Synaptic depression tunes the resonant response to incoming input.

<p>(A) Behavior of the isolated single neuron with subthreshold oscillations and spiking activity. (B-D) Neuron’s response to incoming input delivered at the peak of the subthreshold depolarization as a function of different depression levels. In all cases, the input is received through a dynamic synapse (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145830#pone.0145830.e022" target="_blank">Eq 4</a>) with <i>g</i>_<i>syn</i> = 0.25<i>mS</i>, <i>τ</i>_<i>fac</i> = 0.02<i>ms</i>, i.e., a synapse without facilitation, and <math><mrow><mi>U</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>45</mn></mrow></math>; and different <i>τ</i>_<i>rec</i> values, which define the depression level: low in panel B (<i>τ</i>_<i>rec</i> = 100<i>ms</i>), intermediate in panel C (<i>τ</i>_<i>rec</i> = 400<i>ms</i>) and high in panel D (<i>τ</i>_<i>rec</i> = 800<i>ms</i>). Plots in the right column correspond to the normalized power spectra of the output signal. The stimulation protocol used in these simulations maximizes the resonant response (see main text). Nevertheless, depending on the depression level, the neuron response can go from tonic spiking to pure subthreshold activity without spikes.