Frequency-based modulation of responses.

<p>Example Δ<i>E</i><sub>K</sub><sup>+</sup> traces over time for stimuli presented at 0° (top), 22.5° (middle), and 45° (bottom) following a single stimulation event. Solid lines show the data for weight-modulated orientation tuning of synapses, i.e., based on w<sub>syn(i,j)</sub>(θ), with each synapse’s activation time drawn from a Poisson distribution with λ = 80 ms, as per <b><a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.3002935#pbio.3002935.s013" target="_blank">S10</a>–<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.3002935#pbio.3002935.s016" target="_blank">S13</a> Figs</b>. Dotted lines show the data for frequency-modulated orientation tuning of synapses, i.e., when each synapse is activated by a Poisson train whose frequency depends on the synapse’s orientation preference (see <b><a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.3002935#pbio.3002935.s002" target="_blank">S2 Text</a></b> for details). Timing of inputs is plotted as raster plots (black lines: weight-modulated, gray lines: frequency-modulated). Following the stimulation event, the simulation runs for 2 s to show the return to baseline (Δ<i>E</i><sub>K</sub><sup>+</sup> = 0 mV). The 2 approaches display similar dynamics, reaching same peak Δ<i>E</i><sub>K</sub><sup>+</sup> responses for the similarly tuned segment within ∼200 ms. Δ<i>E</i><sub>K</sub><sup>+</sup> is modulated by the stimulus orientation mainly in the segment receiving similarly tuned inputs. In contrast, the diversely tuned segments sustain a fixed Δ<i>E</i><sub>K</sub><sup>+</sup> irrespective of the stimulus orientation, as per <b><a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.3002935#pbio.3002935.g001" target="_blank">Fig 1G</a></b>. Neighboring segments, receiving diversely tuned synapses, display a sharper decrease in the <i>E</i><sub>K</sub><sup>+</sup> shift for the frequency-modulated input compared to the weight-modulated input. The slow decay to the steady state <i>E</i><sub>K</sub><sup>+</sup> indicates the time window within which a second stimulation would be modulated by the elevated <i>E</i><sub>K</sub><sup>+</sup>. Colors of plotted lines are as <b><a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.3002935#pbio.3002935.s013" target="_blank">S10 Fig</a></b>.</p> <p>(PDF)</p>