Response filters of zebra finch auditory neurons ((a), adapted from [28]) compared to theoretically simulated response filters of a nonlinear feedback inhibitory circuit (d).

<p>(a-c) Adapted from [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004315#pcbi.1004315.ref028" target="_blank">28</a>]. (a) Linear response filters for a single neuron stimulated with inputs of different mean sound amplitudes (colored to match (d)). (b) Ratio of the total positive to total negative component of neuronal filters is computed for an input with high mean amplitude, and an input with low mean amplitude. Each circle shows these values for a different recorded neuron (one example being (a)). The colored circle is derived from the simulated response filters of the principal cell of the nonlinear circuit (d). It uses the ratio of the total positive to total negative component of the simulated filters (plotted in (e)) at the highest input amplitude (red), and the lowest input amplitude (cyan). (c) The BMF (freq. of the peak of the Fourier transform of the linear response filters) for a high mean input, and a low mean input (for different neurons, one example being (a)). The colored circle is derived from the simulated responses of the principal cell of the nonlinear network (d). It uses the BMFs (shown in (f)) of the simulated filters at the highest input amplitude (red) and the lowest input amplitude (cyan). (d) Linear filters estimated to best approximate the response of the principal cell of the nonlinear circuit to white noise stimuli of different amplitudes (Methods). Curves colored to match (a). (e) The ratio of the total positive component of the curves in (d) to the total negative component. Points are colored as in (a,d). The ratios derived from inputs with highest (red) and lowest amplitude (cyan) define the colored circle in (b). (f) The BMF of the responses filters from (d). The BMF values derived from inputs with highest (red) and lowest amplitude (cyan) define the colored circle in (c).