Figure 2. Lateral inhibition in the model can account for the spatial tuning and spatial segregation properties of recorded units. a–c, Left, Model structure. Center, Simulated spatial grid. Right, Raster plots for stimulus conditions indicated by dashed or solid squares in the grid. Top right, Inset, The simulated discriminability for the clean (no-masker) case indicating broad spatial tuning. This clean case is not impacted by the addition of lateral inhibition, and is identical for all networks shown. a, Basic model structure with no lateral inhibitory connections. Simulated multisource spatial grid in model without lateral inhibition lacks the spatial diversity observed in the data. b, Spatial grid produced by the model with one inhibitory connection between 0° and −90°, shows an increase in discriminability when target and masker are presented at 0° and −90°, respectively. c, Model with additional inhibitory connections simulates the spatial response of the recorded unit shown in Figure 1d. d, Subthreshold responses of relay and cortical neurons, R1, R2, and C (b, left), for the labeled time segment (b, right) of one trial when target is presented at 0° and masker at −90°. Direct excitatory currents to R1 (R1 Conduc: black curve) are offset by inhibitory currents from I2 (R1 Conduc: magenta curve), and R1 is unable to reach spiking threshold, as seen in its voltage trace (R1 Voltage: black curve). In contrast, R2 is able to relay its temporal information to C, whose spiking pattern (C Voltage) resembles that of R2 (R2 Voltage).