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Interplay between Subthreshold Oscillations and Depressing Synapses in Single Neurons
Fig 13
Synaptic-dependent discrimination of input patterns.
The dynamics of intrinsic oscillations can be combined with the characteristic time scale of the modulatory input received through a depressing synapse to detect specific input patterns and generate different stereotyped outputs in response. The figure shows the response of a neuron to a pattern delivered through input channels with different depression levels. Plots in the right column correspond to the normalized power spectra of the output signal. In all cases gd = 0.32mS and 
, while the depression level is defined by the value of τrec: 0.02ms in the top panel (i.e., a static synapse), 400ms in the middle panel, and 800ms in the bottom panel. The input pattern consists of seven spikes with the following timing distribution: ISI1–2 = 75ms, ISI2–3 = 105ms, ISI3–4 = 85ms, ISI4–5 = 136ms, ISI5–6 = 46ms and ISI6–7 = 15ms. Black trace in each panel plots the evolution of the corresponding fraction of bound receptors in the synaptic cleft. Short-term synaptic depression leads to specific stereotyped responses to this input. When τrec is in the range 325–550ms (middle panel), the output consists of four spike: two at the beginning of the input pattern presentation and two at the end. In the range 575–800ms (bottom panel), the neuron generates two spikes at the beginning of the input pattern, one at the end and another output spike four oscillations after the end of the stimulation. However, when the pattern arrives through a static synapse or a synapse with lower value of τrec, the response is not regular (note in the top panel the different responses to the pattern and the different subthreshold oscillation regimes after the stimulation).
doi: https://doi.org/10.1371/journal.pone.0145830.g013