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Depolarisation

The process or act of neutralising polarity, depriving of polarity, or the result of such action; reduction to an unpolarised condition.

(Science: physiology) The reversal of the resting potential in excitable cell membranes when stimulated i.e., the tendency of the cell membrane potential to become positive with respect to the potential outside the cell. A positive shift in a cells resting potential (that is normally negative), thus making it numerically smaller and less polarized, for example 90mV to 50mV.

(Science: optics) depolarisation of light, a change in the plane of polarization of rays, especially by a crystalline medium, such that the light which had been extinguished by the analyser reappears as if the polarization had been anulled. The word is inappropriate, as the ray does not return to the unpolarised condition.

Origin: cf. F. Depolarisation.