Theoretical prediction of the effect of a Ca²⁺ buffer on the photoresponse recovery phase.

<p><i>A</i>, average response (<i>n</i> = 9) to the same flash (1.14·10² photons/μm²) having a slow kinetics (<i>black dotted</i> trace) or a fast one (<i>grey dotted</i> trace) fitted by <i>x</i>_<i>s</i><i>(t)</i> with, respectively: <i>A</i>_<i>s</i> = 370, <i>τ</i> = 0.052 s; <i>A</i>_<i>s</i> = 1100, <i>τ</i> = 0.035 s; these responses are from the two cells of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141727#pone.0141727.g004" target="_blank">Fig 4B</a>, whose responses are plotted in <i>black</i> and in <i>red</i>, respectively. <i>B</i>, schematic of the “delayed” feedback, the symbols are explained in the text. The gain is set to 1, so <i>G</i> is the fraction of the response amplitude “feedbacked” to the input. <i>C</i>, <i>red</i> trace, plot of <i>x</i>_<i>s</i><i>(t)</i> with <i>A</i>_<i>s</i> = 5200 and <i>τ</i> = 0.052 s; <i>brown</i> trace, plot of <i>x</i>_<i>o</i><i>(t)</i> (with same <i>A</i>_<i>s</i> and <i>τ</i> of <i>red</i> trace) with <i>G</i> = 0.6 and <i>Δ</i> = 0; <i>green</i> trace, plot of <i>x</i>_<i>o</i><i>(t)</i> with the same parameters of the <i>brown</i> trace but <i>Δ</i> = 0.06 s to fit a representative experimental response with a dual kinetic component recovery (to flash of intensity 4.49·10³ photons/μm², plotted in <i>black</i> in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141727#pone.0141727.g004" target="_blank">Fig 4B</a>; <i>dotted black</i> trace in this panel); parameters of <i>blue</i> trace as the <i>green</i> trace, but <i>Δ</i> = 0.1 s. <i>D</i>, responses with the same colour code of <i>C</i>: <i>red</i> trace, <i>x</i>_<i>s</i><i>(t)</i> with <i>A</i>_<i>s</i> = 12300 and <i>τ</i> = 0.035 s; <i>x</i>_<i>o</i><i>(t)</i> is plotted in <i>brown</i> with <i>G</i> = 0.4 and <i>Δ</i> = 0 s, in <i>green</i> with <i>Δ</i> = 0.055 s, and in <i>blue</i> with <i>Δ</i> = 0.1 s; the <i>green</i> trace fits a representative experimental response with a single kinetic component recovery (to flash of intensity 4.49·10³ photons/μm², plotted in <i>red</i> in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0141727#pone.0141727.g003" target="_blank">Fig 3B</a>; <i>dotted black</i> trace in this panel).