Calcium imaging a single wavelength or two wavelengths expressed as a ratio (ratiometric indicators). The derived fluorescence intensities and ratios are plotted against calibrated values for known Ca levels to learn Ca concentration. Light field microscopy methods extend functional readout of neural activity capabilities in 3D volumes. Calcium imaging Calcium imaging is a scientific technique usually carried out in research which is designed to show the calcium (Ca) status of an isolated cell, tissue or medium. Calcium imaging techniques take advantage of so-called calcium indicators, fluorescent molecules that can respond to the binding of Ca ions by changing their fluorescence properties. Two
Symbol Hence, "outward sign" of something. The meaning "something which stands for something else" was first recorded in 1590, in Edmund Spenser's "Faerie Queene". In considering the effect of a symbol on the psyche, in his seminal essay "The Symbol without Meaning" Joseph Campbell proposes the following definition: "A symbol is an energy evoking, and directing, agent". Later, expanding on what he means by this definition Campbell says: Jared Elisha defined symbolism that is something that stands for another, it can be place, object, or a person Heinrich Zimmer gives a concise overview of the nature, and perennial relevance, of symbols.