Figure 1.

Network structure and simulation protocol. A, Schematics of a multiple-choice motion-discrimination task. A trial begins when a monkey fixates a central point on the monitor. Several targets then appear around the fixation point. After a delay, a noisy motion stimulus appears, and finally the monkey makes a saccade based on the coherent motion direction it perceives. B, Synaptic connectivity within the network. The network consists of excitatory pyramidal cells and inhibitory interneurons. Each neuron is labeled by its preferred motion direction, which is uniformly distributed between −180° and 180°. The synaptic connectivity is heterogeneous except that between interneurons. The connectivity strength depends on the difference in preferred directions between neural pairs. Notably, there are two kinds of connectivity from interneurons to pyramidal cells, with a peak at 0° difference (similar-feature inhibition) or 180° difference (opposite-feature inhibition). C, D, Simulation protocol. Neurons also receive external synaptic currents representing sensory information about the targets and motion stimulus. The rates of presynaptic Poisson spike trains are characterized by the input signals. C, Schematics of time courses of the input signals. The targets are presented at 300 ms, whereas the random-dot array is shown at 1300 ms; both the inputs reach the network after a latency of 200 ms. D, Normalized spatial profiles of the input signals as a function of preferred direction of each neuron.