Robustness to noise.

<p>(A) Coding performance of the network in the presence of synaptic background noise. The vertical axis plots the percentage excess of the standard deviation of the stimulus estimator above its optimal value. Results are reported for percentual decreases in the signal-to-noise ratio, SNR = mean(input)/std(input), of 0% (black), 20% (blue), 50% (red) and 100% (green). A static stimulus is presented during the first 500 ms (grey area). (B) Coding performance of a stochastic network for different output gains: (green), (magenta) and (cyan). The ideal observer is plotted in blue and the performance of the deterministic network in red. A static stimulus is presented during the entire 1500 ms. (C) Schematic illustration of the difference between deterministic and stochastic spike generation. The left and middle panel show two spike trains encoding the same information but starting from different initial conditions. However, neurons in the output population are recurrently connected and “know” therefore perfectly well, when to fire a spike such that the log posterior is represented. If the lateral connections are removed, neurons fire stochastic spike trains that look similar to the deterministic ones but do not encode the same log posterior.