Figure 13.

a, The first-order response of a V1 simple cell. Here, each map shows the response of a neuron as a function of spatial position (x,y) at a different correlation delay (τ). The solid lines connect pairs of maps that were cross-correlated to obtain simulated second-order maps. b, Simulated displacement maps showing predicted responses as a function of spatial displacement (Δx, Δy), with correlation delay τ₂ increasing from left to right. The maps were calculated from the simple cell responses shown in a. On the right is shown the direction-tuning curve for the same neuron in response to a long bar moving in a direction perpendicular to its orientation. c, Space–time map computed from the maps shown in a (left), along with a simulated Δs–Δτ map computed from the displacement maps shown in b (right).