Combination of plasticity with synaptic scaling generates two distinct weight domains representing short-term and long-term storage.

<p>(<b>A</b>) Both domains (STS and LTS) arise from a bifurcation (see main text and <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003307#pcbi.1003307.s001" target="_blank">Text S1</a>) between two stable fixed point domains (continuous lines). Depending on the input, weights either continuously grow (control and STS-domain) or suddenly jump to a high value (LTS-domain). Between both domains there is a transition range (dashed line). Blue dots show results from numerical simulations (<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003307#pcbi-1003307-g001" target="_blank">Figure 1</a>), which match the analytical curve. (<b>B</b>) Fixed points are defined by the intersection between activity- (green) and weight- (blue) nullclines. As long as all three fixed points (green stable; red unstable) exists the phase space is divided into two attractor regimes which are also indicated by arrows (). (<b>C</b>) Higher frequencies shift the activity-nullcline (red line) upwards which results in only one attractor regime (LTS; ). (<b>D</b>) Passive weight decay happens for all synapses as long as there is no consolidation stimulus present. Dashed parts of the curve indicate that LTS-synapses can be consolidated.