Figure 5

Responses of four model GM neurons in the scaling task. Same format as in Fig. 2, except that there are five possible contexts, corresponding to y = -1, -0.5, 0, 0.5 and 1. a: Tuning curves for a model neuron that responds maximally to stimuli at x = -15 and prefers the green condition (y = 0). The order of effectiveness for the five scales was set randomly, so context is encoded discontinuously. b: As in a, but for another neuron that prefers x = 2 and y = 1. c: Tuning curves for a model neuron that encodes context in a smooth, continuous way. The unit responds maximally to stimuli at x = -1 and prefers the cyan condition (y = -0.5). The gain of the cell decreases progressively as y deviates from the preferred scale – note the order of the colors. d: As in c, but for a neuron that prefers x = 9 and y = 1. All units have a maximum gain of 1 and a minimum gain near 0.5. Model responses were based on Equations 1, 3, 5 and 6.