biology:Neuron|neuron]]s may produce [[Physics:Voltage spike|spike]]s seen as peaks of some tens to hundreds of microvolts. Contributions from neighboring neurons may overlap, producing extracellular potentials of up to several millivolts. Spatially integrating over even larger populations of cells, i.e. lumps of [[Biology:Nervous tissue|nervous]] or [[Biology:Muscle|muscular tissue]], will produce signals commonly called [[Biology:Local field potential|local field potential]]s (LFP) that can be recorded either in the tissue or with suitable equipment at the body surface as, e.g., electroencephalogram (EEG), electrocardiogram (ECG), or electromyogram (EMG).

For individual cells, the time course of the extracellular potential theoretically is inversely proportional to the transmembrane current. In practice, however, this is complicated considerably by the very complex [[Biology:Morphology|morphology]] of neurons and the overlap of contributions from adjacent cells.

==See also==
* [[Biology:Local field potential|Local field potential]]

{{DEFAULTSORT:Extracellular Field Potential}}
[[Category:Cell biology]]
[[Category:Electrochemistry]]
[[Category:Electrophysiology]]
[[Category:Membrane biology]]
[[Category:Physical quantities]]



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