First, the rate of increase in inhibitory activity with increasing competitor strength was steeper in the presence of reciprocal inhibition ( Figure S3B, solid magenta versus dashed magenta lines). This increase in steepness reflected, as expected, an iterative amplification of the difference in activity between the two inhibitory units, due to the inhibitory feedback motif. Second, when another CRP was obtained with a different RF stimulus (14°/s), the steady-state inhibitory activity of inhibitory unit 2 FG-4592 datasheet was conspicuously shifted to the right ( Figure S3B, solid blue versus solid

magenta), in contrast to the results from the feedforward circuit ( Figure S2E). This rightward shift in the steady-state inhibitory activity predicted that, following a change in the strength of the RF stimulus, output unit

CRPs would also shift adaptively. We tested this prediction below. For subsequent simulations, we chose the reciprocal-inhibitory parameter values as follows: rin = 0.84 (which yielded the maximum rightward shift of the inhibitory activity; Figure S3C) and rout = 0.01 ( Figure S3D). We asked whether a circuit with reciprocal inhibition of feedforward lateral inhibition could produce the two response signatures critical for categorization in the OTid. To Crenolanib test whether this circuit model can produce switch-like CRPs at the output (OTid) units, we simulated output unit CRPs and, as before (Figure 3B), plotted their transition ranges as a function of each of the

parameters of the inhibitory-response function (Figure 5B). For these plots, the values of din and dout and the values of Histone demethylase the fixed inhibitory parameters were chosen to be the same as those used previously in testing circuit 1 ( Figure 3B). We found that large enough values of the saturation parameter k and small enough values of the half-maximum response loom speed (S50) yielded switch-like CRPs ( Figure 5B). An example of a switch-like CRP, obtained with the same values of the inhibitory parameters used for circuit 1 ( Figure 3C), is shown in Figure 5C. As expected by the steeper inhibitory-response function ( Figure S3B, solid versus dashed magenta), this CRP at the output unit is also steeper (compare with Figure 3C). Next, we tested whether this circuit can produce adaptive shifts in the CRP switch value. As before, we asked whether any combination of input and output divisive inhibition (din and dout, respectively; (2) and (3)) could produce a shift in the CRP switch value with a 6°/s increase in the RF stimulus strength. The strength of reciprocal inhibition was unchanged from before (rin = 0.84 and rout = 0.01). A plot of model CRP shift ratios (ratio of switch-value shift to change in RF stimulus strength) as a function of din and dout shows that a large set of (din, dout) values successfully produced adaptive shifts in the switch value (shift ratio near 1; Figure 5D and Figure S4A).