Figure 9

Non-interference of baseline and modulation. (A) Mean and standard deviation of baseline (green) and modulation (orange) components for the medium contrast are plotted in logarithmic scales for comparison. As in Figure 8, dots and solid lines indicate simulated and predicted values, respectively. Shadings indicate mean±std. As in Figure 5, mean and standard deviation are evaluated over all neurons in the network. (B) The product of the weight matrix $\overrightarrow{W}$ with a baseline, ${\overrightarrow{s}}_B$, and a modulation input vector, ${\overrightarrow{s}}_M$. The entries of the baseline vector are all normalized to one, i.e. the input to each neuron is 1. The operation of the weight matrix on the baseline vector, $\overrightarrow{W}{\overrightarrow{s}}_B$, is plotted in green. The operation of the weight matrix on the modulation vector, $\overrightarrow{W}{\overrightarrow{s}}_M$, for three different orientations (θ = 30°,90°,120°) are plotted in magenta, black and cyan, respectively. The corresponding distributions of individual responses are plotted in the magnified histograms on the right. Note that the assumption of ‘perfect balance’ implies a very narrow distribution around zero. The average (over 12 orientations) of the responses, ${〈\overrightarrow{W}{\overrightarrow{s}}_M〉}_{\theta }$, are plotted in orange. For 12 sample neurons from the network the response vs. orientation of the stimulus are plotted in the inset (center).